B/L hilar lymphadenopathy, along with non caseating granulomas is a characteristic feature of-
**Core Concept**
Bilateral hilar lymphadenopathy (BHL) with non-caseating granulomas is a characteristic feature of sarcoidosis, a multisystemic immune-mediated disorder. Sarcoidosis is characterized by the presence of non-caseating granulomas in affected organs, including the lungs. The exact cause of sarcoidosis is unknown, but it is believed to result from an abnormal immune response to an unknown antigen.
**Why the Correct Answer is Right**
In sarcoidosis, the formation of non-caseating granulomas is thought to result from an abnormal immune response, involving the activation of T-lymphocytes and the release of cytokines such as interferon-gamma. The granulomas in sarcoidosis are typically composed of tightly packed epithelioid cells, lymphocytes, and often, multinucleated giant cells. The hilar lymphadenopathy in sarcoidosis results from the accumulation of activated T-lymphocytes in the lymph nodes. The lungs are the most commonly affected organs in sarcoidosis, and the presence of non-caseating granulomas is a hallmark of the disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while tuberculosis can also cause lymphadenopathy, it typically results in caseating granulomas, which are different from the non-caseating granulomas seen in sarcoidosis.
**Option B:** This option is incorrect because histoplasmosis can cause lymphadenopathy and granulomas, but it typically results in caseating granulomas and is more common in individuals with compromised immune systems.
**Option C:** This option is incorrect because Wegener's granulomatosis can cause granulomas, but it is a vasculitic disorder that primarily affects the respiratory tract and kidneys, and is characterized by the presence of anti-neutrophil cytoplasmic antibodies (ANCA).
**Option D:** This option is incorrect because lymphoma can cause lymphadenopathy, but it is typically characterized by the presence of malignant lymphocytes and is not associated with non-caseating granulomas.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the presence of non-caseating granulomas in the lungs, along with bilateral hilar lymphadenopathy, is highly suggestive of sarcoidosis. However, other conditions, such as tuberculosis and lymphoma, should also be considered in the differential diagnosis.
**Correct Answer:** C.