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BCC subtypes varied between biopsy, excision specimens

The different subtypes of basal cell carcinoma identified as a result of biopsy specimen may vary from the subtypes identified by way of excision, a study has found.

Researchers reviewed histologic results of 100 basal cell carcinoma (BCC) biopsy specimens and their corresponding excisions. The mean age of the patients (48 women, 52 men) in the study was 69 years. A patient’s age was statistically significant with lesion depth (P=.0359).

The researchers recorded the anatomic site, subtype, maximum depth of extension, the contour of the lobules at the leading edge, elastosis characteristics, the presence of necrosis, calcification, and ulceration. They analyzed the concordance between the biopsy specimens and their excisions, concentrating on tumor lobule depth.

Of the biopsy specimens, 59 were classified as nodular, 23 as superficial, 13 as micronodular and five as infiltrative. The results showed a 62% concordance between the subtype of biopsy specimen and the corresponding excision. Forty-four percent of biopsy specimens included a secondary subtype.

The greatest mean depth was found in micronodular tumors (2.01 mm), followed by infiltrative (1.82 mm), nodular (1.68 mm), and superficial (0.71 mm) subtypes.

Subtype reported from biopsy specimens (P=.0002) and excision (P<.0001) mainly correlated to depth. On review of a subsequent excision specimen, 21 lesions (26%) of the 82 initially classified as superficial or nodular on the biopsy specimen were reclassified as micronodular or infiltrative type. A micronodular or infiltrative component was evident in the original biopsy specimen, however, in eight of those lesions (38%).

The researchers noted that their study was limited because BCCs were examined only by standard excision and no other method.

“Although age, elastosis location, and necrosis may be clues to the depth of tumor infiltration, morphologic subtype has the highest correlation with depth,” the researchers said. “Biopsy reporting of BCC should reflect the highest risk growth pattern if a biopsy specimen contains more than one pattern.”