A 51-year-old woman presented to the dermatology clinic with a 2-month history of rapidly progressing hair growth on her face, neck, and upper body in association with fatigue, weight loss, and cough. She had a 37-pack-year history of smoking but had no other relevant medical history and was taking no medications. On examination, lanugo-type hair was observed on the face, ears, neck, and upper trunk. This finding, referred to as acquired hypertrichosis lanuginosa, may be associated with underlying cancer, endocrine disorders, anorexia nervosa, or certain medications. Positron-emission tomography–computed tomography revealed avid nodal disease in the right supraclavicular fossa and a 12-mm opacity in the lower lobe of the right lung. Biopsy of the right supraclavicular lymph node was performed, and a diagnosis of primary lung adenocarcinoma was made. The patient received treatment with chemotherapy and radiation followed by durvalumab. Two months after the start of treatment, the hair growth had slowed substantially, and the cough and weight loss had completely resolved.