Rosai Dorfman Disease: A Myriad of Presentations-Multisystem Involvement Including Bone Marrow.

Background: Rosai Dorfman disease (RDD) is a type of histiocytosis which characteristically involves lymph nodes, involvement of other organs is often rare. Histopathological analysis is essential for establishing a definitive diagnosis. Case report: Our patient had involvement of uncommon sites including bone marrow and spleen at an atypical age of 59 years. Also due to absence of the characteristic CD markers of histiocytes in RDD, we faced certain diagnostic challenges. However, the patient was started on steroids and showed a rapid response. We were able to follow up the patient for nearly a year and have seen improvement in clinical and haematological parameters. Conclusion: Bone marrow infiltration in RDD is a rare presentation. Improving clinician awareness will lead to earlier detection. Following the guidelines, bone marrow aspiration and biopsy should be done promptly in all patients with cytopenia and will help in early identification of RDD. LEARNING POINTS: Histiocytic disorders can mimic a variety of diseases and suspicion must guide us to do tissue biopsy for diagnosis.Treatment regimens vary and the patient's response to treatment also can vary irrespective of the extent of the disease.Cytopenia in Rosai Dorfman disease or any histiocytosis should prompt early bone marrow examination.