Pseudomyogenic hemangioendothelioma (involving skin, bone and soft tissue): a case report with long-term follow-up and review of literature.

INTRODUCTION: Pseudomyogenic hemangioendothelioma is rare, usually indolent vascular tumor characterized immunohistochemically by SERPINE1-FOSB fusion, presenting as multiple bone and soft tissue lesions, affecting males in their 3rd-4th decades. CASE PRESENTATION: We present the case of a 28-years-old male patient with the history of pain in the left lower extremity hindering him in the daily activities. Radiological examinations showed well-defined lytic lesions of the femur, patella, tibia, fibula, talus and calcaneus with low metabolic activity on PET-scan. MR revealed multiple soft tissue involvements of the affected extremity. Multiple skin lesions were located on the extensor surface of the leg. Molecular analysis confirmed the pathognomonic gene fusion. Patient was treated with epirubicin as an eight-cycle locoregional intraarterial monotherapy, achieving clinical control of the disease and substantial improvement in complaints for over 10 years. The patient's complaints decreased substantially, his bony lesions, however, are persisting for over ten years of his follow-up. DISCUSSION: The molecular characteristics and differential diagnostics of the disease is well known, however, due to the rarity of the disease, the wide array of treatment methods and short-term follow-up intervals, there is still no consensus over the most efficient treatment plan. Many chemotherapeutic agents and treatment regimens were utilized throughout the literature, with acceptable outcomes as far as reported but self-limiting character and spontaneous regression of the disease have also been described according to our experience during the very long follow-up period of our patient.