Mammary myofibroblastoma of the male breast: a case report and literature review.

Mammary myofibroblastoma (MFB) is a rare benign spindle cell tumour predominantly affecting males, but also observed in postmenopausal females. Its diagnosis remains challenging owing to overlapping histological features with malignant lesions and limited tissue sampling in core biopsies. We present a case of incidentally discovered mammary MFB in a 63-year-old man and review its clinical, radiological and histopathological characteristics. The patient, who had a history of distal pancreatectomy and splenectomy, presented with an incidental left anterior chest wall nodule discovered on computed tomography scan. Clinical examination revealed a benign left retroareolar lump, confirmed by breast ultrasound and mammography. Ultrasound-guided core biopsy demonstrated characteristic spindle cells, prompting immunohistochemical staining confirming the diagnosis of MFB. The lesion was surgically excised with clear margins. Mammary MFB is commonly seen in postmenopausal women and older men, presenting as painless, mobile breast lumps. Imaging findings are nonspecific, resembling fibroadenomas or fat necrosis. Histologically, MFB lacks mammary ducts or lobules and displays characteristic spindle cells with collagenous stroma. Immunohistochemistry aids in differentiating it from other spindle cell tumours. Surgical excision is curative, with no reported cases with recurrence. Mammary MFB should be considered in the differential diagnosis of breast masses in males and postmenopausal women. Despite the challenges in diagnosis, its benign nature and favourable prognosis warrant timely recognition and appropriate management through surgical excision. Further research is needed to establish clear management guidelines and explore its underlying pathogenesis.