[Sinus histiocytosis with massive lymphadenopathy: FDG-PET/CT documented partial remission after treatment with 2-chlorodeoxyadenosine].

UNLABELLED: Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a very rare disease belonging to a group of histiocytoses (more precisely non-Langerhans cell histiocytoses). Rosai-Dorfman disease is characterised by the presence of atypical histiocytic cells in the sinuses of lymph nodes or in the extranodal lymphoid tissue, absorbing lymphocytes and plasma cells. The structure and function of the absorbed cells is not impaired and they can leave histiocytes as viable cells. This effect is called emperipolesis, whereas ingestion of cells with their destruction is called phagocytosis. In our text we describe a patient with this disease located, characteristically, in supraclavicular lymph nodes, but also in mediastinal lymph nodes. Along with lymphadenopathy skin alterations appeared which were both clinically and histologically described as eczema dermatitis. At the same time as lymphadenopathy also strong headaches started which the patient had never suffered before. Within the first-line treatment prednisone was administered, but no effect was achieved. 2-chlorodeoxyadenosine in 5 mg/m2 s. c. dose was used in the second-line treatment, for 5 successive days in monthly intervals. There were four cycles of this treatment administered overall. Therapy was tolerated without any manifestations of toxicity. Already after the 1st cycle skin alterations as well as headaches entirely disappeared. To assess the effect of treatment the PET/CT examination with 18F-fluorodeoxyglucose (FDG-PET/CT) was made. After 4 cycles of treatment the mediastinal lymph nodes diminished to a physiological size and the accumulation of fluorodeoxyglucose in them was assessed as physiological. Lymphadenopathy in the neck area also significantly diminished by 50-75 % and the accumulation of fluorodeoxyglucose was reduced as well, though it did not reach the norm. Therefore we evaluate the effect of treatment as a partial remission with complete disappearance of skin alterations and headaches. The cause of the eczema and headaches has not been clarified, however considering the same time of their arising and then disappearance after the application of 2-chlorodeoxyadenosine the causal connection with Rosai-Dorfman disease is likely.

KEY WORDS: Castlemans disease - lenalidomide - Rosai-Dorfman disease - rituximab - sinus lymphadenopathy with massive lymphadenopathy - thalidomide - 2-chlorodeoxyadenosine.