A patient presents with painful lesions on the buccal mucosa, and the biopsy shows acantholysis and supra basilare. What is the diagnosis?

The diagnosis of pemphigus vulgaris is supported by the presence of acantholysis and suprabasal clefting observed in the biopsy of the patient's lesions. Acantholysis refers to the loss of cohesion between keratinocytes, which results in the formation of blisters in pemphigus vulgaris. The defining characteristic of this condition is the disruption that occurs above the basal layer of the epithelium, leading to suprabasal lesions.

This autoimmune disorder primarily targets the desmosomes—the structures responsible for cell adhesion in the epidermis—resulting in painful oral lesions and skin blisters. The painful nature of the buccal mucosal lesions is also typical in pemphigus vulgaris, which aligns well with the clinical presentation of the patient.

In contrast, other conditions such as bullous lichen planus typically feature different histological findings, including a band-like infiltrate of lymphocytes at the basement membrane, rather than acantholysis. Erythema multiforme is associated with target lesions and often involves the skin more prominently than the oral mucosa, without the same levels of acantholysis. Systemic lupus erythematosus can cause oral lesions, but they do