Fine-needle aspiration cytology of giant cell fibroblastoma: case report and review of the literature.

Giant cell fibroblastoma is an uncommon soft tissue neoplasm occurring in childhood. It appears to be the juvenile form of dermatofibrosarcoma protuberans, with which it shares some histologic, cytogenetic, and immunohistochemical features. We report, to our knowledge, the second description of the cytologic features of giant cell fibroblastoma. The present case represents a recurrent lesion in the soft tissues of the scrotum of a 17-yr-old male. The aspirate produced moderately cellular smears containing mononuclear cells, usually lying singly, but occasionally forming clusters. The majority of the individual cells possessed scanty bipolar cytoplasm or were devoid of cytoplasm. The nuclei were bland, with small nucleoli. Nuclear membranes frequently contained notches, creases, or folds. Small fragments of metachromatic stroma were present in the background and were often associated with small aggregates of cells. Rare multinucleated giant cells containing bland oval or basillary-shaped nuclei were admixed with the spindle-cell component. Necrosis and mitotic figures were not a component of the smears. Surgical resection of the mass confirmed the diagnosis of giant cell fibroblastoma. We review the characteristic cytologic features of giant cell fibroblastoma and compare them with other soft tissue tumors in the differential diagnosis. Copyright 2002 Wiley-Liss, Inc.