CNS & pituitary tumors

• See Bone topic

• See Lymph node topic

• See Skin nonmelanocytic tumor topic

Definition / general
• See also Lymph node topic
• Rare lytic skull lesion or parasellar mass
• Children and young adults
• May arise from primary histiocytic proliferation with secondary atrophy or from demyelination and gliosis of unknown origin (J Child Neurol 2000;15:150)

Definition / general
• See also Lymph node topic
• Also called sinus histiocytosis with massive lymphadenopathy
• Often (25 - 43%) has extranodal involvement
• Rare (100 cases/year in US) and isolated CNS findings are extremely rare
• Benign but may be associated with systemic disease
• Children and young adults (mean age 41 years, range 22 - 63 years)
• CNS tumors usually associated with dura
• References: Mod Pathol 2001;14:172, Clin Neuropathol 2005;24:112 (isolated CNS disease)

Case #488

C. S100+, CD1a-

Explanation: CNS Rosai-Dorfman disease forms lymphohistiocytic masses with prominent pale S100+, CD1a- histiocytes. Answer A (S100-, CD1a-) is the staining pattern of histiocytes in Erdheim-Chester disease. Answer B (S100+, CD1a+) is the staining pattern of histiocytes in Langerhans cell histiocytosis.

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Reference: Histiocytic tumors