Mandible metastasis of small cell lung cancer mimicking a residual cyst.

Small cell lung carcinoma (SCLC) is an uncommon tumor characterized by an aggressive behavior with early metastasis, usually to the contralateral lung, liver, brain, and bones. There are only five cases of this particular tumor metastasizing to the oral cavity described in the English literature. We present the case of metastatic SCLC in the mandible with radiographic findings resembling a residual cyst. A 66-year-old man with previous diagnosis and treatment for a SCLC was referred to the Stomatology Department with a history of persistent pain in the mandible 1 year after the inferior right pre-molar tooth extraction. The radiographic exam showed a well-delimited radiolucent area on that extracted tooth's region resembling a residual cyst. Biopsy was performed yielding the diagnosis of metastatic SCLC. The patient was referred to the clinical oncologist for chemotherapy. Although uncommon, this tumor should be included in the differential diagnosis of jawbone lesions, particularly when the patient presents a previous diagnosis of SCLC.