Basal cell carcinoma (BCC) subtypes are often misidentified in standard punch and shave biopsy specimens, some of which are ultimately determined to have an aggressive component, according to research published in the January issue of the Journal of the American Academy of Dermatology.
Andrea L. Haws, M.D., of the Baylor College of Medicine in Houston, and colleagues systematically evaluated the correlation of 232 biopsy specimens for subtyping BCC (88 percent shave and 12 percent punch) with the follow-up wide excision. BCC subtype was identified based on standard histopathologic characteristics. Nonaggressive subtypes consisted of superficial and nodular patterns, while micronodular, infiltrative, morpheaform, and metatypical patterns constituted an aggressive subtype.
The researchers found that, overall, 54 percent of BCC specimens were of mixed histologic subtype, and half of these had an aggressive component. The remaining 46 percent of the specimens were single subtypes, of which 30 percent were nodular, 12 percent were superficial, and 4 percent were aggressive subtypes. Although biopsy provided accurate sampling for correct BCC subtyping in the majority of cases (82 percent), 18 percent of biopsy specimens were misidentified. In 40 percent of these discordant cases (7 percent of the total cases), an aggressive component was found in the excision that was not identified in the biopsy specimen. Additionally, among these discordant cases, 19 percent of biopsy specimens were classified as infiltrative but no infiltrative tumor was found in the final excision.
"Because superficial and aggressive growth patterns reflect the biologic behavior of the tumor and can affect treatment, it is important that pathologists and dermatologists are aware of the potential diagnostic pitfalls in BCC subtyping in biopsy specimens," the authors write.
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