Palatine tonsil metastasis is an uncommon manifestation of disseminated malignancy and is exceptionally rare in small-cell lung cancer (SCLC). Because it may mimic benign tonsillar disease or a primary oropharyngeal tumor, diagnosis can be delayed.

A 71-year-old man was admitted after pertrochanteric hip fracture. Preoperative evaluation revealed a left tonsillar mass and a left hilar pulmonary lesion. Computed tomography showed a 3–4 cm lesion involving the left palatine tonsil, a 7.5 cm left hilar mass with mediastinal lymphadenopathy and multiple brain metastases. Bronchial biopsy confirmed SCLC. Tonsillar biopsy showed metastatic SCLC with a matching neuroendocrine immunophenotype, including TTF-1, chromogranin, synaptophysin, and CD56 positivity and a high Ki-67 index. Palliative carboplatin-etoposide was started, but the patient died after two cycles.

This case highlights that unilateral tonsillar enlargement may rarely represent metastatic lung cancer, particularly in the appropriate clinical context and advanced disease. Histopathology with immunohistochemistry is essential to distinguish metastatic SCLC from primary tonsillar malignancy. Early otolaryngologic assessment and biopsy remain the key diagnostic steps in this rare presentation.