Diffuse Large Cell Lymphoma Transformed from Rosai-Dorfman Disease

INTRODUCTION: Rosai-Dorfman disease, also known as Sinus Histiocytosis with Massive Lymphadenopathy, is an almost rare benign entity which mimics non-Hodgkin’s lymphoma, and is characterized by enlargement of lymph nodes. Knowing the difference between these two diseases is critical for the adequate therapeutic approach. The most common presentation of the disease is within the cervical basin, and most of the times, lymph node dissection and removal of their chains is enough for cure.

PATIENT AND METHODS: We describe a 23-yo white woman with past history of persistent cervical lymphadenopathy, who underwent 4 surgical procedures to remove left cervical nodes, diagnosed as Rosai-Dorfman disease within the last 3 years. When relapse after the 4^th surgery happened, the patient came to our Service and sought for a 2^nd opinion consultation.

RESULTS: Pathology reviews were done on the previously collected material, corroborating Rosai-Dorfman disease, except for the review of the slides of the last material, which showed inconclusiveness. Histopathology and immunohistochemistry were then repeated for the last surgical specimens at 2 different Pathology labs, and both confirmed diffuse large cell lymphoma. Patient started on chemo with CHOP 6×, and showed a partial response up to the 3^rd cycle, when the tumor started progressing during the 4^th cycle. Chemo was then changed to ESHAP, which was well-tolerated and promoted CR after 6 cycles. The patient is currently in CR and asymptomatic.

CONCLUSION: Rosai-Dorfman disease is a proliferative reaction to an unknown, unidentified pathogen or specific cause, which leads to lymph node enlargement and extra nodal involvement in 25% of the cases. Some studies have attempted to correlate the presence of klebsiella as a proliferative stimulus present in this disease, but there is not enough evidence to confirm this hypothesis. Interestingly, it may seem that Rosai-Dorfman is a middle step between a truly benign process and malignancy itself because, not only other cases of lymphoma transformed after Rosai-Dorfman’s disease have been reported, but also extra nodal cancer following extra nodal presentation of the disease. Although many clues point to its involvement in the process of carcinogenesis, more clinical and molecular evidence are necessary to tie the link between Rosai-Dorfman disease and cancer.