Desmoid-Type Fibromatosis of the Male Breast Mimicking Breast Carcinoma: A case report
Authors: Dr. Quazi Tasfia
Institution: National Institute of Burn & Plastic Surgery
Introduction
Desmoid-type fibromatosis is a rare, locally infiltrative fibroblastic neoplasm with an estimated incidence of 5–6 cases per million people annually; breast involvement accounts for approximately 0.2–0.3% of breast tumours, and presentation in men is exceptionally uncommon. Its clinical and radiological features may mimic breast carcinoma, making preoperative diagnosis challenging. This is a case report of male breast desmoid-type fibromatosis that was initially suspected to be carcinoma and was later proved by core biopsy and post operative histopathology.
Methods
This is a case report of a 40-year old man who presented with history of progressively enlarging left breast swelling for last 8 months which was associated with occasional pain and got admitted in National Institute of Burn and Plastic Surgery, Dhaka, Bangladesh. All clinical findings, ultrasonographic assessment and postoperative histopathological findings were reviewed for the diagnosis and describe pathological characteristics of the lesion.
Results
Clinical examination revealed a 5 × 6 cm hard, irregular swelling with well-defined margins involving upper outer quadrant of the left breast. There was normal overlying skin, no discharge or retraction of nipples or palpable axillary lymphadenopathy. Based on the clinical features, left breast carcinoma was initially suspected. Ultrasonography of both breasts and axillae however indicated gynecomastia of left breast and fibromatosis was one of the few differential diagnoses. Core needle biopsy demonstrated fibromatosis. Hormonal investigations revealed elevated serum estrogen (161.94 pg/mL; laboratory upper reference limit 50 pg/mL) and low total testosterone (1.68 ng/mL; reference range 2.80–14.00 ng/mL). At the initial examination on 2 July 2024, the overlying skin was normal and the mass was free from the skin and underlying structures. Local excision was initially planned following the core biopsy diagnosis of fibromatosis. However, on the day of surgery, 20 July 2024, the overlying skin appeared inflamed, with skin fixation raising renewed suspicion of malignancy. Consequently, mastectomy with axillary sampling was performed. Histopathological examination revealed desmoid-type fibromatosis characterized by the presence of spindle cells grouped in long fascicles in a dense collagenous stroma. Atypia and mitotic activity were minimal in the cells and no necrosis was found. The tumour was present in the breast adipose tissue, but there was no tumour in the nipple and areola. Superior, inferior, medial and lateral resection margins were clear, whereas the deep margin was close at 1 mm. All 7 axillary lymph nodes had reactive changes, but no evidence of malignancy was seen in the deep resection margin. At the one-month postoperative follow-up, the patient was clinically well.
Conclusion
Desmoid-type fibromatosis should be considered in the differential diagnosis of suspicious male breast masses because it can clinically mimic carcinoma. Correlation of clinical findings, imaging and histopathology is essential for accurate diagnosis and appropriate management. Given its locally infiltrative behaviour and potential for recurrence, assessment of resection margins and appropriate postoperative follow-up are important.