Sarcoidosis

Sarcoidosis is non-necrotizing granulomatous disease of unknown etiology. It classically associated with (pulmonary) hilar lymphadenopathy. It may be found in almost any organ.

Sarcoidosis
Diagnosis in short
Sarcoidosis-like granulomas in a lymph node. H&E stain.
LM	well-formed granulomas often with few surrounding lymphocytes ("naked"), usually non-necrotizing
LM DDx	fungal infections, MAC, tuberculosis, other infections, drug reactions, reactive process to malignancy
Stains	AFB -ve, GMS -ve, PASD -ve
Site	lung, hilar lymph nodes of the lung, skin, heart, other sites
Prevalence	uncommon
Blood work	+/-ACE elevated
Radiology	+/-bilateral hilar lymphadenopathy (very common), +/-interstitial pattern, +/- pulmonary infiltrates, +/-cystic/bullous changes
Clin. DDx	lymphoma, metastatic carcinoma, Wegener's granulomatosis, others

This article covers the topic in general and focuses on the lung aspects. Cardiac sarcoidosis is dealt with separately.

General

• Diagnosis of exclusion - infection, neoplasm, and drugs must be excluded.
• Uncommon.
• Afflicits skin ~25% of the time.

Serology:

• Angiotensin-converting enzyme (ACE) - used for diagnosis and to monitor activity.
  • Elevated in approximately 65% of patients in one series.

Gross

• Lungs - classic location.
• Bilateral hilar lymphadenopathy.

DDx lungs - radiologic:

• Carcinomatosis - interstitial pattern.
• Lymphoma - bilateral lymphadenopathy +/- mediastinal lymphadenopathy.

• 

  Markedly enlarged bilaterally hilar lymph nodes in stage 1 sarcoidosis (WC/Yale Rosen)

• 

  Fibrosis (WC/Yale Rosen)

Microscopic

Features:

• Granulomata, well-formed, non-necrotizing. ‡
  • Negative for microorganisms with special stains.
• Usu. minimal (lymphoid) inflammation; sarcoid granulomas are known as "naked granulomas".
• In lung:
  • Interstitial location +/- centrilobular.

Notes:

• ‡ Reported with necrosis - uncommon.

DDx:

• Infections.
  • Fungal.
  • Mycobacterial, e.g. tuberculosis.
  • Tertiary syphilis.
• Hypersensitivity pneumonitis - usually poorly-formed granulomas, centrilobular, not paraseptal.^{[citation needed]}
• Reaction to treatment/drug.
  • Anti-TNF therapy.
  • Ipilimumab.
• Common variable immunodeficiency.
• Reactive changes associated with tumours:
  • All testicular tumours - esp. seminoma.
  • Lung adenocarcinoma.

Images

• 

  Sarcoidosis - lung. (WC)

• 

  Granulomata in sarcoidosis with asteroid bodies. (WC)

• 

  Schaumann body in sarcoidosis. (WC/Yale Rosen)

• 

  Fibrosis in sarcoid granulomas. (WC/Yale Rosen)

• 

  Muscle involvement in sarcoidosis. (WC/jensflorian)

• 

  Skin involvement in sarcoidosis. (WC/jensflorian)

www:

• Sarcoidosis - several images (upmc.edu).
• Neurosarcoidosis - several images (upmc.edu).

Stains

• AFB -ve.
• PASD -ve.
• GMS -ve.

Note:

• Must be done to exclude infection.

Sign out

• Should be something like sarcoid-like granulomas and clinical correlation required.

A. RIGHT LOWER LOBE LUNG, WEDGE RESECTION:
- GRANULOMATOUS INFLAMMATION, NON-NECROTIZING (SARCOID-LIKE), SEE COMMENT.

B. RIGHT MIDDLE LOBE LUNG, WEDGE RESECTION:
- GRANULOMATOUS INFLAMMATION, NON-NECROTIZING (SARCOID-LIKE), SEE COMMENT.

C. RIGHT LOWER LOBE LUNG, WEDGE RESECTION:
- GRANULOMATOUS INFLAMMATION, NON-NECROTIZING (SARCOID-LIKE), SEE COMMENT.

COMMENT:
The sections show multiple sarcoid-like granulomas with both centrilobular and 
septal involvement. There is a slight upper lobe predominance of the disease.

The main histomorphologic differential diagnoses are: sarcoidosis, 
infectious granulomatous pneumonia.

Sarcoidosis is favoured based on the morphology of the granulomas and the 
lack of microorganisms with special stains (ZN, PASF, GMS).

A serum ACE level should be considered, if not already done.

Clinical and radiologic correlation is required.

See also

• Medical lung diseases.
• Cardiac sarcoidosis.