DOI: https://doi.org/10.36347/sasjs.2026.v12i05.018

Pages: 430-434

Background: Myolipoma of soft tissue is a rare benign mesenchymal neoplasm composed of an admixture of mature adipocytes and well-differentiated smooth muscle cells. It presents a significant diagnostic challenge owing to its nonspecific clinical and radiological features, which often overlap with those of malignant neoplasms such as well-differentiated liposarcoma. Intramuscular or intradeltoid localization is exceptionally uncommon, with very few cases documented in the literature. Case Presentation: A 52-year-old man presented with a slowly enlarging, painless mass in the right shoulder region. MRI demonstrated a well-circumscribed, oval lesion within the deltoid muscle measuring 17 × 25 × 34 mm, exhibiting homogeneous high signal on T1- and T2-weighted sequences with complete fat suppression, consistent with a lipomatous tumor. The mass was surgically excised. Histopathological examination confirmed a myolipoma: mature adipocytes intermingled with benign smooth muscle fibers, without atypia or mitotic figures. Conclusion: Intradeltoid myolipoma is a rare entity whose MRI characteristics closely mimic those of a simple lipoma. Complete surgical excision is both diagnostic and curative. Awareness of this entity is essential to avoid misdiagnosis and inappropriate management.