Accuracy of serial transverse cross-sections in detecting residual basal cell carcinoma at the surgical margins of an elliptical excision specimen

doi:10.1016/j.jaad.2005.02.049

Journal of the American Academy of Dermatology

Volume 53, Issue 3, September 2005, Pages 468-473

https://doi.org/10.1016/j.jaad.2005.02.049 Get rights and content

Background

There has been no published study estimating the proportion of positive surgical margins that is missed when serial transverse cross-sectioning (bread-loafing) is used to histologically evaluate the surgical margins.

Objective

Our purpose was to estimate the accuracy of serial transverse cross-sectioning (bread-loafing) at 4-mm intervals in detecting the presence of residual tumor at the margins of well-defined facial basal cell carcinomas excised as an ellipse with 2-mm surgical margins.

Methods

Forty-two small (<1 cm), well-defined, primary, nonmorpheaform facial basal cell carcinomas that had been excised as an ellipse with 2-mm margins and that had positive surgical margins utilizing en-face Mohs sections were included. After longitudinal bisection of each ellipse, frozen sections were prepared encompassing the entire surgical margin. Transparencies with parallel lines spaced at 4-mm intervals were superimposed on the histologic slides with the lines perpendicular to the epidermal surface. Areas in which the lines intersected tumor at the surgical margin were noted. The percentage of tumors that would be detected by serial cross sections was calculated on the basis of the percentage of these parallel lines that intersected tumor.

Results

The 42 tumors had a total of 50 positive surgical margins. Overall, the cross-sectional lines intersected tumor 44% of the time (95% confidence interval, 37%-51%). Only 5 (10%) of the residual tumors at the surgical margins exceeded 4 mm in their longitudinal dimension. In the 9 sections containing tumor in the deep margin, tumor intersected the lines 39% of the time.

Conclusion

Bread-loafing at 4-mm intervals of elliptical excision specimens from facial basal cell carcinomas excised with 2-mm surgical margins is only 44% sensitive in detecting residual tumor at the surgical margins. We recommend complete histologic margin control by using en face tissue orientation (Mohs technique) to identify residual tumor and reduce the risk of tumor recurrence after elliptical excision of facial basal cell carcinomas.

Section snippets

Methods

A prospective Institutional Review Board–approved study compliant with the principles of the Declaration of Helsinki was conducted in which biopsy-proven, small (<1 cm), well-defined, primary, nonmorpheaform facial basal cell carcinomas were excised as an ellipse. Ellipses were designed as eccentric parallelograms with 2-mm surgical margins of normal-appearing tissue around the visible portion of the tumor.³ The ellipses were bisected longitudinally and flattened laterally to allow complete

Results

A total of 42 tumors that were excised with 2-mm surgical margins and bisected into 2 semiellipses with histologically positive margins on frozen section pathology were identified and included in this study. Of these, 34 had one positive margin and 8 had two positive margins (16 slides). Thus a total of 50 slides (34 + 16) with positive surgical margins were included in the study.

The results of the study are summarized in Table I. The number of slides in which the transverse cross-sectional lines

Discussion

To our knowledge, this is the first study to address the accuracy of the bread-loaf technique in identifying residual basal cell carcinoma at an excisional surgical margin. We selected small (<1 cm), well-demarcated, nonmorpheaform facial tumors, as these tumors are often treated with elliptical excision in clinical practice. Moreover, we used 2-mm surgical margins because 4-mm margins are often not used on the face because of anatomic considerations.

We used 4-mm wide increments to measure

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Mohs micrographic surgery is an established technique in the treatment of cutaneous neoplasms. It offers higher cure rates and the main indications are non-melanoma malignant skin tumors. Few studies have been performed on the treatment of rare tumors through this technique.
To study rare skin tumors and rare variants of basal cell carcinoma and squamous cell carcinoma submitted to Mohs micrographic surgery in a tertiary service in relation to frequency, disease-free evolution, and applicability of this surgical procedure for this group of tumors.
This was a retrospective observational study including rare skin tumors and less common variants of basal cell carcinoma and squamous cell carcinoma treated using Mohs micrographic surgery, between October 2008 and April 2021.
During the study period, 437 tumors were treated using Mohs micrographic surgery, and 22 (5%) rare skin tumors were selected. The tumors comprised three dermatofibrosarcomas protuberans, two atypical fibroxanthomas, two spiradenomas, two hypercellular fibrohistiocytomas, one primary cutaneous adenocarcinoma, one trichoblastoma, one porocarcinoma, one chondroid syringoma, one cutaneous angiosarcoma, one Merkel cell carcinoma, and one sebaceous carcinoma. Six other cases of rare basal cell carcinoma variants with trichoepitheliomatous differentiation, metatypical basal cell carcinoma, and clear cell squamous cell carcinoma were included. There were no cases of recurrence after an average of six years of follow-up.
This is a retrospective study on rare neoplasms carried out in a single referral center, and this surgical technique isn’t widely available in the public service.
This retrospective case series showed that Mohs micrographic surgery is an appropriate treatment for rare skin tumors. They corresponded to 5% of the tumors treated by the technique during a 12-year-period, with no recurrences identified.
Auricular reconstruction after Mohs micrographic surgery: analysis of 101 cases
2021, Anais Brasileiros de Dermatologia
Citation Excerpt :
For this reason, several guidelines indicate Mohs micrographic surgery (MMS) as the first-choice treatment for cutaneous carcinomas at this site.2–4 MMS has the highest cure rates in the treatment of cutaneous carcinomas, as it evaluates 100% of the surgical margins, whereas the wide local excision technique assesses about 1% of the margins by “bread-load” sectioning.5,6 Although MMS allows maximum preservation of healthy tissue, many auricular surgical wounds are a challenge due to the peculiar local anatomy, with evident curves and reliefs.
The ear is a region that has a high prevalence of cutaneous carcinomas and several guidelines indicate Mohs micrographic surgery as the first-choice treatment in such cases. Although the technique allows maximum preservation of healthy tissue, many auricular surgical wounds constitute a challenge due to the peculiar local anatomy, with evident curves and reliefs. Auricular reconstruction should prioritize function before aesthetics, but without leaving the latter aside, since postoperative distortions can have a significant psychological impact.
To describe the authors’ experience in auricular reconstruction after Mohs surgery and to evaluate the most frequently used repair methods.
Retrospective study of consecutive cases submitted to Mohs surgery and auricular reconstruction, over a period of 3 years.
One hundred and one cases were included and the most common repair method was primary closure (n = 35), followed by full-thickness skin graft (n = 30) and flaps (n = 24). In thirty cases, reconstruction methods were associated. Seven patients had complications (partial graft necrosis, postoperative bleeding or infection).
Retrospective design and the absence of long-term follow-up of some cases.
The dermatologic surgeon should be familiarized with different options for auricular reconstruction. Primary closure and skin grafts were the most frequently used repair methods.
Mohs micrographic surgery: a review of indications, technique, outcomes, and considerations
2021, Anais Brasileiros de Dermatologia
Mohs micrographic surgery is a specialized form of skin cancer surgery that has the highest cure rates for several cutaneous malignancies. Certain skin cancers can have small extensions or “roots” that may be missed if an excised tumor is serially cross-sectioned in a “bread-loaf” fashion, commonly performed on excision specimens. The method of Mohs micrographic surgery is unique in that the dermatologist (Mohs surgeon) acts as both surgeon and pathologist, from the preoperative considerations until the reconstruction. Since Dr. Mohs’s initial work in the 1930s, the practice of Mohs micrographic surgery has become increasingly widespread among the dermatologic surgery community worldwide and is considered the treatment of choice for many common and uncommon cutaneous neoplasms. Mohs micrographic surgery spares the maximal amount of normal tissue and is a safe procedure with very few complications, most of them managed by Mohs surgeons in their offices. Mohs micrographic surgery is the standard of care for high risks basal cell carcinomas and cutaneous squamous cell carcinoma and is commonly and increasingly used for melanoma and other rare tumors with superior cure rates. This review better familiarizes the dermatologists with the technique, explains the difference between Mohs micrographic surgery and wide local excision, and discusses its main indications.
Letter to the Editor regarding: “Poorly differentiated cutaneous squamous cell carcinomas (SCCs) have high incomplete excision rates with UK minimum recommended pre-determined surgical margins”
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Surgical margins required for basal cell carcinomas treated with Mohs micrographic surgery according to tumor features
2020, Journal of the American Academy of Dermatology
Citation Excerpt :
A meta-analysis suggested 3-mm margins for nonmorpheaform BCCs less than 2 cm, but data were based on bread loaf (vertical sections) analysis, which limits their validity.17 Bread loaf sections evaluate approximately 1% of the peripheral margins and may miss tumor extension at nonvisualized surgical margins.18,19 An important study demonstrated that narrow margins (1-3 mm) were inadequate for the elliptic excision of primary, well-demarcated nodular BCCs less than 1 cm on the face, given the 20% probability of encountering surgical margins positive for BCCs.20
Basal cell carcinomas (BCCs) with high-risk features are preferably treated by Mohs micrographic surgery. Studies have shown clinicopathologic characteristics that may predict more stages required for clearance. However, few studies have correlated such factors with the number of millimeters removed per stage.
To determine margins necessary for BCC clearance according to tumor features, especially for tumors less than 6 mm, and to suggest initial margins for Mohs micrographic surgery and margins for wide local excision.
Retrospective analysis of 295 consecutive Mohs micrographic surgeries for primary BCCs. Variables analyzed included patient age, sex, immunostatus, lesion size, location, histologic subtype, borders, stage number, and millimeters excised per stage.
BCCs less than 6 mm had a clearance rate of 96% with 3-mm margins. In adjusted multivariable analysis, superficial, micronodular, infiltrative, and morpheaform subtypes were associated with larger margins, whereas clinically well-defined tumors were associated with smaller margins.
Because of the limited sample of certain subtypes, a 3-mm margin is better suited for nodular tumors.
These data help guide initial Mohs micrographic surgery and wide local excision margins required for tumor clearance according to tumor features. Nodular BCCs less than 6 mm may be cleared with 3-mm margins instead of the current 4-mm margin recommendation.
Negative predictive value of biopsy margins of dysplastic nevi: A single-institution retrospective review
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Biopsies of dysplastic nevi processed by bread-loafing allow for limited margin assessment; however, reported biopsy margins often influence management.
To evaluate the negative predictive value of biopsy margins of dysplastic nevi.
A retrospective search of a single academic institution's pathology database was conducted to identify all biopsy specimens of dysplastic nevi between January 1, 2015, and December 31, 2017. Biopsy specimen margin assessments were compared with excision pathology reports to calculate negative predictive value and to assess the frequency of residual nevus on excision after positive biopsy margins.
A total of 1245 dysplastic nevi from 934 patients were identified. Clear biopsy margins had a negative predictive value for the absence of residual nevus on excision of 87.3% for dysplastic nevi of moderate atypia or greater. Residual nevus was identified on excision in 29.41% of cases of dysplastic nevi of moderate atypia or greater when initial biopsy margins were positive.
This was a retrospective, single-institution study. The calculations likely overestimate the true negative predictive value of biopsy margins because of processing of excision specimens by bread-loafing.
This study provides additional evidence that reported biopsy margins are not representative of true margin status.

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Dermatologic SurgeryAccuracy of serial transverse cross-sections in detecting residual basal cell carcinoma at the surgical margins of an elliptical excision specimen

Background

Objective

Methods

Results

Conclusion

Section snippets

Methods

Results

Discussion

J Am Acad Dermatol

J Am Acad Dermatol

Elliptical excisions: variations and the eccentric parallelogram

Arch Dermatol

Mohs micrographic surgery for elliptical excisions of skin tumors: a surgical and histologic study

Dermatol Surg

Dermatologic Surgery
Accuracy of serial transverse cross-sections in detecting residual basal cell carcinoma at the surgical margins of an elliptical excision specimen