Correlation between histologic findings on punch biopsy specimens and subsequent excision specimens in recurrent basal cell carcinoma

Background: The type of treatment for a basal cell carcinoma (BCC) depends on the histologic subtype. Histologic examination is usually performed on incisional biopsy specimens. In primary BCC, the histologic subtype is correctly identified with a punch biopsy in 80.7% of cases. In recurrent BCC, correct identification is more difficult because of discontinuous growth caused by scar formation. Because an aggressive histologic subtype has a significantly higher risk for recurrence in these tumors, the histologic subtype is at least as important in recurrent BCC as it is in primary BCC. Objective: To investigate the correlation between histologic findings on punch biopsy specimens and subsequent excision specimens in recurrent BCC. Furthermore, we sought to clarify how often an aggressive histologic subtype was missed, based on the punch biopsy specimen. Methods: We compared the histologic subtype in a punch biopsy specimen with the subsequent excision specimen in recurrent BCC. All BCCs were coded and judged randomly by the same dermatopathologist. Results: In 24 of 73 investigated BCCs (32.9%), the histologic subtype of the initial biopsy did not match with the histologic subtype of the subsequent excision. Of the 37 excised BCCs with an aggressive histologic subtype, 7 (19%) were missed by the initial punch biopsy. Limitations: Intraobserver variation may have affected the results of this study. Conclusions: Discriminating tumors with any aggressive growth is relevant for treatment. However, in recurrent BCC, the histology of the biopsy specimen does not always correlate with the histology of the definitive excision. This may have important therapeutic implications. (J Am Acad Dermatol 2011;64:323-7.)