Acantholytic invasive squamous cell carcinoma: tumor diameter, invasion depth, grade of differentiation, surgical margins, perineural invasion, recurrence and death rate

BackgroundSquamous cell carcinoma (SCC) may present with or without the feature of acantholysis. MethodsInvestigate invasive acantholytic SCC by microscopic maximum tumor surface diameter, depth of invasion, grade of differentiation, perineural invasion (PNI) and percentage of acantholysis. Assess recurrence following excision. ResultsA total of 1658 consecutive invasive SCC cases were examined, comprising 4.9% acantholytic SCC. Median tumor microscopic maximum diameter was 8mm for acantholytic SCC and 7.3mm for non-acantholytic SCC. Median tumor invasion depth was 1.0mm for acantholytic SCC and 1.5mm for non-acantholytic SCC. Well, moderate and poor differentiation were not significantly different between acantholytic SCC and non-acantholytic SCC. One PNI case was found in 82 acantholytic SCC cases. A total of 77 acantholytic SCC cases were followed up over a median 25 months finding histologic proven recurrence at three acantholytic SCC excision sites. ConclusionsAcantholytic SCC were more likely to be located on head sites with less median depth than non-acantholytic SCC. Increasing percentage of acantholysis within acantholytic SCC was not associated with a shift towards poor differentiation. Histologic margins of 1.2mm may adequately excise small acantholytic SCC. No recorded deaths, low PNI and low recurrence rates suggests acantholytic SCC is low-risk.