Lung adenocarcinoma metastasis to frontal sinus mimicking Pott's puffy tumor.

Metastasis of the lung adenocarcinoma to the paranasal sinuses is a rare clinical entity. We present a 75-year-old male patient who presented with swelling of the forehead and left upper eyelid with proptosis in left eye due to metastasis from lung adenocarcinoma. It appears as a puffy swelling of the forehead like a Pott's puffy tumor. Pott's puffy tumor is a subperiostal abscess of the frontal bone associated with osteomyelitis and usually occurs as a complication of sinusitis or trauma.