Intramammary schwannoma: a palpable breast mass

Schwannomas are benign tumors arising from the peripheral nerve sheath, commonly occurring in the head, neck, and extensor surfaces of the extremities. They can be associated with neurofibromatosis type II. Our case describes a 48-year-old woman with a 2-week history of a left-sided palpable breast mass. She was referred to radiology, where additional imaging revealed a 1.1-cm mass. A biopsy was performed; histology revealed an intramammary schwannoma. Mammography findings include a well-defined mass without calcification. Ultrasound images have shown hypoechoic, encapsulated, and well-defined lesions without calcification. Histologically, schwannomas reveal alternating Antoni A and Antoni B cellular areas. Schwannomas are also S100-positive on immunohistochemistry. This case is best categorized as a BI-RADS 4A lesions. This case report highlights the importance of both imaging and pathology in the diagnosis of breast neoplasms. Although breast schwannomas are not a common entity, they are an important consideration when evaluating a breast mass.