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Lung

Noninfectious granulomatous inflammation

Sarcoidosis

Author: Elliot Weisenberg, M.D.

Last author update: 1 September 2011

Last staff update: 6 March 2023 (update in progress)

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PubMed search: Sarcoidosis [title] lung

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Table of Contents

Cite this page: Weisenberg E. Sarcoidosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungnontumorsarcoidosis.html. Accessed May 29th, 2023.

Definition / general

Multisystemic disease of unknown origin that involves lung or bilateral hilar lymph nodes in 90% of cases

Pathophysiology

May be a manifestation of disordered immune regulations in genetically susceptible individuals after exposure to environmental agents
Increased risk with some HLA genotypes
Increase in pulmonary T cell CD4:CD8 ratio
Increase in T cell derived cytokines IL-2 and IFN-gamma
Increase in other cytokines (IL-8, TNF, others) in microenvironment

Clinical features

Commonly anergy to skin test antigens, polyclonal hypergammaglobulinemia
Presents as perihilar node involvement, diffuse pulmonary disease, pulmonary interstitial fibrosis, localized bronchial stenosis, distal bronchiectasis and atelectasis
Age usually 20 - 40 years, F > M, 90% are black, rare in Chinese or southeast Asians
80% have elevated serum angiotensin converting enzyme (not specific); 65% recover without further problems; 20% have permanent pulmonary loss; 3% die of pulmonary fibrosis or congestive heart failure
A diagnosis of exclusion, since there are no specific criteria for disease; should culture and use special stains
Lungs:
- Either no gross lesion or 1 - 2 cm nodules; often in bronchial submucosa, so biopsies are helpful
Lymph nodes:
- Hilar or mediastinal lymph nodes involved in almost all cases, tonsils involved in 25% of cases
- Nodes are enlarged, may be calcified
Liver / spleen:
- Gross disease in 20%, microscopic involvement in 75% of cases
Bone:
- Xray changes in 20%, usually small bones of hands and feet
Skin:
- Involvement in 30% - 50% with erythema nodosum
- Also mucus membranes
Eye:
- Iritis or iridocyclitis in 20% - 50%
Best prognosis: hilar lymphadenopathy alone
Worst prognosis: pulmonary disease without adenopathy
Necrotizing sarcoid granulomatosis:
- Very rare
- Controversial if this is a distinct form of sarcoidosis
- Usually affects women, often with mild or no symptoms, and excellent prognosis using steroids, immunosuppressive drugs and surgery for localized lesions
- Resembles tuberculosis, fungal infections or granulomatosis with polyangiitis (Wegener's)
- Exclude infections with negative culture and negative histochemical stains

Gross images

Contributed by @AKhannaMBBS on Twitter

Sarcoidosis

Microscopic (histologic) description

Noncaseating epithelioid granulomas with tightly packed epithelioid cells, Langhans giant cells and lymphocytes (T cells), usually in interstitium adjacent to bronchioles and around and within vessel walls, pleura and connective tissue septa
May also be hyalinization, diffuse interstitial fibrosis, fibrinoid necrosis, fibrosis within granulomas, intra- and extracellular inclusions
Pleural involvement in 10%
Schaumann bodies: laminated concretions of calcium and protein
Asteroid bodies: stellate inclusions within giant cells, in 60% of granulomas
Neither is specific for sarcoid (also seen in berylliosis)
Necrotizing sarcoid granulomatosis: extensive, vascular, noncaseating sarcoid-like granulomas invading pulmonary arteries and veins with diffuse necrosis of lung parenchyma

Microscopic (histologic) images

Contributed by Weijie Li, M.D., Mark R. Wick, M.D. and @AKhannaMBBS on Twitter