A 65-year-old man comes to the office due to 2 months of itching, occasional ulceration, and crusting of a skin lesion on his upper chest. A year ago, the patient was diagnosed with squamous cell carcinoma with perineural invasion at the site of the lesion. Surgical resection with clear margins was achieved, followed by adjuvant radiotherapy to the site. He reports no other symptoms. The patient's lesion is shown in the exhibit.
If a biopsy is performed at the periphery of the lesion, which of the following histologic changes is most likely to be seen?

Question

A 65-year-old man comes to the office due to 2 months of itching, occasional ulceration, and crusting of a skin lesion on his upper chest.  A year ago, the patient was diagnosed with squamous cell carcinoma with perineural invasion at the site of the lesion.  Surgical resection with clear margins was achieved, followed by adjuvant radiotherapy to the site.  He reports no other symptoms.  The patient's lesion is shown in the exhibit. 
 If a biopsy is performed at the periphery of the lesion, which of the following histologic changes is most likely to be seen?

Quizplus · Accepted Answer

11ec160b_3903_94ee_9249_9b6a2573f333_MD0001_00 This patient has a persistent, itchy, ulcerating skin lesion with hypopigmentation and telangiectasias at a site of prior radiotherapy, consistent with late-stage radiation dermatitis. Radiotherapy can be used with excision in the treatment of high-risk, invasive skin cancer to kill remaining cancer cells and decrease recurrence risk. Ionizing radiation causes apoptosis of rapidly dividing cancer cells directly by inducing DNA damage and indirectly by generating free radicals. However, all rapidly dividing cells in the area (eg, hair follicle stem cells, melanocytes, basal keratinocytes) treated by the radiation can be affected, initiating a series of characteristic skin changes: Acute (<90 days after radiotherapy): Apoptosis of basal keratinocytes and epidermal edema Dose-dependent effects ranging from erythema to desquamation (ie, skin peeling), superficial ulceration, and/or blistering Pigment changes and loss of skin appendages (eg, hair follicles, sebaceous glands) Late (months to years after radiotherapy): Fibrosis, characterized histologically by homogenization of dermal collagen, due to fibroblast activation by transforming growth factor-beta from damaged tissue and responding immune cells Vascular damage, resulting in chronic hypoxia and ulceration Abnormal, dilated microvasculature (ie, telangiectasias) (Choice A) Full-thickness epidermal necrosis with subepidermal bullae is characteristic of Stevens-Johnson syndrome/toxic epidermal necrolysis. This systemic immune reaction to certain medications (eg, allopurinol, carbamazepine, sulfonamides) results in fever, skin tenderness, desquamation, and widespread blistering. (Choice C) Neutrophilic infiltrates and elongation of dermal papillae are characteristic of psoriasis vulgaris, which typically causes symmetric, salmon-colored scaly plaques with sharply defined borders. (Choice D) During an urticarial reaction, mast cells release inflammatory mediators and cytokines (eg, IL-5) that can recruit eosinophils, resulting in perivascular collections of eosinophils in and around the urticarial lesion. Urticaria usually manifests as pruritic, erythematous plaques (ie, wheal and flare reaction). Educational objective: Late-stage radiation dermatitis occurs months to years after radiation exposure and is characterized grossly by pigment changes, telangiectasias, and chronic ulceration. Typical histologic changes include vascular abnormalities, fibroblast proliferation, and homogenization of dermal collagen (ie, fibrosis) due to the increased expression of transforming growth factor-beta. __________ References: Chronic radiation-induced dermatitis: challenges and solutions. (http://www.ncbi.nlm.nih.gov/pubmed/28003769)

A 65-Year-Old Man Comes to the Office Due to 2