Rosai-Dorfman disease

Case contributed by Ammar Ashraf
Diagnosis certain


Painless left thigh mass for one year. No discharge, skin color changes, fever or history of trauma.

Patient Data

Age: 35 years
Gender: Male

Isodense subcutaneous soft tissue density mass with ill-defined/irregular margins, measuring about 7 x 3 x 5 cm seen in the medial lower left thigh. It shows mild enhancement on the post-contrast study. No calcifications, fat component or hemorrhage is seen in it. The underlying muscles and bones are unremarkable.


Subcutaneous poorly defined lesion measuring about 8 x 7.7 x 3.5 cm, inseparable from the deep fascia investing the thigh muscles. It is solid in nature, displays intermediate signal on T1 and T2-weighted images, has no fat or hemorrhage, shows diffusion restriction and moderate contrast enhancement. No abnormality is seen in the underlying muscles and bones.


Nuclear medicine

Left distal thigh subcutaneous mass showing intense increased uptake (SUV max=16.7), which is suspicious of malignancy.

Case Discussion

Ultrasound-guided biopsy, followed by the complete surgical excision. 

Histopathology: Rosai-Dorfman disease. Size: 9.3 cm in maximum dimension. 


  • CD3 (polyclonal) and CD20 (L26): Stains polyclonal lymphoid cells.
  • S100 (polyclonal) and CD30 (Ber-H2): Negative.


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