**Question:** Enlarging dot sign in fundus fluorescein scanning is seen in -

A. Diabetic retinopathy
B. Central serous chorioretinopathy
C. Retinal vein occlusion
D. Branch retinal vein occlusion

**Core Concept:**
The dot sign is a characteristic finding in retinal vascular diseases. In fundus fluorescein angiography, it represents leakage from small retinal capillaries due to impaired blood-retinal barrier function or occlusion of the capillaries. Enlarging dot sign indicates progression of the disease.

**Why the Correct Answer is Right:**

The correct answer is **B. Central serous chorioretinopathy (CSCR)**. Central serous chorioretinopathy is a condition characterized by the accumulation of fluid under the retina, leading to swelling and potential vision loss. In CSCR, the enlarging dot sign represents leakage from the choriocapillaris layer due to impaired blood-aqueous barrier, causing fluid accumulation in the subretinal space.

**Why Each Wrong Option is Incorrect:**

**A. Diabetic retinopathy (DR)**
Diabetic retinopathy is a complication of diabetes affecting the blood vessels in the retina. While it may have a dot sign, the dot sign in DR is typically small, not enlarging.

**C. Retinal vein occlusion (RVO)**
Retinal vein occlusion (RVO) can cause a dot sign due to leakage, but the dot sign in RVO is usually small and static, not enlarging.

**D. Branch retinal vein occlusion (BRVO)**
Similar to retinal vein occlusion, the dot sign in BRVO is usually small and static, not enlarging.

**Why the Correct Answer is Right:**

Central serous chorioretinopathy (CSCR) is characterized by the accumulation of fluid under the retina, leading to the enlarging dot sign in fundus fluorescein angiography. CSCR often occurs in young adults and can present with visual disturbances, blurred vision, and scotomas. The enlarging dot sign is a distinguishing feature of CSCR, helping differentiate it from other retinal disorders.

**Clinical Pearl:**
Central serous chorioretinopathy may present with a combination of symptoms and findings, making a thorough examination crucial for diagnosis. The enlarging dot sign in fundus fluorescein angiography aids in distinguishing CSCR from other retinal disorders, such as diabetic retinopathy, retinal vein occlusion, and branch retinal vein occlusion.

Understanding the core concept of enlarging dot sign in fundus fluorescein angiography can be helpful in making an accurate diagnosis and guiding treatment decisions for patients presenting with visual disturbances and retinal leakage.