The correct answer is C. This patient has a large basal cell carcinoma, a malignant epithelial neoplasm comprised of cells that resemble hair follicle undifferentiated matrix cells. It is the single most common cancer in humans. The etiology has been linked to excessive sunlight exposure, chemical carcinogens, radiation, and genetic determinants. Clinically, several types are recognized: classic or nodular, superficial, and morpheaform. The nodular type presents as a pink pearly papule or nodule with a rolled border and telangiectasias. It often ulcerates centrally. The course is one of local destruction, and only very large, neglected, and ulcerated basal cell carcinomas have been known to metastasize. The treatment of choice for this patient is Mohs micrographic surgery. In Mohs micrographic surgery, the excision is performed in layers, and during the surgery, frozen sections are prepared that allow viewing of 100% of the margins of excised tissue. If the tumor is viewed close to or near the specially prepared margins, another layer of tissue is excised and frozen sections prepared in the same manner. This procedure is repeated until the margins are clear. Excision of basal cell carcinoma with Mohs micrographic surgery has a recurrence rate of approximately 1%, compared to 8-9% with conventional surgery. It is preferred for lesions that are recurrent, in a high-risk location, are large and ill defined, and in areas where maximal tissue conservation is critical.
Conventional excision with a 4-mm margin (choice A) carries a high risk for “missing” parts of the neoplastic tissue when the lesion is large. In addition, excising with a bigger yet still arbitrary margin on the face, where conservation of tissue is so important, is not practical and makes reconstruction difficult.
Cryosurgery (choice B) is not a good choice for a basal cell carcinoma of such large size because of the lack of margin control and probability that it would cause excessive destruction of the surrounding facial tissue and leave a considerable scar. It is performed by inserting a thermocouple into the central part of the tumor down to subcutaneous tissue, after appropriate local anesthesia is administered, and freezing the area with liquid nitrogen or other cryogens. The depth and length of freezing vary considerably among surgeons and are largely based on experience.
Topical 5-fluorouracil (choice D) is a chemotherapeutic agent that is used for topical treatment of the superficial type of basal cell carcinoma in certain circumstances in which other, more aggressive types of treatment are not indicated, either because of the poor overall health of the patient and associated risk for surgery or because the patient refuses other treatment modalities. It is applied twice daily for a period of 4-6 weeks, leading to ulceration of the tumor and inflammation of the surrounding skin. It is not indicated for treatment of nodular basal cell carcinomas such as the one described.
Imiquimod cream (choice E) is an immune modulator that is FDA approved for the treatment of genital warts. There have been multiple publications of case reports in which it was successfully used for the treatment of superficial basal cell carcinoma in patients in whom more aggressive surgical treatment was not an option. It is not conventional treatment for basal cell carcinoma.