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Rosai-Dorfman disease

Case contributed by Ammar Ashraf

Presentation

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

Patient Data

Age: 35 years
Gender: Male
ct

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.

mri

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.

F-18 FDG PET

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. 

Immunohistochemistry: 

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

 

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