Angioleiomyoma in the Palm: A Diagnostic Challenge

Angioleiomyoma is an uncommon benign vascular smooth muscle tumor, representing <1% of soft-tissue neoplasms in the upper extremity. Its rarity, variable symptoms, and nonspecific imaging features frequently lead to misdiagnosis, with lesions mimicking ganglion cysts, giant cell tumor of tendon sheath, schwannoma, leiomyosarcoma, or glomus tumor. Multidisciplinary radiology review plays a key role in evaluating such indeterminate hand masses. A 57-year-old male presented with a gradually enlarging, painless palmar swelling. Magnetic Resonance Imaging revealed a well-defined, heterogeneously T2-hyperintense subcutaneous lesion with intramuscular extension, tendon encasement, and involvement of the radial digital nerve—features that generated a broad differential at the institutional radiology conference. Surgical exploration showed an encapsulated tumor encasing several digital nerve fibers, which were repaired following en bloc excision. Histopathology demonstrated smooth muscle bundles around thick-walled vessels with myxoid change but no atypia. The presence of myxoid stroma and neurovascular encasement raised concern for neurogenic and other spindle-cell lesions, necessitating targeted immunohistochemistry (IHC). Smooth muscle actin and Desmin positivity with S-100 and Pan-TRK negativity confirmed angioleiomyoma. This case illustrates the diagnostic complexity of palmar angioleiomyoma, driven by clinical ambiguity, nondiagnostic imaging, myxoid stromal change, and unusual neurovascular involvement. Accurate diagnosis requires thoughtful integration of clinical, radiologic, intraoperative, and histopathologic findings. Focused IHC is essential to differentiate angioleiomyoma from its mimics and to guide appropriate management.