Bing-Neel Syndrome and Coexisting Pituitary Macroadenoma in a Patient with Waldenström Macroglobulinemia Revealed by 18F-FDG and 68Ga-Pentixafor PET/CT.

A 63-year-old man presenting with peripheral neuropathies was diagnosed of Waldenström's macroglobulinemia, and Bing-Neel syndrome was subsequently confirmed via cerebrospinal fluid examinations. Besides involvement in bone marrow, lymph nodes, as well as the thoracic and sacral nerve root, 68Ga-Pentixafor PET/CT detected active tracer uptake in bilateral choroid plexus, which was negative in 18F-FDG PET/CT, possibly suggesting the involvement of Bing-Neel syndrome. The coexisting pituitary macroadenoma was FDG-avid but negative in 68Ga-Pentixafor PET/CT. After six cycles of chemotherapy, the follow-up PET/CT showed complete remission of the previous disease, including the high uptake of 68Ga-Pentixafor in choroid plexus. However, the hypermetabolic pituitary macroadenoma remained unchanged.