FINE-NEEDLE ASPIRATION BIOPSY OF FIBROMATOSES

Fibromatoses form a spectrum of clinicopathologic entities characteriz ed by the infiltrative proliferation of fibroblasts that lack malignan t cytologic features. Fibromatoses present as nodular soft tissue mass es almost anywhere in the body and thus are often amenable to fine nee dle aspiration (FNA). This report describes the FNA cytologic findings of fibromatosis in six patients ranging in age from 7 1/2 weeks to 36 years. Two of the lesions arose in the abdominal wall (musculoaponeur otic fibromatosis or extraabdominal desmoid), and one each involved th e plantar surface (Ledderhose's disease), the shoulder and the sternoc leidomastoid muscle (fibromatosis coli). The FNA of the shoulder was i nitially interpreted as nodular fasciitis due to the clinical presenta tion of a rapidly growing mass; an aspirate from the deep musculoapone urotic region was believed to reveal a low grade sarcoma. The FNA diag nosis of musculoaponeurotic fibromatosis in a patient with familial po lyposis coli suggested the diagnosis of Gardner's syndrome. Cytologica lly the aspirates consisted of groups of loosely cohesive, bland-appea ring, spindle-shaped cells having oval to elongated nuclei and cytopla smic tags. Individual spindle cells and rare inflammatory cells were a lso present. The aspirate of fibromatosis coli also contained degenera ting skeletal muscle cells. Tissue confirmation was obtained in four c ases. We believe that FNA is a useful procedure for the initial and re current diagnosis of fibromatoses and in the separation of fibromatose s from other benign and malignant soft tissue lesions. A discussion of other entities that enter into the cytologic differential diagnosis, such as mesenchymal repair, fasciitis and spindle cell types of sarcom a, is presented. From our experience we believe that the clinicopathol ogic features can suggest the diagnosis of fibromatosis, but histologi c confirmation is recommended.