Metastatic melanoma and rare melanoma variants: a review

Primary dermal melanoma

Primary dermal melanoma (PDM) is a rare subtype of melanoma with an estimated incidence of <1%. PDM manifests entirely in the dermis or subcutis and histopathologically mimics cutaneous melanoma metastasis due to its lack of connection to the overlying epidermis. A thorough history and examination, including imaging evaluation for metastatic disease, reveals no prior history or concurrent primary cutaneous or metastatic melanoma lesion. Despite its histopathologic similarities to melanoma metastasis, PDM is associated with an unexpectedly favorable prognosis. This review discusses the clinical and histopathologic features of PDM as a distinct subtype of melanoma, as well as the current approach to clinical staging and management.

Blue Nevus-Like Metastatic Melanoma in a Patient With Primary Lentigo Maligna Melanoma

Metastatic melanoma with unusual histopathology can be diagnostically challenging. One exceptionally rare cutaneous manifestation of metastases is blue-nevus-like metastatic melanoma (BNLMM). A 74-year-old male presented with a blue-gray lesion on his left helix in the same anatomical region of a previously resected lentigo maligna. Histopathological sections demonstrated an atypical biphasic proliferation of dendritic melanocytes with pigment incontinence and epidermal sparing, measuring > 0.05 mm in diameter. Although the majority of the cell population exhibited cytologic features consistent with a blue nevus, there was a subset of dendritic cells with irregular epithelioid contours and rare, typical dermal mitotic figures. Sections showed an increased Mart-1/Ki67 rate. Perineural and angiotropic involvement by the atypical melanocytes was identified. Immunohistochemical (IHC) stains for SOX-10, HMB45, and PRAME highlighted melanocytic proliferation. BAP-1 IHC was retained, and p16 IHC showed complete loss. No previous procedure site changes were present, indicating that the dendritic cell proliferation was separated from the primary invasive melanoma by normal dermis. The histopathological and immunohistochemical findings led to a diagnosis of microsatellite BNLMM. We report this case to highlight the importance of this rare entity and to avoid misdiagnosis of BNLMM, which would significantly impact patient prognosis, treatment, follow-up, and outcomes.

Atypical localization of metastatic melanoma in the gastrointestinal tract

Although most melanomas are diagnosed in early stages of the disease, a significant percentage show metastases from the beginning or during follow-up. The most common route is lymphatic, while hematogenous spread is less frequent. The most common site for metastases is the skin itself, although they can also occur in other organs, including the digestive tract, where the small intestine is the most frequently affected organ. We present the case of a 48-year-old woman with a history of superficial spreading melanoma of the cervical region, surgically treated 7 years prior and in remission, who presented with painless jaundice of 48 hours duration, without fever or other infectious focus. Upon arrival at the Emergency Department, she had a direct bilirubin of 7.9 mg/dL and a CRP of 140 mg/L. An abdominal ultrasound was performed, revealing biliary tract dilation without apparent cause, with secondary, apparently tumoral involvement of the gallbladder. During hospitalization, the study was completed with an abdominal CT scan, visualizing hyperdense lesions with a polypoid appearance in the gallbladder, in addition to the aforementioned intra- and extrahepatic biliary tract dilation. The cause was then identified as a hyperdense mass in the duodenum affecting the papilla, along with two other small hypervascular polypoid lesions in the second portion of the duodenum. With these findings, an ERCP was performed, revealing a papilla with a "pregnant" appearance, compatible with ampulloma, in addition to duodenal pseudopolyps of nonspecific appearance. The anatomopathological analysis was compatible with duodenal metastases from melanoma.

Regulatory Role of IL6 in Immune-Related Adverse Events during Checkpoint Inhibitor Treatment in Melanoma

The landscape of clinical management for metastatic melanoma (MM) and other solid tumors has been modernized by the advent of immune checkpoint inhibitors (ICI), including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors. While these agents demonstrate efficacy in suppressing tumor growth, they also lead to immune-related adverse events (irAEs), resulting in the exacerbation of autoimmune diseases such as rheumatoid arthritis (RA), ulcerative colitis (UC), and Crohn's disease (CD). The immune checkpoint inhibitors offer promising advancements in the treatment of melanoma and other cancers, but they also present significant challenges related to irAEs and autoimmune diseases. Ongoing research is crucial to better understand these challenges and develop strategies for mitigating adverse effects while maximizing therapeutic benefits. In this manuscript, we addressed this challenge using network-based approaches by constructing and analyzing the molecular and signaling networks associated with tumor-immune crosstalk. Our analysis revealed that IL6 is the key regulator responsible for irAEs during ICI therapies. Furthermore, we conducted an integrative network and molecular-level analysis, including virtual screening, of drug libraries, such as the Collection of Open Natural Products (COCONUT) and the Zinc15 FDA-approved library, to identify potential IL6 inhibitors. Subsequently, the compound amprenavir was identified as the best molecule that may disrupt essential interactions between IL6 and IL6R, which are responsible for initiating the signaling cascades underlying irAEs in ICI therapies.

Metastatic triple-negative breast carcinoma mimicking melanoma: A potential diagnostic pitfall

Melanoma, with its diverse histopathologic characteristics, can mimic both benign nevi and neoplasms of various cell lineages. Immunohistochemistry (IHC) can play a vital role in melanoma diagnosis, particularly when the cell lineage is unclear on hematoxylin and eosin sections. Commonly utilized IHC stains for melanoma diagnosis include SOX10, Melan-A, and S100. A relatively novel stain, PReferentially expressed Antigen in MElanoma (PRAME), is also proving useful in accurate melanoma diagnosis. However, none of these stains are completely specific to melanocytes or melanoma, and misinterpretation can lead to incorrect diagnoses. This report presents a unique case of triple-negative breast carcinoma (TNBC) metastatic to the skin exhibiting histopathologic characteristics similar to melanoma, including positivity for SOX10 and PRAME. Our aim is to highlight TNBC metastatic to the skin as a potential diagnostic pitfall.

Hesperidin from Orange Peel as a Promising Skincare Bioactive: An Overview

The pursuit for better skin health, driven by collective and individual perceptions, has led to the demand for sustainable skincare products. Environmental factors and lifestyle choices can accelerate skin aging, causing issues like inflammation, wrinkles, elasticity loss, hyperpigmentation, and dryness. The skincare industry is innovating to meet consumers' requests for cleaner and natural options. Simultaneously, environmental issues concerning waste generation have been leading to sustainable strategies based on the circular economy. A noteworthy solution consists of citrus by-product valorization, as such by-products can be used as a source of bioactive molecules. Citrus processing, particularly, generates substantial waste amounts (around 50% of the whole fruit), causing unprecedented environmental burdens. Hesperidin, a flavonoid abundant in orange peels, is considered to hold immense potential for clean skin health product applications due to its antioxidant, anti-inflammatory, and anticarcinogenic properties. This review explores hesperidin extraction and purification methodologies as well as key skincare application areas: (i) antiaging and skin barrier enhancement, (ii) UV radiation-induced damage, (iii) hyperpigmentation and depigmentation conditions, (iv) wound healing, and (v) skin cancer and other cutaneous diseases. This work's novelty lies in the comprehensive coverage of hesperidin's promising skincare applications while also demonstrating its potential as a sustainable ingredient from a circular economy approach.

Primary lipoblastic nerve sheath tumor in an inguinal lymph node mimicking metastatic tumor: a case report and literature review

Lipoblastic nerve sheath tumors of soft tissue are characterized as schwannoma tumors that exhibit adipose tissue and lipoblast-like cells with signet-ring morphology. They have been documented to arise in various anatomic locations, including the thigh, groin, shoulder, and retroperitoneum. However, to our knowledge, this tumor has not been previously reported as a lymph node primary. We present herein the first case of a benign primary lipoblastic nerve sheath tumor arising in an inguinal lymph node in a 69-year-old man. Microscopic examination revealed a multinodular tumor comprising fascicles of spindle cells, as well as adipocytic and lipoblast-like signet-ring cell component in the context of schwannoma. Despite the presence of some bizarre cells with nuclear atypia, no obvious mitotic activity or necrosis was observed. Immunohistochemical analysis showed strong and diffuse expression of S-100, SOX10, CD56, and NSE in the spindle cells as well as in the signet-ring lipoblast-like cells and the mature adipocytes. Sequencing analysis of the neoplasm identified six non-synonymous single nucleotide variant genes, specifically NF1, BRAF, ECE1, AMPD3, CRYAB, and NPHS1, as well as four nonsense mutation genes including MRE11A, CEP290, OTOA, and ALOXE3. The patient remained alive and well with no evidence of recurrence over a period of ten-year follow-up.

Signet-ring cell sinus histiocytosis: report of the clinicopathologic characteristics of 4 cases with emphasis on the differential diagnosis of signet-ring cell lesions

Signet-ring cell sinus histiocytosis (SRCSH) represents a distinctly rare reactive phenomenon predominantly affecting axillary and pelvic lymph nodes (LNs) of individuals with breast or prostatic adenocarcinoma. Reports of SRCSH in the literature are sparse with only 12 previous examples, thus underscoring the rarity of this process. Here, we report 4 additional SRCSH cases affecting 2 women and 2 men (M/F = 1:1; age range: 50-71 years; mean age = 61 years). In the 2 men, pelvic LNs were excised during radical cystoprostatectomy for genitourinary cancer, whereas in one woman, SRCSH was incidentally discovered in axillary LNs during mastectomy for breast adenocarcinoma. The other female patient presented with a history of aortic valve replacement and enlarged supraclavicular LNs. Microscopically, all involved LNs exhibited marked distention with filling of the subcapsular and medullary sinuses by sheets of signet-ring histiocytes containing a singular large, cytoplasmic vacuole and a crescentic nucleus. Overt cytologic atypia, pleomorphism, and mitoses were absent. Erythrophagocytosis and occasional fibrosis were appreciated. None of the LNs with SRCSH showed evidence of metastatic tumor. Immunohistochemically, signet-ring sinus histiocytes were invariably positive for CD68 and CD163 but were negative for pancytokeratins. The histopathologic characteristics of SRCSH, albeit bland, in conjunction with the patient's medical history, may be misinterpreted as metastatic adenocarcinoma with signet-ring cell configuration. Immunohistochemical confirmation of the histiocytic lineage of the lesional cells in SRCSH usually suffices for rendering an accurate diagnosis. The underlying pathogenetic mechanism and possible biologic significance of SRCSH remain currently unknown.

Is It Time to Supersede the Diagnostic Term "Melanoma In Situ with Regression?" A Narrative Review

Traditionally, the term melanoma in situ (MIS) is used to designate a horizontal (radial) growth phase of malignant melanoma (MM) in which there is no histological evidence of any invasion (or microinvasion) of neoplastic melanocytic cells into the superficial or papillary dermis. In daily dermatopathological practice, we are faced with misleading definitions, such as "melanoma in situ with regression," which risk affecting homogeneity for comparison purposes of pathological reports of malignant melanoma. The authors conducted a literature review using PubMed and Web of Science (WoS) as the main databases and using the following keywords: "Malignant Melanoma in situ" or "Melanoma in situ" and "regression" and/or "radial growth phase regression." A total of 213 articles from both analyzed databases were retrieved; finally, only eight articles in English were considered suitable for the chosen inclusion criteria. In consideration of the absence of studies with large case series, of reviews with meta-analyses, and, therefore, of a broad scientific consensus, expressions including "melanoma in situ with regression" should be avoided in the histopathological report. Instead, they should be replaced with clearer and more exhaustive definitions.