Intraoperative Frozen-Section Evaluation Can Reduce Accuracy of Pathologic Assessment of Sentinel Nodes in Melanoma Patients

Malignant melanoma in the hand: current evidence and recommendations

Malignant melanoma is the leading cause of death from skin cancer. In spite of significant advances in the management of melanoma with the advent of sentinel lymph node biopsy (SLNB) and adjuvant oncological therapies, the death rate continues to increase worldwide. Melanoma in the hand poses additional diagnostic and management challenges. Consequently, these tend to present at a later stage and are associated with a poorer prognosis. It is imperative that hand surgeons treat any pigmented hand lesion with suspicion to ensure rapid diagnosis and treatment. This article outlines the presentation of melanoma, and how to investigate suspicious pigmented lesions of the hand and digits. It guides hand surgeons in their approach to melanoma of the hand, outlining the multidisciplinary team approach as well as current standard surgical and reconstructive options to optimize outcomes.

Histopathologic classification and prognostic factors of melanoma: a 2021 update

Despite the rapid recent advances in molecular analysis of tumors, which allow large-scale and high-resolution genomics, the "gold standard" for melanoma diagnosis continues to be histopathology, in conjunction with clinical characteristics and sometimes with important support of immunohistochemistry. Observations, where postulated that cutaneous melanomas may arise through two distinct pathways, discoveries such as that BRAF^V600E mutations were mostly common in melanomas on sun-exposed skin with little solar elastosis and seminal works for melanoma progression and evolution set the groundwork for the new WHO Classification of Melanoma: a classification of melanoma that not only encompasses histologic but also clinical, epidemiologic, and genetic characteristics. The melanomas were divided into those etiologically related to sun exposure and those that are not, based on their mutational signatures, anatomic site, and epidemiology. On the basis of degree of associated solar elastosis melanomas on the sun exposed skin were further divided by the histopathologic degree of cumulative solar damage (CSD) of the surrounding skin, into low and high CSD. On the low-CSD group of melanomas are included superficial spreading melanomas, while the high-CSD melanomas encompasses lentigo maligna and desmoplastic melanomas. The "non-CSD" classification includes acral melanomas, some melanomas in congenital nevi, melanomas in blue nevi, Spitz melanomas, mucosal melanomas, and uveal melanomas. Nodular and nevoid melanoma may occur in any pathway. A group of intermediate tumors termed melanocytoma is proposed for tumors that in addition to mutations that activate the MAPK pathway, harbor multiple driver mutations, and they are either low-grade or high-grade, to indicate that they may carry a higher risk of malignant transformation. In this review a summary of the most recent WHO classification of melanoma is provided. A short analysis of essential histopathologic prognostic parameters is also provided. The new classification of melanoma discriminates distinct types of melanoma based on their clinicopathologic, and genomic characteristics. Undoubtedly, melanoma research will continue to evolve as new clinical, pathological, molecular data accumulates. The challenge of the forthcoming years is to better characterize the intermediate category of melanocytic lesions.

Detection of cancer metastasis: past, present and future

The clinical importance of metastatic spread of cancer has been recognized for centuries, and melanoma has loomed large in historical descriptions of metastases, as well as the numerous mechanistic theories espoused. The "fatal black tumor" described by Hippocrates in 5000 BC that was later termed "melanose" by Rene Laennec in 1804 was recognized to have the propensity to metastasize by William Norris in 1820. And while the prognosis of melanoma was uniformly acknowledged to be dire, Samuel Cooper described surgical removal as having the potential to improve prognosis. Subsequent to this, in 1898 Herbert Snow was the first to recognize the potential clinical benefit of removing clinically normal lymph nodes at the time of initial cancer surgery. In describing "anticipatory gland excision," he noted that "it is essential to remove, whenever possible, those lymph glands which first receive the infective protoplasm, and bar its entrance into the blood, before they have undergone increase in bulk". This revolutionary concept marked the beginning of a debate that rages today: are regional lymph nodes the first stop for metastases ("incubator" hypothesis) or does their involvement serve as an indicator of aggressive disease with inherent metastatic potential ("marker" hypothesis). Is there a better way to improve prediction of disease outcome? This article attempts to address some of the resultant questions that were the subject of the session "Novel Frontiers in the Diagnosis of Cancer" at the 8th International Congress on Cancer Metastases, held in San Francisco, CA in October 2019. Some of these questions addressed include the significance of sentinel node metastasis in melanoma, and the optimal method for their pathologic analysis. The finding of circulating tumor cells in the blood may potentially supplant surgical techniques for detection of metastatic disease, and we are beginning to perfect techniques for their detection, understand how to apply the findings clinically, and develop clinical followup treatment algorithms based on these results. Finally, we will discuss the revolutionary field of machine learning and its applications in cancer diagnosis. Computer-based learning algorithms have the potential to improve efficiency and diagnostic accuracy of pathology, and can be used to develop novel predictors of prognosis, but significant challenges remain. This review will thus encompass latest concepts in the detection of cancer metastasis via the lymphatic system, the circulatory system, and the role of computers in enhancing our knowledge in this field.

Routine retrieval of pelvic sentinel lymph nodes for melanoma rarely adds prognostic information or alters management

Pelvic sentinel lymph nodes (SLNs) are commonly identified during inguinal SLN biopsy for melanoma, but retrieval is not uniform among surgeons/centers. Few studies have assessed rates of micrometastases in pelvic versus superficial inguinal SLNs. Previous studies suggested that presence of pelvic SLNs was predicted by aggressive pathologic features and that their presence portended a worse prognosis. The objectives of this study were to examine presurgical predictors of pelvic SLNs among patients undergoing inguinal SLN biopsy, assess rates of micrometastases in superficial inguinal versus pelvic SLNs, and determine whether presence of pelvic SLNs was associated with long-term outcomes. Multivariable regression was used to assess presurgical factors associated with presence of pelvic SLNs. Rates of micrometastases in superficial inguinal versus pelvic SLNs in patients who had a pelvic SLN were compared with McNemar's test. Groin recurrence, disease-free survival (DFS), and disease-specific survival were analyzed by Kaplan-Meier method. A multivariable Cox model for DFS was performed. Pelvic SLNs were retrieved in 100/537 (18.6%) superficial inguinal SLN biopsies and no preoperative factors predicted their presence. In patients with a pelvic SLN, micrometastases were present in 3.0% of pelvic versus 34.0% of superficial inguinal SLN biopsies (P<0.001). There were no differences in groin recurrence, DFS, and disease-specific survival for patients with/without pelvic SLNs in univariate analyses (all P>0.2) or in the multivariable Cox model for DFS (hazard ratio: 1.1, 95% confidence interval: 0.6-2.1). In conclusion, pelvic SLNs harbor micrometastases less frequently than superficial inguinal SLNs do, suggesting that omission of pelvic SLN biopsy may be reasonable.

Frozen section analysis of SLNs in trunk and extremity melanoma has a high false negative rate but can spare some patients a second operation

OBJECTIVES

The purpose of this study was to evaluate the accuracy of frozen section (FS) analysis of sentinel lymph nodes (SLN) in melanoma.

METHODS

Five hundred seventy-one patients underwent FS analysis of SLN between 1/2000 and12/2010. Surgical and pathological characteristics, recurrence, and survival were analyzed. Comparisons were made using χ² and Fisher's exact t-test.

RESULTS

One hundred thirty-three (23%) patients were SLN positive of which 63 (47.4%) were identified on FS. 16/70 SLN metastases not identified on FS (23%) were seen only on immunohistochemistry. FS analysis detected 84% of SLN metastasis >2 mm. SLN FS false negative rate was 53%, positive predictive value 100%, negative predictive value 88%, and overall accuracy 89%. Among patients with a FS positive SLN, 17/63 (27%) had additional positive nodes on CLND, versus 1 of 70 (1.4%) with a positive SLN identified only on permanent section pathology (P < 0.0001). The nodal recurrence rate following a negative SLN biopsy was 5%.

CONCLUSIONS

FS analysis for SLNs spared approximately half of patients a second operation. Patients with a positive SLN detected on FS were more likely to have further nodal involvement. In our experience intraoperative pathologic analysis of melanoma SLNs does not impair our ability to detect SLN metastasis or lead to a high rate of false positive results or nodal recurrences. J. Surg. Oncol. 2016;114:879-883. © 2016 2016 Wiley Periodicals, Inc.

Melanoma Extirpation with Immediate Reconstruction: The Oncologic Safety and Cost Savings of Single-Stage Treatment

BACKGROUND

The timing of reconstruction following melanoma extirpation remains controversial, with some advocating definitive reconstruction only when the results of permanent pathologic evaluation are available. The authors evaluated oncologic safety and cost benefit of single-stage neoplasm extirpation with immediate reconstruction.

METHODS

The authors reviewed all patients treated with biopsy-proven melanoma followed by immediate reconstruction during a 3-year period (January of 2011 to December of 2013). Patient demographic data, preoperative biopsies, operative details, and postoperative pathology reports were evaluated. Cost analysis was performed using hospital charges for single-stage surgery versus theoretical two-stage surgery.

RESULTS

During the study period, 534 consecutive patients were treated with wide excision and immediate reconstruction, including primary closure in 285 patients (55 percent), local tissue rearrangement in 155 patients (30 percent), and skin grafting in 78 patients (15 percent). The mean patient age was 67 years (range, 19 to 98 years), and the median follow-up time was 1.2 years. Shave biopsy was the most common diagnostic modality, resulting in tumor depth underestimation in 30 patients (6.0 percent). Nine patients (2.7 percent) had positive margins on permanent pathologic evaluation. The only variables associated with positive margins were desmoplastic melanoma (p = 0.004) and tumor location on the cheek (p = 0.0001). The mean hospital charge for immediate reconstruction was $22,528 compared with the theoretical mean charge of $35,641 for delayed reconstruction, leading to mean savings of 38.5 percent (SD, 7.9 percent).

CONCLUSION

This large series demonstrates that immediate reconstruction can be safely performed in melanoma patients with an acceptable rate of residual tumor requiring reoperation and significant health care cost savings.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Melanoma staging: where are we now?

The seventh version of the American Joint Committee on Cancer (AJCC) Melanoma Staging guidelines, published in 2009, has significant revisions compared with the previous version. The current schema was based on the largest melanoma patient cohort analyzed to date and is the result of a multivariate analysis of 30,946 patients with stages I, II, and III melanoma and 7972 patients with stage IV melanoma. This article summarizes the findings and the new definitions included in the 2009 AJCC Melanoma Staging and Classification. The TNM categories and the stage groupings are defined. Changes in the melanoma staging system are summarized.

The pathology of melanoma

Although melanoma represents only 10% of all skin cancer diagnoses, it accounts for at least 65% of all skin cancer-related deaths. The number of new cutaneous melanoma cases projected during 2010 was 68,000-a 23% increase from the 2004 prediction of 55,100 cases. In 2015, the lifetime risk of developing melanoma is estimated to increase to 1 in 50. As the incidence of melanoma continues to rise, now more than ever, clinicians and histopathologists must have familiarity with the various clinical and pathologic features of cutaneous melanoma.

Advances in sentinel lymph node mapping for patients with melanoma

Sentinel lymph node mapping allows accurate pathological staging for patients with cutaneous melanoma and clinically normal regional nodes. Early technical advances facilitated its widespread acceptance by surgeons. Morbidity as a result of the procedure is well established, but the potential benefit of providing powerful prognostic information outweighs these risks in most patients with intermediate-risk disease.

Sentinel node biopsy for melanoma: an update after two decades of experience

When detected and treated early, melanoma has an excellent prognosis. Unfortunately, as the tumor invades deeper into tissue the risk of metastatic spread to regional lymph nodes and beyond increases and the prognosis worsens significantly. Therefore, accurately detecting any regional lymphatic metastasis would significantly aid in determining a patient's prognosis and help guide his or her treatment plan. In 1991, Don Morton and colleagues presented new paradigm in diagnosing regional lymphatic involvement of tumors termed sentinel lymph node biopsy (SLNB). By mapping the regional lymph system around a tumor and tracing the lymphatic flow, a determination of the most likely lymph node or nodes the cancer will spread to first is made. Then, a limited biopsy of the most likely nodes is performed rather than a more-invasive removal of the entire local lymphatic chain. In 20 years that have followed, a great deal of information has been gained as to its accuracy, prognostic value, appropriate candidates, and its impact on regional disease control and survival. The SLNB has been shown to accurately stage regional lymph node basins in stage I and II melanoma patients with minimal morbidity. More sensitive histologic techniques are now being applied that may allow even greater accuracy in the staging of melanoma patients. Although specific percent risk thresholds are still in question, recommendation for SLNB when melanomas are 1 mm or thicker has gained wide acceptance. SLNB may also be appropriate for patients with melanomas that are between 0.76 and 1 mm thick and have ulceration, high mitotic rates, or reach a Clark level IV. Therefore, melanomas with IB or greater staging should be considered for SLNB.

Melanoma pathology: important issues for clinicians involved in the multidisciplinary care of melanoma patients

Histologic analysis remains the gold standard for diagnosis of melanoma. The pathology report should document those histologic features important for guiding patient management, including those characteristics on which the diagnosis was based and also prognostic factors. Pathologic examination of sentinel lymph nodes provides very important prognostic information. New techniques, such as comparative genomic hybridization and fluorescence in situ hybridization are currently being studied to determine their usefulness in the diagnosis of melanocytic lesions. Recent molecular studies have opened new avenues for the treatment of patients with metastatic melanoma (ie, targeted therapies) and molecular pathology is likely to play an important role in the emerging area of personalized melanoma therapy.

Utility of frozen-section analysis of sentinel lymph node biopsy specimens for melanoma in surgical decision making

BACKGROUND

Debate exists whether frozen-section analysis of sentinel lymph nodes (SLNs) for melanoma is an accurate method to detect disease that has metastasized to the lymph nodes. The purpose of this study was to evaluate the utility of intraoperative frozen section for SLNs in melanoma.

METHODS

We reviewed 133 patients (271 nodes) who underwent SLN biopsy with frozen section for melanoma between April 2003 and September 2007. Frozen-section diagnosis was compared with final diagnosis to determine concordance between intraoperative and postsurgical diagnosis.

RESULTS

A total of 11 nodes (8% of patients) were found to have metastatic disease. All patients underwent lymph node dissections at the time of SLN biopsy. No false-positive SLNs were found on frozen section. The false-negative rate for SLN biopsy frozen section was 8% (1 of 133 patients).

CONCLUSIONS

Intraoperative frozen section can be an accurate and reliable tool in the right setting for analysis of sentinel nodes in cutaneous melanoma and deserves further study.

Pathologic examination of sentinel lymph nodes from melanoma patients

In melanoma patients, the sentinel node biopsy (SNB) procedure is a highly accurate staging method, and the tumor-harboring status of the sentinel node (SN) is the most important prognostic factor for patients with early stage disease. For the SN to provide accurate prognostic information, however, it is essential that all "true" SNs are removed and examined diligently. Pathologists should examine multiple hematoxylin-eosin and immunohistochemically stained sections from each SN, but it is unclear from the currently available evidence what is the most appropriate sectioning and staining protocol. Relevant factors to consider include the accuracy of the procedure, the time, labor, and costs involved, and clinical follow-up data which are likely to vary between institutions; hence, individual protocols should be developed locally by pathologists in consultation with their surgical colleagues. At the Sydney Melanoma Unit, four sequential sections of both halves of each SN are examined. The first and fourth sections are stained with hematoxylin-eosin, the second section is stained for S-100 protein, and the third section is stained for HMB-45. Pathologists should not only identify the presence of melanoma metastases within the SN, but also record the size of the largest metastatic focus, tumor penetrative depth (measured from the inner margin of the node capsule to the deepest tumor cell within the SN), and the percentage nodal cross-sectional area involved (as measured on the slides). Potential diagnostic pitfalls in SN evaluation include the misinterpretation of nevus cells, macrophages, or antigen-presenting interdigitating dendritic cells as melanoma. Careful assessment of the morphologic characteristics of the cells and their immunohistochemical profile should prevent misdiagnosis. Routine frozen section examination of SNs from melanoma patients is not recommended. The utility of ultrasound to detect SN metastases (confirmed by fine needle biopsy) is currently being investigated. Whereas potentially this may avoid the need for formal sentinel lymphadenectomy and histopathologic evaluation in some patients, the lack of sensitivity of currently available ultrasound technologies to detect the small micrometastases (<2 mm in diameter), that are typically present in most melanoma patients with a positive SN, limits its current role. In the future, other techniques, such as the use of carbon particles or antimony analysis, may better localize the site of metastases within SNs and permit more focused and efficient pathologic examination of SNs. At present, the role of nonhistopathologic methods of SN evaluation, such as reverse transcription polymerase chain reaction (RT-PCR) and magnetic resonance spectroscopy, remains unclear, and these techniques require further evaluation.

Sentinel lymph node biopsy for melanoma: aspects of pathologic assessment

Sentinel lymph node (SLN) biopsy affords an accurate, minimally invasive means of staging and determining prognosis in patients with melanoma and for identifying those patients who may benefit from complete regional lymph node dissection. Careful and accurate histopathologic assessment of SLNs is critical to achieving optimal reliability of the technique. Micromorphometric parameters of melanoma deposits in SLNs have been shown to be predictive of regional non-SLN involvement and of clinical outcomes. Several non-histopathologic methods of SLN evaluation have been investigated, and while some of them show promise for the future, excision and histopathologic examination currently remains the gold standard for the evaluation of SLNs.

[Intra-operative cytopathology: techniques, indications, and limitations]

Intraoperative cytopathology is faster, less labor intensive, yields clearer cellular details and can be as accurate as frozen section in the hands of pathologists experienced in the interpretation of cytological preparations. This procedure is particularly valuable for examining small specimens, multiple samples that need to be examined rapidly, and when superior cytological details are required. Nonetheless its use seems to be relatively limited. In this article, we review the general requirements for intraoperative cytology and also detail its value, as well as its limitations and pitfalls.