Pulmonary Sarcoidosis
Definition
- Multisystem disease, usually involving the lung, characterized by noncaseating granulomas
Diagnostic Criteria
- Lung is involved in >90% of cases
- Other organs include heart, eye, kidney, liver, skin
- Noncaseating granulomas
- Tight, well-formed granulomas
- Composed of epithelioid histiocytes and/or multinucleated giant cells
- Sharply circumscribed from surrounding normal lung
- Generally non-necrotizing granulomas
- Small foci of necrosis can be seen, but no caseation (area of acellular necrosis surrounded by histiocytes and giant cells)
- It is especially important to rule out infection in such cases
- Small foci of necrosis can be seen, but no caseation (area of acellular necrosis surrounded by histiocytes and giant cells)
- Mild to moderate surrounding inflammation at most
- Usually "naked granulomas"
- Inclusions frequently seen in giant cells (supportive but not diagnostic of sarcoid)
- Asteroid bodies
- Central core with radiating spikes
- Not birefringent
- 5-30 microns
- Schaumann/conchoid bodies
- Lamellar calcifications
- Largely calcium carbonate, may polarize
- 0.2-1.8 microns
- Hamazaki-Wesenberg bodies
- Oval, yellow-brown bodies
- Frequently appear to bud, simulating yeast
- Not birefringent
- 1-15 microns
- Positive on GMS and AFB stains
- Calcium oxalate
- Irregular birefringent crystals
- 20-150 microns
- Asteroid bodies
- Tight, well-formed granulomas
- Lymphatic pattern of involvement is usually seen
- Follows bronchovascular bundles, interlobular septa and pleura (late in disease)
- Frequently involves submucosa of bronchioles and bronchi
- Results in high yield on bronchoscopic biopsy
- May compress the airway lumen
- With increasing age of lesions, fibrosis may become dominant
- Concentric hyalinizing fibrosis around granulomas
- May compress airways and vessels
- Predominantly involves upper and mid lung fields
- May rarely progress to honeycomb change or cavitation
- Vasculitis seen in over half of cases
- Infiltration of adventitia and media of arteries and veins by any or all of the following:
- Granulomas, giant cells, lymphocytes and plasma cells
- May lead to obstruction and pulmonary hypertension
- Infiltration of adventitia and media of arteries and veins by any or all of the following:
- Rare cases present as nodular sarcoidosis
- Confluent nodule of granulomas
- Usually 1-5 cm
- Usually multiple
- Very rare cases show necrotizing sarcoid granulomatosis
- Variable amounts of necrosis in the presence of sarcoid-like granulomatous pneumonitis and granulomatous vasculitis
- Usually multiple nodules 1-5 cm
- It is especially important to rule out infection
- Localized sarcoid-like reactions can be seen adjacent to neoplasms and other lesions and in draining nodes
- True sarcoidosis is not focal
- Sarcoidosis is a diagnosis of exclusion; the following must be ruled out in every case
- Infection, especially fungi and mycobacteria
- Hypersensitivity pneumonitis
- Collagen vascular disease
- Drug reaction
- Metals/minerals
reaction
- Beryllium and rarely aluminum or talc
Gerald J Berry MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
