Prognostic Significance of Subungual Anatomic Site in Acral Lentiginous Melanoma

A rare case of circumferential osteoinvasive subungual melanoma: A case report

Subungual melanoma is a rarer form of melanoma encountered in clinical practice that often has a poor prognosis because it presents with advanced disease. We report a case of a 46-year-old male with a circumferential osteoinvasive melanoma that invaded the superior and lateral aspects of the periosteum of the distal phalanx. We discuss pathologic findings and common physical exam findings to facilitate earlier diagnosis of subungual melanoma.

Clinical and Histopathologic Features of Subungual Melanoma in 57 Mexican Patients: A 5-Year Cohort Study

Although subungual melanoma is uncommon, it is associated with worse outcomes than melanomas in other locations and accounts for 1% to 23% of all melanomas, depending on the population. The aim of this study was to describe the clinical and histopathologic features of subungual melanoma in a Mexican population. We identified 303 patients with melanoma, and of these, 19% (57 patients with a median age of 71 years) had subungual melanoma. The main sites affected were the lower limbs (52.6%) and the toe (75.4%). The most common histologic subtype was acral lentiginous melanoma (50.9%). Median Breslow thickness was 3 mm, and stage IA tumors were the most common (in 28.1% of patients). Recurrence and metastasis occurred in 19.3% and 8.8% of patients, respectively. The clinical and histopathologic features identified are similar to those described in the literature. Early diagnosis and treatment are crucial for improving prognosis.

[Translated article] Clinical and Histopathologic Features of Subungual Melanoma in 57 Mexican Patients: A 5-Year Cohort Study

Although subungual melanoma is uncommon, it is associated with worse outcomes than melanomas in other locations and accounts for 1% to 23% of all melanomas, depending on the population. The aim of this study was to describe the clinical and histopathologic features of subungual melanoma in a Mexican population. We identified 303 patients with melanoma, and of these, 19% (57 patients with a median age of 71 years) had subungual melanoma. The main sites affected were the lower limbs (52.6%) and the toe (75.4%). The most common histologic subtype was acral lentiginous melanoma (50.9%). Median Breslow thickness was 3 mm, and stage IA tumors were the most common (in 28.1% of patients). Recurrence and metastasis occurred in 19.3% and 8.8% of patients, respectively. The clinical and histopathologic features identified are similar to those described in the literature. Early diagnosis and treatment are crucial for improving prognosis.

Prevalence of subungual melanoma in patients with cutaneous malignant melanoma: A systematic review and meta-analysis

BACKGROUND

Subungual melanoma (SUM) is a rare type of cutaneous malignant melanoma (CMM) associated with poor prognosis, while data regarding its prevalence are scarce.

OBJECTIVES

We sought to provide a comprehensive systematic review and meta-analysis of the prevalence rates of SUM among all types of CMM, considering certain demographic and clinical characteristics.

METHODS

The MEDLINE electronic database was searched systematically to identify eligible studies providing prevalence rate estimates of SUM in patients with CMM. Included studies were further analysed to estimate the relative prevalences of SUM according to study design, study years, geographical region and sex distribution.

RESULTS

Twenty-eight studies met the inclusion criteria. The overall SUM prevalence was 1.9% (95% CI [1.5%-2.3%]). The prevalence of SUM did not differ significantly between population- and hospital-based studies and remained stable over time. However, it was found to be significantly higher in Asians compared to patients of other geographical regions as well as in studies with more men than women compared to those with female preponderance (p < 0.001).

CONCLUSIONS

In all, the overall SUM prevalence among all subtypes of CMM was estimated at 1.9%, without significant changes over time, and was found to exhibit significant variability between subgroups of different geographical regions.

Differences in the Clinical and Molecular Profiles of Subungual Melanoma and Acral Melanoma in Asian Patients

Subungual melanoma (SUM) is a rare type of malignant melanoma that arises beneath the nails. SUM is categorized as a type of acral melanoma (AM), which occurs on the hands and feet. SUM is an aggressive type of cutaneous melanoma that is most common among Asian patients. Recent studies reveal that SUM and AM might have different molecular characteristics. Treatment of melanoma relies on analysis of both clinical and molecular data. Therefore, the clinical and molecular characteristics of SUM need to be established, especially during metastasis. To define the mutation profiles of SUM and compare them with those of AM, we performed next-generation sequencing of primary and metastatic tumors of SUM and AM patients. Subungual location was a better independent prognostic factor than acral location for better overall survival (p = 0.001). Patients with SUM most commonly had the triple wild-type (75%) driven by GNAQ (58%) and KIT (25%) mutations, whereas patients with AM had BRAF (28.6%) and RAF (14.3%) molecular types of mutations. Single-nucleotide variations (SNVs) were more common in SUM than in AM, whereas copy number alterations (CNAs) were more common metastatic lesions of AM. Metastatic tumors in patients with SUM and AM showed increases in CNAs (43% and 80%, respectively), but not in SNVs. The number of CNAs increased during metastasis. When compared with AM, SUM has distinct clinical and molecular characteristics.

Diagnostic utility of PRAME expression by immunohistochemistry in subungual and non-subungual acral melanocytic lesions

BACKGROUND

The immunohistochemical (IHC) marker PReferentially expressed Antigen in MElanoma (PRAME) has shown promise in the diagnosis of melanocytic lesions. A few studies have investigated PRAME IHC expression in acral melanomas, but PRAME expression in subungual melanomas is largely unknown. We evaluated the utility of PRAME IHC expression in distinguishing subungual melanomas (SUM) and non-subungual acral melanomas (AM) from acral nevi (AN).

METHODS

Twenty-two SUM, 20 AM, and 14 AN were identified. IHC studies were performed using an anti-PRAME antibody. The percentage of lesional cells with PRAME expression was recorded and categorized as follows: 0%, 0; 1%-25%, 1+; 26%-50%, 2+; 51%-75%, 3+; and >75%, 4+. Patient demographics and other relevant clinicopathologic parameters were recorded.

RESULTS

Diffuse (4+) PRAME IHC expression was identified in 55% (12/22) SUM and 70% (14/20) AM, respectively. Any PRAME expression (1+ to 4+) was identified in 73% (16/22) SUMs and 95% (19/20) AM, respectively. One of 14 (7%) AN exhibited PRAME expression; interestingly, the pattern of expression was diffuse.

CONCLUSIONS

In our study, PRAME IHC expression was useful in identifying AM, including SUM. However, there are exceptions of PRAME-negative melanomas and PRAME-positive nevi.

Volar location and degree of pigmentation are associated with poor survival and first metastasis pattern in acral melanoma

The risk factors affecting acral melanoma metastasis and prognosis remain unclear. The study included 168 patients with invasive acral melanoma who were followed for ≥3 years. We evaluated patient demographics, stages, clinicopathological features, anatomic site of melanoma including nail versus volar surface, and degree of melanoma pigmentations, sentinel lymph node biopsy results, and the first metastasis sites. Of the 168 patients (mean age 64.5 years; 52.4% male), 43 (25.6%) had invasive melanoma without metastasis, 113 (67.3%) had invasive melanoma with a first lymph node metastasis, and 12 (7.1%) had invasive melanoma with invasive melanoma with a first distant metastasis. Advanced T stage, high mitotic rate, ulceration, and the degree of pigmentation were significant risk factors for metastasis. Amelanotic and mild pigmentation of acral melanoma was associated with first distant metastasis, whereas heavy pigmentation was associated with first lymph node metastasis. Advanced TNM stages, high mitotic rate, volar location (hazard ratio = 2.24, 95% confidence interval 1.18-4.26), and low-pigmentation (hazard ratio = 2.02, 95% confidence interval 1.17-3.49) were associated with melanoma-specific mortality.