Adult Tiger Man: A Case of Dermatomyositis Associated With Thymoma.

The scan demonstrated multiple linear and patchy hypermetabolic lesions in skeletal muscles, mimicking the coat of a tiger, and was referred to as "a tiger man" sign. A 38-year-old man was admitted to our hospital with weakness, shortness of breath, and muscle pain. A CT scan showed a mass in the anterior mediastinum. 18F-FDG PET/CT was performed to evaluate the mass with a preliminary diagnosis of thymoma; heterogeneous 18F-FDG uptake in the mediastinal mass and tiger man findings in skeletal muscles were observed in PET/CT images.