A correlative cytologic and histologic study of malignant fibrous histiocytoma: An analysis of 40 cases examined by fine-needle aspiration cytology

A correlative cytologic and histologic study of 40 cases of histologically highly pleomorphic malignant fibrous histiocytoma (MFH) is presented. The fine‐needle aspiration biopsy was performed preoperatively, and a diagnosis of malignant soft‐tissue tumor could be established in all cases. The cytologic and histologic features corresponded well with each other. The two main cell types were mono‐ and multinucleated, large polymorphic, often bizarre, histiocyte‐like cells and atypical fibroblast‐like cells. For a correct diagnosis of pleomorphic MFH, it is important to recognize atypical large polymorphic tumor cells showing signs of phagocytosis: prominent cytoplasmic vacuolization, cell debris or even well‐preserved cells within the tumor cell cytoplasm. Phagocytic activity was easily demonstrated in air‐dried and May‐Grünwald Giemsa‐stained material. The differential diagnosis of MFH as opposed to other soft‐tissue sarcomas and pleomorphic carcinomas is discussed. Diagn Cytopathol 1986;2:46‐54.