Melan-A positive dermal cells in malignant melanoma in situ

A comprehensive exploration of diverse skin cell types in the limb of the desert tortoise (Testudo graeca) through light, transmission, scanning electron microscopy, and immunofluorescence techniques

The Greek tortoise, inhabiting harsh desert environments, provides a compelling case for investigating skin adaptations to extreme conditions. We have utilized light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and immunofluorescence analysis to describe the structure of the arid-adapted limb skin in the Greek tortoise. Our aim was to identify the cell types that reflect the skin adaptation of this tortoise to arid conditions. Utilizing seven antibodies, we localized and elucidated the functions of various skin cells, shedding light on how the tortoise adapts to adverse environmental conditions. Our findings unveiled numerous scales on the limbs, varying in size and color, acting as protective armor against abrasions, bites, and other potential threats in their rocky habitats. The epidermis comprises four layers: stratum basalis, stratum spinosum, peri-corneous layer, and stratum corneum. Cytokeratin 14 (CK14) was explicitly detected in the basal layer of the epidermis, suggesting a role in maintaining epidermal integrity and cellular function. Langerhans cells were observed between epidermal cells filled with ribosomes and Birbeck granules. Numerous dendritic-shaped Langerhans cells revealed through E-Cadherin signify strong immunity in tortoises' skin. Melanophores were identified using the Melan-A antibody, labeling the cytoplasm, and the SOX10 antibody, labeling the nucleus, providing comprehensive insights into melanophores morphology and distribution. Two types of melanophores were found: dendritic below the stratum basalis of the epidermis and clustered oval melanophores in the deep dermal layer. Varied melanophores distribution resulted in a spotted skin pattern, potentially offering adaptive camouflage and protection against environmental challenges. Numerous myofibroblasts were discerned through alpha-smooth actin (α-SMA) expression, indicating that the Greek tortoise's skin possesses a robust tissue repair and remodeling capacity. B-cell lymphocytes detected via CD20 immunostaining exhibited sporadic distribution in the dermis, concentrating in lymphoid aggregates and around vessels, implying potential roles in local immune responses and inflammation modulation. Employing Tom20 to identify skin cells with abundant mitochondria revealed a notable presence in melanophores and the basal layer of the epidermis, suggesting high metabolic activity in these cell types and potentially influencing cellular functions. These findings contribute to our comprehension of tortoise skin anatomy and physiology, offering insights into the remarkable adaptations of this species finely tuned to their specific environmental habitats.

Histopathologic Characterization of Incidental Lesions Encountered During Mohs Micrographic Surgery With MART-1 Immunohistochemistry

BACKGROUND

As the use of melanoma antigen recognized by T cells (MART-1) immunohistochemistry (IHC) with Mohs surgery increases for the treatment of melanoma in situ and invasive melanoma, surgeons should be aware of MART-1 staining patterns of incidental lesions often encountered on frozen sections. Lack of this knowledge can lead to unnecessary additional surgery, increased health care costs, and loss of valuable laboratory staff time and resources.

OBJECTIVE

To characterize the histopathologic features of incidental lesions encountered during Mohs surgery for melanoma. To review key diagnostic and differentiating features on hematoxylin and eosin staining (H&E) and MART-1 IHC of these lesions.

METHODS

A comprehensive review of frozen-section histopathology slides from Mohs cases with MART-1 IHC at our institution was conducted from 2021 to 2023.

RESULTS

Incidental benign and malignant lesions were identified and characterized on H&E frozen sections and MART-1 IHC. Although such entities can share MART-1 staining characteristics with melanoma in situ or melanoma, distinguishing characteristics on H&E and lack of histopathologic criteria for melanoma on MART-1 IHC can be used to distinguish these incidental lesions from melanoma.

CONCLUSION

Staining of frozen sections for Mohs micrographic surgery with H&E and MART-1 IHC together can differentiate common incidental benign and malignant cutaneous lesions from melanoma.

A Differential Clinical Diagnostic Challenge of a Recurrent, Oral Fibrosarcoma Resembling a Periapical Lesion of Endodontic Origin

A fibrosarcoma is a neoplastic growth originating from malignant, fibroblast-like mesenchymal cells. This malignant tumor shows an increased tendency for expansion and recurrence and a propensity to metastasize, especially to the lungs. Despite their rarity, fibrosarcomas have the potential to manifest in any anatomical location. An oncologist referred their patient due to reported mandibular discomfort, ache, and swelling. The biopsy revealed a fibrosarcoma resembling a periapical lesion of endodontic origin. The timely intervention and the collaboration among different but complementary medical and dental specialties ensure that the patient may enjoy a prolonged life expectancy as symptom-free as possible.

Protective role of Decylubiquinone against secondary melanoma at lung in B16F10 induced mice by reducing E-cadherin expression and ameliorating ROCKII-Limk1/2-Cofiliin mediated metastasis

Melanoma is one of the most consequential skin cancer with a rising death incidences. Silent but belligerent nature of metastatic sprouting is the leading cause of melanoma related mortality. Invasion of metastatic cells and re-expression of E-Cadherin play the crucial role in the establishment of secondary tumor at distal sites. Thus, manipulation of tumor cell invasion in parallel to regulation of E-Cadherin expression can be considered as potential anti-metastatic strategy. Evidences suggested key role of reactive oxygen species associated ROCK activities in the modulation of metastatic invasion via F-actin stabilization. Here, we first-time report Decylubiquinone, a dietary Coenzyme Q₁₀ analog, as an effective attenuator of pulmonary metastatic melanoma in C57BL/6 mice. Current study depicted detailed molecular interplay associated with Decylubiquinone mediated phosphorylation of ROCKII at Tyr722 along with reduced phosphorylation of ROCKII Ser1366 leading to suppression of Limk1/2-Cofilin-F-actin stabilization axis that finally restricted B16F10 melanoma cell invasion at metastatic site. Analysis further deciphered the role of HNF4α as its nuclear translocation modulated E-Cadherin expression, the effect of reactive oxygen species dependent ROCKII activity in secondarily colonized B16F10 melanoma cells at lungs. Thus unbosoming of related signal orchestra represented Decylubiquinone as a potential remedial agent against secondary lung melanoma.

The markers auxiliary in differential diagnosis of early melanomas and benign nevi sharing some similar features potentially leading to misdiagnosis - a review of immunohistochemical studies

Although most melanocytic skin lesions are correctly diagnosed, numerous studies have shown interobserver disagreement. This review analyzes 20 molecules as immunohistochemical markers for distinguishing dysplastic and/or Spitz nevi from early melanomas (in situ, Clark level I or II and/or Breslow thickness at most 1 mm). The detected presence and/or level of tested molecules was significantly different in early melanomas than in dysplastic and Spitz nevi for six and seven potential markers, respectively. The most promising results were obtained for 5-hydroxymethylcytosine, cyclooxygenase-2 and PReferentially expressed Antigen in MElanoma whose levels were different in dysplastic and Spitz nevi compared to early melanomas.

Rate of Immunohistochemistry Utilization in the Diagnosis of Cutaneous Melanocytic Lesions

ABSTRACT

Melanocytic lesions represent a large portion of the workload in many laboratories. Although many melanocytic nevi can be confidently diagnosed based on routine hematoxylin and eosin light microscopy, ancillary testing is often warranted. Various immunohistochemical (IHC) stains are routinely used in the diagnosis of melanocytic lesions. Because melanocytic lesions are frequently encountered in skin specimens, the use of IHC is likely to represent a significant area of resource utilization in dermatopathology laboratories. Our study investigates the rate of IHC utilization in the diagnosis of melanocytic lesions in a high-volume, government-funded, not-for-profit laboratory. Of the 1230 cases of melanocytic lesions investigated, including benign as well as malignant entities, 300 cases involved the utilization of IHC. IHC was used in a larger percentage of melanomas than nevi and in a larger percentage of melanoma in situ cases than invasive melanomas. SOX10 was overwhelmingly the most frequently used IHC.

When "Peripheral" Becomes "Central": Primary and Secondary Malignant Intracerebral Nerve Sheath Tumor: A Case Report and a Systematic Review

BACKGROUND

The intracerebral occurrence of malignant peripheral nerve sheath tumors (MPNSTs) is exceedingly rare, and despite aggressive treatments, local recurrence and poor prognosis are very frequent. Like other brain tumors, these tumors could be primary or secondary, making the term "peripheral" an imprecise term for a primary brain tumor.

OBJECTIVE

To analyze the reported cases of primary and secondary cerebral MPSNTs in terms of diagnosis, treatment, and overall survival. Additionally, we present a case of malignant intracerebral nerve sheath tumor (MINST) treated with radical surgery and radiotherapy.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, one database (PubMed) and crossed references were queried for MPNST with brain metastasis and primary MINSTs from 1971 to 2020. Data regarding demographic features, primary tumor site, risk factors, brain location of the lesion, treatment applied, and overall survival were extracted.

RESULTS

A total of 55 patients were selected (including the reported case): 29 patients were secondary brain MPNST and 26 patients were primary MINST. The mean age was 41.8 ± 22 and 31.2 ± 23 yr, respectively. All brain metastases of MPNST (100%) had a primary tumor elsewhere in the body at the time of diagnosis. The overall survival was significantly shorter in patients with a secondary brain MPNST compared to MINST (P = .002).

CONCLUSION

We present a comprehensive analysis of every reported primary and secondary intracerebral MPNST. The prognosis in terms of survival is worst in the last one despite aggressive treatment. The lack of a primary MPNST in screening tests is sufficient to confirm a MINST at time of diagnosis.

Paracicatricial melanocytes as a sign of melanoma

Intradermal melanocytes in the setting of melanoma represent a diagnostic challenge to dermatopathologists as their presence may represent superficially invasive melanoma vs benign nevus cells or reactive dermal melanocytes. Previous dermatologic literature suggests that the absence of cytologic atypia in intradermal melanocytes and their presence in nonmelanocytic neoplasms lends to their characterization as reactive, benign, melanocytic proliferation. A 67-year-old female presented for evaluation of a 10-mm irregularly pigmented dark brown macule on the left cheek. Initial shave biopsy showed transected malignant melanoma measuring at least 0.6 mm in thickness. Multiple reexcision specimens demonstrated residual melanoma with banal appearing intradermal epithelioid melanocytes within and surrounding the scar. The melanocytes tracked into the skin graft, which had previously been free from involvement. Positron emission tomography-computed tomography (PET CT) and lymph node biopsies did not show evidence of metastatic melanoma. Ten months after her diagnosis and following five surgical excisions, the patient was diagnosed with metastatic melanoma to the brain and succumbed to intracranial hemorrhage. We present a case in which paracicatricial melanoma may simulate benign paracicatricial melanocytic hyperplasia. These findings have significant therapeutic and prognostic implications for the practicing dermatologist and dermatopathologist.

Distinguishing melanophages from tumor in melanoma patients treated with talimogene laherparepvec

Response to talimogene laherparepvec (T-Vec) is difficult to assess as pigmented macrophages that have ingested melanoma cells ('melanophages') persist after injection, mimicking melanoma. We used quantitative immunofluorescence (qIF) to (1) distinguish melanophages from melanoma in biopsies from two patients treated with T-Vec and (2) evaluate the tumor microenvironment pretreatment and posttreatment. Tissues were stained with 4',6-diamidino-2-phenylindole, cluster of differentiation (CD) 3, CD8, CD68, human leukocyte antigen-DR isotype (HLA-DR), and SRY-Box Transcription Factor 10 (SOX10), and multispectral images were analyzed. Post-T-Vec samples showed melanophages with cytoplasmic costaining of CD68, SOX10, and HLA-DR, without nuclear SOX10 expression. qIF revealed a dense immune infiltrate of CD3, CD8, and CD68 cells in post-T-Vec samples. Melanophages from tumors post-T-Vec stain the nuclear melanoma marker SOX10 in their cytoplasms as compared to melanoma cells that stain nuclear SOX10. This novel finding highlights the phagocytosis of melanoma cell components by macrophages after treatment with T-Vec. qIF may assist pathologists in determining whether lesions treated with immunotherapy contain residual viable melanoma.

SOX-10 staining in dermal scars

BACKGROUND

Positive staining for SOX10 and the S100 protein are often used in the evaluation of challenging melanocytic neoplasms including melanoma in patient samples. SOX-10 positivity of non-melanocytes in re-excision specimen could complicate the evaluation of invasive melanoma with an invasive desmoplastic component. Therefore, quantifiable data regarding the positivity of SOX-10 in scars will help dermatopathologists to better identify false positive staining.

METHODS

A retrospective analysis was performed on 50 re-excision specimens from 2013 to 2017, with a diagnosis of squamous cell carcinoma (SCC) or squamous cell carcinoma in situ (SCCIS). Blocks of re-excision specimens containing scars were stained for SOX-10; results were evaluated by a board-certified dermatopathologist. The sum of the five highest numbers of high-power field (HPF) counts as a proxy for "SOX-10 stain factor," and cell morphological features were analyzed. MART-1 and CD68 immunohistochemical staining was performed to study possible lineage of these SOX-10 positive cells.

RESULTS

All 50 specimens showed varying degrees of SOX-10 positivity for histiocytes. SOX-10 positive histiocytes were present in 86% of re-excision scar tissues, of which 71.3% had spindle-shaped or angulated nuclei, and 61.8% had nuclear sizes larger than typical lymphocytes (7 μm). Within the same area of scars, CD68 staining was floridly positive, where as MART-1 staining was overwhelmingly negative.

CONCLUSIONS

This study illustrates a potential diagnostic pitfall of using SOX-10 to evaluate re-excision specimens of melanocytic neoplasms and also suggests a previously undescribed staining pattern in scars of SOX-10 positive cells that are not melanocytes. We postulate that such SOX-10 positive cells may represent a small fraction of histiocytes routinely found in scar tissue.

SOX9 is a dose-dependent metastatic fate determinant in melanoma

Background

In this research, we aimed to resolve contradictory results whether SOX9 plays a positive or negative role in melanoma progression and determine whether SOX9 and its closely related member SOX10 share the same or distinct targets in mediating their functions in melanoma.

Methods

Immunofluorescence, TCGA database and qPCR were used to analyze the correlation between the expression patterns and levels of SOX9, SOX10 and NEDD9 in melanoma patient samples. AlamarBlue, transwell invasion and colony formation assays in melanoma cell lines were conducted to investigate the epistatic relationship between SOX10 and NEDD9, as well as the effects of graded SOX9 expression levels. Lung metastasis was determined by tail vein injection assay. Live cell imaging was conducted to monitor dynamics of melanoma migratory behavior. RHOA and RAC1 activation assays measured the activity of Rho GTPases.

Results

High SOX9 expression was predominantly detected in patients with distant melanoma metastases whereas SOX10 was present in the different stages of melanoma. Both SOX9 and SOX10 exhibited distinct but overlapping expression patterns with metastatic marker NEDD9. Accordingly, SOX10 was required for NEDD9 expression, which partly mediated its oncogenic functions in melanoma cells. Compensatory upregulation of SOX9 expression in SOX10-inhibited melanoma cells reduced growth and migratory capacity, partly due to elevated expression of cyclin-dependent kinase inhibitor p21 and lack of NEDD9 induction. Conversely, opposite phenomenon was observed when SOX9 expression was further elevated to a range of high SOX9 expression levels in metastatic melanoma specimens, and that high levels of SOX9 can restore melanoma progression in the absence of SOX10 both in vitro and in vivo. In addition, overexpression of SOX9 can also promote invasiveness of the parental melanoma cells by modulating the expression of various matrix metalloproteinases. SOX10 or high SOX9 expression regulates melanoma mesenchymal migration through the NEDD9-mediated focal adhesion dynamics and Rho GTPase signaling.

Conclusions

These results unravel NEDD9 as a common target for SOX10 or high SOX9 to partly mediate their oncogenic events, and most importantly, reconcile previous discrepancies that suboptimal level of SOX9 expression is anti-metastatic whereas high level of SOX9 is metastatic in a heterogeneous population of melanoma.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0998-6) contains supplementary material, which is available to authorized users.

Tumor cell cholesterol depletion and V-ATPase inhibition as an inhibitory mechanism to prevent cell migration and invasiveness in melanoma

BACKGROUND

V-ATPase interactions with cholesterol enriched membrane microdomains have been related to metastasis in a variety of cancers, but the underlying mechanism remains at its beginnings. It has recently been reported that the inhibition of this H⁺ pump affects cholesterol mobilization to the plasma membrane.

METHODS

Inhibition of melanoma cell migration and invasiveness was assessed by wound healing and Transwell assays in murine cell lines (B16F10 and Melan-A). V-ATPase activity was measured in vitro by ATP hydrolysis and H⁺ transport in membrane vesicles, and intact cell H⁺ fluxes were measured by using a non-invasive Scanning Ion-selective Electrode Technique (SIET).

RESULTS

Cholesterol depletion by 5mM MβCD was found to be inhibitory to the hydrolytic and H⁺ pumping activities of the V-ATPase of melanoma cell lines, as well as to the migration and invasiveness capacities of these cells. Nearly the same effects were obtained using concanamycin A, a specific inhibitor of V-ATPase, which also promoted a decrease of the H⁺ efflux in live cells at the same extent of MβCD.

CONCLUSIONS

We found that cholesterol depletion significantly affects the V-ATPase activity and the initial metastatic processes following a profile similar to those observed in the presence of the V-ATPase specific inhibitor, concanamycin.

GENERAL SIGNIFICANCE

The results shed new light on the functional role of the interactions between V-ATPases and cholesterol-enriched microdomains of cell membranes that contribute with malignant phenotypes in melanoma.

The High Multiplicity of Prenatal (Congenital Type) Nevi in Adolescents and Adults

In the absence of work on prenatal nevogenesis, it has long been necessary to define congenital melanocytic nevi by clinical detection on neonatal skin examination. They are seen in approximately 1% of newborns, with multiplicity in approximately 3% of cases. Melan-A staining of grossly normal fetal skin recently demonstrated fetal nevi, whose features validated certain traditional histologic criteria for "congenital type" nevi that may not have been detectable at birth. This suggested that many clinically acquired nevi actually formed in utero, like congenital nevi. Prenatal nevi has been suggested as a preferred synonym for "congenital type" nevi. Prenatal nevi were detected in 6 of 25 fetuses (24%), a strikingly higher incidence than congenital nevi in newborns. In this series of 354 patients with prenatal (congenital type) nevi encountered in routine practice at a community hospital, over 30% of both adolescents and adults had multiple prenatal nevi; a strikingly higher rate of multiplicity than congenital nevi in newborns. This high multiplicity may reflect origin beneath the epidermis, with many prenatal nevi working their way up to the surface of the skin decades after birth.

Histiocytic chorioretinitis in a dog

A 3-year-old castrated male mixed-breed dog presented with an acute bullous retinal detachment and thickened choroid of the right eye. Subretinal cytology revealed an atypical cell proliferation suggestive of neoplasia. The eye was enucleated, and the original diagnosis was a histologically benign choroidal melanocytic tumor. Further diagnostics revealed no other systemic abnormalities other than a nonhealing shoulder wound. Six months later, the left eye developed a bullous retinal detachment. This eye responded well to systemic steroids and the dog regained vision within a few weeks of initiating therapy. Results of immunohistochemistry with Melan-A and CD204 of the previously enucleated right eye caused a revision of the histologic diagnosis from melanocytic tumor to histiocytic chorioretinitis. This case highlights the subtle and sometimes confusing distinction between neoplastic and inflammatory processes on both cytology and histopathology.

Conceptual approach to early melanoma detection: models, tools, issues and challenges

Identification and removal of melanoma early in its development remains the most effective treatment. However, identification of early melanoma remains challenging and may result in unnecessary morbidity due to the excess excision of benign melanocytic nevi. Herein, we present a conceptual model of benign and malignant melanocytic growths. The potential differences in the location of the cell of origin as well as considerations for neoplasm progression are also reviewed. Several of the clinical tools currently available, the integration of information from those different sources, and approaches to set an optimum biopsy threshold are discussed. While early detection remains a challenge, significant progress has been made. Insight into melanoma growth processes and appropriate use of available tools can result in the detection of thinner melanomas while also decreasing overall biopsy rates.