Pseudomyogenic hemangioendothelioma: A misleading vascular tumor

INTRODUCTION: Pseudomyogenic hemangioendothelioma (PHE) is a rare vascular soft tissue tumor of intermediate malignancy. The aim of this study was to present a rare case of PHE in the back and to review its clinicopathological features, therapeutic modalities, evolutionary aspects and prognosis. CASE PRESENTATION: We report the case of a 21-year-old man who consulted for a multinodular mass at the scapula level, that increased in size within 2 months. An excisional surgery was performed. Macroscopic examination showed ulcerated centimetric nodules with a crusty surface. Microscopic examination showed a multinodular proliferation arranged in clusters, made of spindle cells or epithelioid cells with variable atypia. Immunohistochemical study showed the expression ofAE1-AE3, ERG and INI-1. There was no staining for EMA, CD34, and CD-31. The diagnosis of PHE was retained. DISCUSSION: PHE affects young adult males and usually develops in the extremities. Clinically, more than half of the patients present with local recurrence. Distant metastases have also been reported. Microscopically, PHE resembles a myoid tumor or epithelioid sarcoma because of the abundant eosinophilic cytoplasm and cell shape. Tumor cells express cytokeratin and inconsistently CD34 and CD31. Hence the need to complete the study of ERG and INI1 expression in all soft tissue epithelioid tumors. The translocation t(7;19)(q22; q13) as well as the expression of FOSB in immunohistochemistry allow to differentiate with epithelioid sarcoma. Surgery is the treatment option. CONCLUSION: PHE is a confusing entity with several mesenchymal neoplasms that must be carefully differentiated. Data regarding age, sex, location, course, and recurrence are important for proper diagnosis.