#dermpathJC April 2017 Summary:

#dermpathJC April 2017:

Thursday, April 27th, 9pm EST

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

Authors: J.H. Pyne, E. Myint, E. M. Barr, S. P. Clark, M. David, R. Na.

Journal of Cutaneous Pathology 2017: 44: 320-327.

Access at: http://onlinelibrary.wiley.com/doi/10.1111/cup.12869/full

 

Journal Club Summary:

Acantholysis (definition): loss of intercellular adhesion between keratinocytes (not intracellular).
Acantholytic SCC may be referred as adenoid SCC, adenoacanthoma, or pseudoglandular SCC. 1st described by Lever in 1947.
Even though it had “pseudoglandular appearance, the acantholytic phenomenon was entirely squamous in nature.
Acantholytic SCC has been more of a histological fascination and not a prognostic one.
Conflicting early papers with closing thoughts that acantholytic SCC could be prognostically bad. Those studies had low power.

Acantholytic SCC:
has been described as an intermediate risk SCC
more prevalent in male patients (male pattern baldness/increased risk of sun damage link perhaps?)
on chronically sun damaged skin such as the head & neck

Which histologic factors indicate higher-risk invasive SCC?
increased tumor diameter
increased tumor depth of invasion
shift towards poor differentiation
Perineural invasion – goes in the report if there

European guidelines for treatment of SCC – from 2015
low-risk SCC – treat with 5mm margin
high-risk SCC – treat with 10mm margin

US treatment guidelines for treatment of SCC of the skin:
Low-risk SCC use 4-6mm margin. If high risk, wider margins or Mohs.
NCCN 2017 guidelines talk about adenoid (acantholytic) SCC as a marker of an increased risk of recurrence or metastasis – Nappi et al. 1989
High risk marker for local recurrence or metastases

Pyne et al. Results:
total of 1656 invasive SCC identified for the study
4.9% cases (82 total) had acantholysis
confirmed independently by 2 pathologists
no significant difference in relation to sex and grade of differentiation bw acantholytic SCC and non-acantholytic SCC
median age (72 years) was similar for both patient groups (with and without acantholysis)
Site most favored for acantholytic SCC (head and cheek/chin)
Site most favored for non-acantholytic SCC (leg – particularly lower leg and forearm) – keratoacanthomatous morphology (from journal club)
Depth of non-acantholytic SCC was significantly deeper than acantholytic SCC: 1.5mm vs 1mm (p<0.001).
Shift from well to poor differentiation did not correlate with an increase in the acantholysis percentage.
Median follow up 25 months for 77 cases

Limitations:
single center study
SCC driving etiology was chronic sun exposure etc.

Discussion:
metastatic potential – SCC diameter of at least 15mm and depth of at least 2mm
poor differentiation and/or increased tumor depth may have confounded recurrence, rather than just the presence of acantholysis alone.
Nappi et al did nit find any PNI in any case of an acantholytic study (1989).

Conclusion:
More appropriate measures of aggressive behavior for SCC: mortality, metastasis and perineural invasion
Low perineural invasion, low recurrence rates, no deaths on followup, may prompt us to think of acantholytic SCC as a low-risk tumor.

I want to extend a special Thank You to Dr. Shea and @JCutaneousPath for their support in making this article open-access for two moths for our first dermpath journal club!

Thank you all for participating,

Sincerely,

Silvija P. Gottesman, MD

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