Positive TTF-1 Expression in Malignant Mesothelioma: A Case Report.

BACKGROUND: The histopathological diagnosis of malignant mesothelioma is based mainly on the immunohistological profile of the neoplasia, using different immunohistochemical markers to distinguish between a malignant mesothelioma and a carcinoma. CASE REPORT: A female patient presented with a right paravertebral rapidly growing tumor and severe pain. Based on the immunohistochemical findings, we present the first case of a malignant mesothelioma with immunohistochemical expression of thyroid transcription factor-1. CONCLUSIONS: The detection of a positive reaction for thyroid transcription factor-1 in the tumor cells may not exclude a malignant mesothelioma.