Which of the most commonest organ involved in sarcoidosis
**Core Concept**
Sarcoidosis is a systemic granulomatous disease characterized by the formation of non-caseating granulomas in various organs. The pathophysiology of sarcoidosis involves an exaggerated cellular immune response, with an imbalance between Th1 and Th2 CD4+ T cells, leading to the activation of macrophages and the formation of granulomas.
**Why the Correct Answer is Right**
The most commonly affected organ in sarcoidosis is the lung, specifically the hilar lymph nodes and the lung parenchyma. This is due to the high concentration of macrophages and dendritic cells in the lung, which are involved in the initiation of the immune response. The granulomatous inflammation in the lung can lead to symptoms such as cough, dyspnea, and chest pain.
**Why Each Wrong Option is Incorrect**
* **Option A:** Skin involvement is common in sarcoidosis, but it is not the most commonest organ involved.
* **Option B:** Liver involvement is seen in a significant proportion of patients with sarcoidosis, but it is not the most frequently affected organ.
* **Option D:** While cardiac involvement can occur in sarcoidosis, it is a less common manifestation of the disease compared to lung involvement.
**Clinical Pearl / High-Yield Fact**
Sarcoidosis can present with a wide range of symptoms, including respiratory, dermatological, and ocular manifestations. A high index of suspicion is necessary for diagnosis, as the disease can mimic other conditions such as tuberculosis and lymphoma.
**Correct Answer:** A. Lung.