Myxofibrosarcoma: cytomorphologic findings and differential diagnosis on fine needle aspiration.

OBJECTIVE To analyze the cytomorphologic findings of myxofibrosarcoma (MFS) on fine needle aspiration (FNA) and examine the differential diagnoses. STUDY DESIGN A retrospective review was undertaken of material from 22 patients with an FNA procedure of their tumor prior to resection. A tally was performed of all the features known in the literature, including myxoid matrix, spindle cells, nuclear pleomorphism, curvilinear vessels, and multinucleated cells. A review of the literature was also performed to elucidate any advances in the use of morphology and other modalities to deconvolute the challenging differential diagnosis. Clinicoradiologic characteristics and immunostaining were also analyzed and correlated. RESULTS FNA diagnoses included high-grade sarcoma (32%), recurrent MFS (23%), spindle cell neoplasm (18%), indeterminate-grade sarcoma (14%), low-grade sarcoma (9%), and pleomorphic adenoma (4%). Of the cases available for morphologic review, myxoid matrix was the most frequent observation (88%), followed by spindle cells (82%), nuclear pleomorphism (76%), multinucleated cells (71%), and curvilinear vessels (65%). Myxoid matrix, spindle cells, and nuclear pleomorphism were very often concomitant observations. CONCLUSION MFS demonstrates characteristic albeit nonspecific morphological findings and can overlap morphologically with other clinically significant entities based on FNA material.