True hypopharyngeal carcinosarcoma: a case report and literature review

OBJECTIVE: Carcinosarcoma consists of carcinomatous and sarcomatous tissues and is an aggressive malignant tumor. It is rarely reported in the hypopharynx. METHODS: A 72-year-old man presented with dysphagia and dyspnea. Laryngoscopy, computed tomography (CT), and (18)F-fluorodeoxyglucose positron emission tomography/CT ((18)F-FDG PET/CT) showed a neoplasm on the left posterior hypopharyngeal wall. The patient underwent bilateral neck dissection and excision of the hypopharyngeal cancer followed by postoperative radiation therapy. RESULTS: Immunohistochemistry revealed carcinomatous cells with membrane positivity for cytokeratin, glucose transporter-1 (GLUT-1), phosphoinositide-3 kinase (PI3K), hypoxia-inducible factor-1α (HIF-1α), and hexokinase-II as well as sarcomatous cells with membrane positivity for smooth muscle actin, GLUT-1, HIF-1α, and PI3K. Histopathology and immunohistochemistry revealed a true carcinosarcoma of the hypopharynx (pT3N0M0, Stage III). CONCLUSIONS: Thorough immunohistochemistry is required for a correct diagnosis of hypopharyngeal carcinosarcoma. (18)F-FDG PET/CT may help to distinguish hypopharyngeal carcinosarcoma from benign tumors.