View source for WBR0804

 {{WBRQuestion
|QuestionAuthor= {{YD}} (Reviewed by  {{YD}})
|ExamType=USMLE Step 1
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|MainCategory=Pathology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|SubCategory=Dermatology
|MainCategory=Pathology
|MainCategory=Pathology
|SubCategory=Dermatology
|Prompt=A 68-year-old man presents to the dermatology clinic complaining of a growing facial ulcer. He explains that the ulcer first developed 3 months ago and has not healed ever since. Physical examination is remarkable for a dark red-colored, asymmetric, ulcerating lesion at the lower lip that measures approximately 1 cm in diameter. Cervical lymphadenopathy cannot be appreciated on physical examination. Skin lesion biopsy demonstrates concentric epithelialized cells with foci of central keratinization. Which of the following is a risk factor for the development of this patient's condition?
|Explanation=Squamous cell carcinoma is a common cancer that affects approximately 100 to 150 per 100,000 persons annually in the United States. Squamous cell carcinoma should be highly suspected in any patient who presents with an ulcerating, non-healing lesion located in a sun-exposed region (such as the face, head, or neck region). Furthermore, physical examination findings, namely the dark-red color, asymmetry, and location at the lower lip, should raise the suspicion of squamous cell carcinoma in this patient. The diagnosis of squamous cell carcinoma requires biopsy, which typically demonstrates concentric epithelialized cells with foci of central keratinization (keratin pearls). The most important risk factor for the development of squamous cell carcinoma of the skin is chronic ultraviolet radiation, often observed among patients with long-standing history of sun exposure and sunburns. Arsenic, which was used in drug manufacturing in the past, is also associated with carcinogenesis and development of squamous cell carcinoma of the skin. Other important risk factors include history of ulcerating or chronic skin lesions (e.g. chronic draining sinuses or osteomyelitis) and precancerous lesions (such as actinic keratosis, bowenoid papulosis, and epidermodysplasia verruciformis). Immunosuppression (transplant, hematologic malignancies, drug-induced), HPV infection (6 and 11), and chronic exposure to ionizing radiation, metal-ore, insecticides, and aromatic hydrocarbons are also predisposing condition. Finally, genetic factors, such as xeroderma pigmentosa or albinisim, are usually associated with the development of early-onset squamous carcinoma of the skin.
|AnswerA=History of heavy smoking
|AnswerAExp=Heavy smoking is associated with several diseases, including cancers. However, history of heavy smoking is not classically associated with the development of squamous cell carcinoma of the skin.
|AnswerB=Chronic silicon exposure
|AnswerBExp=Chronic silicon exposure is associated with the development of pulmonary fibrosis.
|AnswerC=Dark skin
|AnswerCExp=Although all individuals may develop squamous cell carcinoma of the skin, fair skin is a risk factor for the development of squamous cell carcinoma of the skin. 
|AnswerD=Presence of large congenital melanocytic nevus
|AnswerDExp=Large congenital melanocytic nevi are a risk factors for the development of melanoma, not squamous cell carcinoma of the skin.
|AnswerE=Chronic exposure to arsenic
|AnswerEExp=Chronic exposure to arsenic has been associated with the development of squamous cell carcinoma of the skin.
|EducationalObjectives=Squamous cell carcinoma should be highly suspected in any patient who presents with an ulcerating, non-healing lesion at a sun-exposed region. On biopsy, the lesion typically demonstrates concentric epithelialized cells with foci of central keratinization (keratin pearls).Chronic exposure to arsenic has been associated with the development of squamous cell carcinoma of the skin.
|References=Alam M, Ratner D. Cutaneous squamous-cell carcinoma. N Engl J Med. 2001;344:975-83.<br>
First Aid 2014 page 438
|RightAnswer=E
|WBRKeyword=Skin cancer, Squamous cell carcinoma, Keratin pearls, Arsenic, Keratinization, Skin biopsy, Ulcer, Ulcerating lesion, Lower lip
|Approved=Yes
}}