Pulmonary tumor diagnosed as an undifferentiated sarcoma with epithelioid features: a case report

BACKGROUND Pulmonary sarcomas are uncommon accounting for 0.5 % of all primary lung cancers. Undifferentiated sarcomas account for up to 20 % of soft tissue sarcomas. A lung tumor revealed to be an undifferentiated sarcoma with epithelioid features has never been reported in the literature. CASE PRESENTATION A 61-year-old white Moroccan man presented with 2 months' history of hemoptysis and dyspnea. Chest computed tomography showed a cystic mass involving the lower field of his right lung evoking first a hydatid cyst. Abdominal computed tomography revealed bilateral adrenal nodules. Surgical resection of the lung mass was performed. On pathological examination, the tumor was cystic containing necrotic material. A histological diagnosis of undifferentiated sarcoma with epithelioid features was made. A positron emission tomography scan showed involvement of his pleura, left colon, adrenal glands, left thigh muscle, and leptomeninges. CONCLUSIONS Undifferentiated sarcoma with epithelioid features is a rare malignant mesenchymal tumor. Clinical and radiological features are not specific. A differential diagnosis includes sarcomatoid carcinoma, malignant mesothelioma, melanoma, and other epithelioid sarcomas.