A 35-year-old man comes to the office for evaluation of a rash on his elbows. The patient has had this rash intermittently for several months, but lately, it has become more persistent and bothersome. He has had mild associated itching but no pain and has tried a topical moisturizing lotion without relief. The patient installs tile floors for a residential construction company. He has no chronic medical conditions and takes no regular medications. The patient does not use tobacco, alcohol, or illicit drugs. Vitals signs are within normal limits. The rash on his elbow is shown below, and a similar rash is present on the other elbow. Which of the following histologic changes would be most likely if this patient's skin lesion were biopsied?

Question

A 35-year-old man comes to the office for evaluation of a rash on his elbows.  The patient has had this rash intermittently for several months, but lately, it has become more persistent and bothersome.  He has had mild associated itching but no pain and has tried a topical moisturizing lotion without relief.  The patient installs tile floors for a residential construction company.  He has no chronic medical conditions and takes no regular medications.  The patient does not use tobacco, alcohol, or illicit drugs.  Vitals signs are within normal limits.  The rash on his elbow is shown below, and a similar rash is present on the other elbow.  Which of the following histologic changes would be most likely if this patient's skin lesion were biopsied?

Quizplus · Accepted Answer

11ec160b_3902_837d_9249_47cba7e06b67_MD0001_00 This patient has scaly, erythematous plaques consistent with psoriasis. Psoriasis is most common in areas exposed to pressure or friction, such as the extensor surfaces of the elbows and knees, and minor trauma can often precipitate the formation of lesions (Koebner phenomenon). In predisposed individuals, disruption of the epithelial barrier leads to activation of antigen-presenting dendritic cells and subsequently to a self-reinforcing inflammatory cascade characterized by recruitment and activation of T helper cells and proliferation of keratinocytes. On histology, this results in hyperkeratosis (thickening of the stratum corneum) and parakeratosis (retention of nuclei in the stratum corneum), which produce the characteristic silvery scales seen on gross examination. Additional changes include diffuse epidermal hyperplasia (acanthosis), often with elongated and clubbed rete ridges corresponding to the typical erythematous plaques. Perivascular lymphocytes and dilated dermal capillaries are also seen. (Choice B) A granuloma is a localized, nodular, inflammatory structure composed of aggregates of epithelioid macrophages and multinucleated giant cells. They are seen in a variety of infectious (eg, tuberculosis) and autoimmune (eg, sarcoidosis) diseases but are not seen in psoriasis. (Choice C) Eosinophilic infiltrates are a common finding in pemphigus vulgaris, atopic skin diseases (eg, atopic eczema, allergic contact dermatitis), and dermatitis herpetiformis. These disorders generally present with vesicle or bulla formation, fragility of the skin, and, often, intense itching. Plaques and scaling, when present, are mainly due to persistent scratching. (Choice D) Actinic keratosis is characterized by hyperkeratosis and squamous dysplasia and is considered a premalignant lesion to squamous cell carcinoma. It is typically related to chronic ultraviolet exposure and is most common on sun-exposed areas of the scalp, ears, face, and dorsum of the hands. (Choice E) Thinning of the epidermis is a common feature of scleroderma. Although patients with psoriasis treated with high-potency corticosteroids can develop skin atrophy over time, it is not a presenting feature of the disorder. Educational objective: Psoriasis is characterized on histology by hyperkeratosis and confluent parakeratosis of the stratum corneum (producing the characteristic silvery scales seen on gross examination), diffuse epidermal hyperplasia with elongated and clubbed rete ridges (corresponding to the typical erythematous plaques), and dilated capillaries in the dermal papillae.

A 35-Year-Old Man Comes to the Office for Evaluation of a Rash