Melanoma of the vulva and vagina: principles of staging and their relevance to management based on a clinicopathologic analysis of 85 cases

Mucosal Melanoma: Review from a Pathologist Point of View

Mucosal melanomas are rare malignant tumors arising from the epithelia lining the inner mucosal surfaces of the body. Unlike cutaneous melanoma, we have a limited understanding of mucosal melanomas is currently limited. Mucosal melanomas are characterized by genetic alterations quite distinct from cutaneous melanomas; however, their causative and promoting factors are unknown. These melanomas are characteristically diagnosed at a later stage due to their occult locations, leading to a worse prognosis. Dedicated staging systems for mucosal melanomas exist only for sinonasal and conjunctival melanomas. Therefore, risk stratification of patients with mucosal melanomas, particularly those arising from the anogenital area, is challenging. Recent studies have shown that minor modifications of the AJCC 8th Edition cutaneous melanoma staging system can group patients fairly robustly; however, the proposed T-categorization systems have yet to be validated in larger cohorts. We summarize the demographic, clinical, histopathologic, and molecular features of common subtypes of mucosal melanomas and highlight the outstanding needs in this field.

Primary lacrimal sac melanoma: a case report describing the novel use of fine needle aspiration cytology (FNAC) for diagnosis, together with literature review and immunotherapy treatment update

Primary lacrimal sac melanoma (PLSM) is exceedingly rare and associated with high morbidity and mortality. Unfortunately, PLSM often presents insidiously resulting in delayed detection and poor prognosis. A 69-year-old Black man was suspected of having a lacrimal sac tumour following presentation with a left sided watery eye, bloody tears, and a lacrimal mass. Due to the patient's implantable pacemaker, defibrillator, and high anticoagulation, an ultrasound-guided FNAC was performed instead of incisional biopsy, revealing a PLSM. Diagnosis was confirmed following complete tumour resection with free flap reconstruction and neck dissection. Unfortunately, disease progression ensued despite further neck dissection and three cycles of both pembrolizumab and iplimumab. This is the first description of FNAC to accurately diagnose PLSM and highlights its use as an accurate, rapid, and minimally invasive technique that may allow an earlier screening diagnosis of lacrimal sac tumours. We also discuss the outcome of immunotherapy in recent similar cases.

Primary Mucosal Melanoma: Clinical Experience from a Single Italian Center

(1) Background: Mucosal melanoma (MM) is a rare tumor, accounting for about 1% of all diagnosed melanomas. The etiology and pathogenesis of this tumor are unknown. It is characterized by an aggressive phenotype with poor prognosis and a low response rate to approved treatments. (2) Methods: We retrospectively analyzed the clinical features, treatments and outcomes of patients diagnosed with MM from different sub-sites (head and neck, gynecological and gastro-intestinal region) between 2013 and 2023 at our Institute. Survival times were estimated with the Kaplan-Meier method. Multivariate Cox regression was used to test the independence of significant factors in univariate analysis. (3) Results: Twenty-five patients were included in this study; the disease was equally distributed among females and males. The median age at diagnosis was 74 years old. The majority had MM originating from the head and neck (56%), particularly from the nasal cavity. BRAF V600 mutations were detected in 16% of the study population, limited to gastro-intestinal and gynecological MM. At diagnosis, at least half the patients (52%) had the disease located also at distant sites. The median overall survival (OS) in the whole study population was 22 months, with a longer OS for patients diagnosed at an early stage (38 months, p < 0.001). Longer OSs were reported for head and neck MM compared to other anatomic regions (0.06). Surgery of the primary tumor and radiotherapy were performed in 64% and 36% of the study population, respectively. Radiotherapy was performed only in head and neck MM. At multivariate analysis, the single factor that showed a reduced hazard ratio for death was radiotherapy. (4) Conclusions: The overall survival of MM from different sub-sites treated at our Italian Institution was 22 months, with better outcomes for early-stage disease and head and neck MM. Performing radiotherapy may have a protective effect on OS for head and neck MM. New treatment strategies are urgently needed to improve the outcome in this disease.

Proceedings from the Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA)

Mucosal melanoma remains a rare cancer with high mortality and a paucity of therapeutic options. This is due in significant part to its low incidence leading to limited patient access to expert care and downstream clinical/basic science data for research interrogation. Clinical challenges such as delayed and at times inaccurate diagnoses, and lack of consensus tumor staging have added to the suboptimal outcomes for these patients. Clinical trials, while promising, have been difficult to activate and accrue. While individual institutions and investigators have attempted to seek solutions to such problems, international, national, and local partnership may provide the keys to more efficient and innovative paths forward. Furthermore, a mucosal melanoma coalition would provide a potential network for patients and caregivers to seek expert opinion and advice. The Melanoma Research Foundation Mucosal Melanoma Meeting (December 16, 2022, New York, USA) highlighted the current clinical challenges faced by patients, providers, and scientists, identified current and future clinical trial investigations in this rare disease space, and aimed to increase national and international collaboration among the mucosal melanoma community in an effort to improve patient outcomes. The included proceedings highlight the clinical challenges of mucosal melanoma, global clinical trial experience, basic science advances in mucosal melanoma, and future directions, including the creation of shared rare tumor registries and enhanced collaborations.

A rare synchronous presentation of primary malignant melanoma in cervix and vagina

ABSTRACT

Malignant melanoma, primarily a cutaneous malignancy, can also involve mucosal surfaces and constitutes 2% to 7% of all gynecological malignancies. Primary melanoma of the uterine cervix is an uncommon tumor and has poor prognosis. In the female genital tract, the synchronous occurrence of primary malignant melanoma in the cervix and vagina is rare. We report a case of a 48-year-old female patient who presented with a blackish vaginal mass and associated growth in the cervix. Biopsy from the vaginal mass was reported as malignant melanoma. Following this, she underwent radical surgery and adjuvant radiotherapy. After 12 months, the patient is doing well.

Case report: a robotic-vaginal approach for total vaginectomy and hysterectomy with pelvic sentinel lymph node dissection in primary vaginal melanoma: a 10-step technique and literature review

Introduction

Primary vaginal melanoma is extremely rare, has a poor prognosis, and occurs mostly in elderly women. The diagnosis is based on histology and immunohistochemistry of a biopsy. Given the rarity of vaginal melanoma, no standardized treatment guidelines are established; however, surgery is the primary treatment modality in the absence of metastatic disease. Most reports in the literature are retrospective single cases, case series, and population-based studies. The open surgical approach is the main modality reported. Here, we report for the first time a 10-step combined robotic-vaginal technique, with en bloc resection of the uterus and total vagina, for treating clinically early-stage primary vaginal melanoma. In addition, the patient in our case underwent a robotic pelvic bilateral sentinel lymph node dissection. The literature on the surgical approach for vaginal melanoma is reviewed.

Case presentation

A 73-year-old woman was referred to our tertiary cancer center and was clinically staged according to the 2009 International Federation of Gynaecology and Obstetrics (FIGO) staging for vaginal cancer as FIGO-stage I (cT1bN0M0) and according to the American Joint Committee on Cancer (AJCC) for (cutaneous) Melanoma Staging as clinical stage IB. Preoperative imaging with magnetic resonance imaging, FDG-positron emission tomography-computed tomography, and ultrasound of the groins did not reveal any adenopathy nor metastases. The patient was planned for a combined vaginal and robotic en bloc total vaginectomy and hysterectomy, as well as a pelvic bilateral sentinel lymph node dissection.

Results

The surgical procedure was performed in 10 steps described in this case report. The pathology revealed free surgical margins and negative test results for all sentinel lymph nodes. The postoperative recovery process was uneventful, and the patient was discharged on day 5.

Conclusion

The main surgical approach reported for primary early-stage vaginal melanoma is open surgery. A minimally invasive surgical approach, described here as a combined vaginal-robotic en bloc total vaginectomy and hysterectomy, for the surgical treatment of early-stage vaginal melanoma enables precise dissection, low surgical morbidity, and fast recovery for the patient.

Assessing Rates of Positive Surgical Margins After Standard Excision of Vulvar Melanomas

BACKGROUND

Vulvar melanoma is a rare malignancy with frequent recurrence and poor prognosis. National guidelines recommend wide local excision of these tumors with allowances for narrower margins for anatomic and functional limitations, which are common on specialty sites. There is presently a lack of data of margin positivity after standard excision of vulvar melanomas.

OBJECTIVE

We aim to evaluate the rate of positive margins after standard excision of vulvar melanomas.

MATERIALS AND METHODS

Retrospective cohort study of surgically excised vulvar melanomas from the NCDB diagnosed from 2004 to 2019.

RESULTS

We identified a total of 2,226 cases. Across surgical approaches and tumor stages, 17.2% (Standard Error [SE]: 0.8%) of cases had positive surgical margins. Among tumor stages, T4 tumors were most commonly excised with positive margins (22.9%, SE: 1.5%). On multivariable survival analysis, excision with positive margins was associated with significantly poorer survival (Hazard Ratio 1.299, p = .015).

CONCLUSION

We find that positive margin rates after standard excision of vulvar malignancies are higher than for other specialty site melanomas. Our data suggest that use of surgical approaches with complete margin assessment may improve local control and functional outcomes for patients with vulvar melanoma as they have for patients with other specialty site melanomas.

Current Trends in Mucosal Melanomas: An Overview

Primary mucosal melanomas (MMs) are uncommon tumors originating from melanocytes located in the mucous membranes at various anatomic sites within the body. MM significantly differs from cutaneous melanoma (CM) regarding epidemiology, genetic profile, clinical presentation, and response to therapies. Despite these differences, that have important implications for both disease diagnosis and prognosis, MMs are usually treated in the same way as CM but exhibit a lower response rate to immunotherapy leading to a poorer survival rate. Furthermore, a high inter-patient variability can be observed in relation to therapeutic response. Recently, novel "omics" techniques have evidenced that MM lesions have different genomic, molecular, and metabolic landscapes as compared with CM lesions, thus explaining the heterogeneity of the response. Such specific molecular aspects might be useful to identify new biomarkers aimed at improving the diagnosis and selection of MM patients who could benefit from immunotherapy or targeted therapy. In this review, we have focused on relevant molecular and clinical advancements for the different MM subtypes in order to describe the updated knowledge relating to main diagnostic, clinical, and therapeutic implications as well as to provide hints on likely future directions.

Effectual surgical perineal reconstruction of malignant mucosal vulvar melanoma

OBJECTIVE

To demonstrate a successful surgical treatment and reconstruction in a case of malignant mucosal vulvar melanoma.

CASE REPORT

A 52-year-old woman had stage II bulky malignant mucosal vulvar melanoma and received wide surgical excision with partial vulvectomy. She underwent 2-steps reconstructive vulvoplasty and vaginoplasty with skin grafting 1 year after initial surgical treatment. There was no evidence of recurrence after 3 years of follow-up.

CONCLUSION

Vulvar melanoma is a rare malignant neoplasm. Wide local excision with reconstruction can relieve pelvic discomfort and restore local function after the surgery.

Gynecologic tract melanoma in the contemporary therapeutic era: High rates of local and distant disease progression

BACKGROUND

Gynecologic tract melanoma (GTM) is a rare malignancy with historically poor outcomes. The current study examines patterns of care and oncologic outcomes in a large single-institution cohort from the contemporary therapeutic era.

METHODS

Patterns of care and predictors of outcomes were evaluated for all GTM patients without metastatic disease at diagnosis who were treated at our institution between 2009 and 2020 with >6 months of follow-up.

RESULTS

Of the 124 patients included, anatomic subsites were vulvar (n = 82, 66%), vaginal (n = 34, 27%), or cervical (n = 8, 6%). Primary tumor was resected for 85% (n = 106) with surgical nodal evaluation for 60% (n = 75). Systemic therapy, most commonly immune checkpoint inhibitors (ICI, 58% systemic therapy), was used to treat all except one unresectable patient (17/18) and 33% (35/106) of resectable patients. Seven patients received neoadjuvant ICI. Fourteen patients received adjuvant radiation therapy to the pelvis (RT, 13% of those undergoing resection). With a median follow-up of 45 months, 100 patients (81%) recurred. Four-year actuarial outcomes were: 46% local control, 53% nodal control, 36% distant metastasis-free survival, 17% disease-free survival, 49% melanoma-specific survival and 48% overall survival. Mitotic rate > 10/mm2, nodal involvement and non-vulvar anatomic subsite were associated with poor outcomes. Patients treated after 2016 did not have significantly better outcomes than those treated earlier.

CONCLUSIONS

Patients with GTM continue to have poor outcomes in the contemporary therapeutic era with particularly notable poor local disease control relative to other mucosal melanoma subtypes. More effective oncologic therapy is needed.

Genitourinary melanoma: An overview for the clinician

Genitourinary (GU) melanoma is a rare presentation of melanoma accounting for approximately 0.5% of all melanomas. GU melanomas include primary melanomas of the vulva, vagina, uterine cervix, ovary, penis, scrotum, urethra, bladder, ureter, and kidney. These melanomas are often diagnosed in advanced stages and stigma is thought to contribute to delays in presentation. As the likely diagnosing provider, it is imperative that dermatologists, urologists, and gynecologists are aware of these uncommon sites of presentation. While there have been major advances in the treatment of melanomas as a whole in the last 10 years, their applications to GU melanomas have often been overlooked. GU melanomas have not been included in many of the major phase III clinical trials which brought contemporary advanced treatments to market and the prognoses for GU melanomas remain poor. Due to the rarity of GU melanomas, much of the literature provides generalized recommendations across multiple different organs affected by GU melanomas or omits certain topics, making it difficult to appreciate the fundamentals of the individual presentations. This review aimed to provide background information on the pathogenesis and epidemiology of the different sites of GU melanomas and categorize data specific to the presentation, staging, treatment, and prognosis of each type of GU melanoma to guide the clinician. It was also meant to encourage a multidisciplinary approach to the management of these patients as it spans the expertise of surgical oncologists, medical oncologists, radiation oncologist, dermatologists, urologists, and gynecologists.

Oral Malignant Melanoma in a Patient With Neurofibromatosis Type 1: An Extremely Rare Association

Neurofibromatosis type 1 (NF1) is a genetic disorder associated with high rates of neural crest-derived tumors, both benign and malignant. Many series have identified cutaneous melanoma as a rare tumor among cancers occurring in individuals with NF1 disease, but the mucosal location has to date never been reported. In this paper, we report an oral melanoma occurring in a patient with NF1 disorder, diagnosed at a locally advanced stage, successfully managed by definitive external beam radiotherapy, along with a comprehensive literature review on the melanoma-NF1 association.

Epidemiology and Molecular Profile of Mucosal Melanoma: A Population-Based Study in Southern Europe

Simple Summary

There are few population-based studies focused on the epidemiology of mucosal melanoma, a rare neoplasm. Its poor prognosis, the different etiology from cutaneous melanoma and the lack of effective treatment beyond corrective surgery, make the knowledge of the mutational profile of this type of cancer a useful tool in understanding its natural history and also for the investigation of new target therapies. The aim of our population-based study is to analyze the incidence and survival of mucosal melanoma, which mainly arises from the head and neck sphere, genitourinary tract and rectal area, and to carry out the mutational analysis of selected cases. We used the Girona Cancer Registry database, which registered all cancer cases in Girona, a province of Spain in southern Europe, during the period of 1994–2018.

Abstract

Background: Mucosal melanoma is a rare neoplasm on which few epidemiological population-based studies have been published. A good surgical approach is the standard treatment, but the prognosis is worse than that of skin melanoma. The analysis of mucosal melanoma’s mutational profile can help to develop target therapies in advanced disease or adjuvant settings. Methods: We analyzed the database of the Cancer Registry of Girona, a region located in the north-east of Spain, in the period of 1994–2018. We selected cases of primary invasive melanoma, excluding those located in the skin, eye, central nervous system and an unknown primary site. Epidemiological analysis included incidence and survival. Mutational profile analysis was performed with a custom gene panel. Results: Forty-two patients were identified: 14 (33%) had vulvar-vaginal melanoma, 15 (35.7%) had rectal melanoma, 12 (28.6%) had melanoma located in the head and neck sphere and 1 male patient had a urethral melanoma. European age-standardized incidence rates for vulvar-vaginal, rectal and head and neck melanoma were 0.09, 0.1 and 0.09 cases/100,000 inhabitant-years, respectively. Five-year observed survival rates were 37.5%, 20% and 25% for these types of cancers. NRAS Q61 was the most frequent mutation found. Conclusion: Our study confirms the steady incidence and low survival of mucosal melanomas in a region of southern Europe. NRAS and NF1 play a role in the molecular landscape of mucosal melanoma. MEK and PI3K/mTOR inhibitors could be reasonable treatment options and are being studied in clinical trials.

Vulvar Melanoma: Molecular Characteristics, Diagnosis, Surgical Management, and Medical Treatment

Ten percent of all women have pigmented vulvar lesions. Fortunately, most of these are benign but 1% of all melanomas in women affect the vulva. While the mortality rate of cutaneous melanoma has dropped by 7% annually during the last 5 years, the prognosis of vulvar melanoma remains dismal: the 5-year overall survival rate is 47% compared with 92% for cutaneous melanoma. The current evidence suggests that this likely results from a combination of delayed diagnosis and different tumor biology, treatment strategies, and treatment response. Although many landmark trials on checkpoint inhibitors included mucosal and vulvar melanomas, the results were often not reported separately. Post-hoc analyses indicate overall response rates between 19 and 37% for checkpoint inhibitors. A recently published retrospective study on vulvar melanomas suggests an objective response in 33.3% with a similar safety profile to cutaneous melanoma. Tyrosine kinase inhibitors may be considered in recurrent disease if a c-KIT mutation is present.

Prognostic Roles of BRAF, KIT, NRAS, IGF2R and SF3B1 Mutations in Mucosal Melanomas

BACKGROUND

The prognostic value of commonly recurrent mutations remains unclear in mucosal melanomas.

METHODS

Clinicopathologic parameters of 214 cases of mucosal melanomas diagnosed in 1989-2020 in several clinical institutions were analyzed. NRAS, KIT, BRAF, IGF2R and SF3B1 mutational analyses by Sanger sequencing and next generation sequencing-based assay were performed in a subset of cases.

RESULTS

Of the triple (BRAF, NRAS, NF1)-negative cases, APC, KIT and KRAS are detected mainly in sinonasal, vulvovaginal and anorectal melanomas, respectively. NRAS, KIT, BRAF, IGF2R and SF3B1 mutations are detected in 19% (37/198), 22% (44/197), 12% (25/201), 16% (22/138) and 15% (20/133) of cases, respectively. In univariate analyses, advanced stage (p = 0.016), 65 years or older (p = 0.048) and presence of ulceration (p = 0.027) are significantly correlated with worse overall survival (OS), respectively. NRAS mutation significantly correlates with worse OS (p = 0.028) and worse melanoma-specific survival (MSS) (p = 0.03) for all cases of mucosal melanomas. In multivariate analyses, NRAS mutation remains as an independent predictor of worse OS (p = 0.036) and worse MSS (p = 0.024).

CONCLUSION

NRAS mutation is a predictor of worse survival, independent of stage in mucosal melanomas. The significance of frequently mutated IGF2R in mucosal melanomas remains unclear.

Management of Noncutaneous Melanomas

Noncutaneous melanomas are rare subtypes of melanoma with high rates of metastatic disease and poor overall survival. One-third to one-half of cases are amelanotic, which may contribute to a delay in diagnosis. Immunohistochemistry staining with typical melanoma markers helps confirm the diagnosis. There is no standard staging system across mucosal melanomas. Elective nodal dissection is not recommended and there is a paucity of data to support use of sentinel lymph node biopsy. Mutational analysis should be routinely performed. Systemic therapy options include targeted inhibitors, immunotherapy, and cytotoxic chemotherapy, although further studies are needed to confirm their efficacy.

Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

Surgical Management of Vulvar Melanoma: A Case Series

Vulvar malignant melanoma is the second most common subtype of vulvar cancer, accounting for 5-10% of all vulvar cancers. The prognosis is still very poor, although some advances have been achieved in the last years. One of the most significant changes in its management has been the development of less invasive surgical techniques that diminish the risk of postoperative morbidity and long-lasting sequelae. In this article, we review the surgical management of the pathology, based on the comment of 3 cases with vulvar melanoma treated at our institution.

Mucosal Melanomas of the Anogenital Tract: Clinical and Pathologic Predictors of Patient Survival

Primary anogenital mucosal melanomas (AGMs) are rare aggressive malignancies that are typically diagnosed at an advanced stage. Ulceration is a common feature in AGMs and may not correlate with outcome. Therefore, staging of AGMs similar to primary cutaneous melanomas, based on tumor thickness and ulceration, may not robustly predict outcome. Derivation of site-specific staging systems is essential for prognostication and optimal management of these patients. To this end, recent retrospective studies have revealed tumor thickness (TT) and mitotic rate (MR) as features of most prognostic significance as follows: in anorectal (TT only) and vulvar (TT and MR) melanomas.

Immunotherapy combined with high- and low-dose radiation to all sites leads to complete clearance of disease in a patient with metastatic vaginal melanoma

A 73-year-old woman with metastatic vaginal mucosal melanoma that had progressed on ipilimumab and nivolumab experienced clinical and radiographic complete response to dual checkpoint inhibitor immunotherapy given in combination with high-dose plus low-dose radiation. General characteristics and treatment options in this disease are highlighted.

[Interdisciplinary S2k guidelines on the diagnosis and treatment of vaginal carcinoma and its precursors-recommendations on surgical pathology for histopathological workup, diagnostics, and reporting]

Primary vaginal carcinoma is rare. There are two pathogenetic pathways, one associated with HPV high-risk infection and another one with inactivation of p53. Vaginal Paget's disease is rare and mostly associated with vulvar disease or represents intravaginal spread of associated locoregional cancer. Diagnostic vaginal biopsies should be examined by step sections on H&E. Sentinel lymph nodes should be processed completely using ultrastaging. Morphology-based prognostic factors with good clinical evidence are tumour stage and lymph node status. Molecular markers are not currently relevant for treatment decision and prognosis.

Cancer of the Vulva: A Review

BACKGROUND

Vulvar cancers, although rare, are becoming an increasingly serious threat to women's health. Cancer of the vulva accounted for 0.3% of all new cancers in the United States in 2019, with 6,070 newly diagnosed cases. This review details the epidemiology, pathogenesis, diagnosis, staging, and treatment of vulvar malignancies.

OBJECTIVE

To review cancer entities of the vulva, including vulvar intraepithelial neoplasms, squamous cell carcinoma (SCC), malignant melanoma, basal cell carcinoma, neuroendocrine tumors, and adenocarcinomas.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to cancer of the vulva.

RESULTS

Vulvar intraepithelial neoplasms represent premalignant precursors to SCC of the vulva. There are several different histopathologic subtypes of SCC, and treatment is dependent on characteristics of primary tumor and lymph node involvement. Melanoma is the second most common cancer to affect the vulva, and staging is based on tumor, node, and metastatic spread.

CONCLUSION

Vulvar malignancies are rare, and diagnosis is dependent on biopsy and pathologic evaluation. Treatment for vulvar malignancies depends on histopathologic diagnosis but ranges from wide local excision with or without lymph node biopsy or dissection to radiation therapy with chemo- or immunotherapy. Overall survival varies by diagnosis.

Evaluation of treatment, prognostic factors, and survival in 198 vulvar melanoma patients: Implications for clinical practice

OBJECTIVE

To identify clinicopathological characteristics, treatment patterns, clinical outcomes and prognostic factors in patients with vulvar melanoma (VM).

MATERIALS & METHODS

This retrospective multicentre cohort study included 198 women with VM treated in eight cancer centres in the Netherlands and UK between 1990 and 2017. Clinicopathological features, treatment, recurrence, and survival data were collected. Overall and recurrence-free survival was estimated with the Kaplan-Meier method. Prognostic parameters were identified with multivariable Cox regression analysis.

RESULTS

The majority of patients (75.8%) had localized disease at diagnosis. VM was significantly associated with high-risk clinicopathological features, including age, tumour thickness, ulceration, positive resection margins and involved lymph nodes. Overall survival was 48% (95% CI 40-56%) and 31% (95% CI 23-39%) after 2 and 5 years respectively and did not improve in patients diagnosed after 2010 compared to patients diagnosed between 1990 and 2009. Recurrence occurred in 66.7% of patients, of which two-third was non-local. In multivariable analysis, age and tumour size were independent prognostic factors for worse survival. Prognostic factors for recurrence were tumour size and tumour type. Only the minority of patients were treated with immuno- or targeted therapy.

CONCLUSION

Our results show that even clinically early-stage VM is an aggressive disease associated with poor clinical outcome due to distant metastases. Further investigation into the genomic landscape and the immune microenvironment in VM may pave the way to novel therapies to improve clinical outcomes in these aggressive tumours. Clinical trials with immunotherapy or targeted therapy in patients with high-risk, advanced or metastatic disease are highly needed.

Non-human-papillomavirus-related malignancies of the vulva: A clinicopathological study

BACKGROUND

Malignant tumor of the vulva is the fourth gynecological malignancy in frequency. Close to 70% of all vulvar malignancies are related to high-risk human papillomavirus (HPV) infection.

METHODS

A search for non-HPV-related malignant tumors of the vulva was performed in the last 20 years (2000-2020) in the pathology database of a single tertiary institution. We aim to estimate the prevalence of non-HPV-related malignancies in our population, describe clinicopathological features of these tumors and investigate the expression of some potential therapeutic targets.

RESULTS

A total of 71 patients were recovered; 26 patients (36%) had the diagnosis of extramammary Paget disease, 17 patients (24%) had basal cell carcinomas, 17 patients (24%) had primary melanomas, 10 patients (14%) had metastatic disease to the vulva and one patient (1%) had a primary dermatofibrosarcoma protuberans. Fifty-four percent of patients with extramammary Paget disease had a secondary malignancy and 12.5% had invasive disease. Programmed death-ligand 1 (PDL-1) was positive in seven out of nine primary melanomas and Her2/neu was overexpressed in six out of seven extramammary Paget disease.

CONCLUSION

Non-HPV-related malignancies are important differential diagnoses in patient with vulvar lesions. Additional research is necessary to further understand these complex malignancies and potential new therapeutic targets.

Primary malignant melanoma of the vagina

Primary malignant melanoma of the vagina is a rare gynaecological neoplasm with an aggressive course of disease. Although not many cases have been reported in the literature, its manifestations appear to be fairly consistent. The challenge comes in knowing how to approach this cancer clinically, since information about its staging and treatment is limited. In this report, we present a case of an 84-year-old postmenopausal woman in whom a suspicious vaginal lesion was discovered incidentally during a procedure. Wide local excision was carried out at a later date and histopathology confirmed a malignant melanoma of the vagina contained locally with no radiological finding of distant metastases. No additional treatment was given, and three monthly follow-ups were arranged for this patient. We review the literature and briefly discuss the epidemiology, treatment approaches, prognostic factors and expected outcomes of this rare disease.

Predictive biomarkers and tumor microenvironment in female genital melanomas: a multi-institutional study of 55 cases

Female genital melanomas are rare. At diagnosis, most affected patients have advanced disease. Surgery remains the primary treatment, and adjuvant therapy is largely ineffective. Recently, immune checkpoints and the mitogen-activated protein kinase pathway have been explored as treatment targets. However, evaluation of these biomarkers in genital melanomas is limited. We evaluated the clinicopathological features of 20 vulvar, 32 vaginal, and three cervical melanomas and assessed programmed cell death ligand 1 (PD-L1) expression, CD8 tumor-infiltrating lymphocyte density, mismatch repair proteins, VE1 immunohistochemistry, and KIT and BRAF mutations. The median age of the patients was 66 years, and median tumor sizes were 25, 30, and 20 mm for vulvar, vaginal, and cervical tumors, respectively. Mean mitotic figures were 18, 19, and 30 per mm². Thirty-seven patients (67%) had operable tumors. After a median follow-up of 15 months, only nine patients (16%) were alive. Eight of the nine survivors did not have lymph node metastasis. Using 5% as the threshold, PD-L1 expression was observed in 55%, 50%, and 33% of vulvar, vaginal, and cervical tumors, respectively, when the Roche SP263 antibody was used and 20%, 53%, and 0%, respectively, when the Dako 28-8 antibody was used. The median CD8 tumor-infiltrating lymphocyte density was significantly higher in vulvar/vaginal than cervical melanomas and correlated with PD-L1 expression. No cases exhibited loss of mismatch repair proteins. Five cases harbored KIT mutations, three of which were hotspots. BRAF V600E mutation was not detected. Univariable analysis showed that tumor size greater than or equal to 33 mm, mitotic figures of greater than or equal to 10 per mm², lymph node metastasis, and low CD8+ tumor-infiltrating lymphocyte density were adverse prognostic factors. Thus, patients with genital melanomas have a poor prognosis, and evaluation of multiple biomarkers is necessary to identify patients who may benefit from immunotherapy or targeted therapy.

Feasibility of Carbon Ion Radiotherapy in the Treatment of Gynecological Melanoma

BACKGROUND

Malignant melanoma of the lower genital tract is a rare disease known to have a poor prognosis. Because of the high rate of distant metastasis and unsatisfactory survival benefit, a more conservative treatment approach, instead of extensive surgery, may be warranted. Gynecological melanoma is a radioresistant tumor, an ideal disease to test the biological efficacy of carbon ion radiotherapy (CIRT).

AIM

To report our preliminary experience with CIRT in the treatment of gynecological melanoma at the National Center of Oncological Hadrontherapy (CNAO).

PATIENTS AND METHODS

Between January 2016 and February 2017, four patients were admitted for CIRT at CNAO. A case of cervical melanoma was treated with palliative aim because of large volume macroscopic disease, while three cases of vaginal melanoma were irradiated with a total dose of 68.8 Gy (relative biological effectiveness) in 16 fractions delivered over 4 weeks (4 days a week).

RESULTS

The age of women ranged between 49 and 72 (median=60.5 years) years. Treatment was well tolerated in all patients and all women completed the scheduled treatment course. During CIRT, toxicity was mild. For patients with vaginal disease, local control was 10.23 and 12.6 months, while that for cervical malignant melanoma was 7.3 months. All patients experienced systemic progression, with median distant metastasis-free survival of 11.7 months. The median overall survival for the whole patient group was 11.41 months.

CONCLUSION

In our first experiences, CIRT appears to be a safe non-invasive option for malignant melanoma of the lower genital tract, but more data and longer follow-up are necessary in order to evaluate the effectiveness and late effects.

Vulvar malignant melanoma: Pathogenesis, clinical behaviour and management: Review of the literature

Vulvar malignant melanoma (VMM) is a rare disease, accounting for 5% of all vulvar malignancies and is characterized by low survival and high recurrence rates. It is considered as a distinct entity of mucosal melanoma. Prognostic factors are higher age, advanced Breslow thickness, and lymph node involvement whilst central localization and ulceration status are still under debate. Surgery is the cornerstone for the treatment of primary VMM, however, it can be mutilating due to the anatomical location of the disease. Elective lymph node dissection is not part of standard care. The value of sentinel lymph node biopsy in VMM is still being studied. Radiation therapy and chemotherapy as adjuvant treatment do not benefit survival. Immunotherapy in cutaneous melanoma has shown promising results but clinical studies in VMM are scarce. In metastatic VMM, checkpoint inhibitors and in case of BRAF or KIT mutated metastatic VMM targeted therapy have shown clinical efficacy. In this review, we present an overview of clinical aspects, clinicopathological characteristics and its prognostic value and the latest view on (adjuvant) therapy and follow-up.

Frequent PD-L1 Expression in Malignant Melanomas of the Vulva

Blockade of immune checkpoint pathways such as the programmed cell death protein 1 pathway (PD-1/PD-L1) is an emerging approach in the treatment of solid tumors. In malignant melanoma, the efficiacy of antibodies against PD-L1 has been shown to be associated with PD-L1 protein expression. To evaluate whether this approach may be of use in the rare cases of primary melanoma of the vulva, we have evaluated a series of 13 cases for PD-L1 expression as well as additional molecular alterations of KIT, NRAS, KRAS, and BRAF. PD-L1 expression was detected in 69% of cases and was not associated with any other molecular alteration, tumor stage or morphology. In conclusion, targeting PD-L1 by selective antibodies may be of benefit in the treatment of these uncommon tumors.

Melanoma of the Vulva and Vagina: Surgical Management and Outcomes Based on a Clinicopathologic Reviewof 68 Cases

OBJECTIVE

This study sought to evaluate the clinicopathologic features, surgical management, and survival of patients over 12 years at two academic centres.

METHODS

Patients diagnosed with vulvar or vaginal melanoma between 2002 and 2014 were identified through pathology databases. Clinical and pathologic data were extracted from the medical records. The Kaplan-Meier method was used to calculate recurrence-free survival and overall survival (OS), and univariate analyses using a Cox proportional hazard model were used to detect covariates related to survival.

RESULTS

Patients with vulvar melanoma were more likely to undergo surgical excision (84.0% vs. 55.6%, P = 0.0243) and were more likely to achieve negative margins (70.0% vs. 16.7%, P < 0.0001). Forty-eight percent of patients with vulvar melanoma had a lymph node evaluation; sentinel node biopsies were performed in 32%. Actuarial median OS for vulvar melanoma was 45 months compared with 10.48 months for vaginal melanoma. A subset of 10 patients with vulvar melanoma who survived longer than 60 months was identified. Eight significant predictors of OS were demonstrated for vulvar melanomas: clinical stage, maximum tumour size, tumour thickness, lymphovascular space invasion status, clinically enlarged lymph nodes, sentinel lymph nodes, lymph node status, and radiation treatment. Patients with positive or indeterminate margin status demonstrated a higher risk of recurrence than did patients with negative margins (hazard ratio 2.60; 95% CI 1.14-5.90).

CONCLUSION

Surgical excision with adequate margins is the mainstay of primary management when feasible. Lymph node evaluation, including sentinel nodes, may be considered in selected patients. Vulvar and vaginal sites differ markedly with respect to pathology, initial management, and survival, and they should be evaluated separately.

Combatting mucosal melanoma: recent advances and future perspectives

Mucosal melanomas are a rare subtype of melanoma and are associated with a particularly poor prognosis. Due to the rarity of the diagnosis, and the pace with which the management of cutaneous melanoma has evolved over recent years, there is little good evidence to guide management and evidence-based clinical guidelines are still in development in the UK. In this review we provide an overview of the management of mucosal melanoma, highlighting the critical differences between cutaneous and mucosal melanomas, before examining recent advances in the systemic treatment of this disease and likely future directions.

Melanoma of the lower genital tract: Prognostic factors and treatment modalities

Primary melanomas originating from the gynecological tract are rare and aggressive cancers. The vulva is the most frequent site (70%), followed by vagina and more rarely by cervix. The clinical outcome of patients with female genital tract melanoma is very poor, with a 5-year overall survival (OS) of 37-50% for vulvar, 13-32% for vaginal, and approximately 10% for cervical melanoma. In this systematic review, we analyzed the pathogenesis and the different factors influencing the prognosis of melanomas of the lower genital tract, with particular emphasis on biologic variables that may influence new therapeutic approaches. We evaluated the different treatment modalities described in the literature, in order to offer a possible algorithm that may help the clinicians in diagnosing and treating patients with these uncommon malignancies.

Raised vulvar lesions: be aware!

Vulvar melanoma is a rare and deadly cancer in women, and the prognosis is often poor. There are limited studies on the dermoscopic features of vulvar melanoma. Described criteria include the presence of blue, gray, or white colors. Herein we present the clinical and dermoscopic characteristics of a hypopigmented and heavily pigmented nodule in a 92-year-old and an 80-year-old woman. Dermoscopy in the former revealed structureless milky-red to white areas, remnants of brown pigmentation at the base and polymorphic vessels, while the latter displayed structureless blue-gray areas with black dots and peripheral lines at the base. In both cases, histopathology revealed a stage III melanoma. Our two cases along with a review of the literature suggest that the dermoscopic features described for diagnosing cutaneous nodular melanoma, apply also for vulvar melanoma. Clinicians should always raise the suspicion if observing plaques or nodules with a dermoscopic polymorphic vascular pattern and blue-black color on the genitals of postmenopausal women.

Clinical patterns and management of primary mucosal melanoma: a single centre experience

BACKGROUND

Primary mucosal melanomas (MM) are rare neoplasms arising from melanocytes in mucosal membranes. Delayed diagnosis and aggressive disease biology contribute to a poorer prognosis. The clinical patterns of MMs treated in a large tertiary centre, and the differences between MMs in the head and neck versus other anatomical sites are described.

METHODS

A retrospective review of 43 patients diagnosed with MM in the head and neck, urogenital, esophageal and anorectal sites from 1993 to 2015 was conducted.

RESULTS

Distribution of head and neck, urogenital and gastrointestinal MM were 42, 30 and 28% respectively. Disease extent was local in 44%, regional in 40% and distal in 12% at diagnosis. Head and neck MMs were more likely to be diagnosed at an earlier stage as compared to other sites (P = 0.04). Surgery was performed with curative intent in 72%, while 2% had palliative surgery for symptom control. Of the remaining patients who did not undergo surgery, four had palliative chemotherapy and/or radiotherapy. Median disease-free survival was 13 months (1-179 months). There was a significantly longer time to locoregional recurrence in head and neck MM (16 months) compared to other sites (11 months) (P = 0.03). The 2-year overall survival was also significantly higher in head and neck MM (P = 0.003).

CONCLUSION

MM of the head and neck is diagnosed at an earlier stage and associated with a longer time to locoregional recurrence. Surgical resection is the mainstay of treatment and may offer long-term survival benefit in selected patients.

Photodynamic Therapy for Metastatic Melanoma Treatment: A Review

This review article is based on specifically targeted nanoparticles that have been used in the treatment of melanoma. According to the Skin Cancer Foundation, within 2017 an estimated 9730 people will die due to invasive melanoma. Conventional treatments for nonmalignant melanoma include surgery, chemotherapy, and radiation. For the treatment of metastatic melanoma, 3 therapeutic agents have been approved by the Food and Drug Administration: dacarbazine, recombinant interferon α-2b, and high-dose interleukin 2. Photodynamic therapy is an alternative therapy that activates a photosensitizer at a specific wavelength forming reactive oxygen species which in turn induces cell death; it is noninvasive with far less side effects when compared to conventional treatments. Nanoparticles are generally conjugated to photosynthetic drugs, since they are biocompatible, stabile, and durable, as well as have a high loading capacity, which improve either passive or active photosensitizer drug delivery to targeted cells. Therefore, various photosynthetic drugs and nanoparticle drug delivery systems specifically targeted for melanoma were analyzed in this review article in relation to either their passive or their active cellular uptake mechanisms in order to deduce the efficacy of photodynamic therapy treatment for metastatic melanoma which currently remains ongoing. The overall findings from this review concluded that no current photodynamic therapy studies have been performed in relation to active nanoparticle platform photosensitizer drug carrier systems for the treatment of metastatic melanoma, and so this type of research requires further investigation into developing a more efficient active nano-photosensitizer carrier smart drug that can be conjugated to specific cell surface receptors and combinative monoclonal antibodies so that a further enhanced and more efficient form of targeted photodynamic therapy for the treatment of metastatic melanoma can be established.

Gynecologic melanomas: A clinicopathologic and molecular analysis

OBJECTIVE

Melanoma originating from gynecologic sites (MOGS), including the vulva, vagina, and cervix, is a rare and aggressive form of melanoma with poor long-term clinical outcome. The clinicopathologic features of vulvar and non-vulvar tumors remain relatively understudied, and in contrast to cutaneous melanomas at non-sun-exposed sites, MOGS typically do not harbor BRAF mutations. Thus, we sought to analyze the clinicopathologic and molecular features of MOGS.

METHODS

A large retrospective cohort of patients with MOGS (n=59) at a single large academic institution over a 28-year period was identified. Associations among clinicopathologic characteristics were assessed via standard statistical approaches, and clinical outcome was examined using Cox regression analysis. Sanger sequencing was utilized to identify mutations in hotspot regions of BRAF, KIT, NRAS, and CTNNB1.

RESULTS

Tumors involving the vagina and/or cervix (non-vulvar) are significantly associated with high-risk clinicopathologic features, including increased tumor thickness, ulceration, positive resection margins, lymph node metastasis, and poor long-term clinical outcome (with increased risk of death due to disease). The aggressive clinical behavior of non-vulvar tumors is independent of advanced clinical stage and lymph node metastasis in multivariate analysis. Targeted molecular analysis confirms an overall low rate of oncogenic mutations in our MOGS cohort, although KIT mutations (particularly in exon 11) are relatively enriched.

CONCLUSIONS

Overall, our results show that non-vulvar MOGS are aggressive tumors with poor long-term clinical outcome and indicate that few targeted therapeutic options are currently available to patients with MOGS.

Mucosal melanoma: clinical, histological and c-kit gene mutational profile of 86 French cases

BACKGROUND

Mucosal melanomas are rare and highly aggressive tumours. Few studies evaluated mucosal melanomas of locations other than the head and neck region, and other than those of the Asian population.

OBJECTIVES

The objective of this study was to analyse the clinical and histological features, as well as the mutational status of c-kit and b-raf gene of mucosal melanoma in any localization in a French series.

METHODS

We investigated clinical (sex, age, performance status, survival, treatment of the patients and lack of pigmentation of the tumours) and histopathological features (ulceration, Breslow's index, mitotic rate), as well as the mutational status of c-kit and b-raf of 86 mucosal melanomas diagnosed in 15 years in four French University Hospitals.

RESULTS

Most melanomas affected women (72%) and the genital region (46.5%). A fifth of melanomas were amelanotic. 81% of melanomas had a Breslow's index ≥1, whereas all glans melanomas, and most vulvar melanomas had a Breslow index ≤1 mm. Overall survival was 54% at 3 years; 11.6% of the 43 tested mucosal melanomas were c-kit-mutated while the 15 tested genital melanomas were not. The c-kit gene mutation did not influence the overall survival. Age ≥ 50, amelanotic type and performance status ≥1 were not poor prognostic factors in our series.

CONCLUSION

This study confirmed that mucosal melanomas are rare and could be difficult to diagnose being often amelanotic and in hidden sites. Most melanomas were thick at the diagnosis, but glans and vulvar melanomas were thinner probably because of their greater visibility. The frequency of the c-kit mutation varied depending on the initial tumour site. In our series, the prognosis was poor, independently from c-kit mutations and the patient's general health and age. The presence of metastasis at diagnosis was associated with a worse prognosis indicating the importance of an early diagnosis.

Dermoscopy of Malignant Skin Tumours: What's New?

Dermoscopy represents a new and effective tool that assists dermatologists in improving the accuracy of clinical diagnosis in onco-dermatology. The aim of this article is to provide an overview of the latest and important dermoscopic progress and observations in this ever-evolving field of dermatology.

Primary Vaginal Melanoma, A Rare and Aggressive Entity. A Case Report and Review of the Literature

Malignant melanoma of the vagina is a rare, aggressive malignancy of poor prognosis. It principally affects post-menopausal women, with a mean age of 57 years, and the factors that contribute to its appearance are not well known. The first case of primary malignant vaginal melanoma was reported in 1887 and modern literature has noted about 500 cases, globally. Vaginal melanomas constitute 0.3% of all malignant melanomas and fewer than 3% of all vaginal carcinomas. To date there is no clear consensus regarding treatment. An early, accurate diagnosis and prompt investigation is essential in reaching appropriate treatment decisions. We present a clinical case of primary vaginal melanoma and review the literature briefly, presenting the current treatment plans and updates of this rare gynecological malignancy. Considerations, epidemiology, associated risk factors, response to therapy and expected outcome are also discussed.

CONCLUSION

Primary malignant vaginal melanoma is a rare but aggressive melanoma that affects women in their 6th and 7th decade of life. The tumor appears as a dark node or spindle but can also be amelanotic. The size of the tumor is indicative of the prognostic factors. Surgery seems to be the only efficient treatment. Postoperative adjuvant therapy might help in preventing recurrence of the tumor. The survival rate is largely dependent on nodal and distant metastasis of the disease after initial tumor resection. There is a dire need to form a proper therapeutic regime to control this disease.

Surgical Management and Prognostic Factors of Vulvovaginal Melanoma

OBJECTIVE

The aim of the study was to evaluate the surgical management and the role of different prognostic factors on survival outcomes of women affected by genital (i.e., vulvar and vaginal) melanoma.

MATERIALS AND METHODS

Data of patients undergoing primary surgical treatment for genital melanoma were evaluated in this retrospective study. Baseline, pathological, and postoperative variables were tested to identify prognostic factors. Five-year disease-free survival (DFS) and overall survival (OS) were analyzed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

Overall, 98 patients met the inclusion criteria. Sixty-seven (68%) and 31 (32%) patients in this study population were diagnosed with vulvar and vaginal melanoma, respectively. Median (range) DFS and OS were 12 (1-70) and 22 (1-70) months, respectively. Considering factors influencing DFS, we observed that at multivariate analysis, only vaginal localization (hazard ratio [HR] = 3.72; 95% CI = 1.05-13.2) and number of mitoses (HR = 1.24; 95% CI = 1.11-1.39) proved to be associated with worse DFS. Nodal status was the only independent factor influencing 5-year OS in patients with vulvar (HR = 1.76; 95% CI = 1.22-2.54; p = .002) and vaginal (HR = 3.65; 95% CI = 1.08-12.3; p = .03) melanoma.

CONCLUSIONS

Genital melanomas are characterized by a poor prognosis. Number of mitoses and lymph node status are the main factors influencing survival. Surgery is the mainstay of treatment. A correct and prompt diagnosis is paramount.

Clinical and Imaging Features of Noncutaneous Melanoma

OBJECTIVE

The purpose of this article is to summarize the epidemiologic characteristics, clinical aspects, and radiologic appearance of as well as the management considerations and differential diagnoses for noncutaneous primary melanomas occurring at specific anatomic sites. Primary ocular, sinonasal, meningeal, biliary, adrenal, alimentary tract, and genitourinary melanomas are highlighted.

CONCLUSION

Noncutaneous primary melanomas are a complex group of malignancies with biologic findings that are unique when compared with findings for cutaneous melanomas. Each noncutaneous primary melanoma has its own specific diagnostic and management challenges, depending on the anatomic location where they arise.

[Laparoscopic anterior pelvic exenteration in a patient with locally advanced melanoma]

BACKGROUND

Pelvic exenteration is one of the most mutilating surgical procedures with high post-operative morbidity. The laparoscopic technique aims to reduce perioperative complications and reduce post-surgical recovery.

OBJECTIVE

We present the first case of laparoscopic anterior exenteration for locally advanced melanoma, held at the National Cancer Institute and published in Mexico.

CASE REPORT

Patient 60 years of age diagnosed with invasive vulvar melanoma with bladder extension upon whom laparoscopic anterior pelvic exenteration with external urinary reconstruction was performed. Time in surgery was 505minutes and estimated blood loss was 400ml. No complications occurred during or immediately after surgery. The final histopathological study reported: nodular lesion that completely replaces the clitoris and spreads to the left labia majora, measures 3×2.5×2cm and is located relative to the free margins with perineural invasion intraepithelial spread in space and urethra and bladder trigone.

CONCLUSIONS

The laparoscopic anterior pelvic exenteration is a safe alternative in well-selected patients, with acceptable time in surgery, surgical complications and recovery time.

Tumor Thickness and Mitotic Rate Robustly Predict Melanoma-Specific Survival in Patients with Primary Vulvar Melanoma: A Retrospective Review of 100 Cases

Purpose: Primary vulvar melanoma (PVM) is the second most common vulvar malignancy. Despite their distinct anatomic site and unique molecular-genetic alterations, PVMs are staged according to the American Joint Committee on Cancer (AJCC) guidelines for primary cutaneous melanomas (PCM). However, whether parameters derived for PCM also apply to PVM remain a critical yet largely unexplored clinical question. The objective of this study was to determine the parameters predictive of survival in PVM.Experimental Design: We retrospectively reviewed 100 patients with PVM and determined associations between clinical and histopathologic parameters and disease-specific survival (DSS) and overall survival (OS).Results: Univariate Cox regression analysis demonstrated older age (>56 years), greater tumor thickness, higher dermal mitotic rate, ulceration, lymphovascular invasion, perineural invasion, microscopic satellitosis, and absence of precursor nevus associated with decreased OS. Furthermore, age, midline, and/or multifocal involvement, greater tumor thickness, higher dermal mitotic rate, ulceration, lack of regression, lymphovascular invasion, perineural invasion, and microscopic satellitosis associated with decreased DSS. Multivariate analysis demonstrated tumor thickness, dermal mitotic rate, lymphovascular invasion, microscopic satellitosis, and absence of precursor nevus independently predicted shorter OS. Only tumor thickness and increased dermal mitotic rate (≥2/mm²) independently predicted reduced DSS. In comparison with the AJCC T-category, a novel, bivariate T-category based only on tumor thickness and dermal mitotic rate robustly predicted OS and DSS in our patient cohort.Conclusions: In the largest single institutional study of PVM, we demonstrate a combination of tumor thickness and mitotic rate comprise a simple but robust T-category to direct staging and prognosis. Clin Cancer Res; 23(8); 2093-104. ©2016 AACR.