Infantile myofibromatosis: diagnosis suggested by fine-needle aspiration biopsy

A newborn male infant presented with multiple subcutaneous and parenchymal lesions. These lesions, thought clinically to represent disseminated neuroblastoma, were assessed via fine-needle aspiration biopsy. The spindled cells and associated collagen were interpreted as a type of fibromatosis, most probably infantile myofibromatosis. This diagnosis was subsequently confirmed histologically, and the patient experienced spontaneous involution or regression of all lesions by 18 mo of age. To our knowledge, this is the first documented case of this entity initially suggested on the basis of a fine-needle aspiration biopsy specimen.