Fine needle aspiration cytology findings of myxoinflammatory fibroblastic sarcoma: A case report.

Myxoinflammatory fibroblastic sarcoma (MIFS) is rare low-grade soft-tissue tumor that occurs in extremities. Clinically it is difficult to differentiate from benign lesions, such as nodular fasciitis, and malignant tumors, such as liposarcoma. We report a case of MIFS in the forearm of a 34-year-old man. The resected tumor measured 5.3 × 2.7 × 2.5 cm3 , had a lobular structure with indistinct boundary, and consisted of a large amount of translucent and yellow mucous-like substrate. Cytological examination of a preoperative puncture aspiration specimen showed histiocyte- and fibroblast-like tumor cells in a mucous-like matrix together with scattered lipoblast- and ganglion-like cells. Nuclear chromatin of the tumor cells showed a fine granular appearance but no notable hyperchromasia. There were no clear malignant findings. On Giemsa staining of the tumor cells, there were fine granular and hyaline intracytoplasmic substances that showed purple to reddish-purple metachromaticity. Prominent inflammatory cells were not observed in the specimens. MIFS should be considered in the differential diagnosis for a myxoid tumor in the extremities.