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| Fig. 44.1 Variants of basal cell carcinoma (BCC). A, Nodular BCC demonstrating characteristic dilated blood vessels. B, Noduloulcerative BCC above the eyebrow, demonstrating pearly appearance and central ulceration. C, Large superficial spreading BCC demonstrating multiple small plaques with focal scale and crust. (Panels A and B courtesy of James E. Fitzpatrick, MD.) |
BCCs may have more than one clinical or histologic appearance. The most common presentation is as nodular BCCs, which are typically slow-growing lesions with a smooth or pebbly surface. They characteristically appear translucent or pearly and often demonstrate dilated vessels (Fig. 44-1A). They can gradually break down, bleed, and form ulcers (noduloulcerative BCC, Fig. 44-1B). Superficial spreading BCC are thin lesions that demonstrate a horizontal growth pattern. They present as erythematous, minimally indurated, slow-growing plaques with variable scale that are most commonly located on the trunk (Fig. 44-1C). They can be confused with tinea corporis, nummular dermatitis, or other NMSCs such as Bowen’s disease.
Morpheaform (also desmoplastic or sclerosing) BCCs are a type of infiltrative lesion that may resemble scars or even normal skin. Microscopically, they are composed of narrow cords and strands of basaloid cells that infiltrate between the collagen bundles. This variant can easily be missed, even by experienced dermatologists, and has a higher rate of recurrence after treatment than other BCC subtypes. Their true extent is often much greater than the appearance suggests.
Basal cell carcinomas can also be completely or focally pigmented and mistaken for malignant melanoma. A rare variant of BCC looks like a large skin tag or fibroma. This variant is usually found on the trunk of older men and is called a
Pinkus tumor orfibroepithelioma of Pinkus.
