Synchronous peritoneal carcinomatosis from a buccal squamous cell carcinoma: a case report focusing on possible metastatic mechanisms and novel therapeutic modalities.

A 53-year-old male patient was diagnosed with squamous cell carcinoma of buccal mucosa with synchronous diffuse peritoneal carcinomatosis, a very rare presentation for oral cancer. His disease was highly resistant to intensive systemic chemotherapy and progressed rapidly. So far as we know, there were only five cases with peritoneal involvement by metastatic head and neck cancer reported prior to this patient in the English literature. Immunohistochemistry study revealed that tumour specimens from both oral cavity and peritoneum were negative for tumour necrosis factor alpha and CD24 but positive for CD44 and CD36. These four molecules have been disclosed to be involved in the process of peritoneal metastasis from ovarian cancer. Their roles in the metastatic pathway and possible therapeutic policy targeting at them will be thoroughly discussed.