Atypical Type A Thymoma Variant Manifesting Polymyalgia Rheumatica.

We report a case of atypical type A thymoma variant manifesting polymyalgia rheumatica. A 68-year-old man underwent extended thymectomy with concomitant resection of the pericardium and right lung for an anterior mediastinal tumor. He was diagnosed with atypical type A thymoma variant with pericardial invasion. He developed pain in his extremities 1 year and 2 months after surgery. Detailed examinations resulted in a diagnosis of polymyalgia rheumatica and bone metastasis of thymoma. He was treated with oral prednisolone for polymyalgia rheumatica. His symptoms and bone lesion have been stable up to the present time of 3.5 years post-surgery.