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This is one of the most common diagnostic scenarios facing a surgical pathologist, not only during routine sign-out but also during frozen section analysis. When is a margin of excision for a cutaneous neoplasm truly negative? A recent article by Phil LeBoit, chief of dermatopathology at University of California at San Francisco, provides some helpful advice. The following points are taken verbatim from his excellent article. If a neoplasm fulfills any of these criteria, it should not be reported as completely excised.

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1. The neoplasm extends close to the edge of the specimen, and the area of the margin is obscured by electrocautery or other artifact.

2. The neoplasm extends close to the edge of the specimen, and part of the tissue at the margin is out of the plane of section.

3. The neoplasm extends close to the edge of the specimen, and a scar is present between the neoplastic cells and the margin

4. The distance between nests of a dermal neoplasm (e.g. a basal cell carcinoma) is anywhere close to that between the most lateral, or deepest nest and the margin. As a rule of thumb, there should be about double the distance between the last nest and the margin as the greatest gap between nests in the neoplasm.

5. Stroma seen between the nests of a neoplasm (e.g. the fibrosing granulation tissue-like stroma of a superficial basal cell carcinoma) is present between a nest of neoplastic cells and the margin.

7. A neoplasm is so subtle (e.g. desmoplastic melanoma) that immunoperoxidase staining should be employed to distinguish between fibrosis around a biopsy site and residual neoplasm.

8. An ulcer produced by currettage (to determine the size of a subsequent excision) extends to the edge of the specimen.

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Given these helpful observations, this current case shows a basal cell carcinoma that cannot be reported as completely excised. By applying the principle #4, the deepest nest is certainly closer than the distance between the greatest gaps between the other nests of basal cell carcinoma. Perhaps just as important, this is a micronodular variant of basal cell carcinoma, one of the three types of locally aggressive basal cell carcinomas which should always be reported in the diagnosis (the other two types are sclerosing/morpheaform and infiltrative). These variants are notorious for their deeply infiltrative growth. In particular, the micronodular variant is composed of very bland basaloid cells with minimal to absent stromal host response. Especially on frozen sections, these nests can easily be mistaken for a benign hair follicle. In this case, a comment should be made that although no tumor is present at the inked margins, there is a good likelihood that the tumor is incompletely excised and a re-excision is recommended.

Leboit PE. Am J Dermatopathol 2004;26:259-262.
The Doctor's Doctor-Basal Cell Carcinoma

Comments

This is a pretty stunning case. I would have called the margins negative. Using LeBoit's criteria, I think most basal cell carcinomas biopsied would NOT have clear margins. I'm curious about others' comments.I was familiar with some of the LeBoit margin criteria, but not all of them and I suspect that most of the punch and shave biopsies that we see would have positive margins under the the LeBoit criteria. As a side note, when I was in residency at UCSF, we didn't assess margins on punch and shave biopsies and were even instructed not to ink them (in case someone wanted to take photos for publication). Margins were only evaluated on excisional biopsies (ellipses and above). Great info ...i would have called the case of the month "clear margins" and i was not familiar with the "LeBoit margin criteria" thank you.

Worthwhile discussion both in terms of the types of basal cell carcinoma, ie aggressive types, and also the concept of margins.

	Basal Cell Carcinoma-Margins Not Clear
	This is one of the most common diagnostic scenarios facing a surgical pathologist, not only during routine sign-out but also during frozen section analysis. When is a margin of excision for a cutaneous neoplasm truly negative? A recent article by Phil LeBoit, chief of dermatopathology at University of California at San Francisco, provides some helpful advice. The following points are taken verbatim from his excellent article. If a neoplasm fulfills any of these criteria, it should not be reported as completely excised. ------- 1. The neoplasm extends close to the edge of the specimen, and the area of the margin is obscured by electrocautery or other artifact. 2. The neoplasm extends close to the edge of the specimen, and part of the tissue at the margin is out of the plane of section. 3. The neoplasm extends close to the edge of the specimen, and a scar is present between the neoplastic cells and the margin 4. The distance between nests of a dermal neoplasm (e.g. a basal cell carcinoma) is anywhere close to that between the most lateral, or deepest nest and the margin. As a rule of thumb, there should be about double the distance between the last nest and the margin as the greatest gap between nests in the neoplasm. 5. Stroma seen between the nests of a neoplasm (e.g. the fibrosing granulation tissue-like stroma of a superficial basal cell carcinoma) is present between a nest of neoplastic cells and the margin. 6. Perineural invasion is present anywhere close to a margin. 7. A neoplasm is so subtle (e.g. desmoplastic melanoma) that immunoperoxidase staining should be employed to distinguish between fibrosis around a biopsy site and residual neoplasm. 8. An ulcer produced by currettage (to determine the size of a subsequent excision) extends to the edge of the specimen. ----- Given these helpful observations, this current case shows a basal cell carcinoma that cannot be reported as completely excised. By applying the principle #4, the deepest nest is certainly closer than the distance between the greatest gaps between the other nests of basal cell carcinoma. Perhaps just as important, this is a micronodular variant of basal cell carcinoma, one of the three types of locally aggressive basal cell carcinomas which should always be reported in the diagnosis (the other two types are sclerosing/morpheaform and infiltrative). These variants are notorious for their deeply infiltrative growth. In particular, the micronodular variant is composed of very bland basaloid cells with minimal to absent stromal host response. Especially on frozen sections, these nests can easily be mistaken for a benign hair follicle. In this case, a comment should be made that although no tumor is present at the inked margins, there is a good likelihood that the tumor is incompletely excised and a re-excision is recommended. References n Leboit PE. Am J Dermatopathol 2004;26:259-262. The Doctor's Doctor-Basal Cell Carcinoma Comments `This is a pretty stunning case. I would have called the margins negative. Using LeBoit's criteria, I think most basal cell carcinomas biopsied would NOT have clear margins. I'm curious about others' comments.I was familiar with some of the LeBoit margin criteria, but not all of them and I suspect that most of the punch and shave biopsies that we see would have positive margins under the the LeBoit criteria. As a side note, when I was in residency at UCSF, we didn't assess margins on punch and shave biopsies and were even instructed not to ink them (in case someone wanted to take photos for publication). Margins were only evaluated on excisional biopsies (ellipses and above). Great info ...i would have called the case of the month "clear margins" and i was not familiar with the "LeBoit margin criteria" thank you.` `Worthwhile discussion both in terms of the types of basal cell carcinoma, ie aggressive types, and also the concept of margins.`
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	Additional Sites of Interest
	DermpathMD This site provides interesting case studies and practical information on dermatopathology for practicing pathologists and dermatologists. The Doctor's Doctor This web site was created by pathologists to inform the public about the role of pathologists in health care, and to give patients access to interpretations of their medical reports, particularly laboratory tests and surgical pathology reports. Pathologist Mentor This site is a resource for pathology groups seeking to establish a mentoring program for new pathologists. There are timely articles as well as examples of contracts and projects.