• Common systemic disease
• Etiology unknown
• Widespread noncaseating granulomas, that resolve or cause fibrosis
• May have associated erythema nodosum, uveitis, hypercalcemia, arthritis
• 95% of patients have abnormal chest radiograph with lymphadenopathy and or lung opacities
• HRCT centriacinar nodules along bronchovascular bundles, septa,and periphery of lobule
• Definitive diagnosis with transbronchial, lymph node, or liver biopsy
• Most patients have a good prognosis with resolution of findings in < 2 years
• Major complications include respiratory failure from fibrosis, mycetomas,hemorrhage, and cor pulmonale

Chest radiography

• Abnormal chest radiograph – 95%
• 5 to 15% have normal chest radiograph at onset
  
  • Lymphadenopathy, (80%) most common finding – bilateral hilar/paratracheal
    Usually not visible at 2 years; may persist for many years
    Nodes may calcify, sometimes eggshell calcification
  • Lung disease, (<50%), often manifest with nodal regression
  • Pattern and Distribution:
    • Reticulonodular opacities (90%)
    • Large airspace nodules with air bronchograms
    • Fibrosis mid and upper lung zones
    • Upper lobe cyst formation with aspergilloma

    Stage 0 – clear chest radiograph (5 – 15%, at presentation)

    Stage 1 – lymphadenopathy (45 – 65%); 60% resolve completely

    Stage 2 – lymphadenopathy and lung opacities (30 – 40%)

    Stage 3 – Lung opacities (10 – 15%)

    Stage 4 – fibrosis with or without lymphadenopathy (5 – 25%)

  • Atypical appearance
    • Atypical lymphadenopathy - unilateral hilar, posterior mediastinal
    • Airway compression
    • Unilateral lung disease
    • Cavitary lung lesions
    • Pleural effusion

CT/HRCT

• CT may show lymphadenopathy at left paratracheal, AP window, anterior mediastinum, retroperitoneal
• HRCT, may be abnormal with normal CXR
• Predominantly involves the mid and upper lung zones
• Pattern: 1 – 5 mm centrilobular nodules along brochovascular structures, septa, and periphery of lobule
• Often extends in a swath from the hilum to lung periphery
• Ground glass opacities
• Progressive massive fibrosis, distortion, honeycombing, cysts, bullae, traction bronchiectasis
• Mycetomas in cavities and cysts
• Large and small airway stenoses

• Granulomatous diseases : TB, fungal infection, berylliosis, extrinsic allergic alveolitis
• Diseases with granuloma-like reactions: lymphoma, carcinoma, metastases
• Chronic eosinophilic pneumonia, BOOP

• Common systemic disease
• Widespread noncaseating granulomas, that resolve or cause fibrosis
• Etiology unknown
• Well-formed granulomas ; central epitheliod histiocytes and multinucleate giant cells surrounded by lymphocytes, monocytes and fibroblasts
• Lymphatic distribution

• 10 times more common in blacks, female predominance
• Onset – usually age 20 to 40
• Asymptomatic, or fatigue, malaise, weight loss, fever, respiratory symptoms, erythema nodosum, uveitis, skin lesions, arthropathy, bone lesions
• In < 2% TB precedes sarcoidosis or develops later
• 80% of cases resolve completely; in 20% fibrosis develops that may destroy and distort the lung
• Anemia, leukopenia, elevated sedimentation rate, hypercalcemia, nephrolitiasis
• Cutaneous anergy
• Raised ACE level, not specific
• Diagnosis from lung, lymph nodes, and liver
• Bronchoscopy and transbronchial biopsy – positive in 90% of cases, even if CXR is normal
• BAL – increased CD4/CD8 ratio, nonspecific finding
• Usually not treated; steroids in severe cases
• Recurrence in transplanted lung has been reported
• Prognosis worse in blacks
• Mortality – 2 – 7%; death from respiratory failure, cor pulmonale, hemorrhage

Miller BH, Rosado-de-Christenson ML, McAdams HP, et al. Thoracic sarcoidosis: radiologic-pathologic correlation Radiographics 15:421-437, 1995
Rockoff SD , Rohatgi PK. Unusual manifestations of thoracic sarcoidosis AJR 144:513-528, 1985
Traill ZC, Maskell GF , Gleeson FV. High-resolution CT findings of pulmonary sarcoidosis AJR 168:1557-1560, 1997