|Year : 2015 | Volume
| Issue : 1 | Page : 47-51
Histopathological review of breast tumors in Kano, Northern Nigeria
Imam Mohammed Ibrahim1, Yawale Iliyasu2, Aminu Zakari Mohammed1
1 Department of Pathology, Aminu Kano Teaching Hospital, Kano, Nigeria
2 Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna, Nigeria
|Date of Submission||07-Sep-2014|
|Date of Acceptance||02-Nov-2014|
|Date of Web Publication||17-Feb-2015|
Imam Mohammed Ibrahim
Department of Pathology, Aminu Kano Teaching Hospital, PMB 3452, Kano
Context: Breast tumors are common worldwide, and various reports suggest an increasing incidence in Nigeria, which necessitates an urgent need to differentiate benign from malignant tumors. Aims: To classify, grade and to determine the changing pattern, frequency, age and sex distribution of breast tumors seen in a tertiary hospital. Materials and Methods: This was a 10-year retrospective study of all breast tumors diagnosed at the Pathology Department of a Teaching Hospital from 1 January 2001 to 31 December 2010. Results: A total of 1,566 breast tumors were diagnosed during the study period, of which 1035 (66.1%) were benign, and 531 (33.9%) were malignant. Fibroadenoma was the commonest benign breast tumor followed by fibrocystic change, and they accounted for 47.1% and 25.4% of benign breast tumors respectively. Out of the 531 malignant cases reviewed; 496 (93.4%) were females, and 35 (6.6%) were males with a female to male:ratio of 14.2:1.0. The age range of malignant cases was between 21 and 79 years with a mean age of 42.0 years. Invasive ductal carcinoma was the predominant histological type with 316 cases (59.5%). This was followed by medullary carcinoma with 61 (11.5%) cases, invasive lobular carcinoma and invasive papillary carcinoma each with 37 (6.9%) cases. Three hundred and ninety-eight cases satisfied the criteria for grading, out of which 237 (59.5%) cases were classified in Grade 1, 133 (33.4%) cases in Grade 2 and 28 (7.1%) cases in Grade 2. Conclusions: Breast tumors are quite common which are mostly benign and are seen in both sexes with a striking female preponderance. The findings are generally similar to most previous studies from Nigeria, Africa and western world with minimal variations.
Keywords: Benign, breast, grading, malignant, Nigeria, tumors
|How to cite this article:|
Ibrahim IM, Iliyasu Y, Mohammed AZ. Histopathological review of breast tumors in Kano, Northern Nigeria. Sub-Saharan Afr J Med 2015;2:47-51
|How to cite this URL:|
Ibrahim IM, Iliyasu Y, Mohammed AZ. Histopathological review of breast tumors in Kano, Northern Nigeria. Sub-Saharan Afr J Med [serial online] 2015 [cited 2021 Jun 21];2:47-51. Available from: https://www.ssajm.org/text.asp?2015/2/1/47/150471
| Introduction|| |
Tumors of the breast are among the most common human neoplasm which occur worldwide amongst females of various age groups and less frequently in men.  The incidence and histological subtypes of these tumors vary from one region of the world to the other, and increasing awareness of breast cancer has stimulated profound interest in breast diseases. 
The most common symptoms are pain and palpable breast lumps. Other clinical features include nipple discharge, nipple deformity such as retraction and occasional skin changes. Despite the presence of mammography and fine needle aspiration cytology, tissue biopsy remains the gold standard for diagnosis, and this can be obtained by different techniques such as needle core, incisional or excisional biopsies.
Generally, as with most neoplasms of other organs, benign breast tumors occur more frequently in clinical practice than malignant cases in both sexes. Fibroadenomas are found most frequently in young women and together with fibrocystic disease are the two benign tumors of the breast most often encountered worldwide.
Breast cancer constitutes a major public health issue globally with incidence rates being higher in developing countries, and also higher in urban areas than in rural areas. Morbidity associated with benign tumors is minimal, unlike breast cancer and its treatment which constitute great physical, psychological and economic challenge in resource-limited societies. While mortality rate is declining in the developed world as a result of screening, early diagnosis and improved cancer treatment, in Africa, breast cancer has overtaken cervical cancer as the most common malignancy affecting women. Incidence rates appear to be rising due to changes in demography, socioeconomic, epidemiologic risk factors, better reporting and increasing awareness of the disease. 
| Materials and methods|| |
This is a retrospective study of all breast tumors that were histologically diagnosed in the Pathology Department of a Teaching Hospital over a 10-year period from 1 January 2001 to 31 December 2010. The laboratory request forms and duplicate copies of histology reports of all cases were retrieved, and relevant clinical information such as age and sex were extracted.
The corresponding slides were also retrieved and in few cases of faded and missing slides, fresh sections were cut from archival paraffin tissue blocks and routinely stained with hematoxylin and eosin. Special stains including periodic acid-Schiff and mucicarmine stains were deployed where necessary and the slides were then reviewed. The tumors were classified into histogenetic groups according to the 2005 WHO International Classification of breast tumors  and graded using Nottingham  grading system. The results were then analyzed and presented using relative frequency tables.
| Results|| |
A total of 1,566 breast tumors were diagnosed during the 10-year review period, out of which 1,035 (66.1%) were benign and 531 (33.9%) malignant with a benign to malignant ratio of approximately 2:1 [Table 1] and [Table 2]. Of the benign cases, there were 487 (47.1%) patients with fibroadenoma, 263 (25.4%) fibrocystic change, 62 (6.0%) tubular adenoma, 58 (5.6%) lactational adenoma, 34 (3.3%) with sclerosing adenosis and 26 patients (2.5%) with blunt-duct adenosis. There were 50 patients (4.8%) with benign phyllodes and 12 patients (1.0%) with ductal papilloma. The remaining 43 patients had a variety of pathological diagnoses as shown in [Table 1]. The mean age of patients with a benign tumor was 29 years with a range of 13-63 years. Eighty-seven percent of the patients with fibroadenoma presented before 30 years of age with the majority of patients in the 21-30 year age group [Table 1]. Gynaecomastia, which was the only benign tumor in males, constituted 14 (1.4%) benign cases.
|Table 1: Age distribution of benign breast tumors according to histopathological subtype|
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|Table 2: Age distribution of malignant breast tumors according to histopathological subtype|
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Invasive ductal carcinoma (IDC) was the most common histological type among the 531 malignant breast tumors accounting for 316 (59.5%) cases. This was followed by medullary carcinoma (MC), lobular carcinoma, papillary carcinoma, apocrine carcinoma, metaplastic carcinoma and mucinous carcinoma accounting for 61 (11.5%), 37 (6.9%), 37 (6.9%), 19 (3.6%), 15 (2.8%) and 14 cases (2.6%), respectively. The frequencies of other histological types of malignant breast tumors are shown in [Table 2].
The overall age range of malignant breast tumors was 15-80 years with a mean age of 42.0 years. The highest frequency of 153 (28.8%) cases occurred in the fourth decade while the lowest frequency of 4 (0.6%) cases occurred in the second decade as shown in [Table 2]. Four hundred and ninety-six (93.4%) malignant cases were seen in females and 35 (6.6%) in males giving a female:male ratio of 14.2:1.
A total of 398 malignant breast cases satisfied the criteria for grading, which is based on tubule formation, mitotic index and nuclei pleomorphism. Two hundred and thirty-seven (59.5%) cases were classified as Grade 1, 133 (33.4%) cases as Grade 2 and 28 (7.1%) of the cases as Grade 3 [Table 3].
|Table 3: Nottingham Grading of Breast Cancer according to histological types|
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| Discussion|| |
Breast tumors are very common and in most studies within and outside Nigeria the frequency of benign breast tumors outnumber that of malignancies,  but the proportions however vary. This study also found benign breast tumors to be overwhelmingly preponderant over malignant tumors comprising two-third (66.3%) of breast neoplasms and is <73% earlier reported in our center a decade ago.  The observed preponderance of benign tumors over malignant varieties is in consonance with findings from Hong Kong,  Afro-Caribbean  and Ghana  where 89.1%, 80% and 48% of breast tumors were reported to be benign respectively. The finding of this series is also comparable with reports from Zaria,  Gombe,  Ife,  Calabar  and Benin,  Nigeria, where 71.3%, 59.5%, 79%, 73.4% and 90% of the cases were benign respectively.
Of the benign breast tumors, fibroadenoma was found to be the commonest variant accounting for 487 (47.1%) cases and mostly occurred (56.5%) in patients within the third decade of life. Similar preponderance of fibroadenoma amongst benign tumors of the breast was also reported in other studies from Ghana  and Kenya.  The result of this study also agrees with findings in other parts of Nigeria, ,,,, but differs from an earlier study  in our center, Ibadan  Nigeria and amongst Caucasians  where fibrocystic change was reported to be the commonest benign breast lesion.
Fibrocystic change was the second most frequent benign breast lesion (25.4%) in this study, and the vast majority of the patients (48.3%) are seen in the fourth decade. This is in consonance with studies done in Saudi Arabia, India and Nepal. ,,
Gynecomastia, the only benign male breast tumor constitutes 1.4% of all the benign breast tumors in this series, demonstrating a decline in frequency when compared to 6% reported in an earlier study  in our center. Higher percentages were also recorded in Zaria,  Ife  and Makurdi,  Nigeria.
Cancer of the breast is common in our environment. Although the true incidence has not yet been ascertained, there are studies to suggest its increasing prevalence in Nigeria. Our study showed that breast cancer was diagnosed in 33.7% of all breast specimens received which is similar to 31.8% reported in Ilorin  but is >26.6% reported in Calabar  and 21% in Ife, Nigeria. 
It has been stated that breast cancer is rare in Caucasian women under 30 years and that the Nigerian peak is 10-15 years earlier than the peak age for Caucasians.  The age distribution of breast cancer in this study is comparable with findings from other parts of Nigeria, , and it is noteworthy that 10% of the patients were between 21 and 30 years of age. The mean age of patients with carcinoma of the breast in this series occurred in the premenopausal period (42.0 years), which is relatively <46.5 years obtained in an earlier study conducted in our center.  Other African authors reported similar findings from Nigeria. ,, This is in contrast to findings in Arabs  and in developed countries  where breast cancer peak incidence occurs in older patients.
Invasive ductal carcinoma (no special type [NST]) is the most common histologic type of breast cancer worldwide accounting for 40-75% of breast cancer in published series.  It accounted for 59.5% of the histopathological types in this study, and this is comparable to studies in Ibadan,  Zaria  and Gombe,  Nigeria which found IDC constituting 49.2%, 65.8% and 68.8% of all malignant breast tumors respectively. Higher proportions of this tumor were recorded in Lagos (94%),  Jos (91%),  Ilorin (78%),  and Ife (97.3%).  The decline in relative proportion of IDC in this series may be due to the fact that this is a referral hospital-based study and the figures found may not be a true reflection of relative incidence of IDC in our environment.
Medullary carcinoma was the second most common histologic type in this study accounting for 11.5% of cases, which agrees with an earlier finding  from our center.
Male breast carcinomas constituted 6.6% of malignant cases in this study as against the 2.2% recorded in an earlier study done in Kano  and is more than the 1% found in developed countries.  Higher incidence rates were also documented in some countries like Kenya (12.5%),  Uganda (5%),  and Zambia (15%). 
In this study, 398 malignant breast tumors were graded and 237 (59.5%) cases were categorized in Grade 1. Grades 2 and 3 constituted 133 (33.4%) and 28 (7.1%) cases respectively. This contrasts with a study done in Port Harcourt  where they found 21.0% of the tumors to belong to Grade 1, 26.0% in Grade 2 and 53.0% in Grade 3.
| Conclusion|| |
The results of this study have shown that breast tumors are quite common with benign tumors (66.1%) being nearly twice as common as malignant tumors (33.9%). Benign tumors are common problems in females of reproductive age group, with fibroadenoma being the commonest type in this study followed by fibrocystic change. Fibroadenoma is most common in the third decade of life, whereas fibrocystic change is most common in the fourth decade of life. There is overall declined in mean age of patients with malignant breast tumors in our study with IDC (NST) being the most common type followed by MC. This is similar to findings from other Nigerian and African studies with minimal variations.
The major challenges with breast cancer in our setting include low literacy levels and socioeconomic factors, as well as ignorance. Therefore, there is a need for public awareness campaign about the importance of self-breast examination and the need for early presentation. It is also advised that histologic assessment for all breast lumps should be routinely done to evaluate the risk factors for malignancy.
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[Table 1], [Table 2], [Table 3]
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