A rare case of neonatal bilateral cervical fibromatosis coli diagnosed by fine needle aspiration cytology

Fibromatosis Coli or Sternomastoid Tumor also known as Pseudotumor of Infancy is a benign, rare fibroblastic lesion presenting in infants as neck swelling or mass. This benign tumor of uncertain etiopathogenesis usually appears in first two months of life and is one of the causes of congenital torticollis. On ultrasonography, a diagnosis of cervical lymphadenopathy was suggested. FNAC was performed from both the swellings and a diagnosis of Fibromatosis Coli was made based on these cytomorphological findings. Cytological findings of FC includes bland appearing mature fibroblasts and varying proportion of mature and immature skeletal muscle fibers in a clean background devoid of hemorrhage and necrosis. We present a case of one month old afebrile female infant, vaginally delivered at home, presented to the Pediatric OPD with bilateral neck swelling noticed by the mother 2 weeks following birth. FNAC is a rapid and useful tool in its diagnosis and management along with radiological investigations such as USG, CT, MRI.