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

Punch 'scoring': a technique that facilitates melanoma diagnosis of clinically suspicious pigmented lesions

AIMS

Early recognition and accurate diagnosis underpins melanoma survival. Identifying early melanomas arising in association with pre-existing lesions is often challenging. Clinically suspicious foci, however small, must be identified and examined histologically. This study assessed the accuracy of punch biopsy 'scoring' of suspicious foci in excised atypical pigmented skin lesions to identify early melanomas.

METHODS AND RESULTS

Forty-one excised pigmented skin lesions with a clinically/dermoscopically focal area of concern for melanoma, with the suspicious focus marked prior to excision with a punch biopsy 'score' (a partial incision into the skin surface), were analysed. Melanoma was diagnosed in nine of 41 cases (22%). In eight of nine cases (89%) the melanoma was associated with a naevus, and in seven of nine (88%) cases the melanoma was identified preferentially by the scored focus. In six of nine cases (67%), the melanoma was entirely encompassed by the scored focus. In one case of melanoma in situ, the diagnostic material was identified only on further levelling through the scored focus. In 28 of 32 of non-melanoma cases (88%), the scored focus identified either diagnostic features of a particular lesion or pathological features that correlated with the clinical impression of change/atypia including altered architecture or distribution of pigmentation, features of irritation or regression.

CONCLUSIONS

The 'punch scoring technique' allows direct clinicopathological correlation and facilitates early melanoma diagnosis by focusing attention on clinically suspicious areas. Furthermore, it does not require special expertise in ex-vivo clinical techniques for implementation. Nevertheless, in some cases examination of the lesion beyond the scored focus is also necessary to make a diagnosis of melanoma.

Guidelines of the Brazilian Dermatology Society for diagnosis, treatment and follow up of primary cutaneous melanoma--Part I

The last Brazilian guidelines on melanoma were published in 2002. Development in diagnosis and treatment made updating necessary. The coordinators elaborated ten clinical questions, based on PICO system. A Medline search, according to specific MeSH terms for each of the 10 questions was performed and articles selected were classified from A to D according to level of scientific evidence. Based on the results, recommendations were defined and classified according to scientific strength. The present Guidelines were divided in two parts for editorial and publication reasons. In the first part, the following clinical questions were answered: 1) The use of dermoscopy for diagnosis of primary cutaneous melanoma brings benefits for patients when compared with clinical examination? 2) Does dermoscopy favor diagnosis of nail apparatus melanoma? 3) Is there a prognostic difference when incisional or excisional biopsies are used? 4) Does revision by a pathologist trained in melanoma contribute to diagnosis and treatment of primary cutaneous melanoma? What margins should be used to treat lentigo maligna melanoma and melanoma in situ?

Assessment of Cutaneous Melanoma by Use of Very- High-Frequency Ultrasound and Real-Time Elastography

OBJECTIVE

The primary objective of this study was to evaluate the usefulness of very-high-frequency ultrasound as tool for assessment of skin melanoma by investigation of the correlation between the ultrasound measurement of the thickness of a melanoma and the histopathologically measured Breslow index. The secondary objective was to assess the potential role of real-time elastography in the preoperative evaluation of skin melanoma.

SUBJECTS AND METHODS

The study included 42 cutaneous melanoma lesions in 39 adult subjects examined in the division of ultrasound of a department of radiology between September 2011 and January 2015. Gray-scale sonographic features at 40 MHz (thickness, echogenicity, contour) and real-time strain elastographic (qualitative and semiquantitative, strain ratio) characteristics were evaluated and compared with the pathologic results.

RESULTS

The melanoma lesions had a homogeneous hypoechoic appearance with a regular contour and stiff or medium consistency. The mean difference between Breslow index and ultrasound thickness was -0.05 mm (95% CI, -0.24 to 0.13 mm), sustaining the absence of significant differences between these two measurements. A strong relation was identified between real-time elastographic appearance and strain ratio for the relations between lesion and hypodermis and between lesion and neighboring dermis (p < 0.002) or hypodermis.

CONCLUSION

Our study showed that very-high-frequency ultrasound and real-time elastography can be useful examinations for comprehensive preoperative evaluation of cutaneous melanoma.

Punch biopsy of melanoma causing tumour cell implantation: another peril of utilising partial biopsies for melanocytic tumours

The recommended initial management for suspected melanoma is excisional biopsy. The use of partial biopsies of melanocytic tumours poses potential problems including misdiagnosis due to either unrepresentative sampling or the difficulty in evaluating important diagnostic features; an inaccurate assessment of Breslow thickness and other important prognostic features; and the induction of changes capable of mimicking melanoma (i.e., pseudomelanoma). Misdiagnosis, in turn, may lead to inappropriate management of the patient and an adverse outcome. In this report we document a previously unrecognised pitfall of partial biopsies of melanocytic tumours: implantation of tumour cells at the biopsy site potentially leading to the overestimation of tumour thickness or a misdiagnosis of the presence of microsatellites in the subsequent wide excision specimen.

Data set for pathology reporting of cutaneous invasive melanoma: recommendations from the international collaboration on cancer reporting (ICCR)

An accurate and complete pathology report is critical for the optimal management of cutaneous melanoma patients. Protocols for the pathologic reporting of melanoma have been independently developed by the Royal College of Pathologists of Australasia (RCPA), Royal College of Pathologists (United Kingdom) (RCPath), and College of American Pathologists (CAP). In this study, data sets, checklists, and structured reporting protocols for pathologic examination and reporting of cutaneous melanoma were analyzed by an international panel of melanoma pathologists and clinicians with the aim of developing a common, internationally agreed upon, evidence-based data set. The International Collaboration on Cancer Reporting cutaneous melanoma expert review panel analyzed the existing RCPA, RCPath, and CAP data sets to develop a protocol containing "required" (mandatory/core) and "recommended" (nonmandatory/noncore) elements. Required elements were defined as those that had agreed evidentiary support at National Health and Medical Research Council level III-2 level of evidence or above and that were unanimously agreed upon by the review panel to be essential for the clinical management, staging, or assessment of the prognosis of melanoma or fundamental for pathologic diagnosis. Recommended elements were those considered to be clinically important and recommended for good practice but with lesser degrees of supportive evidence. Sixteen core/required data elements for cutaneous melanoma pathology reports were defined (with an additional 4 core/required elements for specimens received with lymph nodes). Eighteen additional data elements with a lesser level of evidentiary support were included in the recommended data set. Consensus response values (permitted responses) were formulated for each data item. Development and agreement of this evidence-based protocol at an international level was accomplished in a timely and efficient manner, and the processes described herein may facilitate the development of protocols for other tumor types. Widespread utilization of an internationally agreed upon, structured pathology data set for melanoma will lead not only to improved patient management but is a prerequisite for research and for international benchmarking in health care.

Histological ulceration as a prognostic factor in cutaneous melanoma: a study of 423 cases in Spain

INTRODUCTION

Histological ulceration in cutaneous melanoma carries a high risk of metastasis and has a poor prognosis. However, some epidemiological and survival studies of patients with cutaneous melanoma do not consider histological ulceration as one of the main prognostic factors.

MATERIALS AND METHODS

Epidemiological, clinical, histological and survival characteristics of all patients diagnosed with cutaneous melanoma over a 10-year period (1994- 2003) were retrospectively analysed.

RESULTS

Ulcerated melanoma was observed in 77 of 423 patients (18.2%). Ulceration was significantly associated with male sex, deeper tumour thickness, positive sentinel lymph node biopsy and metastasis (p<0.001). Histological ulceration indicates a high relative risk (RR) of death from melanoma (RR 9.41; 95% CI 4.52-19.59) and a significant risk of metastasis (RR 5.72; 95% CI 3.56-9.19) (p<0.001).

CONCLUSIONS

Histological ulceration is associated with lower overall survival and disease-free survival in patients with cutaneous melanoma. Presence of ulceration must be included in the clinical history of patients with melanoma to ensure a careful diagnostic work-up and follow-up.

Melanoma update: diagnostic and prognostic factors that can effectively shape and personalize management

Routine light microscopy remains a powerful tool to diagnose, stage and prognose melanoma. Although it is very economical and efficient, it requires a significant level of expertise and, in difficult cases the final diagnosis is affected by subjective interpretation. Fortunately, new insights into the genomic aberrations characteristic of melanoma, coupled with ancillary studies, are further refining evaluation and management allowing for more confident diagnosis, more accurate staging and the selection of targeted therapy. In this article, we review the standard of care and new updates including four probe FISH, the 2009 American Joint Commission on Cancer staging of melanoma and mutant testing of melanoma, which will be crucial for targeted therapy of metastatic melanoma.

Evolving concepts in melanoma classification and their relevance to multidisciplinary melanoma patient care

In the initial period after melanoma was recognised as a disease entity in the early 1800's, it was subclassified on the basis of its presumed origin (from a precursor naevus, from a melanocytic precursor lesion acquired during adult life or in previously blemish-fee skin). In 1967 the eminent American pathologist, Dr Wallace Clark, proposed a histogenetic classification for melanoma in which the disease was subdivided predominantly on the basis of histopathological features of the intra-epidermal component of the tumour adjacent to any dermal invasive component. The subtypes were superficial spreading melanoma (SSM), lentigo maligna melanoma (LMM) and nodular melanoma (NM). Whilst additional entities, including acral lentiginous melanoma, mucosal melanoma, desmoplastic melanoma and naevoid melanoma have since been recognised, SSM, LMM and NM remain in the latest (2006) version of the WHO melanoma classification. Clark's histogenetic classification has been criticised because the criteria upon which it is based include clinical features (such as the site of the melanoma) and non-tumourous histopathological features (such as the character of the associated epidermis and the degree of solar elastosis) and also because of overlap in defining features, lack of an independent association with patient outcome and minimal relevance as a determinant of clinical management. However, such criticisms fail to acknowledge its importance in highlighting the myriad of clinical and histological guises of melanoma, which if not recognized by clinicians and pathologists will inevitably lead to a delay in diagnosis and a concomitant adverse clinical outcome. Recently, mutually exclusive oncogenic mutations in melanomas involving NRAS (15-20%), BRAF (50%), CKIT (2%), and GNAQ/GNA11 (50% of uveal melanomas) have been identified. This might herald the beginning of a new molecular classification of melanoma in which the biologically distinct subsets share a common oncogenic mechanism, behave clinically in a similar fashion and require similar clinical management. These discoveries are already being successfully exploited as therapeutic targets in clinical trials of metastatic melanoma patients with promising activity. Whilst there remains much to be discovered in this rapidly evolving field, there is already great optimism that more rational and effective therapies for melanoma patients will soon be widely available.