Metastatic proximal-type epithelioid sarcoma presenting as a chest lesion with a pathological fracture of the humeral neck

Abstract

Introduction: Proximal-type epithelioid sarcoma is a rare soft tissue neoplasm which occurs mostly in young males and is much rarer than classic distal sub type. A young male, with a known diagnosis of neurofibromatosis type 1 (NF1) presenting with metastatic proximal-type epithelioid sarcoma is reported. Case Report: A 30-year-old male with known NF1, hypothyroidism, epilepsy, presented with a right shoulder pain of two weeks duration. Plain radiographs revealed an expansile lytic lesion, an aggressive periosteal reaction in right humeral head with an underlying pathological fracture. A well-defined extrapulmonary mass with a lobulated margin in upper zone of right hemithorax with inferior rib erosion of 3rd rib and the 3rd intercostal space widening were also observed. Contrast-enhanced computed tomography (CECT) chest and abdomen confirmed peripherally located poorly enhancing soft tissue mass with lobulated margins arising from posterior chest wall along with a subdiaphragmatic deposit. Multiple lytic lesions in right head of humerus with an underlying pathological fracture of surgical neck, T2, T6, and L3 vertebral bodies, and pelvic bones were observed too. Diagnosis of malignant peripheral nerve sheath tumor with metastases was made and ultrasound-guided biopsy of chest wall lesion was performed. Histology and immunohistochemistry (IHC) revealed a proximal type epithelioid sarcoma. The patient was managed with palliative surgery and oncological follow-up. Conclusion: Presentation of proximal-type epithelioid sarcoma with disseminated metastases in a patient with NF1 masquerading malignant peripheral nerve sheath tumor (MPNST) and the challenges of diagnosis on clinical, radiological, and histopathology as well as IHC perspectives of this rare disease entity is highlighted.