PULMONARY EPITHELIOID HEMANGIOENDOTHELIOMA: A RARE ENTITY WITH INSIDIOUS ONSET

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Sarcomas are rare, malignant tumors of connective tissue origin. Epithelioid hemangioendothelioma (EHE) is an exceedingly rare vascular sarcoma of endothelial origin, with an incidence of less than one per one million. Patients are typically asymptomatic or manifest symptoms related to organ involvement. We present a case of an asymptomatic woman with an incidental discovery of pulmonary EHE. CASE PRESENTATION: A 26 year old woman with no smoking history presented with vague abdominal pain. Her exam and initial labs were unremarkable. Abdominal imaging revealed nodules at the lung bases, and subsequent thoracic imaging revealed innumerable nodules throughout the lung parenchyma without pleural involvement. CT-guided transthoracic biopsy revealed filling and distension of alveolar spaces by a neoplastic proliferation of small, bland cells with perinuclear vacuoles within a hyalinized stroma. Immunohistochemical staining showed the neoplastic cells to be positive for ERG and CD31. These imaging and pathology findings were consistent with stage IV metastatic pulmonary EHE. She was referred to a sarcoma center of excellence, and surveillance was recommended. DISCUSSION: EHE is a vascular subtype of sarcoma of low-grade malignancy most commonly involving the liver and lungs. Pulmonary EHE can be asymptomatic or present with non-specific symptoms of dyspnea, cough, hemoptysis, or weight loss. Diagnosis is made with histopathologic epithelioid morphology and immunohistochemical vascular characteristics. Our patient's biopsy tissue stained positive for markers of vascular differentiation. CD34 and Factor VIII-related antigen are additional markers that may be used to identify vascular features of EHE. Disease course is unpredictable, and factors associated with a poor prognosis include pleural effusion and hemoptysis. Disease rarity precludes established treatment guidelines. Surgical resection should be considered for solitary lesions. Past reports have shown some responsiveness to taxane, anthracycline, or IFN-2a therapy. Anti-VEGF therapies show promise for eliciting partial response or as maintenance therapy. Still, many cases are indolent and a surveillance strategy may be reasonable. In our patient, surveillance was supported by her asymptomatic disease without poor prognostic factors. The development of significant symptoms or progressive disease would prompt further consideration of treatment. CONCLUSIONS: EHE is an extremely rare sarcoma subtype most commonly affecting the liver or lungs. Diagnosis is made on immunohistopathology and treatment options include surgical resection, surveillance, or anti-angiogenic agents. It is an important, albeit uncommon diagnosis to consider for diffuse pulmonary nodules seen on imaging. REFERENCE #1: Semenisty V, Naroditsky I, Keidar Z, Bar-Sela G. Pazopanib for metastatic pulmonary epithelioid hemangioendothelioma—a suitable treatment option: case report and review of anti-angiogenic treatment options. BMC Cancer. 2015;15(1):402. doi:10.1186/s12885-015-1395-6 REFERENCE #2: Chevreau C, Le Cesne A, Ray-Coquard I, et al. Sorafenib in patients with progressive epithelioid hemangioendothelioma: A phase 2 study by the French Sarcoma Group (GSF/GETO). Cancer. 2013;119(14):2639-2644. doi:10.1002/cncr.28109 REFERENCE #3: Agulnik M, Yarber JL, Okuno SH, et al. An open-label, multicenter, phase II study of bevacizumab for the treatment of angiosarcoma and epithelioid hemangioendotheliomas. Ann Oncol. 2013;24(1):257-263. doi:10.1093/annonc/mds237 DISCLOSURES: No relevant relationships by Mohammad Ahmed, source=Web Response No relevant relationships by Gustavo Cumbo-Nacheli, source=Web Response No relevant relationships by Connor Kerndt, source=Web Response No relevant relationships by Ranuka Sinniah, source=Web Response