BACKGROUND: Metastatic cancer to the vulva is a rare diagnosis and is estimated to account for 5-8% of all vulvar cancers. CASE: A 57-year-old postmenopausal woman was referred for the evaluation of a new vulvar mass. CT scan of the pelvis demonstrated a 4 x 6 cm lobular mass of the left labia. An outpatient excisional biopsy revealed a poorly differentiated large cell carcinoma with prominent necrosis and focal perineural invasion consistent with a bronchogenic carcinoma. A subsequent PET scan of the chest revealed a large primary lung carcinoma confirmed by CT-guided biopsy that was identical to the vulvar tumor. CONCLUSION: This case represents the only literature described primary lung carcinoma presenting as a vulvar metastasis.