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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 5  |  Issue : 1  |  Page : 9-20

The clinicopathological features of lower gastrointestinal tract endoscopic biopsies in Benin City, Nigeria


Department of Pathology, University of Benin Teaching Hospital, Benin City, Nigeria

Date of Web Publication12-Apr-2017

Correspondence Address:
Darlington Ewaen Obaseki
Department of Pathology, University of Benin Teaching Hospital, Benin City
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2320-3846.204418

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  Abstract 

Background: Despite the increasing incidence of colorectal cancer in Nigeria, there is no established colorectal screening program in Nigeria and only a few studies have been done on the pathologic features of colonoscopic biopsies in Nigeria.
Materials and Methods: The lower gastrointestinal tract biopsy specimens were assessed in the histopathology surgical day books. The demographic information on the age and sex and the clinical information, presenting complaints and endoscopic findings were obtained from the original request cards. All of the archival slides were retrieved and reviewed with the diagnosis confirmed. Also, all available formalin fixed and paraffin embedded tissue blocks of lower gastrointestinal colonoscopic biopsies were sectioned at 3-5μm and stained with haematoxylin and eosin. Each lesion was diagnosed based on specific pathologic findings, clinical history and endoscopic findings as a guide. Neoplastic lesions were classified using the World Health Organization classification (2010].
Study Design: The study aims to describe the common lesions diagnosed on lower gastrointestinal (GI) endoscopy. The clinical history, endoscopic findings, slides, and paraffin-embedded blocks of all endoscopic biopsies of the lower GI tract seen from 2008 to 2012 were studied, and data obtained were analyzed using the SPSS version 16 software.
Results: Two hundred and forty-nine specimens were studied. Fifty-seven (22.9%) of these biopsies were normal colonic mucosa and 192 (77.1%) of these biopsies had remarkable pathologies. The most common clinical indication for colonoscopy in this study was hematochezia and over half of these patients (48.6%) had malignant lesions. The most common lesions seen on endoscopy were polyps which were seen in 18.5% of cases. Seventy (36.5%) of these lesions were malignant, with epithelial cancers 67 (95.7%) being the vast majority. Thirty-five (18.2%) of the lesions were benign neoplastic lesions, 52 (27.1%) were inflammatory lesions, 18 (9.4%) were inflammatory bowel disease, 10 (5.2%) were hyperplastic polyps, and 7 (3.6%) were vascular lesions.
Conclusion: A wide spectrum of lesions was diagnosed in this study with the predominant lesion diagnosed being malignant neoplastic lesions. The most common clinical indication for endoscopy was hematochezia with over half of these patients having a malignant lesion.

Keywords: Cancer, endoscopy, gastrointestinal, histopathology, polyps


How to cite this article:
Umana IO, Obaseki DE, Ekanem V J. The clinicopathological features of lower gastrointestinal tract endoscopic biopsies in Benin City, Nigeria. Saudi Surg J 2017;5:9-20

How to cite this URL:
Umana IO, Obaseki DE, Ekanem V J. The clinicopathological features of lower gastrointestinal tract endoscopic biopsies in Benin City, Nigeria. Saudi Surg J [serial online] 2017 [cited 2017 Aug 23];5:9-20. Available from: http://www.saudisurgj.org/text.asp?2017/5/1/9/204418


  Introduction Top


Lesions of the lower gastrointestinal (GI) tract account for a substantial source of morbidity and mortality worldwide. In most countries, GI diseases are a large burden on the health-care services, with GI pathology being a major workload of surgical pathology.[1]

There is a wide range of diseases that can affect the lower GI tract, ranging from inflammatory to neoplastic lesions.[1]

Globally, colorectal cancer is the 4th most common cancer after breast, prostate, and lung cancer, with an incidence rate of 9.8% and estimated 1.24 million new cases diagnosed in 2008.[2],[3]

Colorectal cancer alone accounts for the death of at least 609,051 persons yearly.[2]

Worldwide, a total of 663,000 cases were diagnosed yearly in males, with an incidence rate of 10%, while in women, 571,000 cases were diagnosed, with an incidence rate of 9.4%.[2],[3]

Africa has a much lower incidence rate than the Western world, with an incidence rate of 5.9/100,000 and a mortality of 20,889/100,000.[2]

The incidence of colorectal cancer is said to be on the increase in developing countries.[4] The incidence rate of colorectal cancer in Nigerian males is 7.1% and in females is 4.4%.[2] This is remarkably low, compared to the statistics reported from the United Kingdom and the United States of America.[2] Studies done in Southwestern Nigeria on malignant GI tumors showed that 56% of these tumors were colorectal adenocarcinoma.[4] In another study in Southwestern Nigeria, colorectal carcinoma accounted for 5.8% of all the malignancies diagnosed.[5] Eze et al. in Benin City showed that colorectal carcinoma accounted for 2% of all malignancies diagnosed within a 20-year period.[6]

Several studies have confirmed the strong relationship between colorectal polyps and colorectal cancer, and there is an overwhelming universal agreement that preexisting polyps are a major risk factor in the subsequent development of colorectal cancers.[7] Approximately 95% of all colorectal carcinomas are believed to arise from adenomas.[8]

Regular bowel cancer screening has been shown to reduce the risk of dying from bowel cancer by as much as 16%.[9] It has been shown that targeted prevention and early detection programs could help reverse the increasing trend of colorectal cancer in most developing countries.[10] At present, there is no established colorectal screening program in Nigeria and only a few studies have been done on the histopathological features of colonoscopic biopsies in Nigeria.[11]


  Materials and Methods Top


This is a 5-year (January 01, 2008, to December 31, 2012) retrospective, descriptive study of lower GI tract endoscopic lesions reported in the Department of Morbid Anatomy, University of Benin Teaching Hospital (UBTH), and the Biogenics Histopathology Laboratory (a private Histopathology Laboratory based in Benin).

Colonoscopic biopsies recorded in the surgical pathology register of the department from 2008 to 2012 were studied and relevant demographic and clinical information were extracted from the registers, original request cards, and patient case files.

A total of 249 biopsies out of the 305 met our study criteria while 56 were excluded from the review due to missing blocks and insufficiency of sample biopsied.

All available formalin-fixed and paraffin-embedded tissue blocks were sectioned at 3–5 μm and stained with hematoxylin and eosin. Special histochemical stains, periodic acid-Schiff and Alcian blue, were used for lesions that required the special stains. The pathological reports and diagnoses of all cases studied were reviewed, and all cases were reconfirmed, classified, and graded.

The data generated in this study were entered into a Spreadsheet and analyzed using the Statistical Package for Scientific Solution Version 16 SPSS Inc., Chicago, Illinois, USA for frequencies, mean, mode, and median. The results were presented in tables and charts.


  Results Top


A total of 19,525 biopsies were received at the Morbid Anatomy Department of the UBTH and the Biogenics Histopathology Laboratory over the 5-year period of this study. Lower GI tract endoscopic biopsies were 305 accounting for 1.6% of the samples processed in both laboratories during the study period. Fifty-six out of the 305 lower GI biopsies were excluded due to missing blocks, missing clinical data, and insufficiency of sample biopsied; the remaining 249 biopsies met our study criteria and thus constituted our study population.

On histological evaluation, 192 (77.1%) of the endoscopic biopsies had a pathologic diagnosis while 57 (22.9%) of them were normal colonic mucosa.

Of the 192 patients, 99 (51.6%) were male and 93 (48.4%) were female, giving a male to female ratio of 1.1:1. The age ranged from 18 to 96 years, with a mean of 53.8 ± 14.3 years. The median age was 54 years and the mode was 50 years [Figure 1].
Figure 1: Age and gender distribution of the study population

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For ease of statistical analysis, the biopsies were classified in six groups based on histopathologic diagnoses [Figure 2].
Figure 2: Frequency of lower gastrointestinal lesions on endoscopy

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Group 1: Malignant neoplastic lesions

There were a total of seventy malignant lesions diagnosed histologically and this accounted for 36.5% of the pathologic lesions seen, making it the largest group of lesions to be diagnosed [Figure 2].

There were 59 (84.3%) adenocarcinomas, 7 (10%) mucinous adenocarcinomas, 1 (1.4%) signet ring cell carcinoma, 2 (2.9%) neuroendocrine tumors, and 1 (1.4%) GI stromal tumor (GIST) [Table 1].
Table 1: Age and gender distribution of the lower gastrointestinal histopathological lesions

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The adenocarcinomas were the greater majority in this group and consisted of 28 well-differentiated adenocarcinomas, 29 moderately differentiated adenocarcinomas, and two poorly differentiated adenocarcinomas.

The peak age group at which malignant lesions were diagnosed was 50–59 years age group, closely followed by the 60–69 years age group for both males and females [Table 2]. The youngest person diagnosed with a malignant neoplasm was an 18-year-old male who had a mucinous adenocarcinoma. The oldest person diagnosed with a malignancy was 90 years who had a moderately differentiated adenocarcinoma [Table 1].
Table 2: Age and gender distribution of the pathologic lesion types

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There were 38 males and 32 females, with a male to female ratio of 1.2:1 with malignant lesions.

Fifty-three of these malignant lesions were located in the rectum accounting for 70% of the lesions located in the rectum. Forty-four of the adenocarcinomas, all neuroendocrine tumors, and mucinous carcinoma were located in the rectum. The signet ring carcinoma was located in the transverse colon. The anatomical site for GIST was not specified [Table 3].
Table 3: Site distribution of the histopathologic lesions

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The predominant clinical presentation in the patients with malignant lesions was hematochezia 39 (55.7%), followed by constipation 9 (12.9%) and weight loss 7 (10%) [Table 4].
Table 4: Clinical complaint versus pathologic diagnosis

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Thirty-three (56%) of the patients with adenocarcinoma presented with hematochezia, while 5 (71.4%) of the patients with mucinous carcinoma and the patient with GIST presented with hematochezia. Six of the patients with adenocarcinoma presented with constipation while two of the patients with mucinous carcinoma presented with constipation. Of the seven patients who presented with weight loss, six of them had adenocarcinoma, two mucinous carcinoma, and a case of signet ring carcinoma.

On endoscopy, most of the tumors 55 (78.6%) were visualized as a mass; either a colonic mass in 34 (48.6%) of the cases or an ulcerated bleeding mass in 21 (30%) of the cases. Of the 34 cases with colonic mass, 28 of them were adenocarcinomas, four were mucinous carcinomas, and one case each of neuroendocrine tumor and GIST [Table 5].
Table 5: Gross endoscopic findings correlated with histopathologic diagnosis

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Group 2: Benign neoplastic lesions

There were a total of 35 (18.2%) benign neoplastic lesions diagnosed [Figure 2].

The lesions comprised 34 (97.1%) neoplastic polyps and 1 (2.9%) anal intraepithelial neoplasia (AIN).

The neoplastic polyps comprised 22 tubular adenomas, six serrated adenomas, five tubulovillous adenomas, and one villous adenoma.

Of the 22 tubular adenomas, 17 had low-grade dysplasia and five were of high-grade dysplasia. All of the serrated adenomas had low-grade dysplasia. Only one of the tubulovillous adenoma had high-grade dysplasia. The villous adenoma was of high-grade dysplasia [Table 6].
Table 6 : Grades of dysplasia in the adenomatous polyps

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The AIN diagnosed was also of high-grade dysplasia.

The peak age group for the benign neoplastic lesions was 50–59 years age group, closely followed by the 60–69 years age group for both males and females [Table 1]. None of these lesions were seen in the age group of 0–19 years. There was one case of tubular adenoma seen in 84 and 96 years' old.

There were 17 males and 18 females in this group, with a male to female ratio of 1:1.

One-third 11 (31.4%) of these tumors were located in the rectum; the 2nd most common site was the sigmoid and transverse colon with five (14.3%) of the lesions located there [Table 3].

The predominant clinical presentation was hematochezia 12 (34.2%). The other majority 7 (20%) of them were asymptomatic, only presenting for routine screening [Table 4].

On endoscopy, 24 (68.6%) were visualized grossly as a polyp. The 2nd most common endoscopic finding was an irregular colonic mucosa; this was seen in 7 (20%) cases [Table 5].

Group 3: Inflammatory lesions

There were a total of 52 (27.1%) inflammatory lesions, making it the 2nd largest group diagnosed histologically [Figure 2].

These inflammatory lesions comprised 23 focal active colitis, 17 acute infectious colitis, five diverticular colitis, five inflammatory polyps, and two diversion colitis [Table 1].

The peak age group at which inflammatory lesions were diagnosed was 50–59 years age group, closely followed by the 60–69 years age group for both males and females. The youngest age group 0–19 years and the oldest age group 90–99 years did not have any of these lesions [Table 2].

There were 27 males and 25 females, with a male to female ratio of 1.1:1 [Table 2].

Most of these lesions 26 (50%) spanned more than one section of the colon; this included 13 cases of acute infectious colitis, ten cases of focal active colitis, and three cases of diverticular colitis. Other commonly involved sites with six (11.5%) cases each were the rectum with one case of acute infectious colitis, two cases of focal active colitis, one case of diversion colitis, and two cases of inflammatory polyps and the sigmoid colon with four cases of acute infectious colitis and two cases of focal active colitis [Table 3].

The predominant clinical presentation was diarrhea - 12 (23.1%) - which was the complaint in ten cases of focal active colitis and two cases of acute infectious colitis. The 2nd most common clinical complaint was abdominal pain 11 (21.2%) with five cases each of acute infectious colitis and focal active colitis and one case of inflammatory polyp [Table 4].

On endoscopy, one-third of the inflammatory lesions 16 (30.8%) had normal colonoscopic findings; these were seen in seven cases of acute infectious colitis and nine cases of focal active colitis. The 2nd most common endoscopic finding was hyperemic colonic mucosa 12 (23.1%), with six cases of focal active colitis, five cases of acute infectious colitis, and one case of inflammatory polyp [Table 5].

Group 4: Idiopathic inflammatory bowel disease

There were a total of 18 (9.4%) idiopathic inflammatory bowel disease (IBD) diagnosed. There were 11 (61.1%) cases of ulcerative colitis (UC) which was the greater majority in this group, 6 (33.3%) cases of Crohn's disease, and 1 (5.6%) case of indeterminate colitis seen [Table 1].

The peak age group for IBD was the 50–59 years age group, for both males and females [Table 1]. Another peak was seen in the 2nd decade. Of 11 UC cases, the majority (four cases) were seen in the 50–59 years age group and three in the 20–29 years age group. The cases of Crohn's disease was seen more in the 50–59 years age group with four cases here, while the remaining two cases were seen in the 20–29 years age group. There was only one case of indeterminate colitis which was seen in the 50–59 years age group.

There were 12 males and six females, with a male to female ratio of 2:1 [Table 2].

A majority 10 (55.6%) of the IBD cases spanned more than one anatomical site of the colon; four cases of UC and six cases of Crohn's disease. Four cases were located in the rectum; three cases of UC and one case of indeterminate colitis. There were two cases of UC in the sigmoid colon and one case of UC in the descending colon [Table 3].

The predominant clinical presentation was diarrhea and abdominal pain. There were six cases of IBD; three UC and three Crohn's disease presenting with abdominal pain. Four cases of UC and one case of Crohn's presenting with diarrhea [Table 4].

On endoscopy, most of the IBD lesions (7) were visualized as irregular colonic mucosa; five cases of UC and two cases of Crohn's disease. The 2nd most common endoscopic finding was hyperemic mucosa with three cases, one case of UC and two cases of Crohn's; two colonic masses, one case of UC and one case of indeterminate colitis [Table 5].

Group 5: Hyperplastic polyps

There were a total of 10 (5.2%) of hyperplastic polyps [Figure 2]. They comprised 21% of the polyps diagnosed in this study [Figure 3] and [Figure 4], making them the 2nd most common after the tubular adenomas.
Figure 3: Frequency distribution of the lower gastrointestinal lesions by gender

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Figure 4: Histopathologic characterization of the polyps

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The peak age group for the hyperplastic polyps was 50–59 years age group for both males and females [Table 1]. None of these lesions were seen in the 0–19 years age group.

There were two males and eight females in this group, with a male to female ratio of 1:4.

A majority 5 (50%) of these tumors were located in the rectum; the 2nd most common site was the sigmoid with four (40%) of the lesions located there [Table 3].

The predominant clinical presentation was hematochezia 4 (40%). The other majority 3 (30%) of them were asymptomatic, only presenting for routine screening [Table 4].

On endoscopy, 6 (60%) were visualized grossly as a polyp. The 2nd most common endoscopic finding was an irregular colonic mucosa, this being seen in two (20%) cases [Table 5].

Group 6: Vascular lesions

There were a total of seven vascular lesions accounting for 3.6% of the lesions diagnosed histologically [Figure 2].

These lesions comprised three hemorrhoids and four cases of ischemic colitis [Table 1].

There were three cases of hemorrhoids with one case each in the 40–49 years, 60–69 years, and 70–79 years age groups, while of the four cases of ischemic colitis, two were in the 20–29 years age group, one in the 30–39 years age group, and one in the 70–79 years age group [Table 1].

There were three males and four females with these vascular lesions. The male to female ratio was 1.5:2. A total of two males and one female had hemorrhoids, while one male and three females had ischemic colitis [Figure 3].

Four of the vascular lesions were located in the rectum, two in the anus, and one in the transverse colon, of which three of the ischemic colitis were located in the rectum and one in transverse colon, while two of the hemorrhoids were located in the anus and one in the rectum [Table 3].

The predominant clinical presentation was hematochezia with five cases presenting with this complaint. There was one case each of anal pain and constipation [Table 4].


  Discussion Top


This study evaluates the clinicopathological features of lower GI tract endoscopic biopsies done in Benin City.

Of the 249 samples included in this study, 192 had pathologic diagnoses while 57 were normal colonic mucosa biopsies. About a quarter 57 (22.9%) of the samples received were found to be normal colonic mucosal biopsies. Of these 57 biopsies, 27 of the patients had symptoms. Twelve of them had constipation, six had hematochezia, while three had anal pain and a previous malignancy. There was one case each of abdominal swelling, weight loss, and a suspicious barium enema result.

The symptomatic population of patients who had normal colonic mucosa could be explained by the fact that many functional disorders of the bowel may not have features that are histologically obvious.

Clinical complaints such as anal pain could have arisen from anal fissures and abrasions in the anal canal while the cases of hematochezia could be attributed to bleeding hemorrhoids or massive upper GI bleeding. Poor sampling may have also lead to a missed diagnosis.

Of the pathological lesions diagnosed, malignant neoplastic lesions constituted 37% of this number, (non-IBD) inflammatory lesions 27%, benign neoplastic lesions 18%, hyperplastic polyps 5%, IBDs 9%, and vascular lesions 4%.

The malignant lesions were the predominant lesions seen 70 (37%). This concurs with the findings in Ife where Alatise et al. recorded colorectal cancer as the most predominant lesion diagnosed.[12] Irabor in Ibadan had similar findings with malignant lesions being the most frequently diagnosed lesion on lower GI endoscopy.[13] Sahu et al. in India had only 8.3% (32) cases of malignancy.[14]

Colorectal adenocarcinoma was the predominant malignant lesion diagnosed accounting for 67 cases (95.7%). Abdulkareem et al. in Southwest Nigeria reported similar findings with colorectal adenocarcinoma being the predominant malignancy in the GI tract.[4] Abdulkareem et al. in another study found colorectal adenocarcinoma to be the most common GI tract malignancy, where it accounted for 87% of all colorectal cancers and cancers in the anal region.[5]

Other studies done in different geographical areas of Nigeria showed colorectal carcinoma to be the predominant type of malignancy in the lower GI tract.[15],[16],[17] Ahmad et al. in Pakistan also found adenocarcinoma to be the predominant lesion in the lower GI tract.[18]

The male to female ratio of patients with colorectal cancer was 1.2:1 and is in the same range as that seen by Abdulkareem et al., who had a male to female ratio of 1.35:1.[4] The male to female ratio in this study is similar to that seen in the Western world.[3]

The 1st peak age observed for colorectal carcinoma was in 50–59 years age group. This is similar to what was seen in studies done by Eze et al. in Benin, Ibrahim et al. in Ilorin, Seleye-Fubara and Gbobo in Port Harcourt, and Dakubo et al. in Ghana, where the peak age was in the 5th decade.[6],[19],[20],[21] This was slightly different from what was reported by Abdulkareem et al where the peak age was in the 4th and 5th decade,[4] while this study had peak age occurring in the 5th and 6th decade.

We also had fewer cases of colorectal cancer occurring before 40 years 12 (17.1%); this concurs with what was seen in studies done by Abulkareem et al., Ibrahim et al., and Terhaar Sive Droste et al.[4],[19],[22]

The peak age for colorectal carcinoma occurred two decades earlier than that seen in the Western world, where their peak age was in the 7th decade.[3] This may be attributed to a longer life expectancy in the Western world when compared to the shorter life expectancy in Nigeria. According to the Centers for Disease Control and Prevention, the life expectancy in Nigeria for women is 54 years and for men is 52 years. Furthermore, in this study, there were fewer respondents from the 7th decade with more respondents in the 4th, 5th, and 6th decade of life.

The predominant type of colorectal cancer was the invasive adenocarcinoma which was also the predominant pattern seen in several other studies.[4],[5],[6],[15],[17],[19],[23]

The anatomical location of the adenocarcinoma concurs to what was seen in both local and international studies done in Southwestern Nigeria, Benin City, Jos, Ilorin, Ghana, and Amsterdam, in which a majority of them were located in the rectum 53 (75.7%).[4],[5],[6],[16],[19],[21],[22],[24]

This study had only one case of GIST. It is said to be the most common mesenchymal tumor of the GI tract.[25] Abdulkareem et al. in a study categorizing the GI mesenchymal lesions found the majority (54%) to be located in the stomach and 23% of the cases to be located in the large bowel.[25] This could explain why it was not a common finding in this study since our biopsies were from the lower GI tract.

Hematochezia was the presenting complaint of over half of the patients with colorectal cancer. Eze et al. in Benin had obstruction as their main clinical complaint.[6] This discrepancy may be due to the fact that this study was based on endoscopic biopsies. A study in Accra recorded similar findings with hematochezia being the most frequent clinical symptom.[21] Terhaar et al. also had similar findings.[22]

In this study, a large number of the lesions 78.6% were visualized as a mass on endoscopy; this is similar to what was seen by Ibrahim et al. in Ilorin.[19]

There were 35 benign neoplastic lesions accounting for (18.2%) of the lesions diagnosed. Majority of these lesions (97.1%) were polyps. The predominant polyp in this study was the tubular adenoma 62.9%, mostly of the low-grade pattern. This was in contrast to similar studies done in Nigeria where only few polyps were reported.[11],[12],[13]

The reason for a larger number of polyps in our study may be attributed to the fact that this study had a larger population size. Studies done in India and Saudi Arabia reported very few polyps too, with Sahu et al. in India having 18 (4.7%) in their study and Al Quorain et al. having 35 (2.2%) in their study.[14],[26]'

The tubular adenomas are the most frequently seen type of polyps in this study. This is similar to what Ibrahim et al. reported in Ilorin.[27] This also concurs with other international studies on polyps by Clark et al. in a multicenter study in Scandinavian Europe, Lindgren et al. in Sweden, Hodadoostan et al. in Iran, Li et al. in China, and Foss et al. in the United Kingdom, who had similar findings with the adenomatous polyps being the most frequently diagnosed type of polyp.[28],[29],[30],[31],[32]

This could be attributed to the established colorectal carcinoma screening programs in these centers where the peak age group for colorectal carcinoma are usually targeted for screening, hence the higher incidence of the adenomatous polyps. From this study, the peak age group is synonymous with the international screening age for colorectal carcinoma.

The peak age of diagnosis was 50–59 years, similar to the 1st peak age for colorectal carcinoma. The similarity in the peak age for the adenomatous polyps and colorectal carcinoma has been explained by several studies, where it was observed that the prevalence rate of adenomatous polyps was found to correlate with the regional incidence rates of colorectal carcinoma.[28],[33]

Further, fewer than 10% of all adenomas become cancerous, but about 95% of colorectal cancers develop from adenomas. These adenomas are said to occur rarely in individual <49 years. It takes an estimated time of 2–5 years for a complete malignant transformation to occur.[34]

In addition, the majority of the adenomas seen at this peak age of 50–59 years were of low-grade dysplasia; this will give enough time for further mutations to occur for malignant transformation and is a possible explanation for the 2nd peak age of colorectal carcinoma which occurred a decade or more later than the 1st peak age.

The male to female ratio of this study is 1:1.2. This is in contrast to what was seen in Ilorin, where they had a male to female ratio of 2.1:1.[27]

The polyps were frequently located in the rectum. This location was similar to the location of the colorectal carcinoma.[4],[6],[16],[19] Foss et al. also had a similarity in the location of the polyps.[32] This, however, differs from what was seen in the Iranian study where the predominant location was the ascending colon and cecum.[30]

Polyps usually occur in a similar site of the colon, where we have a higher occurrence of colorectal carcinoma.[28] This concurs with what is seen in this study, with the adenomatous polyps and colorectal carcinoma being mostly located in the rectum.

There were ten hyperplastic polyps. These made up 5.2% of the lesions diagnosed, making it the 2nd most common polyp diagnosed in this study. In Iran, hyperplastic polyps were the predominant nonneoplastic polyps seen in a study done by Hodadoostan et al., where 9% of the polyps where nonneoplastic, which concurs with what was seen in this study.[30] However, Li et al. in China reported hyperplastic polyps as the 3rd most common polyp (11.06%) in their study.[31] Ahmad et al. reported ten cases of hyperplastic polyps in their study.[18]

There were 52 (non-IBD) inflammatory lesions accounting for 27.1% of the lesions seen in this study. These lesions are of great importance because they are often a differential diagnosis with IBD and its important; a misdiagnosis is not made as this will affect the clinical management of the patient.

These lesions are not uncommon and have been reported in studies on lower GI endoscopy by Irabo in Ibadan, Sahu et al. in India, Al Quorain et al. in Saudi Arabia, Ahmad et al. in Iran, and Shah et al. in the United States of America.[13],[14],[18],[26],[35]

The vast majority of these lesions were the focal active colitis 44%, acute infectious colitis 32.7%, and diverticular colitis 9.6%.

Focal active colitis is the majority in this group. Diarrhea was the main presenting complaint in these patients. This is similar to what was seen in a study done by Greenson et al.[36] It was also seen in patients who were asymptomatic; this also concurs with what was reported by Greenson et al.[36] Most of the cases of focal active colitis on clinical follow-up were found to be infectious typically common in immunosuppressed patients and this patients presented with diarrhea.[36] Although the clinical information of immunosuppression was not documented in this study, it can be inferred since a majority of the patients with focal active colitis presented with diarrhea.

There is not much documentation on this lesion in our local studies.

Acute infectious colitis is a common finding in this study. Most of the patients here presented with either hematochezia or abdominal pain. This concurs with what was seen in studies by Surawicz and Belic and Greenson et al.[36],[37]

The main etiologic agents here tend to be bacterial,  Salmonella More Details or Shigella. These patients often go undiagnosed, except when symptoms persist and they present to a gastroenterologist.

It can be a mimic of IBD as the patients have similar symptoms; the main distinguishing factor on histology is the absence of crypt distortion and basal plasmacytosis.

Diverticular colitis was one of the findings in this study. Patients mainly presented with hematochezia and were in the 5–8th decade of life. This is similar to the findings seen in a study done by Alatise et al. in Ife, who had patients aged 41–85 years and the most common presenting complaint was bleeding per rectum.[38] Studies done by Nielsen et al. and Reinus and Brandt also reported similar findings.[39],[40]

There were a total of 18 cases of IBD diagnosed in this study accounting for 9.4% of the pathological lesions diagnosed.

IBD is now more reported in Nigeria as shown by several local case reports in Nigeria.[41],[42],[43],[44]

Of these 18 cases, 11 were UC, six Crohn's disease, and three indeterminate colitis. An average of three cases of IBD/year was diagnosed in this study over the 5-year study period. This is similar to a study done by Alatise et al., who reported 12 cases of IBD over a 3-year period.[43] Another study in Northern Nigeria by Ukwenya et al. reported four cases of IBD over a 3-year period.[42]

UC is the most frequently diagnosed IBD in this study. This concurs with what has been seen in our local studies, where Ukwenya et al. reported three cases of UC and one case of Crohn's disease while Alatise et al. reported eight cases of UC and four cases of Crohn's disease.[42],[43] Similarly, Senbanjo et al. in Lagos reported a case of UC in a pediatric patient and Irabor in Ibadan also had two cases of UC.[13],[44] UC was also one of the frequently diagnosed inflammatory pathologies seen on lower GI endoscopy internationally as seen in studies done by Al Quorain et al. in Saudi Arabia with 5.72% of cases being UC and 0.9% being Crohn's disease.[26] Sahu in India and Ahmad et al. in Pakistan had UC as the most common diagnosis in their study.[14],[18]

IBD may have been underdiagnosed in the past due to overlapping features with other non-IBD colitis such as infectious colitis. Improved and better diagnostic facilities in our hospitals, such as endoscopy and radiographic imaging, have aided in making accurate diagnosis of IBD.

The trend of UC being more diagnosed is similar to what was seen initially in the Western world, where as a society becomes more industrialized, UC begins to emerge with a lower incidence of Crohn's disease, and eventually, Crohn's disease emerges with its incidence matching that of UC.[45]

In this study, there were two peak age groups for IBD, the 50–59 years age group and the 20–29 years age group. This is similar to what is seen internationally.[45],[46] However, IBD can occur at any age.[45]

There was a male preponderance seen in IBD in this study. This may be due to the fact that there were more UC cases diagnosed. Globally, UC is said to affect males more than females while Crohn's disease affect females more.[45] Our local studies also report a male preponderance.[42],[43] This study had more males in the study population; this can explain why there were more males with Crohn's disease.

The main clinical complaint of most of the patients in this study is abdominal pain and diarrhea. This concurs with what was seen in our local studies.[42],[44]

Seven (3.6%) of the lesions diagnosed were of vascular etiology. The lesions were mostly ischemic colitis. It affected both the younger and older age groups, which is not different from what has been reported.[47],[48]

Very little is seen on vascular lesions in our local studies. Alatise et al., however, in Ife reported one case of vascular ectasia.[12]

Three cases of hemorrhoids were diagnosed in this study. This is in contrast to what was seen in studies done in Ibadan by Irabor, Ismaila and Misauno in Jos, and Alatise in Ife, where they reported more cases of hemorrhoids.[11],[12],[13] More cases of hemorrhoids were also seen by Sahu in India.[14]

The few cases of hemorrhoids in this study may be attributed to poor sampling by the endoscopist as most of the lesions seen as hemorrhoids on endoscopy were diagnosed as normal colonic mucosa. Most of the patients with these lesions presented with hematochezia which was a similar finding in Ife.[12]


  Conclusion Top


This analysis of a cohort of colonic biopsies arises from a diverse group of clinical indications, the most important of which is hematochezia. Half of the biopsies that were done for hematochezia were found to be malignant while another third were due to neoplastic polyps some of which are adenomatous.

Further, the study showed that there was a high diagnostic yield in patients who had positive endoscopic findings and that symptomatic patients had a higher diagnostic yield than those who presented with no symptoms. This is a clear indication that most of the symptomatic patients have lesions that can be seen histologically.

From this study, we saw that the majority of the patients who were scoped were symptomatic and very few of them presented for routine screening despite the fact that the mode age was 50 years, the recommended age for screening.

This study shows that colonoscopy and colonic biopsy although not yet widely practiced in Nigeria should be seen as a tool that is essential in the management and control of lower GI malignancies in the country.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]



 

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