A Rare Case of Thymic Rosai-Dorfman Disease Mimicking Malignancy on ¹⁸F-FDG PET/CT

• Published in: Tomography
• Main Authors: Tongtong Jia, Bin Zhang, Xiaoyi Zhang, Xin Xu, Shibiao Sang, Shengming Deng
• Format: Article
• Language: English
• Published: MDPI AG 2022-11-01
• Subjects: Rosai-Dorfman disease; sinus histiocytosis with massive lymphadenopathy; histiocytosis; ¹⁸F-FDG PET/CT
• Online Access: https://www.mdpi.com/2379-139X/8/6/237
• ISSN: 2379-1381; 2379-139X

Background Rosai-Dorfman disease (RDD), the massive lymphadenopathy characterized by the proliferation of sinus histiocytosis, is a relatively idiopathic benign disease with unknown etiology. We reported a rare case of thymic RDD detected by ¹⁸F-FDG PET/CT. A 23-year-old man with right-sided chest pain underwent ¹⁸F-FDG PET/CT scan, showing increased ¹⁸F-FDG uptake in an anterior mediastinal mass corresponding to a thymic lesion at an enhanced CT scan. The patient was referred to surgery with the clinical suspicion of thymic malignancy. The histological examination and immunohistochemical results confirmed RDD. Conclusions This was the first case report of RDD isolated to the thymus and initially presented with chest pain. Moreover, there was no characteristic painless neck lymphadenopathy at any stage of the disease course. Thus, for young patients with thymus mass, RDD should be considered a rare but possible diagnosis.