Superficial Basal Cell Cancers Demonstrate Higher Rates of Mixed Histology on High-Risk Anatomical Sites

Abstract

BACKGROUND The Mohs Appropriate Use Criteria (MAUC) have come into question recently regarding the most appropriate treatment for superficial basal cell carcinoma (sBCC). At the heart of this debate is the limited body of evidence describing tumor behavior of sBCC based on clinical factors relevant to the MAUC. OBJECTIVE To determine whether sBCC is more likely to harbor aggressive subtypes in high-risk anatomical locations and in immunocompromised patients. MATERIALS AND METHODS A single institution retrospective review produced 133 evaluable Mohs cases performed on sBCC over a 10-year period. All slides from the respective cases were reviewed for the presence of histologic patterns other than known sBCC. Cases were then grouped by both MAUC anatomical zone (H, M, and L) and patient immune status for statistical analysis. RESULTS A significantly higher rate of mixed histology (MH) was observed when comparing Zone H with Zone L across all patients, healthy patients, and immunocompromised patients. The same was true when comparing Zone M with Zone L for all patients and healthy patients (immunocompromised did not reach significance). CONCLUSION The authors' data very clearly demonstrate a higher rate of MH in sBCC of the head and neck which provides strong support to the current MAUC scoring.

Response to ‘A call to standardize the BCC:SCC ratio’: reply from the authors

“…Indeed, histopathological studies have confirmed what is known in practice, i.e. that BCCs are frequently of mixed‐tumour categories, with superficial BCC usually found coexisting with other (dermal) subtypes 5 …”

“…that BCCs are frequently of mixed-tumour categories, with superficial BCC usually found coexisting with other (dermal) subtypes. 5 In terms of the epidemiological utility of the BCC:SCC ratio, we strongly hold that its use is enhanced by the exclusion of SCCis. This is illustrated in organ transplant recipients where a marked reversal of the ratio enables us to appreciate the high morbidity and mortality that occurs as a consequence, 6 and thus to deploy appropriate service provision to detect and treat invasive SCC early.…”

Histopathological discrepancy between biopsy and Mohs micrographic surgery in keratinocyte carcinoma: A 464 case series in an Australian population

“…However, in all these studies, the correlation was made between the biopsy sample and the excision specimen obtained via traditional surgery, as studies comparing biopsies and in‐MMS specimen did not provide sufficient data for analysis. A study that specifically looked for invasive subtypes in MMS specimens amongst the biopsy‐proven superficial BCCs showed the highest proportion (57.9%; 77/133) 15 . Perhaps this can be explained by surgical excision of biopsy‐proven superficial BCC being offered when, despite the biopsy results, signs of invasive BCC are clinically evident.…”

“…A study that specifically looked for invasive subtypes in MMS specimens amongst the biopsy-proven superficial BCCs showed the highest proportion (57.9%; 77/133). 15 Perhaps this can be explained by surgical excision of biopsy-proven superficial BCC being offered when, despite the biopsy results, signs of invasive BCC are clinically evident. In addition, MMS tends to be recommended over traditional surgery for lesions on the head and neck.…”

“…A supplementary study evaluating the incidence of BCC with mixed histopathological subtypes in MMS surgical sections was included. 14 Additional three studies focusing on an invasive component in biopsy-reported superficial BCC 15 or SCC in situ 16,17 were also incorporated. However, as the methodology of the latter differed, their results were not included in the calculation of the mean (Table 4).…”