A Rapidly Growing Desmoid Tumor of the Anterior Chest Wall in a Young Woman: A Case Report.

Desmoid tumors (DTs), or aggressive fibromatosis, are rare fibroblastic neoplasms of connective tissue origin. They are locally invasive with a high rate of recurrence, although metastasis is rare. Their clinical behavior varies widely, as some tumors exhibit progressive growth, while others remain stable or may spontaneously regress. Symptoms depend largely on tumor size and location. We present the case of a 25-year-old woman who developed a painful, enlarging mass in the right breast region over two months. Imaging revealed a 100 × 60 mm lesion involving intrathoracic structures and musculature, located posterior to a breast implant. Core needle biopsy confirmed an extra-abdominal DT of the anterior chest wall. Taking into account the symptom severity and rapid tumor progression, the patient underwent surgical resection with chest wall reconstruction using polypropylene mesh and titanium rib prostheses. Postoperative imaging showed complete resection, and the patient remained free of recurrence at two, four, and five years of follow-up. While conservative management with surveillance is increasingly recommended for stable DTs, surgery remains the primary treatment for symptomatic or fast-growing tumors, although new non-invasive methods are on the rise. Accurate diagnosis requires a combination of imaging and histopathological confirmation, and long-term follow-up is essential because of the risk of recurrence. This case highlights that early and complete surgical management, combined with appropriate reconstruction, can lead to favorable long-term outcomes and improved patient quality of life.