**Question:** Dermatomyositis associated with Anti-Mi2 antibodies shows strong association with

A. Systemic sclerosis
B. Sjogren's syndrome
C. Polymyositis
D. Systemic lupus erythematosus

**Core Concept:** Dermatomyositis is a group of rare autoimmune diseases characterized by inflammation of the muscles and skin. Anti-Mi2 antibodies are a specific marker for dermatomyositis, particularly in the subtype called "anti-melanoma differentiation-associated gene 5 (MDA5) associated dermatomyositis." The disease typically affects adults and is associated with specific clinical features and laboratory findings.

**Why the Correct Answer is Right:** Dermatomyositis associated with Anti-Mi2 antibodies shows strong association with Polymyositis (C). Polymyositis is another autoimmune disorder affecting the muscles, and the combined presence of dermatomyositis and polymyositis indicates a more aggressive form of the disease.

**Why Each Wrong Option is Incorrect:**

A. Systemic sclerosis (scleroderma): This disease is characterized by fibrosis (scarring) of the skin and internal organs, distinct from the muscle inflammation seen in dermatomyositis.
B. Sjogren's syndrome: This is an autoimmune disorder affecting the exocrine glands, particularly salivary and lacrimal glands, and is not associated with dermatomyositis or anti-Mi2 antibodies.
D. Systemic lupus erythematosus: This is a systemic autoimmune disease affecting multiple organs, including skin, joints, kidneys, and blood vessels, but it is not specifically associated with dermatomyositis or anti-Mi2 antibodies.

**Clinical Pearl:** Dermatomyositis associated with Anti-Mi2 antibodies is a rare but important clinical entity to recognize, as it indicates a more aggressive disease course and requires prompt diagnosis and treatment initiation.

**Correct Answer:** Polymyositis (C)