Adult benign thoracic lymphangiomas typically present as incidental mediastinal lesions, or, more rarely, as solitary pulmonary nodules. Symptomatic compression of vital structures may require lesion resection or sclerotherapy. In the present report, we describe the incidental finding of a solitary pleural-based pulmonary lymphangioma in a 38-year-old woman with chronic arm and shoulder pain. Positron emission tomography revealed that the lesion was highly fluorodeoxyglucose-avid. Biopsy exposed benign tissue consistent with lymphangioma. After continued radiographic tests, the lesion was determined to be an unlikely source of the patient’s chronic pain. The present report is, to our knowledge, the first published case of solitary pleural-based pulmonary lymphangioma in the medical literature.