A case report of tongue metastasis from lung squamous cell carcinoma and literature review.

RATIONALE: Tongue metastasis from lung cancer is extremely rare, and the prognosis of these patients is rather poor.

PATIENT CONCERS: A 56-year-old man was found a 4-cm cavity lesion in the left upper lobe, which was initially misdiagnosed as tuberculosis.

DIAGNOSES: A case of lung squamous cell carcinoma that metastasized to the base of a patient's tongue.

INTERVATIONS: We send the biopsy of the lung and the tongue lesions for gene sequencing.

OUTCOMES: He received systemic chemotherapy, but continued to have pain at the base of his tongue and died 7 months later.

LESSONS: From sequencing data, mutations in KRAS proto-oncogene, GTPase (KRAS), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and tumor protein p53 (TP53) were found in the tumor biopsy of the patient. All of these were indicators of poor prognosis.