Sarcoidosis

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
Molecular	PCR for tuberculosis -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

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

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.

Molecular

• PCR for Tuberculosis -ve.

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.