Reliability of Biopsy Margin Status for Basal Cell Carcinoma

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• In this study at Geisinger Health System spanning 1 year, 122 basal cell carcinoma (BCC) biopsies with initial negative margin assessment were examined. Of these, 53 (43.4%) were found to have involved margins after exhaustive sectioning of the biopsy tissue block. Margin positivity after initial negative assessment was not associated with tumor subtype.

• Biopsy margin assessment cannot be relied on for determining treatment plans for basal cell carcinoma, and dermatopathologists should consider omitting this information or qualifying its limitations on reports.

– Caroline K. Crabtree, MD

Written by

 

 

Robert T. Brodell MD, FAAD

As a dermatopathologist and clinical dermatologist with 36 years of experience, I admit to changing my ideas about reporting margins in shave and punch biopsies a number of times. All clinicians and pathologists agree that the completeness of excision can best be determined by an elliptical excision with bread-loafing of the specimen, or with Mohs surgery or similar frozen section techniques. Without laborious sectioning of a shave/punch biopsy specimen as performed by these authors, a bisected shave or punch specimen does not permit visualization of all margins. However, even the best techniques are imperfect. Mohs surgery is only 99% certain to remove lesions without a recurrence due to technical limitations and human error. Depending upon the thickness of bread-loafed sections, basal cell may extend to a margin that is not detected in elliptical excisions. In addition, the presence of marginal involvement of basal cell carcinoma may not lead to recurrence. This is perhaps because of local inflammation following the biopsy destroying the residual tumor.

Thus, we live in an imperfect world and dermatopathologists are also obliged to adapt to our referring physicians, who often request that we provide a margin in certain specimens (although I sometimes wonder if some of this is automatic from medical records software). They are not cavalier about this approach, but rather have the advantage of clinical-pathologic correlation and follow-up appointments. Part of the solution is educating clinicians to name their procedure shave or punch biopsy if they do not want a margin reported and shave or punch excision if they wish to have the margin reported.

Let's consider a couple of cases:

Case 1: A dermatologist performs a "saucerization" shave excision of a pigmented lesion with features most suggestive of a dysplastic nevus encompassing 1 mm of normal skin around the lesion. The pathology demonstrates a compound dysplastic nevus with mild atypia, and the report includes a statement: "The lesion appears to be completely excised in the sections of this specimen which were examined." The clinician reassures the patient and asks him/her to report any recurrent pigment at this site, check the spot on the first day of every month at home, and return for a visit for one year. This risk of morbidity and mortality is low, and the clinician feels comforted by the fact that the lesion they removed with a clinical 1 mm margin appeared to be excised in the histopathology. Most would agree that this is not an approach that would be taken if the pathology had pathologic evidence of malignant melanoma.

Case 2: A dermatologist performs a "saucerization" shave excision of a pigmented lesion with features most suggestive of a dysplastic nevus encompassing 1 mm of normal skin around the lesion. The pathology demonstrates a compound dysplastic nevus with moderate to severe atypia. The pathologist includes a statement: "While this lesion appears to be completely excised in the sections of this specimen which were examined with 1 mm of uninvolved tissue, all margins cannot be examined in a tangential specimen of this type. Complete excision is suggested." The clinician notes that no pigment remains at the site and schedules a narrow elliptical excision to ensure that the lesion does not recur. They might also decide in an infirm, elderly patient who would like to avoid additional surgery to closely watch this site instead of immediately excising the lesion, especially if it were near a vital structure.

In summary, I agree with the authors who state: "Dermatopathologists should consider modifying how margin status is reported, either by omitting it or clarifying its limitations on the pathology report." My referring clinicians favor provision of an additional data point (the margin in the section studied) and clarifying the limitations of the margin in reporting shave and punch specimens. This system works much better in healthcare systems that permit clinicians to select the dermatopathologist of their choice for all of their specimens. Each learns to trust the communication of clinical information to the pathologist in the requisition and the methodology of reporting by the dermatopathologist.  Allowing for uncertainties in medicine, all of us are focused on the best interest of the patient.

Abstract

The reporting of biopsy margin status for basal cell carcinoma (BCC) varies among dermatopathologists. For biopsy specimens with seemingly negative margins, the question arises if the tumor extends beyond the margin in unexamined sections. We sought to determine the reliability of negative margin status for BCC and identify if any factors were predictive of positive true margins. We examined BCC biopsy specimens initially determined to have negative margins after routine sectioning and re-evaluated the margin status after complete tissue block sectioning of the initial biopsy specimen was performed. Our findings remind clinicians of the limitations of margin assessment and provide impetus for dermatopathologists to consider modifying how margin status is reported.

Cutaneous Medicine for the Practitioner

Reliability of Biopsy Margin Status for Basal Cell Carcinoma: A Retrospective Study

Cutis 2020 Dec 01;106(6)315-7, MC Brady, EW Hossler 

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Benjamin Hidalgo-Matlock
Skin Care Physicians of Costa Rica

Clinica Victoria en San Pedro: 4000-1054
Momentum Escazu: 2101-9574

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