Sarcoidosis is an idiopathic disease characterized by non-caseating granulomas, and although it commonly presents as a pulmonary disease (95% of patients), it can affect virtually any organ system (30% of patients present with an extrapulmonary manifestation). Interestingly, women are more likely to have skin or ocular involvement and men are more likely to have cardiac involvement.
Manifestations by organ system:
- Cutaneous (25%): papular (especially at tattoos and scar sites!), nodular, and plaque disease--but also erythema nodosum and lupus pernio
- Ocular (25%): including uveitis, keratoconjunctivitis sicca, and eyelid or conjunctival granulomas as well as lacrimal gland involvement and orbital masses
- Upper respiratory tract (15%): laryngeal and nasal/sinus disease (can be atrophic or more nodular) DON'T BE FOOLED: sinus granulomatosis can also be associated with granulomatosis with polyangiits and syphilis!
- CV (5% clinical, but autopsy studies up to 70%!): heart block (conduction system abnormalities), arrhythmias, heart failure, valvular dysfunction, pericardial disease, also pulmonary hypertension from severe scarring of the lung parenchyma
- Reticuloendothelial system: peripheral lymphadenopathy, hepatosplenomegaly and liver/spleen granulomas/nodules
- Musculoskeletal system (10%): symmetric polyarthritis (especially the ankle joints), which is actually a periarthritis
- Renal: hypercalcemia (from excess calcitriol from activated macrophages) leading to nephrocalcinosis and nephrolithiasis as well membranous nephropathy and GNs
- Central Nervous System (5%): peripheral neuropathy, cranial mononeuropathy (commonly Bells palsy), and aseptic meningitis
- Exocrine/endocrine: salivary/parotid glands (with xerostomia and dry eye similar to Sjogrens and IgG4 related disease) and anterior pituitary and thyroid infiltration
Biopsy is often required to make the diagnosis--but certain cases such as presentations of Lofgren syndrome (erythema nodosum, hilar adenopathy, migratory polyarthralgia, and fever) are so classic that biopsy is not necessary.
Most often, sarcoidosis is benign--but no clinical parameters allow an accurate prediction of the clinical course of this disease. Lung fibrosis, cutaneous disease, and neurologic disease do suggest chronicity. Some extrapulmonary manifestations require prompt treatment as summarized in this In the Clinic article from Annals 2012: