Orbit & optic nerve

Inflammatory pseudotumor

Topic Completed: 1 February 2014

Minor changes: 24 December 2020

Copyright: 2004-2021, PathologyOutlines.com, Inc.

PubMed Search: Inflammatory pseudotumor [title] orbit

Nat Pernick, M.D.
Page views in 2020: 2,180
Page views in 2021 to date: 2,435
Cite this page: Pernick N. Inflammatory pseudotumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/eyeorbitinflammatorypseudo.html. Accessed December 8th, 2021.
Definition / general
  • May not be a specific disease process, but due to various causes (paranasal sinus tumors, Rosai-Dorfman disease, inflammatory fibrosclerosis, dysthyroid ophthalmopathy, cholesterol or keratin granulomas, traumatic fat necrosis, prior hemorrhage or abscess)
  • More common than infectious granulomas
  • Usually ages 20 - 49 years with good health and sudden onset of exophthalmos with variable lid or conjunctival edema
Case reports
  • Steroids (alleviate signs and symptoms)
  • Excision
Gross description
  • Indurated orbital mass, often surrounding optic nerve and enveloping extraocular muscles
Gross images

AFIP images
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Fibrotic mass surrounds the eye

Microscopic (histologic) description
  • General:
    • Edematous tissue with excessive production of ground substance, chronic inflammatory cells, vascular proliferation and hyperplastic connective tissue
    • May have periphlebitis with tissue eosinophilia
  • Inflammatory myofibroblastic tumor:
    • Combinations of fibroblasts and myofibroblasts in background of plasma cells and other inflammatory cells
  • Rosai-Dorfman related:
    • Large histiocytes, some with lymphocytophagocytosis, lymphocytes and plasma cells, often with prominent fibrosis
Whole mount images

AFIP images
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Dense fibrotic tissue
with focal lymphocytes
surrounds the eye

Microscopic (histologic) images

AFIP images
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Inflammation and
fibrosis involve the
orbital adipose tissue

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Chronic inflammatory
cells infiltrate an
extraocular muscle

Positive stains
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