Rosai-Dorfman disease (RDD)

Sinus histiocytosis with massive lymphadenopathy (SHML)

Epidemiology and Etiology:

•  1^st or 2^nd decades mostly
• any age may be affected
• blacks predisposed
• endemic areas:
• Africa
• Caribbean
• US
• Western Europe
• Unknown etiology
• Reactive
• Likely infectious or immune defect
• Stimulation of monocytes / macrophages via macrophage colony stimulating factor (M-CSF) may be main mechanism
• May coexist with Langerhans Cell Histiocytosis

Common sites:

• cervical (by far most common and most affected)
• other lymph nodes
• extranodal sites (involved in >25%)
• eyes
• ocular adnexa (esp. orbit)
• head and neck
• upper respiratory tract
• skin and subcutaneous
• skeletal system
• CNS
• Rarely other sites
• Widespread sometimes
• Almost universally spared:
• Lung
• Spleen
• Bone marrow (excluding focal bone lesions)

Gross features:

•  massive, painless, bilateral neck lymph node enlargement typically
• lymph nodes matted together
• gray to golden yellow cut surface (fat)

Histologic features:

• prominent perinodal fibrosis
• capsular and pericapsular fibrosis and inflammation
• intranodal fibrosis is minimal or absent
• pronounced dilation of lymph sinuses
• partial or complete architectural effacement
• occupied by histiocytes, lymphocytes, plasma cells
• admixture of B and T cells
• histiocytes:
• large vesicular nucleus
• abundant clear cytoplasm
• neutral lipids
• intact lymphocytes within the cytoplasm of many cells (emperipolesis / lymphocytophagocytosis)
1. this feature is very sensitive, but not specific for Rosai-Dorfman
• sometimes plasma cells and RBCs are present in cytoplasm
• may see:
• small microabscesses
• foci of necrosis
• intersinusal tissue:
• variable but sometimes impressive number of mature plasma cells
• Russel bodies may be seen

Immunophenotype:

Marker:	Sensitivity:	Specificity:
S100 (strong)
CD1a (neg)
Oil red O

Molecular features:

Other features:

• EM:
• Histiocytes:
• Extensive pseudopodia
• Lacking Birbeck’s granules
• Lacking viral particles or other evidence of infection
•  clinical features:
• fever
• peripheral blood:
• leukocytosis
• elevated ESR
• polyclonal hypergammaglobulinemia
• relatively unaffected by therapy
• course:
• many quick and complete spontaneous resolution
• others protracted course for years or decades (particularly in widespread extranodal involvement)
• some recur at another site
• some have died due to extensive disease or immune abnormalities such as amyloidosis

References:

•  Rosai 9^th (2004)