Fact-sheet: Sarcoidosis


Updated on 11/13/2025 at 10:16 AM

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Definition

Systemic inflammatory disease characterized histologically by non-necrotizing epithelioid and giant cell granulomas.

The pathophysiological hypotheses suggest an inappropriate immune response to environmental or infectious antigens (mycobacteria) in genetically predisposed individuals (HLA-DQB10210, HLA-DRB10301).

Clinical features

  • Predominant pulmonary involvement: 90% of cases
  • Weight loss, dry cough, dyspnea, arthralgia
  • lymphadenopathy
  • cutaneous involvement: erythema nodosum
  • ophthalmologic involvement: uveitis
  • cardiac involvement, which may progress to heart failure
  • neurosarcoidosis

Predominates in young adults aged 20 to 40 years, in women (F/M=1.5), in Black patients, and in Scandinavian countries.

Laboratory findings

  • Hypercalcemia
  • Elevated angiotensin-converting enzyme (ACE)

Radiography

4 stages of thoracic involvement on chest radiography:

  • stage 1: bilateral and symmetric mediastinal lymphadenopathy
  • stage 2: mediastinal lymphadenopathy and pulmonary infiltrate
  • stage 3: parenchymal involvement alone, without lymphadenopathy
  • stage 4: pulmonary fibrosis

Ultrasound

Lymphadenopathy

CT

Numerous possible lesions, which often makes the diagnosis difficult.

Reference examination for the evaluation of thoracic sarcoidosis.

Most typical thoracic finding: micronodules with a lymphatic distribution (peribronchovascular thickening, fissural and pleural micronodules) with mediastinal and hilar lymphadenopathy.
In order of frequency:

  • micronodules
  • peribronchovascular thickening
  • ground-glass opacity
  • fibrotic masses
  • nodules
  • consolidations
  • septal lines
  • honeycombing

MRI

Reference examination for the evaluation of:

  • neurosarcoidosis
  • cardiac sarcoidosis

Management

The diagnosis relies on a combination of clinical, biological, and radiological findings.

Definitive diagnosis is histopathological, except in cases of Löfgren syndrome (erythema nodosum, arthritis, and lymphadenopathy).
Benign course with spontaneous regression in 80% of cases within two to three years; in severe cases, treatment with systemic corticosteroids

Differential diagnosis

Differential diagnoses of thoracic sarcoidosis:

  • pleuropulmonary tuberculosis
  • thoracic lymphoma (lymphadenopathy)
  • lymphangitic carcinomatosis
  • drug-induced interstitial lung disease
  • hypersensitivity pneumonitis