American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which histological feature is often observed in basal cell carcinoma?

1. Keratin pearls

2. Peripheral palisading nuclei

3. Increased mitotic figures

4. Large atypical nuclei

The correct answer is: Peripheral palisading nuclei

Basal cell carcinoma is characterized by specific histological features that aid in its identification. One prominent feature is the presence of peripheral palisading nuclei. This refers to the arrangement of nuclei at the edges of nests of tumor cells that resemble a fence or palisade. This pattern is indicative of the proliferation of basaloid cells, which are typical in basal cell carcinoma. In contrast, keratin pearls are associated with squamous cell carcinoma, not basal cell carcinoma, where the tumor cells are more differentiated. Increased mitotic figures can indicate higher levels of cell division commonly seen in more aggressive tumors, but they are not a distinguishing feature of basal cell carcinoma specifically. Large atypical nuclei often suggest malignancy; however, they reflect a more undifferentiated state and are less characteristic of basal cell carcinoma specifically compared to peripheral palisading. Thus, the presence of peripheral palisading nuclei serves as a key histological marker for diagnosis in cases of basal cell carcinoma.