Cytological diagnostic clues in fine needle aspiration of breast myofibroblastoma: a case report.

Myofibroblastoma of the breast is a rare, benign mesenchymal tumor derived from the stroma and tends to occur mainly in middle-aged to elderly men. There are a few cases reported in the literature describing its cytological features. We report the cytological and histological findings of a breast myofibroblastoma in a 68-year-old man. He presented with a palpable nodule of 2-months duration in his left breast. The cytological smears obtained by fine needle aspiration showed less cohesive cellularity in a fascicular arrangement consisting of spindle cells with elongated cytoplasm, occasional nuclear grooves, and intranuclear cytoplasmic inclusions associated to fragments of stromal collagen. The cytological diagnosis was a mesenchymal proliferation suggesting the possibility of myofibroblastoma which was confirmed on histopathological examination. The breast myofibroblastoma has distinctive cytological features that in conjunction with the clinical and radiological data allow a specific diagnosis.