**Question:** Biopsy of the parotid gland in a patient with Sjogren's syndrome shows -

A. lymphocytic infiltration
B. fibrosis
C. atrophy
D. ductal plugging

**Correct Answer:** .

**Core Concept:** Sjogren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, leading to dysfunction and eventually glandular atrophy. The parotid gland biopsy is a diagnostic tool used to confirm the presence of Sjogren's syndrome.

**Why the Correct Answer is Right:** In a patient with Sjogren's syndrome, the parotid gland biopsy demonstrates lymphocytic infiltration, which is characteristic of this condition. This infiltration involves lymphocytes, plasma cells, and other immune cells, causing inflammation and destruction of the glandular tissue.

**Why Each Wrong Option is Incorrect:**

A. Lymphocytic infiltration: This is the correct answer and thus not relevant to be considered wrong.
B. Fibrosis: While fibrosis can occur in advanced stages of Sjogren's syndrome, the primary finding on parotid gland biopsy is lymphocytic infiltration.
C. Atrophy: Atrophy is a consequence of the lymphocytic infiltration and fibrosis that occurs over time, not a primary finding on biopsy.
D. Ductal plugging: This is a consequence of the gland dysfunction caused by the inflammation and fibrosis in Sjogren's syndrome, not a primary finding on biopsy.

**Clinical Pearl:** Biopsy of the parotid gland is essential in confirming the diagnosis of Sjogren's syndrome, as it reveals the characteristic lymphocytic infiltration, which is not present in other conditions with glandular dysfunction. This helps differentiate Sjogren's syndrome from other autoimmune conditions like Sjogren's disease and Sjogren's triad.