Recurrent Calcifying Aponeurotic Fibroma: A Potential Relapse with Early Onset

Summary: Calcifying Aponeurotic Fibroma (CAF) is a rare, benign soft tissue tumor predominantly occurring in the extremities of young individuals. It features fibromatosis-like and chondroid components with calcifications and has an unpredictable recurrence potential. Here, we report a recurrent CAF case in a 4-year-old girl presenting with a 1.5 cm painless, progressively enlarging soft tissue mass on the palmar aspect of her right hand. On examination, the lesion was well-defined, mobile, and non-tender. The mass was surgically excised. Microscopic evaluation showed an infiltrative fibromatosis-like component with nodular hyalinized/chondroid areas and central calcifications. The absence of nuclear atypia or significant mitotic activity confirmed the tumor's benign nature. Immunohistochemistry revealed vimentin positivity and focal SMA expression, suggesting fibroblastic differentiation. S100 positivity in chondroid regions supported the CAF diagnosis, while CD34 and panCK negativity excluded other soft tissue tumors. Despite complete surgical excision, the tumor recurred locally two years later. The recurrence of CAF remains unpredictable, and it is crucial to closely monitor young patients under 5 years of age for potential relapses. Regular monitoring ensures timely detection and management of relapses to optimize outcomes.