Basal cell carcinoma (BCC) is the most common type of skin cancer and is also one of the most common forms of neoplastic disease generally. Although it is not usually very difficult to diagnose BCC, the multiple morphologic variants of the disease can give rise to various—and in some cases compromised—differential diagnoses. One such variant is the cylindromatous pattern or phenotype, which has been described only rarely in the literature and is not mentioned in the main dermatopathology textbooks.1–3

A 91-year-old man with skin phototype II consulted with our dermatology department for an erythematous, nonulcerated papule on the left cheek that had appeared 4 months earlier and had a maximum diameter of 1cm. A clinical diagnosis of BCC was established and the lesion was excised. Histologic examination revealed an extremely thin, monostratified epidermis under focal pressure from numerous geographic basaloid nodules in the dermal layer that reached the depth of the dermal-hypodermal junction (0.5cm) (Fig. 1). The surfaces of the proliferating geographic nests were joined to the stratum basale, from which they appeared to originate. The lesional cells showed mild-to-moderate atypia and were arranged in palisades on the periphery of the nodules, which were surrounded by retraction artifact (Fig. 2). Although there were cystic changes in some basaloid nodules, in others a striking cylindromatous pattern was present. The cylindromatous pattern was defined by the presence of an intensely collagenized and hyalinized stroma around the tumor nodules, with the presence of hyaline prolongations extending toward the center of the nodules, forming well-defined terminal cylinders and creating an appearance similar to that of cylindromas (Fig. 3). With the application of periodic acid–Schiff and Alcian blue staining techniques, the cylindromatous structures were stained magenta while the cystic structures were stained blue, demonstrating their mucinous content. An intense lymphocytic infiltrate was observed in the peritumoral stroma. On the basis of these findings, a diagnosis of nodular BCC with a cylindromatous phenotype was established. The recommended treatment, excision with free margins, was sufficient. The lesions have not recurred after 1 year of follow-up.

Figure 1.

Basal cell carcinoma with a cylindromatous pattern. Macroscopic and microscopic image showing basaloid cells infiltrating the dermis.

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Figure 2.

Basal cell carcinoma with a cylindromatous pattern. Detail of a tumor cell nest composed of basaloid cells forming peripheral palisades surrounded by retraction artifact. Abundant amorphous, hyaline, basement-membrane-type material is observed inside the tumor (hematoxylin-eosin, original magnification ×100).

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Figure 3.

Basal cell carcinoma with a cylindromatous pattern. Both images show various tumor areas characterized by the presence of amorphous, hyaline material surrounded by basal cells with mild-to-moderate atypia (hematoxylin-eosin, original magnification ×200 and ×400).

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The cylindromatous component can be present in addition to any of the classic BCC patterns, which would provide a clue to the correct diagnosis.4–6 The cylindromatous component can be predominant in some cases (as in our patient) or can be the only component present. In such cases, it is useful to check for nuclear atypia, which is mild-to-moderate in BCC and absent in common cylindroma, the main histologic differential diagnosis. The presence of peripheral palisading and retraction artifact around the tumor cell nests, although nonspecific, is useful in making a differential diagnosis with adnexal lesions that have a cylindromatous phenotype.1 One such lesion is cylindromatous carcinoma, which, as is common in malignant adnexal neoplasms, exhibits greater cellular pleomorphism, frequent mitotic figures, some atypias, and foci of necrosis—rare findings in BCCs. Immunohistochemical techniques do not appear to play an important role in the diagnosis of neoplasms with a cylindromatous pattern.1–3