Infantile myofibroma in a prematurely born twin: a case report

Infantile myofibromatosis is a rare benign tumor of infancy and childhood that occurs in solitary, multiple, and generalized forms with similar histology but different clinicopathologic and prognostic implications. Even solitary tumors need follow-up, as the type of presentation will be determined over time. It is necessary to differentiate this entity from other more aggressive tumors, especially rhabdomyosarcoma, which is treated by chemotherapy prior to excision. We describe a prematurely born twin girl who had at birth a solitary tumor of the cervicoscapular region, involving the dermis and subcutis. A fine-needle aspiration biopsy (FNAB) specimen obtained soon after her birth suggested a diagnosis of benign neoplasm. The tumor was excised 1 month later, at which time it was significantly enlarged, ulcerated, and also exhibited worrisome histologic features including mitoses and infiltrative growth. It had the characteristic histologic pattern of infantile myofibromatosis, and myofibroblastic features of tumor cells were confirmed immunohistochemically and ultrastructurally. During the follow-up period of 39 months, there was no sign of recurrence or new tumors.