Diplopia Presenting in a Case of Pineal Metastasis of Pulmonary Sarcomatoid Carcinoma Refractory to Treatment

A 42-year-old male presented with diplopia, headache, and nausea. Magnetic resonance imaging (MRI) of the brain showed pineal tumor, and chest computed tomography (CT) demonstrated a lung tumor. Disorientation developed, with occurrence of hydrocephalus, and we performed neuroendoscopic surgery for biopsy of the pineal tumor and third ventriculostomy. The lung tumor was biopsied under bronchoscopic and CT guidance, and based on the pathological results, we diagnosed pineal metastasis of pulmonary sarcomatoid carcinoma (cT3N1M1b Stage IVA). Stereotactic radiotherapy for the metastatic pineal tumor and systemic chemotherapy (carboplatin + pemetrexed) were pursued, but hemorrhage of the tumor occurred, hydrocephalus worsened, and neoplastic meningitis was diagnosed by MRI. Therapy was switched to nivolumab, but without effect, and the patient succumbed. Even among lung tumors, sarcomatoid carcinoma is rare. There are also few reports of lung tumors metastasized to the pineal gland. Our case report of pineal tumor regarded as metastasis of pulmonary sarcomatoid carcinoma also includes a discussion of the literature.