Diagnosis of fibromatosis colli by fine needle aspiration (FNA) cytology.

This study presents eight cases of fibromatosis colli accurately diagnosed by FNA cytology. Fibromatosis colli is a rare fibroblastic lesion that manifests in the sternocleidomastoid muscle during the first to second months after birth. The tumours varied in size from 1 to 3 cm and engaged the lower, middle as well as the upper part of the sternocleidomastoid muscle. The FNA cytology smears showed mostly mature fibroblasts in a background of pink granular material and fragments of striated muscle fibres with degeneration. The cytological presentation together with the typical clinical setting will allow a definitive and accurate diagnosis, avoiding surgery.