Myxofibrosarcoma: a correlative cytologic and histologic study of 13 cases examined by fine needle aspiration cytology.

A correlative cytologic and histologic study of 13 myxofibrosarcomas is presented. The myxofibrosarcomas were grouped histologically into four grades (I to IV) according to the degree of cellularity, atypica and prevalence of mitotic figures. Cytologically, the neoplasms exhibited two types of malignant cells: an elongated, spindle-shaped, fibroblast-like cell and a larger, histocyte-like cell, often embedded in myxoid material. Some aspirates contained small capillary-like fragments. The degree of cellular and nuclear polymorphism and the quantitative distribution between the two types of cells in the different grades corresponded to the histologic classification. The differential diagnosis between myxofibrosarcoma and other myxoid soft tissue neoplasms is discussed. Staining the aspirated material with Alcian blue at different pHs helps to distinguish between myxomatous mesenchymal neoplasms containing nonsulphated glucosaminoglycans, such as myxofibrosarcoma, and those containing sulphated ones, such as myxoid chondrosarcoma and chordoma.