Diagnosis of sternomastoid tumor of infancy by fine-needle aspiration cytology.

Sternomastoid tumor of infancy, also known as fibromatosis colli or muscular torticollis, is a benign fibroblastic lesion of the sternocleidomastoid muscle presenting as a firm, fusiform, non-tender neck mass of 1-3 cm in greatest dimension in the perinatal period. Various modalities are used for the diagnosis including radiographic studies, fine-needle aspiration cytology (FNAC), and open biopsy. We report eight cases of sternomastoid tumor of infancy diagnosed by FNAC. The objective of the study is to present the role of FNAC in the diagnosis of sternomastoid tumor with its cytomorphological features. FNA was done by using 23-guage needle and 10 ml disposable plastic syringe. The wet smears were fixed in 95% ethanol and processed for Papanicolaou stain. The dried smears were stained with May-Grünwald-Giemsa stain. The smears were studied for cytomorphologic features. The age of the patients ranged between 2 and 10 weeks. Male: Female ratio was 1.6:1. Six of eight had history of prolonged labor, two had history of breech presentation, and three had history of forceps assisted vaginal delivery. Cytologic findings included singly scattered and loose clusters of benign fibroblasts with moderate amount of unipolar to bipolar cytoplasm and plumped, ovoid nuclei. Many multinucleated giant cells consistent with atrophic muscle fibers were also seen. FNAC is a reliable, safe, and cost-effective method and can provide a rapid and reliable diagnosis of sternomastoid tumor of infancy.