A 64-year-old man comes to the physician with several lesions on his forehead. The patient has been a gardener for much of his life. The photograph below shows findings from the physical examination. On palpation, the lesions have a rough grainy texture. Biopsy reveals atypical keratinocytes with hyperkeratosis and parakeratosis. This patient's lesions put him at greatest risk for developing which of the following conditions?

Question

A 64-year-old man comes to the physician with several lesions on his forehead.  The patient has been a gardener for much of his life.  The photograph below shows findings from the physical examination.  On palpation, the lesions have a rough grainy texture.  Biopsy reveals atypical keratinocytes with hyperkeratosis and parakeratosis.  This patient's lesions put him at greatest risk for developing which of the following conditions?

Quizplus · Accepted Answer

This patient's forehead lesions are characteristic of actinic keratoses (AKs), which are small, scaly, erythematous lesions with a sandpaper texture occurring on sun-exposed areas. On light microscopy, AKs show hyperkeratosis (hyperplasia of the stratum corneum), parakeratosis (retention of nuclei in the stratum corneum), and atypical keratinocytes with pleomorphic nuclei and multiple mitoses. There may also be pigment irregularities and dilated blood vessels affecting the surrounding skin, which are consistent with chronic sun exposure. AKs do not invade the dermis and are considered to be premalignant lesions. Over several years, a small percentage of AKs transform into invasive squamous cell carcinoma (SCC), a change reflected by an increase in lesion size and thickness, dermal invasion, and metastatic potential. (Choice A) Basal cell carcinoma (BCC) is the most common skin cancer. It arises on sun-exposed areas and has a very low tendency to metastasize (in contrast to melanoma). BCC often presents as pearly papules with central depression or ulceration. Histologically, BCC features nests of basaloid cells and peripheral palisading of nuclei. It is far more likely for AK to progress to SCC than to BCC. (Choice B) Dermatofibromas (superficial benign fibrous histiocytomas) result from the benign proliferation of fibroblasts. They commonly arise on the lower extremities as solitary nodules. (Choice C) Kaposi sarcoma is associated with human herpesvirus-8 (HHV-8) and classically occurs in patients with HIV. Lesions typically appear as palpable macules, plaques, and nodules that are usually a dark brown to violet color. (Choice D) Melanoma is a cancer arising from the malignant transformation of melanocytes. Lesions have irregular borders and marked color variegation. AK is not a precursor to melanoma. (Choice E) Psoriasis commonly presents as hyperkeratotic plaques that affect the scalp, knees, and elbows. It is characterized histologically by clubbed rete ridges, hyperkeratosis, neutrophils in the stratum corneum, and perivascular lymphocytic infiltrates. Educational objective: Actinic keratoses (AKs) are small (usually <1 cm), erythematous epidermal lesions with adherent scale that are the result of chronic sun exposure. Histologic findings include keratinocyte atypia, hyperkeratosis, and parakeratosis. A small percentage of AKs progress to invasive squamous cell carcinoma; therefore, frequent monitoring is necessary. __________ References: The impact of the current United States guidelines on the management of actinic keratosis: is it time for an update? (http://www.ncbi.nlm.nih.gov/pubmed/21103312)

A 64-Year-Old Man Comes to the Physician with Several Lesions