Excerpt
Necrobiotic xanthogranuloma (NXG) is a rare, chronic, progressive non-Langerhans cell histiocytosis. Previous reports indicate that periorbital involvement and skin and subcutaneous nodules are the most frequent presentation [
1‐
3]. We report here NXG involving multiple organs, including some unusual
18F-fluorodeoxyglucose (
18F-FDG) avid NXG locations. A 40-year-old man with a 6-month history of asymptotically increasing, multiple, purplish-red skin nodules was admitted to our hospital. Histopathological examination of skin biology specimens from the right waist showed diffused lymphocytic infiltration (
i, black arrow) in the dermis and subcutaneous tissue, which were the primary areas with extensive necrobiosis, as well as a prominent granulomatous infiltrate (
i, red arrow). Combined with clinical and pathological examination, the final diagnosis was NXG.
18F-FDG positron emission tomography/computed tomography (PET/CT) scan was recommended to establish a clear diagnosis of possibly a systemic tumor disease and malignancy after histological diagnosis. The maximal intensity projection (MIP,
a) image shows abnormally intense
18F-FDG uptake in the skin and subcutaneous tissues of multiple locations (
d). Interestingly, widespread abnormal
18F-FDG-avid areas are noted along the vessels (
a, black arrows) and scrotum (
a, red arrows), which were rare sites in previous reports. Lesions were also present in the muscles (
a, black arrowheads), lung (
b), and myocardium in the right atrium (
c), with an SUVmax of 14.1. Due to the lack of a uniform treatment protocol, a therapeutic strategy depending on current case reports and reviews was given [
4]. The patient was then treated with chemotherapy, including cyclophosphamide, vincristine, and prednisone, combined with lenalidomide for 2 months; the multiple purple-red nodules in the whole body of this patient were smaller and reduced than before, and the follow-up
18F-FDG PET/CT showed that systemic lesions improved (MIP,
h) and no FDG-avid lesions were detected in the lung (
e), myocardium (
f), and subcutaneous tissues (
g). …