A middle aged female patient comes with recurrent painful blisters over oral mucosa and genital area. She gives history of similar lesion in the past. A biopsy from the lesion shows suprabasal split on histopathology and IgG deposits in immunofluorescence microscopy as shown below. What is the most likely diagnosis?

**Core Concept**
The patient's symptoms and histopathological findings suggest a chronic autoimmune blistering disease characterized by suprabasal split and the presence of autoantibodies.

**Why the Correct Answer is Right**
The patient's presentation of recurrent painful blisters on the oral mucosa and genital area, along with a history of similar lesions, points towards a chronic autoimmune condition. The biopsy findings of a suprabasal split on histopathology and the presence of IgG deposits in immunofluorescence microscopy are indicative of pemphigus, a group of autoimmune diseases characterized by autoantibodies against desmoglein proteins, which are essential components of the epidermal cell-to-cell adhesion. In pemphigus, the autoantibodies target the desmoglein proteins, leading to a breakdown of the epidermal cell-to-cell adhesion and resulting in blister formation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a distractor for diseases with similar blistering manifestations, but it does not match the histopathological and immunofluorescence findings described in the question.
**Option B:** This option might be a distractor for diseases with mucosal involvement, but it does not match the suprabasal split and IgG deposits seen in pemphigus.
**Option C:** This option might be a distractor for diseases with autoimmune blistering manifestations, but it does not match the specific histopathological and immunofluorescence findings described in the question.

**Clinical Pearl / High-Yield Fact**
Pemphigus is a group of autoimmune diseases characterized by autoantibodies against desmoglein proteins, and it is essential to differentiate it from other autoimmune blistering diseases such as bullous pemphigoid, which shows a subepidermal split.

**Correct Answer:** B. Bullous Pemphigoid.

✓ Correct Answer: B. Pemphigus vulgaris