Aggressive Fibromatosis of the Chest Wall: A Case Report with Magnetic Resonance Imaging and Histopathological Findings

Summary

A 25-year-old female patient was admitted to the hospital with complaint of right breast swelling. Physical examination revealed a hard palpable mass in the right breast that was affixed to the chest wall. The patient had undergone right mastectomy for a 2x3.5 cm mass with a histopathological diagnosis of Aggressive fibromatosis (AF) approximately 3 years ago. Contrast enhanced and non-contrast-enhanced MRI of the breast and thorax were performed for the new palpable breast mass and they revealed a 6x9 cm irregular-shaped mass with irregular margins extending into the right breast. The mass was isointense on T1-weighted images (T1-WI) and hyperintense on fat-suppressed T2-WI. MRI demonstrated invasion of the pectoral and intercostal muscles and the ribs. Fine needle aspiration biopsy was performed. Microscopically, the tumor was composed of fibroblastic spindle-shaped cells embedded in abundant collagenous tissue without epithelial components. The tumor cells were immunoreactive for smooth muscle actin and negative for desmin, CD34, and S100. This phenotype was consistent with the diagnosis of fibromatosis. Based on these findings, radiotherapy was recommended first and then a wide surgical excision was decided.