Composite Hemangioendothelioma with Concurrent Pyoderma Gangrenosum Treated with Pazopanib: A Case Report

A 40-year-old man with an eight-year history of a cutaneous mass complicated by subsequent pyoderma gangrenosum developed systemic disease. Pleural fluid cytology initially suggested pleural mesothelioma (PM), whereas a subsequent subcutaneous biopsy was interpreted as epithelioid hemangioendothelioma (EHE). Through a retrospective re-evaluation of previous skin specimens and comparison with current pathological findings, a final diagnosis of composite hemangioendothelioma (CHE) was established. Pazopanib (PAZ) achieved radiologically stable disease for five months; however, he died of progressive respiratory failure. This case highlights the diagnostic challenges of extremely rare CHE and suggests that PAZ may have a limited therapeutic impact on advanced CHE with malignant pleural effusions.