Fibromatosis colli in infants. A cytologic study of eight cases

OBJECTIVE: To review eight cases of fibromatosis colli and assess their cytomorphologic features. STUDY DESIGN: Cytologic smears from eight patients diagnosed as having fibromatosis colli on fine needle aspiration cytology were reviewed. RESULTS: Cytologic features of fibromatosis colli are bland-appearing fibroblasts and degenerative atrophic skeletal muscle in a clean background. Besides these, we found a large number of muscle giant cells; numerous bland, bare nuclei; and parallel clusters of fibroblasts. Collagen was seen in all cases. CONCLUSION: A confirmatory, noninvasive diagnosis of fibromatosis colli can be made by fine needle aspiration cytology alone; invasive diagnostic and therapeutic measures are best avoided. Excision biopsy may not be necessary and should be reserved for cases with a strong clinicopathologic suspicion of malignancy.