Pleural desmoid tumor mimicking a myofibroblastic neoplasm: Imaging-pathologic correlation

Desmoid tumors are rare, locally aggressive soft-tissue neoplasms that may present a diagnostic challenge due to overlapping imaging and histopathologic features with other myofibroblastic lesions. We report the case of a 41-year-old woman presenting with a 2-year history of right-sided chest pain and progressive numbness of the right upper extremity. Contrast-enhanced computed tomography (CT) demonstrated a large pleural-based mass with chest wall extension. Initial biopsy suggested an inflammatory myofibroblastic tumor; however, further characterization with magnetic resonance imaging (MRI) and subsequent surgical resection were performed. Definitive diagnosis was established by histopathologic and immunohistochemical analysis, confirming desmoid-type fibromatosis. Despite partial symptom improvement after surgery, follow-up imaging at 30 months demonstrated persistent soft-tissue involvement at the thoracic inlet with tumor progression, correlating with ongoing neurologic symptoms. This case highlights the importance of radiologic–pathologic correlation for accurate diagnosis and emphasizes the locally aggressive behavior and recurrence potential of pleural desmoid tumors, particularly when critical structures are involved.