A polymorphic challenge

We describe the case of a 19-year-old boy, who presented with diffuse lymph node enlargements and prominent involvement of his parotid glands. After a four-month history of unsuccessful diagnostic investigations, he was finally diagnosed with Kikuchi-Fujimoto's disease (KFD), a rare histiocytosis of unknown aetiology affecting lymph-nodes throughout the body. The diagnosis of KFD can only be made by histopathologic characterization of affected lymph-nodes, while, according to literature, clinical and imaging features can only suggest the presence of such particular disease. Furthermore, as happened in the case of our patient, KFD tends to be hardly distinguishable from lymphoid malignancies and to overlap with other systemic immune-mediated diseases, such as adult onset Still's disease and systemic lupus erythematosus. The significant involvement of intra-parotid lymph-nodes in our patient's case further extended the diagnostic spectrum to include Sjogren's syndrome.