[Langerhans cell sarcoma with pulmonary manifestation, mediastinum involvement and bronchoesophageal fistula. A rare location and difficulties in histopathological diagnosis].

Langerhans cell sarcoma, a neoplastic proliferation of Langerhans cells with malignant cytologic features, is a very rare disease. Only a few cases have been documented in the English-language literature. Special methods, like immunohistochemistry and/or ultrastructural examination, are indispensable for appropriate diagnosis. Correct diagnosis is difficult. In fact, the disease is often misdiagnosed. We present the case of a 47 year-old man with a large mass in the middle lobe of the lung, infiltrating anterior mediastinum, with multiple pulmonary round lesions and enlargement of local lymph nodes, and with bronchoesophageal fistula. Clinical examination indicated the possibility of advanced primary lung cancer. However, the first histological diagnosis was Langerhans cell histiocytosis. In spite of treatment, the progression of pulmonary lesions was observed. Therefore, upper- and middle-lobectomy was performed. The diagnosis of Langerhans histiocytosis was confirmed microscopically again. Nevertheless, the patient's condition deteriorated progressively and he was admitted to the National Tuberculosis and Lung Diseases Research Institute in order to establish a final diagnosis. Revision of earlier resected specimens, as well as an immunohistochemical and ultrastructural examination of samples, taken once again from a bronchial tumor, led to the establishment of a diagnosis of a unique form of Langerhans cell sarcoma with rare pulmonary manifestation.