A case of mammary myofibroblastoma diagnosed with cytomorphological, cell block and immunohistochemistry findings.

Myofibroblastoma (MFB) is a rare benign spindle cell tumor originating from myofibroblasts in the breast stroma. MFB typically presents as a slow-growing, well-circumscribed, solitary mass ranging from 1 to 4 cm in size. It has been reported in adults, and frequently seen in older males and in postmenopausal females. The lesion is composed of stromal cells showing fibroblastic and myofibroblastic differentiation at the morphological, immunohistochemical and ultrastructural levels. To date, the literature includes only about 24 MFB cases confirmed via fine-needle aspiration and cytological evaluation. Here, we present a patient with MFB that was diagnosed via conventional smear slides and cell block, in addition to immunohistochemical analysis.