Uterine carcinosarcoma metastatic to the lung as large-cell neuroendocrine carcinoma with synchronous sarcoid granulomatosis.

A 58-year-old woman underwent a curative total abdominal hysterectomy with bilateral salpingo-oophorectomy for a uterine carcinosarcoma. Fifteen months later, PET and CT scan revealed three pulmonary nodules and multiple lymphadenopathy. An atypical lung segmentectomy with dissection of the regional lymph nodes was performed. Two of the three nodules showed morphological and immunohistochemical profiles consistent with the diagnosis of large-cell neuroendocrine carcinoma (LCNEC). The third nodule, the surrounding pulmonary parenchyma and lymph nodes showed diffuse sarcoid granulomatosis. Re-review of the histology of the uterine carcinosarcoma revealed LCNEC morphology with immunohistochemical and genetic profiles identical to the lung cancers, finally deemed as metastatic deposits. Systemic sarcoidosis was ruled out. To our knowledge this is the first case of uterine carcinosarcoma with LCNEC features metastatic to the lung and occurring in association with sarcoid reaction.