DOI: https://doi.org/10.36347/sjmcr.2026.v14i05.097

Pages: 1266-1270

Background: Desmoid-type fibromatosis (DTF) is a rare, locally aggressive but non-metastasizing soft tissue tumor arising from musculoaponeurotic structures. Its occurrence in the foot is exceedingly uncommon, and its varied imaging appearance frequently poses diagnostic difficulties. Case Presentation: We report the case of a 47-year-old woman with no relevant medical history who presented with a painless swelling of the left foot evolving over several years. Magnetic resonance imaging (MRI) revealed an intra- and supra-aponeurotic mass tracking through the inter-metatarsal spaces, measuring approximately 85 mm in its greatest dimension, demonstrating low signal on T1-weighted sequences, heterogeneous signal on T2-weighted sequences, hyperintensity on STIR sequences, and avid enhancement following gadolinium administration. The initial differential diagnosis included synovial sarcoma and Morton's neuroma. Biopsy followed by surgical excision confirmed the diagnosis of desmoid-type fibromatosis on histopathological examination. The postoperative course was notable for local recurrence, without radiological evidence of aggressive behavior. Conclusion: DTF of the foot is a rare entity with non-specific imaging features that can mimic more aggressive tumors. A thorough histopathological analysis is mandatory for definitive diagnosis. Given its propensity for local recurrence despite negative surgical margins, long-term follow-up is essential. This case highlights the importance of including desmoid fibromatosis in the differential diagnosis of soft tissue foot masses.