@lollya74 @eal, Welcome to Mayo Clinic Connect. I ran across an article that may be helpful by searching on Google Scholar (https://scholar.google.com/).
The article is a special report done on June 28th, 2018 - Consensus recommendations for the diagnosis and clinical management of Rosai-Dorfman-Destombes disease: https://ashpublications.org/blood/article/131/26/2877/39185/Consensus-recommendations-for-the-diagnosis-and

The report includes information gathered by doing an English-language search of PubMed for RDD-related literature from 1965 until 2018. The treatment section of the report includes treatment information that may be helpful when you talk with your hematologist. Here is the Introduction taken from the report:

"Rosai-Dorfman-Destombes disease (RDD) is a rare non–Langerhans cell histiocytosis (LCH) first described in 1965 by a French pathologist, Pierre Paul Louis Lucien Destombes, who reported 4 children and young adults with lymphadenopathy and sinus histiocytosis upon histologic analysis.1 Four years later, Juan Rosai and Ronald Dorfman analyzed 34 cases of the same entity under the name sinus histiocytosis with massive lymphadenopathy.2 Characteristic lesional histiocytes are S100+, CD68+, and CD1a− and demonstrate variable frequency of emperipolesis. Historically, RDD has been considered a self-limited disorder of unknown etiology, although few patients have poor outcomes.3 Patients with classical RDD present with bilateral cervical lymphadenopathy, but 43% of patients with RDD present with extranodal disease.3 RDD is a heterogeneous entity that can occur as an isolated disorder or in association with autoimmune, hereditary, and malignant diseases. Because of the wide clinical spectrum of RDD and the consequent variety of specialists evaluating and treating such patients, there is a need for an evidence-based approach to the evaluation and treatment of this protean condition."

There is a PDF button on the side of the page that allows you to print or download the 14 page report that might be helpful for your doctor.

Have you considered seeking help at a major teaching hospital or the Mayo Clinic?