A Rare Case of Lung Nuclear Protein in Testis Carcinoma

Nuclear protein in testis carcinoma is a very rare but extremely aggressive highgrade carcinoma characterized by the presence of a fusion NUT gene – an oncogene. It is also called midline carcinoma because it mainly affects structures along the midline – head, neck, and lungs. We report a case of a woman with lung nuclear protein in testis carcinoma, diagnosed by bronchoscopic fibro-punch biopsy. The histological examination showed massive infiltration of bronchial wall of predominantly spindle-shaped neoplastic cells with unclear cytoplasmic borders. In some areas groups of rounded cells with clearly visible nucleoli and high mitotic rate were present. Foci with necrosis were also found. Immuno-histochemistry showed positive expression of cytokeratin, p63, CD56 and nuclear protein in testis antibodies and negative reaction for TTF1 and chromogranin A in neoplastic cells. The proliferative activity of tumor cells was very high (> 70%). Immunohistochemical study of the nuclear protein in testis expression is mandatory in cases with poorly differentiated lung tumors, with predominantly midline mass.