Collision lung tumor associating typical carcinoid tumor to sclerosing hemangioma

Collision tumors associating carcinoid tumor and sclerosing pneumocytoma have rarely been reported in the literature. The clinical presentation may be challenging especially in cases showing multiple and bilateral nodules. This case illustrates the association of both tumors diagnosed incidentally and illustrates a full spectrum of neuroendocrine lesions and sclerosing pneumocytoma. The authors present the case of a 52-year-old patient presenting an abdominal pain revealing a vesicular lithiasis and multiple pulmonary nodules. Radiologic follow-up of the asymptomatic lung lesions revealed the stabilization of a left lobe lesion with a disappearance of the other lesions. A lobectomy with a mediastinal lymph node curettage was performed. The microscopic examination revealed both tumor components associating a typical carcinoid tumor to a sclerosing pneumocytoma in association to lesions of diffuse neuroendocrine hyperplasia present in the peri-tumoral parenchyma. This case illustrates radiologic, gross, and microscopic features of a rare pulmonary tumor.