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ORIGINAL ARTICLE
Year : 2016  |  Volume : 4  |  Issue : 3  |  Page : 113-117

A descriptive study of bladder tumors in Benin City, Nigeria: An analysis of histopathological patterns


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

Date of Web Publication14-Nov-2016

Correspondence Address:
Gerald Dafe Forae
Department of Pathology, University of Benin Teaching Hospital, P.M.B. 1111, Benin City
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2320-3846.193986

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  Abstract 

Aims and Objectives: This study is aimed at determining the frequency and histopathological patterns including grading and staging of bladder tumors as seen in University of Benin Teaching Hospital, Benin City, Nigeria and to compare with similar research works elsewhere. Materials and Methods: A retrospective study of all data of surgical excision and cystoscopic bladder biopsies received over a 10-year period (2003-2012) at the Department of Histopathology, University of Benin Teaching Hospital, Benin City, Nigeria. Histological criteria published by the World Health Organization/International Society of Urological Pathology were used for the diagnosis and grading of these tumors. Results: A total of 75 bladder lesions were received in the Pathology Department. Of these, 64% were males and 36% were females giving a male to female ratio of 1.7:1.0. The peak and mean age incidence of urothelial bladder lesions was 60-69 years and 54.9 years ± 8.6 standard deviation, respectively. Bladder tumors accounted for 74.7% of all bladder lesions. Fifty-one (68%) cases out of 75 lesions were malignant tumors. Transitional cell carcinoma (TCC) was the most commonly encountered histological pattern accounting for 64.7% of bladder cancer. High grade papillary urothelial carcinoma was the most common tumor grade accounting for 51.4%. Only 40.6% cases were urothelial confined carcinoma (PTa) while 29.7% each accounted for lamina propria (PT1) and muscle (PT2) invasive carcinoma. Conclusion: Bladder tumors are more commonly encountered in males with the majority of cases occurring in the 7 th decade. Both high-grade TCC in stage (PT2) and low-grade carcinomas stage (PTa) were relatively common patterns seen in this study.

Keywords: Bladder, histopathology, malignancy, transitional cell carcinoma, tumors


How to cite this article:
Forae GD, Ugiagbe EE, Mekoma DF. A descriptive study of bladder tumors in Benin City, Nigeria: An analysis of histopathological patterns. Saudi Surg J 2016;4:113-7

How to cite this URL:
Forae GD, Ugiagbe EE, Mekoma DF. A descriptive study of bladder tumors in Benin City, Nigeria: An analysis of histopathological patterns. Saudi Surg J [serial online] 2016 [cited 2021 May 14];4:113-7. Available from: https://www.saudisurgj.org/text.asp?2016/4/3/113/193986


  Introduction Top


Studies have shown that bladder cancer is the 9 th most commonly encountered malignancy globally. It has an estimated global annual incidence rate of 330,000/year and mortality rate of 130,000/year. [1] According to the 2012 cancer statistics report, bladder cancers constituted the 4 th most prevalent cancer of males in the United States of America after prostate, lung, and colorectal cancers in that order. It thus accounted for 7% of estimated new cancer cases in males. [2] In European series, reports have shown that the highest incidence rate is seen in Belgium and Italy accounting for 42.5/100,000 and 41/100,000 population studies, respectively. [3] Several other European countries including Switzerland and Slovenia have lower incidence rates of 12/100,000 and 10/100,000, respectively. [4] However, the lowest incidence rates were found in South American countries and Asian countries. [3],[4] Studies from African series have shown that bladder cancer is most commonly encountered in Egypt [5] with rates up to 37/100,000 and 30,000 new cases annually. [6]

In Western countries, tobacco smoking is a major risk factor accounting for up to 50%-65% of urothelial bladder cancer. However, occupational-related hazards accounted for 20%-25% of urothelial bladder cancer of which transitional cell carcinoma (TCC) was the most common type. [6] In contrast, serial studies of some other African countries (including Egypt) where chronic irritation of the bladder epithelium by schistosoma haematobium accounted for the major risk factor for bladder cancer show that the majority of cases are Squamous cell carcinoma (SCC) [7],[8]

Cases of bladder tumors reported in Nigeria are extremely rare, and the few data available are hospital based. There are currently no publications regarding Histopathological patterns of bladder tumors in Southern states of Edo, Delta, and Bayelsa. This study, therefore, aims to show the frequencies and histological pattern including grading and staging of bladder tumors in (University of Benin Teaching Hospital [UBTH]) Benin City, Nigeria.


  Materials and Methods Top


Study setting and design

This work is a retrospective study of all data of surgical excision specimens of the bladder, and cystoscopic bladder biopsies received over a 10-year period at the Department of Histopathology, University of Benin Teaching Hospital, Benin City, Nigeria. These specimens were sent from the Departments of Surgery in UBTH and other public and private hospitals in the Benin City metropolitan area and neighboring Southern states of Delta, Bayelsa, and South-Western state of Ondo. The major sources of information include the surgical pathology day-books and histology reports of all bladder lesions diagnosed within the period.

Specimen sampling and laboratory procedure

All specimens sent for histology were formalin fixed paraffin embedded tissues sectioned at 3-5 μ and stained with hematoxylin and eosin. Special histochemical stains (periodic acid-Schiff, Mucicarmine were used to demonstrate glandular lesions while reticulin demonstrates connective tissue). Histological patterns and types including grading and staging of urothelial bladder tumors were based on the new World Health Organization/International Society of Urological Pathology (WHO/ISUP) classification. [9] Thus these patterns and types include urothelial papilloma, papillary urothelial neoplasm of low malignant potential (PUNLMP), low grade and high grade urothelial papillary carcinoma. The grading includes: Ta (papillary urothelial confined carcinoma), T1 (lamina invasive papillary carcinoma), T2 (muscle invasive carcinoma). [10]

Data management

Data were entered using Microsoft Excel package and transferred to statistical package for the social sciences version 17, SPSS Incorporated, Chicago, Illinois, USA. The cases were analyzed using simple SPSS statistical tables. The results obtained were analyzed with respect to age, sex, and tumor types including grading and pathological staging.


  Results Top


During this 10-year period, a total of 75 urothelial bladder lesions were received in the Pathology Department. Of these, 48 (64%) were from males and 27 (36%) were from females given a male to female ratio of 1.7:1.0. The patients' age range was 7-86 years. The peak age incidence for all bladder lesions was in the 60-69 years age group, this accounted for 25.3% as seen in [Table 1]. The median and mean ages were 52.3 years and 54.9 ± 8.6 years, respectively [Table 1]. In all, 51 cases (68%) were malignant while 24 (32%) were nonmalignant. Among the nonmalignant lesions, inflammatory lesions constituted 18 (24%) of all cases while tumor-like lesions accounted for six (8%) of all cases.
Table 1: Frequency and sex distribution of all bladder lesions


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[Table 2] shows the histological diagnoses of bladder lesions. Bladder tumors accounted for 74.7% of all bladder lesions while urothelial bladder tumor accounted for 66% of all bladder tumors. Malignant bladder tumors accounted for only 68% and 94.5% of bladder lesions and tumors, respectively. In this study, TCC was the most commonly encountered class of carcinoma constituting 33 cases or 64.7% of all bladder cancer and 33 cases or 44% of all bladder lesions. This was followed by adenocarcinoma accounting for ten cases or 19.5% of all bladder malignancy and ten cases or 13.3% of all bladder lesions. SCC constituted only three cases accounting for 5.9% of bladder cancers.
Table 2: Overall histopathological patterns of bladder lesions


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[Table 3] shows the grading and staging of urothelial bladder tumors. In all the 37 graded cases, high-grade papillary urothelial carcinoma was the most common tumor accounting for 19% or 51.4%. This is followed by low-grade papillary urothelial tumors constituting 12 cases or 32.4%. Among this series, urothelial papilloma was four cases or 10.8% while PUNLMP constituted two cases or 5.4%. For pathological staging, 15% or 40.6% cases were urothelial confined carcinoma (PTa) while lamina propria invasive carcinoma (PT1) and muscle invasive carcinoma (PT2) constituted 11 or 29.7% each.
Table 3: Grading and staging of urothelial bladder tumors


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  Discussion Top


In this series, the mean age of patients with bladder lesions was 54.9 years. This finding is similar to reports by Mapulanga et al. [11] who reported a comparable mean age of 57.5 years. Nevertheless, a slightly lower mean age of occurrence of 48.8 years was documented in Kano, Northern Nigeria. [12] In contrast, a much higher value of 60 years was reported by Thomas and Onyemenen [13] in Ibadan Western Nigeria. Again studies from the USA recorded 67 years as the mean age of urothelial bladder tumors especially urothelial cancer. [13],[14] This study has demonstrated that urothelial bladder tumors are more common with males as compared to their female counterparts. Specifically we found the male to female ratio to be 1.7:1. This is similar to reports by Bowa et al. [15] where the male to female ratio was 2:1. In contrast our report of male:female ratio of 1.7:1 is higher than the 1.3:1 reported by Mapulanga et al. [11] Other related studies in Nigeria have reported a wide male to female discrepancy ratio as high as 5:1 and 4:1.

In this study, the peak age for bladder tumors was seen in the 7 th decade of life. This is comparable to what obtains in Caucasian series especially in the United Kingdom where its peak age incidence was seen in the 7 th decade. [16],[17],[18] Waihenya and Mungai [19] in Kenya also documented the 7 th decade to be the peak incidence of urothelial bladder cancer. Ochicha et al. in Kano, Northern Nigeria reported a peak age incidence of the 5 th decade. However, this study is differing from studies in Zambia where the majority of bladder tumor occurred below the sixth decade of life. [19]

The reason for these discrepancies is partly due to geographic and ethnic variations as etiological risk factors have a significant role to play in these variations. Studies have shown that schistosomiasis is highly implicated as a risk factor in areas with reported relatively lower peak age incidence while tobacco smoking, occupational, and chemical carcinogens like aniline dyes have been implicated in geographic regions with higher peak incidence age group. In our series, the prevalence of schistosomiasis was extremely low in Benin and its environs. This has accounted for the relatively higher peak age group incidence seen in this geographic locale. Notably, several studies have documented the high prevalence of schistosomiasis in association with SCC while TCC is more common with aniline, azo dyes, and smoking. [20],[21] However, no such have been reported in literature in Benin City.

In this series, malignant tumors are the more common of all urothelial bladder lesions. Besides, TCC was the most common urothelial bladder lesion constituting 64.7% of all bladder cancers as well as 44% of all bladder lesions. This finding is similar to reports documented in Egypt where TCC constituted 67% of all histologically confirmed bladder tumors. [20] In addition, TCC accounted for 63% of bladder cancers documented by the Middle East Cancer Consortium. [3],[21] Furthermore, similar studies from Caucasian series have also confirmed TCC as the most common form of bladder cancer among them. On the other hand, our findings are contrary to studies by Ochicha et al. [12] in Kano where SCC was the most common pattern of bladder cancer constituting 53% while TCC and adenocarcinoma came a distance second and third positions with 35% and 4%, respectively. Yet again, our study is contrary to reports documented by Mapulanga et al. [11] where SCC was the most common type of bladder tumor constituting 60.4% and TCC constituting 30.2%. Once more, our report is dissimilar to reports of Bowa et al. [15] where SCC was the most common type of bladder cancer accounting for 23.4% while adenocarcinoma constituted 22.2%. The reason for this discrepancy is associated with the different risk factors involved in the etiology of bladder cancers.

In this study, we found that early pathological stages (PTa and PT1) accounted for 70.3% while late stage cancer accounted for 29.7%. This is similar to the findings of Matalka et al. [22] and Laishram et al. [23] where early stage cancer (pTa and pT1) accounted for 71.8% and 73%, respectively. This is similar to other Caucasian reports. [24],[25],[26] According to the WHO/ISUP grading of urothelial neoplasm, PUNLMP accounted for 5.4%; low-grade accounted for 33.4% while high grade accounted for 51.4%. The reason for this low turn-out of early presentation is due to ignorance, poverty, and preference to use of alternative medications. This is in contrast to reports documented by Laishram et al. [23] and Ahmed et al. [24] where low-grade tumors accounted for the majority of cases. Another reason for this discrepancy may be due to late presentation of cases to tertiary institutions in our locality and other environmental risk factors which is beyond the scope of this research.


  Conclusion Top


This study has shown that bladder tumors are more commonly encountered in males with the majority of the cases occurring in the 7 th decade. High-grade TCC in late stage (pT2) and low-grade carcinoma in early stage (pTa) were relatively common WHO/ISUP patterns seen in this study.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
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    Tables

  [Table 1], [Table 2], [Table 3]


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