Hilar lymph nodes are exapanded by coalescing sheets of epithelioid granuolomas. Touton giant cells composed of a ring of peripheral nuclei are present.
Back to back granulomas composed of plump epithelioid histiocytes with scant remaining lymphoid cells are seen.
Occasionally calcification of multinucleated giant cells is noted.
Sarcoidosis is a multisystem disease characterized by the proliferation of non-caseating granulomas usually in the lung or lymph nodes. The clinical course varies from indolent and mild to a severe debilitating disease.
Tends to occur in young adults, with a peak incidence in ages 20-29. About 60% are asymptomatic, but when symptoms do occur they are often vague such as fatigue, weight loss, arthralgias, etc. Rashes, papules and skin nodules may appear-- skin lesions may be granulomatous or non-specific.
One can develop the combination of erythema nodosum, bilateral hilar lymphadenopathy and arthralgia, referred to as Löfgren syndrome. Involvement of the liver, heart, or brain can lead to symptoms related to these organs such as arrhythmias for cardiac involvement, 7th nerve paralysis in neurosarcoid, etc. Uveitis, lacrimal gland enlargement and parotitis are also potential problems.
Most individuals do not require treatment and remain asymptomatic, while some requiring treatment respond to steroids, and others do not. For unresponsive patients, methotrexate or azathioprine may be employed.
The natural course is extremely variable. Radiographic remission is most likely in those with mediastinal adenopathy alone, without direct pulmonary involvement. 10-30% develop chronic pulmonary problems such as pulmonary fibrosis, pulmonary hypertension and/or bronchiectesis, and most sarcoid-related deaths are pulmonary related. Patients carry increased risk of cancer, such as lung cancer and lymphoma. Sarcoid can also develop in the setting of malignancy.