A 45-year-old man had right chest and back pain for 15+ days without any cause, each lasting 3-10 minutes, and sometimes it could radiate to the right shoulder. Chest computed tomography (CT) scan showed bony destruction in the dorsal segment of the 4th rib on the right. Metastatic disease was suspected and for this reason, fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT was performed. The images demonstrated increased 18F-FDG activity in the dorsal segment of the 4th rib on the right with osteolytic bony destruction. Postsurgical pathological examination showed aneosinophilic abscess (EA).

Intracranial Rosai-Dorfman disease is quite rare. Here, we report a 67-year-old man with a 90 day history of pain and numbness in his right limbs. The patient was suspected of suffering from melanoma. Then he received craniotomy and was finally diagnosed with intracranial Rosai-Dorfman disease. MEDLINE was used to search the related literature; and the diagnosis, mechanism, treatment and prognosis of this rare tumor are discussed.

A 74-year-old woman with a history of melanoma 10 years ago presented worsening swelling pain associated with a lump in her inner left thigh. Metastatic disease was suspected and for this reason, FDG PET/CT was performed. The images demonstrated peripherally increased FDG activity in the lump with a centrally photopenic region. Postsurgical pathological examination showed a hemosiderotic fibrolipomatous tumor.