Trousseau's syndrome is well known as a thromboembolism found in patients with cancer. This report presents a rare case of synchronous cancer of the oral cavity and stomach diagnosed in association with multiple cerebral infarctions. An 85-year-old man was admitted to the Department of Neurology in Kyoto University Hospital due to sudden onset numbness in his face and arm. MRI revealed multiple small embolisms in the cerebrum and cerebellum. Despite appropriate diagnostic evaluation, the cause of the acute cerebral infarctions remained uncertain. Several days after his admission, the patient complained of discomfort in his mouth and so was referred to the Department of Oral and Maxillofacial Surgery. Clinical examination revealed a hard elastic tumor in the left maxillary molar region. An incisional biopsy yielded a pathological diagnosis of squamous cell carcinoma. In an endoscopic examination of the upper gastrointestinal tract, he was diagnosed with gastric adenocarcinoma. Additionally, PET-CT findings indicated an inoperable gastric tumor with regional lymph node and lung metastases. In view of the patient's poor general condition and progressive disease, he elected to pursue only supportive care. He was then discharged and allowed to return home; the patient continued on supportive care for 2 months before he died.
