A rare case report of epithelioid hemangioendothelioma of the left buttock: Challenges in diagnosis and management.

Rationale: Epithelioid hemangioendothelioma (EHE) is a rare vascular malignancy which poses significant diagnostic and therapeutic challenges due to its variable course and lack of standardized treatment protocols. In this case, the lesion's benign appearance and ambiguous histology delayed definitive diagnosis.

Patient Concerns: A 46-year-old woman presented with a recurrent soft tissue mass in the left buttock. Initial impression with partial biopsy favored a benign neoplasm, complicating the diagnosis.

Diagnoses: Histopathological examination confirmed EHE, characterized by epithelioid endothelial cells and positive immunohistochemical staining for vascular markers.

Interventions: Complete surgical resection was performed, with no adjuvant therapy administered postoperatively.

Outcomes: Surveillance over 24 months revealed no evidence of local recurrence or distant metastasis. Follow-up computed tomography on 18 month revealed no evidence of recurrence.

Lessons: Comprehensive histopathological evaluation are critical for proper diagnosis of EHE. Surgical resection is the first line treatment for localized EHE. Long-term monitoring is essential due to the unpredictable metastatic potential.