Primary intraosseous Rosai-Dorfman disease: a clinicopathological analysis of fourteen cases

Abstract

Objective: To investigate the clinicopathological characteristics, histogenesis, immunophenotypes and molecular genetic features of primary intraosseous Rosai-Dorfman disease (RDD) for improving diagnostic accuracy and differential diagnosis. Methods: This retrospective study included 14 RDD cases diagnosed from January 2009 to January 2019 at Beijing Jishuitan Hospital, China. The immunohistochemical staining for S-100, cyclin D1, CD1a and CD207 expression was analyzed. The BRAF V600E and KRAS mutation analyses were performed using the Scorpions amplification refractory mutation system (ARMS) fluorescence quantitative PCR. Results: There were 6 female and 8 male patients, aged from 2 to 64 years (mean 31.4 years). All of the 14 cases occurred in the bone without lymph node disease, while one patient developed additional lesions within vertebra and nasal cavity. Radiographically, the lesions were lytic with sclerotic margins. Histologically, the lesions percolated through the medullary cavity in an infiltrative fashion and alternating hyper- and hypo-cellular regions of histiocytic clusters (seen as alternating dark and light zones at low magnification). Large histiocytes also showed emperipolesis. Some cases had areas of fibrosis and dense lymphoplasmacytic infiltrates. There were vasculitis and an increased number of plasma cells in the cases involving multiple sites. One case showed concurrence of RDD and Langerhans cell histiocytosis(LCH) with inconspicuous increase of Langerhans histiocytes. Immunohistochemical staining showed that the large histiocytes were positive for S-100, CD68 and CD163 in all cases. The nuclear immunoreactivity for cyclin D1 was observed in 13 of the 14 cases. S-100, CD1a and CD207 were positive in the case with concurrence of RDD and LCH. ARMS-PCR results showed that BRAF V600E mutation was observed in the cases with concurrence of RDD and LCH, while there were no KRAS mutations (7/7). Follow-up information was available for 12 patients and ranged from 9 to 49 months. Three of the 12 patients experienced recurrences after the first surgery. Conclusions: Primary intraosseous RDD is rare, and its concurrence with LCH is a very rare phenomenon. Its clinical symptoms, imaging, and pathological manifestations need to be distinguished from other bone lesions. The molecular detection of BRAF V600E and the nuclear expression of cyclin D1 mutations can be used for the diagnosis and differential diagnosis of RDD.