All are features of sarcoidosis except
**Core Concept**
Sarcoidosis is a systemic granulomatous disease characterized by the formation of non-caseating granulomas in various organs, most commonly the lungs and lymph nodes. The pathophysiology of sarcoidosis involves an abnormal immune response with an overproduction of Th1 lymphocytes and the release of cytokines such as TNF-alpha and IFN-gamma.
**Why the Correct Answer is Right**
Sarcoidosis typically presents with bilateral hilar lymphadenopathy on chest X-rays, and patients may experience symptoms such as cough, dyspnea, and fatigue. The disease can also affect other organs, including the skin, eyes, heart, and nervous system. The granulomatous inflammation in sarcoidosis leads to an increase in serum angiotensin-converting enzyme (ACE) levels, which is used as a diagnostic marker.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hypercalcemia is a common feature of sarcoidosis due to increased vitamin D production by activated macrophages in granulomas.
**Option B:** This option is incorrect because erythema nodosum is a skin manifestation of sarcoidosis, characterized by tender, erythematous nodules on the lower extremities.
**Option C:** This option is incorrect because uveitis is a common ocular manifestation of sarcoidosis, characterized by inflammation of the uveal tract.
**Clinical Pearl / High-Yield Fact**
Sarcoidosis is a classic example of a disease that can mimic other conditions, such as tuberculosis, lymphoma, and rheumatoid arthritis. A high index of suspicion and a thorough clinical evaluation are essential for making an accurate diagnosis.
**Correct Answer:** D