Sarcoidosis

Sarcoidosis is a chronic systemic granulomatous disease of unknown etiology, characterized by the presence of noncaseating granulomas in any organ system of the body. Involvement of the head and neck is noted in 10% to 15% of patients (17). Please see Chapter 6 for a detailed discussion of sarcoidosis.

Epidemiology. Sarcoid has a slight female preponderance and occurs in all age groups, although more commonly in young adults.

Pathogenesis. An etiology for sarcoid has not been established. Hallmark pathologic findings for the disorder include noncaseating granulomata consisting of modules of epithelioid histiocytes surrounded by a mixed inflammatory infiltrate (Fig. 7). Intracytoplasmic inclusions, asteroid and Schaumann bodies, can be seen. Special stains for a multiplicity of microorganisms are noted to be negative.

Clinical Manifestations. Any organ system may be affected by sarcoid, but pulmonary and cutaneous involvement are typically noted. Otolaryngologic signs and symptoms include cervical lymphadenopathy (occurring in 50% of patients affected with head and neck disease), pharyngotonsillitis, nasal discharge and epistaxis, and salivary gland enlargement. Concurrent involvement of the uveal tract and parotid gland, "uveoparotid fever" or "Heerfordts syndrome," may be accompanied by facial nerve palsy.

Diagnosis. The differential diagnosis of sarcoid includes mycobacterial infection, fungal disease, and cat-scratch syndrome. The confirmation of sarcoid is usually secured with a demonstration of the typical histiologic characteristics on tissue biopsy in the absence of an identifying infectious agent. The recommended evaluation of patients with suspected sarcoid includes chest radiographs, PPD with anergy panel, serum profile including liver function studies, erythrocyte sedimentation rate (ESR), and angiotensin

FIGURE 8 Histologic section from lymph node affected by sarcoidosis demonstrating non-caseating granulomas. Source: Photo courtesy of Dr. Robert Brown.

converting enzyme (ACE) levels. Although the ESR is elevated in most patients with sarcoid, it is nonspecific. The ACE level is elevated in the majority (80%) of patients with sarcoid but may be elevated in other rare granulomatous entities (Gaucher's disease and leprosy) and is not pathognomonic. However, when the clinical suspicion for sarcoid is high, elevation in ACE will support the diagnosis of the disease. Further, the ACE level will indicate the activity of the disease and thus may serve to assess treatment response.

Treatment. Therapy for sarcoid, especially for early-stage asymptomatic disease, is usually not necessary, because the disorder frequently undergoes spontaneous remission. Patients with more advanced disease, such as those with symptomatic pulmonary involvement, are treated with systemic corticosteroids; the majority responds favorably to treatment.

Prognosis. Most patients (70%) experience spontaneous resolution or successful treatment of disease. A small percentage of patients progress to advanced multisystem disease, leading to restrictive pulmonary disease and respiratory failure.

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