Rosai-Dorfman disease

Digital cases

 HPC:290

Images

 https://twitter.com/dozing_dog/status/724843235567345664
 https://twitter.com/BeynonMD/status/733528203260661760
 https://twitter.com/BeynonMD/status/733528203260661760
 https://twitter.com/DrBMcGinn/status/1496200793862594571

Localization

 lymph node (nodal Rosai-Dorfman disease)
 extranodal Rosai-Dorfman disease

• skin (12558621), hypodermis (1498408, 3401030)
• pleura (14652824)
• intracranial (14608579, 12637307), brain (12601463), meninges
• nasal region (12761707)
• breast (12760958, 9416494, 9199644)
• thyroid (12699598, 12683901)
• bone (12652340, 9653919, 9526780, 2013464)
• gastrointestinal tract (12562257 10746683, 17400399)
• eye (12479625), lacrymal gland
• kidneys (10587134, 10471758, 9072605, 1456886)
• pancreas (10370692, 11555773)
• salivary glands (9472588)
• liver (8771474)
• larynx
• heart (cardiac Rosai-Dorfman disease) (19962176)

Types

 mostly isolated
 rarely multicentric (12622452)

Synopsis

 large, pale, histiocytic cells (Rosai-Dorfman cells) exhibiting emperipolesis (cytophagocytosis)

Immunohistochemistry

 S-100+
 CD68+
 CD1a-

Electron microscopy

 Birbeck granules are absent

Associations

 acute lymphoblastic leukemia (11496358#)
 lymphoma (9031615, 9006752)
 follicular lymphoma (10786808)
 nodular lymphocyte predominant Hodgkin disease (10786808, 8522313)
 chronic autoimmune thyroiditis (10710276)
 inflammatory pseudotumor (9059366)
 systemic lupus erythematosus (11555773)

Molecular biology

 Activating KRAS-K117N missense mutation (26922062)

References

 Rosai-Dorfman Disease Harboring an Activating KRAS K117N Missense Mutation.
Shanmugam V, Margolskee E, Kluk M, Giorgadze T, Orazi A. Head Neck Pathol. 2016 Feb 27. PMID: 26922062