Immunohistochemical techniques in Mohs micrographic surgery: their potential use in the detection of neoplastic cells masked by inflammation

Review of Perineural Invasion in Keratinocyte Carcinomas

Perineural invasion is an infiltrative process of peripheral nerves by the primary neoplasm within the immediate vicinity. Aggressive forms of keratinocyte carcinomas, such as basal cell and squamous cell carcinomas, may feature perineural invasion, which is often associated with tumor recurrence and poorer prognosis. Diagnosis requires a high clinical suspicion. Imaging and histopathology are used to assess for extent of disease while surgical excision with complete circumferential peripheral and margin assessment is the treatment goal. However, there is still significant uncertainty about adjuvant chemotherapy and definitive management guidelines. Here, we summarize the current understanding of this complex pathogenic process, the clinical presentation, and the significance of perineural inflammation. We also discuss the recommendations about staging, prognosis, adjuvant radiotherapy, and general guidelines for managing keratinocyte carcinomas with perineural invasion. A better understanding of perineural invasion is essential to improve diagnosis, tailor interventions, and mitigate patient morbidity and mortality.

Use of a novel 1-hour protocol for rapid frozen section immunocytochemistry, in a case of squamous cell carcinoma treated with Mohs micrographic surgery

For squamous cell carcinoma (SCC) treated using Mohs micrographic surgery (MMS), interpretation of haematoxylin and eosin-stained frozen sections can be challenging. In these situations, ancillary use of immunostaining is a useful tool for the Mohs surgeon. However, use of immunostaining in MMS laboratories is limited, mainly because current manual immunostaining platforms are subject to operator error, and automated immunostaining, albeit accurate, is too slow for inclusion in MMS. In this report, we describe a novel 1-hour protocol for rapid frozen section immunocytochemistry, using the pancytokeratin markers AE1/AE3. This protocol has been specifically designed to integrate the speed of manual techniques and the accuracy of automated platforms, making it a valuable addition to the MMS laboratory. We propose that in selected or histologically challenging cases, there is a role for the use of this novel protocol, allowing the Mohs surgeon to more confidently declare tumour clearance, thus preventing further unnecessary surgery and preserving healthy tissue.

Morpheaform Basal Cell Carcinomas With Areas of Predominantly Single-Cell Pattern of Infiltration: Diagnostic Utility of p63 and Cytokeratin

BACKGROUND

Morpheaform basal cell carcinoma (BCC) is a variant of BCC characterized by narrow strands and nests of basaloid cells with dense sclerotic stroma. The histologic extent often exceeds the clinical impression, leading to high recurrence rates after standard excision. The authors encountered a case with single-cell invasion distant from the main tumor. To date a systematic review of single-cell infiltration in morpheaform BCC has yet to be performed.

DESIGN

Ten morpheaform BCCs, 10 nonmorpheaform aggressive BCCs, 5 desmoplastic trichoepitheliomas, and 2 microcystic adnexal carcinomas were identified by database search and confirmed on hematoxylin and eosin. Cases were evaluated by hematoxylin and eosin, immunohistochemical staining for p63, and (in a subset) broad-spectrum cytokeratin. Single-cell pattern was defined as individual cells, 2-cell clusters, or single-file invasion.

RESULTS

Three types of single-cell pattern were identified: intratumoral (single cells within the main tumor mass), peripheral, and distant. Single cells were typically a minor component relative to larger tumor nodules and strands. Eight of the 10 cases of morpheaform BCC demonstrated areas of single-cell pattern: 3 intratumoral, 3 peripheral, and 2 with distant spread (0.75 and 1.0 mm from the main tumor). Eight of the 10 aggressive BCC demonstrated a peripheral single-cell pattern. Rare intratumoral single cells were identified in 3/5 desmoplastic trichoepitheliomas and 1/2 microcystic adnexal carcinomas.

CONCLUSION

Single-cell pattern is frequently a component of morpheaform BCC. Tumor cells at a significant distance from the main component were unique to morpheaform BCC. Thus, when evaluating margins for morpheaform BCC, increased caution is recommended, and immunohistochemical stains for p63 or cytokeratins may be helpful.

Diagnostic utility of p63 (Ab-1) and (Ab-4) tumor markers in the squamous cell carcinomas of head and neck

P63 is a gene product required in cell cycle regulation which plays vital roles in tumor differentiation. Aims of the present study were to assess the frequency, pattern, sensitivity and specificity of two p63 protein clones P63 4A4 and P63 4A4+Y4A3 in squamous cell carcinomas (SCCs). Thirty cases of head and neck region SCC diagnosed on the basis of HandE staining were examined along with 60 cases of head and neck region biopsies other than squamous cell carcinoma, negative on HandE staining, were taken as control. Immunostaining was performed on slides according to the Thermo Scientific UltraVision LP detection System. P63 4A4+Y4A3 clone is more sensitive 96.6% in comparison to 86% in P63 4A4 with having greater NPV of 98.3%. The results signify the importance of P63 4A4+Y4A3 marker over the old markers and may be used as a confirmatory marker of squamous cell carcinoma.

Mohs frozen tissue sections in comparison to similar paraffin-embedded tissue sections in identifying perineural tumor invasion in cutaneous squamous cell carcinoma

BACKGROUND

Perineural invasion (PNInv) in cutaneous squamous cell carcinoma (cSCC) increases the risk of recurrence, possibly because of suboptimal identification on frozen or paraffin-embedded tissue sections. Perineural inflammation (PNInf) may portend PNInv.

OBJECTIVE

We sought to correlate identification of PNInv and PNInf in hematoxylin-eosin-stained Mohs frozen sections with PNInv and PNInf identified in similarly oriented paraffin-embedded sections obtained in cases of cSCC.

METHODS

We reviewed same patient Mohs frozen and paraffin-embedded tissue sections for all patients presenting within a 2-year period to our Mohs micrographic surgical unit for removal of cSCC with PNInv or PNInf identified on either type of tissue section.

RESULTS

Of 537 patients undergoing surgical resection of cSCC, 21 (3.9%) had either PNInv (n = 11) or PNInf (n = 10) on frozen sections. PNInv on Mohs frozen sections was identified in 11 cases and confirmed on paraffin-embedded sections in 9 cases (82%). Paraffin-embedded sections failed to identify PNInv present in Mohs frozen sections in two (2/11), or 18% of cases. PNInf on Mohs frozen sections was confirmed on paraffin-embedded sections in 3 cases (30%), but PNInv was identified in 5 cases (50%).

LIMITATIONS

Our results are a retrospective case review from a specific time period by one institution. Furthermore, it is impossible to compare identical tissue specimens using two sequential tissue processing techniques.

CONCLUSION

PNInv can be accurately identified with Mohs frozen sections. PNInf on Mohs frozen sections suggests the presence of PNInv and requires further histologic investigation.

Special stains in Mohs surgery

The excellent cure rates associated with Mohs micrographic surgery depend on accurate interpretation of complete and high-quality microscopic frozen sections. Reliable interpretation of microscopic slides is only possible if the surgeon can distinguish tumor cells from surrounding normal tissue. By highlighting tumor cells with a chromogen that is visible on light microscopy, immunostaining allows the Mohs surgeon to distinguish tumor from normal cells in these challenging scenarios. This article focuses on practical aspects involving the most commonly used immunostains in dermatologic surgery, including MART-1 for melanocytic neoplasms, cytokeratin stains for keratinocytic neoplasms, and CD34 stains for dermatofibrosarcoma protuberans.

Immunostaining in Mohs micrographic surgery: a review

BACKGROUND

With the advent of incorporating the immunoperoxidase staining technique into the processing of frozen tissue, the use of Mohs micrographic surgery (MMS) has been expanded to include several high-risk tumors such as lentigo maligna, malignant melanoma, and dermatofibrosarcoma protuberans.

OBJECTIVES

To thoroughly review the English medical literature pertaining to the use of immunohistochemical staining techniques on frozen sections during MMS and to summarize the basic relevant outcomes from the different relevant studies.

MATERIALS AND METHODS

Medline search was conducted, with the following words used in the search criteria: "Mohs surgery,""staining,""immunostaining," and "immunoperoxidase." RESULTS Generally, all immunostains showed advantage over the traditional hematoxylin and eosin approach. Studies of MART-1 in melanoma chemosurgery indicated that it is typically crisp and has less background staining than MEL-5 and better staining consistency than HMB-45. In cases of desmoplastic melanomas, S100 is the stain of choice.

CONCLUSION

Immunostaining offers an advantage in MMS. Large, randomized, prospective studies comparing the different immunostains are still lacking in the literature. The authors have indicated no significant interest with commercial supporters.

Double-bladed scalpel: a new option for harvesting margins in head and neck cancers

BACKGROUND

In advanced head and neck tumors margins are very rarely comprehensively checked by frozen sections. The goal of this study was to analyze a new proposal for harvesting margins using a double-bladed scalpel.

METHODS

Thirty-eight patients underwent a comprehensive resection of advanced head and neck tumors with a double-bladed scalpel. Margins were mapped and checked by frozen sections, while tumor resection continued. When positive margins were identified, they were excised again, and checked by frozen sections.

RESULTS

Thirty-three patients (87%) had clear skin and soft tissue margins at frozen sections. Five patients (13%) had focal skin and soft tissue-positive margins at frozen sections, which were re-excised. Two patients (5%) had skin and soft tissue-positive margins only at permanent sections. One was reoperated and 1 received radiation therapy. The 3-year local control rate was 58%.

CONCLUSIONS

In this preliminary study, the double-bladed scalpel appeared to be an interesting option for complete intraoperative evaluation of surgical margins of advanced head and neck tumors.

Frozen section of skin specimens

CONTEXT

Skin cancers are the most common malignancies in this country. Treatment of these tumors often involves assessment of margins, which may be performed by frozen section.

OBJECTIVE

This article discusses indications for frozen section, various approaches to gross examination of specimens, Mohs micrographic surgery, diagnostic pitfalls, methods to improve diagnostic accuracy, and special techniques.

DATA SOURCES

The authors' extensive experience and review of the published literature.

CONCLUSIONS

Frozen sections play a vital role in the evaluation of margins of basal cell carcinomas and squamous cell carcinomas. The role of frozen sections in evaluation of soft tissue tumors is controversial. With rare exception, they have no role in the evaluation of melanocytic tumors.

Surgical Margins in the Treatment of Nonmelanoma Skin Cancer and Mohs Micrographic Surgery

Traditional surgical treatment of nonmelanoma skin cancer includes excision with subsequent evaluation of surgical margins, either via frozen sections intraoperatively or after excision and closure. Accurate communication between surgeon and pathologist regarding the meaning of surgical margins should be confirmed. Recurrences of tumor growth may in part be attributed to asymmetrical tumor growth patterns with extension of tumor in an unanticipated direction. Mohs micrographic surgery is an outpatient procedure that maximizes surgical margin evaluation while minimizing the amount of tissue that must be excised. This article will discuss the concept of surgical margins in excisions of nonmelanoma skin cancer and the role of Mohs micrographic surgery.

Preparation of frozen sections

BACKGROUND

For dermatologists the preparation of frozen sections means micrographic surgery. The preparation of frozen sections is meant to be rapid, but has multiple, discrete steps that demand attention to detail.

OBJECTIVE

The objective was to summarize both the proven and the cutting-edge techniques of frozen section preparation.

MATERIALS AND METHODS

Reports from the medical literature were used to augment techniques used in our practices.

CONCLUSION

We dissect each step of micrographic cancer removal, report on the standard and preferred methods of tissue preparation, and summarize the progress achieved in the past decade.

"Now you see it...now you don't." Carmoisine vital dye facilitates complete removal of cutaneous neoplasia by intraoperative visual enhancement

Patients presenting for excision of squamous cell carcinomata, including Bowen's disease, in sun-damaged skin often present with poorly defined, morphoeic or multifocal neoplasms, the extent of which can be difficult to identify intraoperatively. Use of vital staining has been commonly used to aid identification and appropriate excision of squamous lesions of the oral cavity and upper aerodigestive tract but has not been readily adopted for cutaneous lesions. We report a case of a morphoeic squamous cell neoplasm of the web space and fingers to illustrate the merits of vital staining cutaneous squamous neoplasms with the simple dye Carmoisine E122. This assists with intraoperative tumour identification and facilitates adequate oncological resection and appropriately planned reconstruction. By comparison with other methods such as Mohs, it is a simple, cheap, and rapid aid that may be used by surgeons of all grades to improve identification of the extent of the neoplasm, without special equipment.

Adjuvant cytokeratin staining in Mohs micrographic surgery for basal cell carcinoma

BACKGROUND

Mohs micrographic surgery (MMS) is a technique that offers excellent cure rates in the treatment of basal cell carcinoma (BCC). One of the reasons for its success is the 100% visualization of the resection margins. Still, recurrences do occur in 2% to 5% of the treated BCCs. It has been suggested that BCC cells in frozen sections stained with hematoxylin and eosin (H&E) may be missed.

OBJECTIVE

To determine whether an additional immunohistochemical staining with a cytokeratin marker (MNF 116) indicates BCC cells in sections in which the H&E-stained frozen sections were negative.

METHODS

The Mohs procedure was performed under standard conditions in which H&E-stained slides were judged by the Mohs surgeon and the pathologist. After the H&E slides where judged negative, an extra slide was stained using immunohistochemistry and a monoclonal antibody against cytokeratin (MNF 116).

RESULTS

A total of 143 complete slides were stained and judged by two Mohs surgeons and a pathologist. One of the 143 slides stained with MNF 116 showed positive staining where the H&E slides were negative, which is 0.7% of the slides. However, this single slide represents a failure of nearly 2% of the treated patients.

CONCLUSION

Frozen sections stained with H&E in MMS offer enough security in detecting BCC cells during surgery; however, adjuvant cytokeratin staining can be useful in very selected cases of aggressive growing BCC.

Immunohistochemical staining of lentigo maligna during Mohs micrographic surgery using MART-1

BACKGROUND

Lentigo maligna (LM) often displays extensive subclinical spread. Mohs micrographic surgery (MMS) has been proposed to help delineate the true histologic margin; however, visualizing atypical melanocytes on frozen section is challenging and often requires confirmatory permanent paraffin sections.

OBJECTIVE

Our aim was to use a monoclonal antibody to rapidly stain frozen sections during MMS to facilitate better visualization of atypical melanocytes.

METHODS

Frozen sections of LM during MMS were stained with MART-1 (melanoma antigen recognized by T cells) and compared with paraffin-embedded sections.

RESULTS

We found 100% correlation between frozen sections stained with MART-1 and paraffin-embedded sections.

CONCLUSIONS

Atypical melanocytes can be better visualized on frozen sections of LM by using MART-1 rather than hematoxylin and eosin. This allows for easier identification during MMS and better chance of complete removal of LM lesions.

Dense inflammation does not mask residual primary basal cell carcinoma during Mohs micrographic surgery

BACKGROUND

Areas of dense inflammation are commonly removed during Mohs micrographic surgery for basal cell carcinoma because of the concern that they may mask areas of tumor.

OBJECTIVE

Our purpose was to determine whether inflammation masks tumor during Mohs surgery for primary basal cell carcinoma.

METHODS

Twenty-five consecutive cases of primary basal cell carcinoma with areas of dense inflammation encountered during Mohs surgery were sectioned and stained with hematoxylin and eosin and Ber-EP4.

RESULTS

In no cases did the dense inflammation mask residual tumor.

CONCLUSION

Dense inflammation does not mask primary basal cell carcinoma during Mohs surgery and should be carefully evaluated before additional surgery is performed.

Current histologic preparation methods for Mohs micrographic surgery

BACKGROUND

Recently Mohs micrographic surgery, which is widely used for the removal of nonmelanoma skin cancers, has been used to remove lentigo maligna with both rush permanent sections and frozen sections. Several investigators have incorporated the use of immunohistochemical techniques to aid in the interpretation of the specimens.

OBJECTIVE

To determine the current practices of Mohs surgery laboratories, including the use of immunostains and automation of laboratory processes.

METHODS

A total of 108 laboratories responded to a written questionnaire with 13 items about the types of tumors resected, routine stains performed, average number of slides processed per day, and use of automation and immunostains.

RESULTS

Forty-nine percent of the laboratories are completely manual and 51% are automated. The Linistainer automated system, which is the predominant one used, decreased processing time by about 30% and provided an estimated 21-30% improved quality. Automation was associated with the number of slides processed. Immunostaining is performed by a limited number of laboratories which use the technique for basal and squamous cell carcinoma, lentigo maligna, and dermatofibrosarcoma protuberans.

CONCLUSION

Automation of routine slide preparation with a Linistainer decreased staining variability by providing a consistent environment, and decreased processing time. Most laboratories do not perform immunostaining. The relatively high cost of reagents, lack of a reliable automated process, the additional time to process specimens, and the additional technician and physician time makes the procedure impractical for many laboratories.

Ber EP4 and epithelial membrane antigen aid distinction of basal cell, squamous cell and basosquamous carcinomas of the skin

AIMS

Seventy-five skin tumours were studied to investigate the value of immunohistochemistry in differentiating basal cell, squamous cell and basosquamous carcinomas of the skin.

METHODS AND RESULTS

Archived paraffin-embedded tissue samples of basal cell carcinomas (n = 39), squamous cell carcinomas (n = 23) and basosquamous carcinomas (n = 13) were stained immunohistochemically using a panel of antibodies. All of the basal cell carcinomas stained positively for Ber EP4, in contrast to the group of squamous cell carcinomas, that showed no staining. Basosquamous carcinomas all showed at least some areas of Ber EP4 positivity. None of the basal cell carcinomas, but most of the squamous cell carcinomas (22 of 23) expressed epithelial membrane antigen (EMA). Only one of the basosquamous carcinomas expressed EMA positivity focally. CAM 5.2, carcinoembryonic antigen (CEA) and 34betaE12 antibodies lacked specificity in relation to the different tumour types.

CONCLUSION

Distinction of basal and squamous cell carcinomas of the skin can be readily achieved with routine immunohistochemistry using Ber EP4 and EMA. Identification of basosquamous carcinoma is also facilitated with this method.

Current concepts: the use of immunoperoxidase techniques in mohs micrographic surgery

Mohs micrographic surgery is used for the removal of certain malignant tumors, both ensuring complete excision by histologic examination of margins as well as minimizing normal tissue loss. Recently, several investigators have incorporated the use of immunoperoxidase techniques to aid in the removal of selected high-risk carcinomas, sarcomas, and melanomas. We describe the basic principles of immunoperoxidase and review recent articles in which immunoperoxidase was used as an adjunct to routine hematoxylin-eosin staining in Mohs micrographic surgery. Additionally, we show examples of selected tumors comparing routine hematoxylin-eosin stains and immunoperoxidase. We believe the use of immunoperoxidase can be of significant value in the removal of certain high-risk tumors. In particular, this technique is useful in "unmasking" malignant cells in areas of dense inflammation, identification of some cases of perineural invasion, identification of pagetoid spread in carcinomas and melanomas, and finally in helping to identify subtle margins in dermatofibrosarcoma protuberans.

Mohs micrographic surgery

Mohs micrographic surgery (MMS) is a specialized type of minimal marginal surgery that offers cure rates superior to other options in the treatment of contiguous skin cancers in selected settings. Developed by Dr. Frederic E. Mohs, the technique originally required in situ tissue fixation before excision. Most Mohs micrographic surgeons now use the fresh tissue technique exclusively. Horizontal frozen histologic sections of the excised tumor permit more complete microscopic examination of the surgical margin than traditional methods. Residual tumor is graphically mapped and malignant extensions are pursued with staged excisions until the tumor is removed. Maximum sparing of tumor-free adjacent tissue is achieved with histologic mapping of the tumor boundaries, thus optimizing subsequent wound reconstruction. The history, techniques, indications, cure rates, and current controversies of MMS are reviewed.

Squamous cell cancer: a practical approach

Cutaneous squamous cell carcinoma (SCC) is the second most common form of skin cancer and is treated frequently by dermatologists. For many years, the level of knowledge regarding treatment of SCC has taken a backseat to the treatment of basal cell carcinoma and malignant melanoma. As dermatologists become more surgically proficient and assume a leading role in the surgical care for cutaneous carcinoma, a thorough knowledge of the appropriate management of SCC is of paramount importance. In particular, it is essential to recognize that, unlike basal cell carcinoma, certain SCC have a significant metastatic potential and require more comprehensive care. This review targets the etiology, pathogenesis, clinical presentation, histopathology, and treatment of SCC. Particular attention is focused on providing appropriate care for SCC and recognizing and arranging appropriate management for high risk SCC.

The use of monoclonal antibody stains in Mohs micrographic surgery

The recent application of monoclonal antibody stains to Mohs micrographic surgery may lead to increased accuracy in the excision of certain difficult tumours. Immunohistochemical techniques may also increase the range of tumours regularly treated by Mohs surgery. The concept is very much in its infancy, and controlled trials with long-term follow-up are required before the real worth of the process can be evaluated.