Large Pleural Lipoma Manifesting With Chronic Shoulder Pain

Musculoskeletal symptoms related to orthopedic conditions are highly prevalent worldwide and are a leading cause of morbidity. However, non-orthopedic conditions may also present with musculoskeletal symptoms. For example, shoulder pain may be caused by gastrointestinal, hepatobiliary, cardiac, and neurological pathologies. We report the case of a 32-year-old man who presented to the orthopedic clinic with a complaint of left shoulder pain for the past three months. He described the pain as sharp in nature. The pain was constant and was not related to the shoulder movements. It was not associated with morning stiffness. He had no history of preceding trauma. On examination, both shoulders were symmetrical with no evidence of deformities. Palpation over the shoulder region did not elicit any tenderness. The range of motion in both the active and passive movements was intact. The Neer and Jobe tests were negative. Also, the sensory examination was intact, and laboratory findings were normal. The patient underwent a plain frontal radiograph of the chest, which revealed a large well-circumscribed lobulated mass lesion in the left hemithorax, arising from the pleural lining. A thoracic CT scan was then performed to provide further characterization of the mass lesion and it re-demonstrated the mass as having homogeneous fat-attenuation with thin septations, probably representing pleural lipoma. The tumor was successfully resected via open thoracotomy. The patient's symptoms resolved and he had no recurrence after one year of follow-up. Pleural lipoma is a very rare benign mesenchymal tumor. The case highlights the importance of considering non-orthopedic conditions in the differential diagnosis of shoulder pain in patients with normal physical examination findings. A CT scan is vital to make the diagnosis and can show the accurate anatomic relations with respect to the tumor for surgical planning.