A 67-year-old woman presents to her primary care physician for evaluation of persistent skin lesions on her upper extremities for the past 2 weeks. She states that the lesions begin as blisters before popping and becoming painful erosions. Her past medical history is significant for cystinuria treated with penicillamine. On physical examination, she has numerous bullae and erosions on her upper extremities, with similar erosions on her oral mucosa. The bullae are Nikolsky sign positive.
Which of the following best describes the most likely histologic appearance of this patient’s lesions?
A) Acantholysis with “tombstoning” of basal keratinocytes
This patient is presenting with pemphigus vulgaris, an autoimmune bullous condition caused by IgG antibodies directed at desmosomes. Mucosal involvement and a positive Nikolsky sign (lateral expansion of bullae upon gentle pressure) distinguish this condition from bullous pemphigoid. Pemphigus vulgaris is often idiopathic but may also be drug induced. Penicillamine, used to treat cystinuria, is a common offending agent.
Answer choice B: Acanthosis and hyperkeratosis with koilocytic nuclear change, is incorrect. This describes verrucae, which are caused by infection with human papillomavirus (HPV). These lesions have a warty appearance and present as raised, rough papules.
Answer choice C: Acanthosis with persistence of nuclei in the stratum corneum, is incorrect. This describes psoriasis, which typically presents as silvery scaling on extensor surfaces.
Answer choice D: Nests of basal cells with peripheral palisading, is incorrect. This describes basal cell carcinoma (BCC), which is the most common human malignancy. BCC typically presents on sun-exposed areas as a pearly nodule with rolled edges, central ulceration, and telangiectasias.
Answer choice E: Thickening of the stratum spinosum, is incorrect. This describes the changes associated with acanthosis nigricans, which is commonly seen in diabetes mellitus or as a sign of gastric malignancy.
Key Learning Point
Pemphigus vulgaris is a type II hypersensitivity reaction characterized by autoantibodies against desmosomes, leading to flaccid bullae on physical exam and acantholysis on histology.
