Discussion:
In nodular BCC aggregates of basaloid cells extend from the epidermis into the dermis with surrounding connective tissue stroma. Peripheral palisading of cells and stroma retraction artifact aid in diagnosis. Frequently in Mohs sections, differentiating BCC from benign hair follicles is necessary. Ordering a recut slide (shown above) may help secure the diagnosis of BCC. Helpful clues to differentiate follicle from BCC include: 1) BCC shows subtle stroma retraction artifact even in frozen sections; 2) Typical peripheral palisading may not present but BCC cells tend to be more basophilic and crowded with haphazard arrangement of center cells; 3) As opposed to BCC, morphology of a hair follicle (for example, hair shaft keratin, inner root sheath, and out root sheath) may become more evident when one tracks multiple subsections; and 4) one would not usually see vellus hair follicles in the deeper portion of the dermis but may see structures such as basophilic hair bulbs.
