When Nature Heals: A Case of Spontaneous Remission in Breast Desmoid Tumor

Desmoid tumors are rare mesenchymal neoplasms arising from musculoaponeurotic structures, which affects predominantly women. They are characterized by aggressive local invasion, with no metastatic potential but a high propensity for local recurrence. Imaging modalities such as ultrasound, CT, and MRI are essential for assessing local extension, guiding surgical planning, and monitoring for recurrence. Histological analysis remains the gold standard to confirm the diagnosis. Treatment options range from surgical resection to non-surgical approaches, including chemotherapy, radiotherapy, and hormonal therapy such as tamoxifen. Recent guidelines increasingly advocate for active surveillance as an initial strategy, particularly to minimize treatment-related morbidity, given the potential for spontaneous regression in some cases. We report the case of a 73-year-old woman who presented with a palpable mass in the left breast, exhibiting some suspicious features on Ultrasound. Histological analysis confirmed the diagnosis of mammary fibromatosis. Surgical resection was initially performed, and the Follow-up imaging with CT and MRI later demonstrated a local recurrence with infiltration of adjacent structures. The case was reviewed in a multidisciplinary tumor board [MDT], where a decision was made to pursue active surveillance. Remarkably, MRI follow-up after three months revealed spontaneous regression of the recurrent soft tissue mass.