|Year : 2016 | Volume
| Issue : 3 | Page : 137-141
Benign tumors of the breast in Kano, Northern Nigeria: A 10-year experience and review of literature
Mohammed Ibrahim Imam1, Raphael Solomon2, Ibrahim Yusuf1
1 Department of Pathology, Bayero University/Aminu Kano Teaching Hospital, Kano, Nigeria
2 Department of Pathology, Aminu Kano Teaching Hospital, Kano, Nigeria
|Date of Web Publication||14-Oct-2016|
Mohammed Ibrahim Imam
Department of Pathology, Aminu Kano Teaching Hospital, P.M.B 3452, Kano 700001
Background: Benign breast tumors are common worldwide and various reports suggest an increasing incidence in Nigeria which necessitates an urgent need to differentiate it from malignant tumors. The study was carried out to classify and determine the pattern, frequency, age, and sex distribution of benign breast tumors seen in a tertiary hospital. Materials and Methods: This was a 10-year retrospective study of all benign breast tumors diagnosed at the Pathology Department of a teaching hospital from January 1 2001 to December 31 2010. Results: A total of 1566 breast tumors were diagnosed during the study period, 1035 cases of benign breast tumors constituting 66.3% of all breast tumors were seen. The female to male ratio was 72.9:1. The overall mean age for benign breast tumor was 29 years with a peak age occurrence in the third decade. Fibroadenoma (FA) was the most common benign breast tumor followed by fibrocystic change and they accounted for 47.1% and 25.4% of benign breast tumors with mean age of 24.7 years and 33.4 years, respectively. FA has a peak occurrence in the third decade while fibrocystic change has a peak occurrence in the fourth decade. Other major tumors encountered were tubular adenoma (6.0%), lactating adenoma (5.6%), benign phyllodes (4.8%), sclerosing adenoma (3.3%), and blunt duct adenoma (2.5%). Gynecomastia (1.4%) was the only benign breast tumor seen in males.Conclusions: Benign breast tumors are quite common, presenting mostly as FA and fibrocystic change. The tumors are seen in both sexes with a striking female preponderance and occurred predominantly in young females with a peak in the third decade. The findings are generally similar to the most previous studies from Nigeria, Africa, and the Western world with minimal variations.
Keywords: Benign, breast, fibroadenoma, Nigeria, tumors
|How to cite this article:|
Imam MI, Solomon R, Yusuf I. Benign tumors of the breast in Kano, Northern Nigeria: A 10-year experience and review of literature. Sahel Med J 2016;19:137-41
|How to cite this URL:|
Imam MI, Solomon R, Yusuf I. Benign tumors of the breast in Kano, Northern Nigeria: A 10-year experience and review of literature. Sahel Med J [serial online] 2016 [cited 2019 Aug 23];19:137-41. Available from: http://www.smjonline.org/text.asp?2016/19/3/137/192397
| Introduction|| |
Breast tumors are commonly seen in clinical practice worldwide among females of various age groups, and less frequently in men. Benign breast tumors usually outnumber malignant subtypes by a wide margin and account for 90% of clinical cases. The incidence of benign breast tumors begins to rise in the second decade of life and peaks in the third and fourth decades. The most common symptoms are pain and palpable lumps. Diagnosis of benign breast tumors can be made by the use of mammography, ultrasound, magnetic resonance imaging, fine needle aspiration, and by incision or excision biopsies. Fibroadenoma (FA) is found most frequently in young women and together with fibrocystic change are the two main benign diseases of the breast most commonly encountered. Though some studies have been conducted on benign breast tumors in Nigeria, including a previous study carried out in our center a decade ago, there is still need for further studies to determine the changing trends, if any, in the incidence and histopathological pattern of this lesion. It is, with these in mind that we undertook this review of benign tumors of the breast and to establish a basis for further studies.
| Materials and Methods|| |
This is a retrospective study of all benign breast tumors that were histologically diagnosed in the Pathology Department of a teaching hospital over a 10-year period from January 1 2001 to December 31 2010. Laboratory request forms and duplicate copies of histology reports of all cases diagnosed as benign breast tumor 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 were utilized where necessary, and the slides were then reviewed. The tumors were classified into histogenetic groups according to 2005, World Health Organization, International Classification of breast tumors. The results were then analyzed and presented using relative frequency tables.
| Results|| |
A total of 1566 breast tumors were diagnosed in the histopathology laboratory of our center from January 1 2001 to December 31 2010 (10 years). One thousand and thirty-five (66.3%) of the breast specimens were benign tumors, and these formed the basis of this study. The ratio of benign to malignant breast tumors was thus approximately 2:1. Of the benign tumors, 1,021 (98.6%) were from female patients while 14 (1.4%) were from male patients.
Of the benign cases, there were 487 (47.1%) patients with FA, 263 (25.4%) with fibrocystic change, 62 (6.0%) tubular adenoma (TA), 58 (5.6%) lactating adenoma (LA), 34 (3.3%) with sclerosing adenosis (SA), 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 [Figure 1]. The remaining 43 patients had a variety of pathological diagnoses as shown in [Table 1].
|Figure 1: Pie chart showing the histopathologic distribution of benign breast tumors. FA: Fibroadenoma; CYS: Fibrocystic change; LA: Lactating adenoma; SA: Sclerosing adenosis; TA: Tubular adenoma; BP: Benign phyllodes; GYN: Gynecomastia; BDA: Blunt duct adenoma; DP: Ductal papilloma|
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|Table 1: Age distribution of benign breast tumors according to histological subtype|
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The overall mean age for benign breast tumors was 29.0 years, with a wide age range of 13–63 years, and a peak age occurrence in the third decade (432 [41.7%] cases).
The mean age of patients with FA, which was the most common benign breast tumor was 22.4 years with a range of 13–59 years. Eighty-seven percent of patients with FA presented before the age of 30 years with majority presenting in the 21–30 year age range [Table 1]. Fibrocystic change, the second most common lesion, accounted for 263 (25.4%) cases with a mean age of 33.6 years, age range of 17–67 years, and a peak incidence in the fourth decade. TA occurred predominantly in the second decade with a mean age of 23.8 years.
Gynecomastia, which was the only benign tumor in males, constituted 14 (1.4%) benign cases. The age range of patients with gynecomastia was 32–53 years, with a mean of 44.2 years, and a peak in the fifth decade [Table 1].
| Discussion|| |
Breast tumors are very common and in most studies within and outside of 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 lower than 73% earlier reported study in our center, a decade ago. The observed preponderance of benign tumors over malignant varieties is in consonance with findings from Hong Kong, and Afro-Caribbean  where 89.1% and 80% 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.
The mean age of patients seen with benign tumors in this study was 29 years and 65.0% of them were in the age group of 21–40 years with peak incidence (41.7%) in the age group of 21–30 years. These results are consistent with the study by Otu  in which majority of the patients were below the age of 30 years. Reports from Zaria, Ilesha, Gombe, and Calabar  in Nigeria also found the highest proportion of cases being below the age of 40 years.
Of the benign tumors, FA was found to be the most common variant accounting for 487 (47.1%) cases and was most commonly seen (56.5%) in patients within the third decade of life. A similar preponderance of FA among benign tumors of the breast was also reported in other studies from Ghana  and Kenya. This finding is also similar to the reports from Zaria, Ilesha, Gombe, Ife, and Calabar  but contrasts with the findings from Ibadan, and among Caucasians, where fibrocystic change was reported to be the most common benign breast lesion. In a previous study, carried out in our center a decade ago, the fibrocystic change was also reported as the most common benign histological lesion comprising 34.3% of all cases. FA of the male breast is extremely rare and no case was found in this study.
Fibrocystic change was the second most common benign breast lesion (25.4%) seen in this study and the vast majority of the patients (48.3%) with fibrocystic change were in the fourth decade. This is in consonance with several studies done in Saudi Arabia, India, Nepal, Kenya, and Benin, where fibrocystic change was found to be second in frequency to FA. This pattern is the reverse of what has been found in the United States of America, and Pakistan  where fibrocystic change was more common than FA.
Fibrocystic change is an important breast lesion because of its high frequency (second to FA in this study) and the ability of some of its subtypes to mimic the clinical and radiographic appearance of carcinoma. Hormones also play a role in its development, but the exact pathogenesis still remains to be established.
Phyllodes tumor is said to be a rare fibroepithelial tumor, which account for <1% of all breast neoplasms. This study, however, found it to account for 4.8% of the breast biopsies performed.
Duct papilloma was seen in only 1.0% of cases in this study. Khanzada et al. reported 4.7% frequency within three years in Pakistan, while Mc Farlane  in Jamaica reported 6.7% over a 2-year period. This finding is comparable to 0.6% in Ibadan, but is lower than 1.7% and 2.8% reported in Ife  and Makurdi, respectively. LA which occurred in 5.6% of patients clustered around the reproductive age group, and is comparable to 5.2% and 3.3% reported in Makurdi  and Ife, respectively, but is higher than 1.6% documented in Zaria.
Gynecomastia was the only benign breast tumor recorded in males in this study. It constituted 1.4% of all the benign tumors demonstrating a decline in frequency when compared to 6% reported, a decade ago in our center. This finding is lower than 4.9%, 1.9%, 2.4%, and 3.4% recorded in Zaria, Ibadan, Makurdi, and Ife, respectively. The incidence of this disease in Nigerian male patients compares well with the 1% quoted in Caucasian series  but is lower than the 12% reported in Uganda. The mean age of 42 years found in our study is slightly at variance with most published reviews, which report a bimodal age distribution at puberty/adolescence and in the elderly. This study also found only 3 cases of adolescents with gynecomastia which may be attributed to the fact that this is a referral hospital-based study and figures quoted may not be a true reflection of the relative incidence of gynecomastia in adolescents in our environment.
Our study also found 62 (6.0%) cases of TA, which is comparable to the finding in Ife, but is higher than 2.4% recorded in Zaria. SA accounted for 34 (3.3%) cases which is lower than 4.5% reported in Ibadan, and is higher than 1.4% documented in Zaria. Lipoma constituted 0.7% of all the benign cases seen, which is consistent with 1% and 0.6% seen in Afro-Caribbean  and Ibadan, respectively. Other rare benign breast tumors observed include granular cell tumor (0.9%) and schwannoma (0.5%).
Finally, there is a glaring increase in the frequency of benign breast tumors in our center. An earlier study  averages 32 cases of such tumors recorded annually, but the index study revealed a significant increase in the relative frequency to 104 cases per annum. However, heightened awareness among women and enlightenment drives may have contributed to the increase in the frequency of presentation and diagnosis.
| Conclusion|| |
The results of this study have shown that the prevalence of benign breast tumors was on the increase, and are the common problems in the females of reproductive age group. The tumors were mostly FA and fibrocystic change occurring in young females with a peak in the second and third decades, respectively. Gynecomastia, the only benign breast tumor in males seen in this study constituted 1.4% of all the benign tumors. Routine mammographic screening of high-risk groups, aimed at early detection of the premalignant lesions, is highly indicated. It is also advised that histologic assessment of all breast lumps should be routinely done to evaluate the possibility of malignancy.
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Conflicts of interest
There are no conflicts of interest.
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