Toward Minimal Residual Disease-Directed Therapy in Melanoma.

Many patients with advanced cancers achieve dramatic responses to a panoply of therapeutics yet retain minimal residual disease (MRD), which ultimately results in relapse. To gain insights into the biology of MRD, we applied single-cell RNA sequencing to malignant cells isolated from BRAF mutant patient-derived xenograft melanoma cohorts exposed to concurrent RAF/MEK-inhibition. We identified distinct drug-tolerant transcriptional states, varying combinations of which co-occurred within MRDs from PDXs and biopsies of patients on treatment. One of these exhibited a neural crest stem cell (NCSC) transcriptional program largely driven by the nuclear receptor RXRG. An RXR antagonist mitigated accumulation of NCSCs in MRD and delayed the development of resistance. These data identify NCSCs as key drivers of resistance and illustrate the therapeutic potential of MRD-directed therapy. They also highlight how gene regulatory network architecture reprogramming may be therapeutically exploited to limit cellular heterogeneity, a key driver of disease progression and therapy resistance.

Diagnostic Biopsy via In-Office Frozen Sections for Clinical Nonmelanoma Skin Cancer.

BACKGROUND: Treatment of nonmelanoma skin cancer (NMSC) by Mohs surgery has traditionally relied on previous pathologic evaluation of paraffin-embedded tissue. Tissue processing by frozen sections allows for expedited diagnosis and treatment; however, data on its accuracy are limited. OBJECTIVE: To measure the accuracy and outcomes of biopsy via frozen sections for clinical NMSC. METHODS: Biopsies of clinical NMSCs processed via frozen sections with in-office diagnosis rendered by one Mohs surgeon were retrospectively reviewed by one board-certified dermatopathologist. Discordant diagnoses were re-read in blinded fashion by both physicians. If still discordant, final diagnosis was determined by consensus discussion. Inter-rater reliability was calculated using Cohen's kappa statistic. RESULTS: Two hundred ninety-seven lesions from 208 patients were included. Correlation between in-office and final diagnosis was 0.876 indicating "almost perfect" concordance. Sensitivity and specificity of in-office diagnosis for detecting malignancy were 98.1% and 94.4%. Seven cases (2.0%) had a clinically relevant change in final diagnosis, but appropriate treatment had been rendered. Two benign lesions (0.7%) initially diagnosed as malignant underwent excision. CONCLUSION: In-office biopsy via frozen sections is highly accurate in confirming NMSC. This practice may speed diagnosis and treatment thus improving outcomes and patient satisfaction.

Lupus and scleroderma overlap features in a 28-year-old man with anti-PL-12 anti-synthetase syndrome.

A 28-year-old man with clinically and laboratory diagnosed anti-PL-12 anti-synthetase syndrome (AS) in 2009 developed cutaneous lupus lesions, discoid lupus lesions, and sclerodacytly with finger-tip ulcerations four years following his AS diagnosis. Laboratory tests including +ANA, +anti-dsDNA antibody, +anti-Smith antibody, and +anti-RNP antibody in 2014 confirmed the diagnosis of progression to an overlap syndrome including systemic lupus erythematosus. The patient now also has clinical findings (sclerodacytly, Raynaud phenomenon, finger-tip ulcerations) consistent with scleroderma overlap. In each stage of his evolving connective tissue disease, cutaneous findings have been central to the recognition and monitoring of his overlap syndromes.

Melanocytic nevi excised during B-Raf proto-oncogene (BRAF) inhibitor therapy: A study of 19 lesions from 10 patients.

BACKGROUND: There are limited descriptions of histopathology and immune profiles of new or changing melanocytic nevi in the setting of B-Raf proto-oncogene (BRAF) inhibitor therapy. OBJECTIVE: We sought to identify their distinctive features. METHODS: Clinical charts and histologic review, neuroblastoma RAS viral (v-ras) oncogene homolog genotyping, and immunohistochemistry for HMB-45, BRAFV600E, phosphorylated extracellular signal-regulated kinase (pERK), phosphorylated protein kinase B, CD4, and CD8 were performed on 19 melanocytic nevi from 10 patients and 23 control nevi. RESULTS: BRAF inhibitors were administered for metastatic melanoma (7), colonic adenocarcinoma (2), and papillary thyroid carcinoma (1). The average duration of BRAF inhibition before lesion excision was 8 months. Frequently associated histologic features included pigmentation of the stratum corneum, hyperpigmented keratinocytes, dermal melanophages, and deep HMB-45 expression. The lesions were BRAFV600E and neuroblastoma RAS viral (v-ras) oncogene homolog wild-type, expressed diffuse weak-moderate pERK, and possessed a predominance of CD8(+) in comparison with CD4(+) T lymphocytes within the dermal infiltrates. LIMITATION: This is a retrospective study of a small and heterogeneous group. CONCLUSION: The nevi associated with BRAF inhibitor therapy invariably lack BRAFV600E mutation. BRAF inhibition appears to cause an increased cytotoxic T-cell response and increased mitogen-activated protein kinase activity in BRAF wild-type lesions, supported by pERK expression, possibly resulting in an activated phenotype characterized by increased melanin pigmentation and deep HMB-45 expression.

Use of Photodynamic Therapy and Sterile Water to Target Adipose Tissue.

BACKGROUND: Neither photodynamic therapy (PDT) nor sterile water has not been well studied for the treatment of adipose tissue. OBJECTIVE: This investigation studied 2 different modalities, verteporfin PDT and sterile water, on adipose tissue compared with control. MATERIALS AND METHODS: Four light-skinned pigs were used. Test sites received verteporfin PDT or sterile water injection. Control sites received injection of verteporfin without PDT, normal saline injection, no intervention, exposure to laser only, or insertion of a needle or cannula only. Sites were evaluated clinically, by ultrasound, and with histology 4 to 6 weeks after treatment. RESULTS: There was a decrease in adipose tissue by ultrasound after verteporfin PDT (15%, p < .001) and sterile water (2%, p = .23). Verteporfin without PDT showed a decrease in adipose tissue (17%, p = .21). All other control sites showed an increase in adipose tissue. Histologically, verteporfin PDT and sterile water showed moderate damage (median Grade 2, p < .001) 4 to 6 weeks after intervention. CONCLUSION: Verteporfin decreased adipose tissue after treatment. Sterile water injection had a statistically significant effect on adipose tissue histologically but did not substantially decrease the adipose tissue by ultrasound 4 to 6 weeks after intervention. Longer follow-up may be needed.

Rhabdomyosarcoma arising in a giant congenital melanocytic nevus.

A number of lesions have been documented to arise within congenital melanocytic nevi (CMNs). Although the most frequent malignancy arising within a CMN is melanoma, the association between rhabdomyosarcoma and CMN has rarely been documented. We present a case arising in a 4-month-old girl with a giant CMN. She presented for evaluation of a pedunculated lesion at the superior gluteal crease that had been present since birth and exhibited rapid growth. Biopsy of the lesion revealed two distinct components: an expansile proliferation of pleomorphic cells with varying degrees of cellularity and a proliferation of banal-appearing melanocytic nevic cells. The cells of the expansile proliferation displayed a wide range of morphologic features, including nests of round cells, spindle-shaped cells, and more differentiated rhabdomyoblasts within a myxoid, highly vascularized stroma. Cross-striations, a marker of skeletal muscle differentiation, were present. These tumor cells were strongly immunoreactive with desmin, myo-D1, and myogenin. Fluorescence in situ hybridization analysis with PAX3/7-FKHR probes was negative. A diagnosis of embryonal rhabdomyosarcoma in association with CMN was made. Initial excision revealed tumor at the margins, and the patient underwent reexcision with subsequent chemotherapy with vincristine, actinomycin D, and cyclophosphamide. She was disease-free at the 6-year follow-up. It has been postulated that the combination of melanocytic and rhabdomyoblastic cells within the same lesion may imply derivation from a common pluripotent stem cell or neural crest cell. Clinicians following patients with giant CMN should consider rhabdomyosarcoma in the differential diagnosis of lesions arising within the nevus.

Dermal Granuloma Annulare After SARS-CoV-2 Vaccination: A Rare Complication.

Granuloma annulare (GA) is an inflammatory granulomatous skin disease of unknown etiology that is self-limiting in nature. However, it is hypothesized that trauma, medications, malignancy, viral infections, different vaccines, and hypersensitivity reactions can trigger the formation of GA. Only three cases of post-SARS-CoV-2 vaccination-related GA have been reported so far. Here, we report the fourth documented case of post-SARS-CoV-2 vaccination-related generalized GA.

Correction: Landscape of Targeted Anti-Cancer Drug Synergies in Melanoma Identifies a Novel BRAF-VEGFR/PDGFR Combination Treatment.

[This corrects the article DOI: 10.1371/journal.pone.0140310.].

Extensive Perineural Invasion vs Nerve Caliber to Assess Cutaneous Squamous Cell Carcinoma Prognosis.

Importance: Perineural invasion (PNI) is an adverse risk feature in cutaneous squamous cell carcinoma (CSCC) that affects patient prognosis and disease management. However, research comparing different PNI patterns on patient outcomes is limited. Objective: To compare 4 assessments of PNI in CSCC, their associations with poor outcomes, and implications for their inclusion in the Brigham and Women's Hospital (BWH) staging system. Design, Setting, and Participants: This retrospective cohort study was performed at a single tertiary care institution and compared 4 PNI assessments: nerve caliber, number of involved nerves per section, PNI maximal depth, and PNI location with respect to tumor. Patients with primary, localized, invasive CSCC with PNI diagnosed between January 1, 2000, and December 31, 2017, were identified via an electronic in-house database. Available pathology slides were secondarily reviewed by study authors. Relevant patient and tumor characteristics and outcomes were abstracted from the medical record. Data analysis was performed between September 6 and October 20, 2022. Main Outcomes and Measures: Risks of recurrence, disease-specific death, and a composite end point (any poor outcome) were calculated via multivariable stepwise Fine and Gray competing-risks regression. Considered revisions to the BWH staging system were assessed via receiver operating characteristic curves and test characteristics. Results: This study included 140 patients with CSCC, with a mean (SD) age of 75.1 (11.2) years. More than half of the patients were men (93 [66.4%]), and most identified as White (132 [94.3%]). Of the 4 PNI assessments studied, only involvement of multiple nerves was associated with poor outcomes. Perineural invasion of 5 or more distinct nerves (extensive PNI [ePNI]) was independently associated with local recurrence (subhazard ratio [SHR], 13.83 [95% CI, 3.50-54.62]; P < .001), disease-specific death (SHR, 6.20 [95% CI, 1.59-24.21]; P = .009), and any poor outcome (SHR, 10.21 [95% CI, 2.88-36.15]; P < .001). A revised BWH staging system with substitution of ePNI for large-caliber PNI resulted in improved area under the curve and test characteristics compared with current BWH staging criteria that use nerve caliber as the measure of PNI. Conclusions and Relevance: The findings of this cohort study suggest that ePNI is the best prognostic measure of PNI. Because ePNI obviated the need for a micrometer and had superior prognostic capacity to nerve caliber in this cohort, ePNI should be considered for inclusion in CSCC tumor staging. Inclusion of ePNI as a high-risk factor in CSCC staging systems may optimize patient selection for primary treatment and adjuvant interventions.

Histologically challenging melanocytic tumors referred to a tertiary care pigmented lesion clinic.

BACKGROUND: The histopathologic diagnosis of some melanocytic tumors is extraordinarily difficult. With this in mind, melanocytic tumors from patients referred to the Massachusetts General Hospital (MGH) Pigmented Lesion Clinic (PLC) are routinely reviewed in the MGH Dermatopathology Unit. OBJECTIVE: We sought to determine the frequency of diagnostically challenging cases from patients treated at the MGH PLC, as measured by a change in the diagnosis upon review of the referral materials. METHODS: We retrospectively reviewed the MGH and referral pathology reports for 478 consecutive cutaneous melanocytic tumors: 126 from 1996-1997 and 352 from 2010-2011. Differences in diagnosis and in therapeutic impact were evaluated. RESULTS: Changes in diagnosis occurred in 168 of 478 cases (35%), more frequently when the original diagnostician was a general pathologist (P = .003). A similar fraction of diagnoses were changed from malignant to benign or vice versa, in both historic and contemporary cohorts. In 64 patients (13%), changes in diagnosis led to a change in therapy. Changes in stage or grading led to the most changes in therapy (78%; 50/64) versus changes from benign to malignant or vice versa (22%; 14/64). LIMITATIONS: This is a retrospective study with the bias of a tertiary-care referral center. CONCLUSIONS: These findings demonstrate the diagnostic difficulty of a subset of melanocytic tumors and highlight the utility of review by more than one pathologist; patient treatment is affected in more than 10% of cases. Identification of melanoma prognostic factors and melanocytic nevus grading led to clinically significant changes in diagnosis leading to a change in patient management.

Increased diagnosis of thin superficial spreading melanomas: A 20-year study.

BACKGROUND: Diagnostic practice by dermatopathologists evaluating pigmented lesions may have evolved over time. OBJECTIVES: We sought to investigate diagnostic drift among a group of dermatopathologists asked to re-evaluate cases initially diagnosed 20 years ago. METHODS: Twenty nine cases of dysplastic nevi with severe atypia and 11 cases of thin radial growth-phase melanoma from 1988 through 1990 were retrieved from the pathology files of the Massachusetts General Hospital. All dermatopathologists who had rendered an original diagnosis for any of the 40 slides and the current faculty in the Massachusetts General Hospital Dermatopathology Unit were invited to evaluate the slide set in 2008 through 2009. RESULTS: The mean number of melanoma diagnoses by the 9 study participants was 18, an increase from the original 11 melanoma diagnoses. A majority agreed with the original diagnosis of melanoma in all 11 cases. In contrast, a majority of current raters diagnosed melanoma in 4 of the 29 cases originally reported as dysplastic nevus with severe atypia. Interrater agreement over time was excellent (kappa 0.88) and fair (kappa 0.47) for cases originally diagnosed as melanoma and severely atypical dysplastic nevus, respectively. LIMITATIONS: The unbalanced composition of the slide set, lack of access to clinical or demographic information, access to only one diagnostic slide, and imposed dichotomous categorization of tumors were limitations. CONCLUSIONS: A selected cohort of dermatopathologists demonstrated a general trend toward the reclassification of prior nonmalignant diagnoses of severely atypical dysplastic nevi as malignant but did not tend to revise prior diagnoses of cutaneous melanoma as benign.

In Memoriam-Martin C. Mihm, Jr.

Martin C [...].

STAG2 regulates interferon signaling in melanoma via enhancer loop reprogramming.

The cohesin complex participates in the organization of 3D genome through generating and maintaining DNA loops. Stromal antigen 2 (STAG2), a core subunit of the cohesin complex, is frequently mutated in various cancers. However, the impact of STAG2 inactivation on 3D genome organization, especially the long-range enhancer-promoter contacts and subsequent gene expression control in cancer, remains poorly understood. Here we show that depletion of STAG2 in melanoma cells leads to expansion of topologically associating domains (TADs) and enhances the formation of acetylated histone H3 lysine 27 (H3K27ac)-associated DNA loops at sites where binding of STAG2 is switched to its paralog STAG1. We further identify Interferon Regulatory Factor 9 (IRF9) as a major direct target of STAG2 in melanoma cells via integrated RNA-seq, STAG2 ChIP-seq and H3K27ac HiChIP analyses. We demonstrate that loss of STAG2 activates IRF9 through modulating the 3D genome organization, which in turn enhances type I interferon signaling and increases the expression of PD-L1. Our findings not only establish a previously unknown role of the STAG2 to STAG1 switch in 3D genome organization, but also reveal a functional link between STAG2 and interferon signaling in cancer cells, which may enhance the immune evasion potential in STAG2-mutant cancer.

Primary subcutaneous Alternaria alternata infection of the hand in an immunocompromised host.

We describe a case of a progressive subcutaneous Alternaria alternata infection in the hand of a patient with chronic lymphocytic leukemia (CLL). The diagnosis was based upon the examination of tissue biopsy and isolation of the etiologic agent in culture. The identity of the isolate was determined by phenotypic characteristics and by sequencing the ITS and D1/D2 regions of the rDNA. Despite combination therapy with voriconazole and micafungin, the lesion continued to progress. Posaconazole therapy, along with surgical excision of the infected tissue, resulted in the eradication of infection. The limitations of the clinical management of invasive Alternaria infections are discussed.

AJCC melanoma staging update: impact on dermatopathology practice and patient management.

Changes in the 2010 American Joint Commission on Cancer melanoma staging guidelines include the evaluation of primary tumor mitotic index (mitogenicity) and the recognized prognostic significance of a single melanoma cell in a sentinel lymph node. These revised criteria have important practice implications for dermatopathologists as well as for dermatologists, oncologists and surgeons who treat patients with cutaneous melanoma.

Histologic processing and reporting of cutaneous pigmented lesions: recommendations based on a survey of 94 dermatopathologists.

BACKGROUND: Standard operating procedures for laboratory processing and reporting of margins of cutaneous pigmented lesions do not exist. We conducted a survey of 94 dermatopathologists to evaluate these practices. OBJECTIVES: We sought to: (1) identify dominant practices among dermatopathologists; (2) determine the impact of the procedure, intent to excise, and histologic diagnosis on the process of margin evaluation; and (3) propose guidelines based on these findings. METHODS: The survey consisted of 44 questions focused on the impact of procedure (punch, shave, or ellipse), intent (excision or biopsy), and histologic diagnosis (common nevus, congenital nevus, atypical nevus, melanoma) on processing and margin reporting. RESULTS: For ellipses, or specimens indicated as excisions, the majority practice (76%-98%) was to ink the specimens. Although more than 90% of observers report the margins on all melanomas and atypical nevi, fewer than 50% of respondents report margins on all nonatypical nevi. LIMITATIONS: The study consists of a survey sample of dermatopathologists and does not represent the practices of those who did not respond to the survey. CONCLUSIONS: Based on the results of this survey we have arrived at the following recommendations: (1) ink all specimens that are ellipses or designated as excisions; (2) tips should be evaluated separately if the specimen is an ellipse; (3) obtain levels in cases with tumor in the tip but not at ink if the specimen is an ellipse or excision and the diagnosis is atypical nevus or melanoma; and (4) report margins on all atypical nevi and melanomas.

Epidermal growth factor receptor gene status by fluorescence in situ hybridization in malignant, atypical, and benign hidradenomas.

BACKGROUND: Epidermal growth factor receptor (EGFR) protein overexpression and gene amplification are important prognostic factors in various tumors and EGFR inhibitors are now available as promising chemotherapeutic agents. There is little information in the literature regarding the EGFR protein and gene status in hidradenocarcinomas which has an aggressive biologic course characterized by repeated local recurrences and systemic metastasis. We have previously reported EGFR protein overexpression in malignant, atypical, and benign hidradenomas and would like to further evaluate their gene status by fluorescence in situ hybridization. METHODS: Fluorescence in situ hybridization by 2-color probe Vysis LSI EGFR SpectrumOrange/CEP 7 SpectrumGreen Probe (Abbott Molecular) and EGFR immunostain (H11, Dakocytomation) were performed in 15 malignant, 15 atypical, and 7 benign hidradenomas. RESULTS: High polysomy and low trisomy was noted in 1 and 4 hidradenocarcinoma, respectively; however, EGFR overexpression was seen only in 1 low trisomy case. Disomy is noted in the remaining 29 cases (9 hidradenocarcinomas, 15 atypical hidradenomas, and 5 benign hidradenomas). EGFR overexpression was seen in 3/12 (25%) malignant hidradenomas, 7/15 (47%) atypical hidradenomas, and 3/5 (60%) benign hidradenomas; none of these cases demonstrated EGFR gene amplification. CONCLUSIONS: Polysomy/trisomy is more frequently seen in hidradenocarcinoma than atypical and benign hidradenomas. The role of EGFR inhibitor therapy in hidradenocarcinoma cases with protein overexpression remains unclear. Lack of correlation between the protein expression and polysomy/gene amplification suggests that molecular mechanisms other than gene amplification play a role in EGFR overexpression in malignant, atypical, and benign hidradenomas.

Topographical Evaluation of Penile Lichen Sclerosus Reveals a Lymphocytic Depleted Variant, Preferentially Associated With Neoplasia: A Report of 200 Cases.

Since the seminal study of Hart and Helwig in 1975, there are few detailed pathological studies of lichen sclerosus (LS). The aims of this study were to provide a detailed histopathological description of penile LS, as well as to explore its relationship with penile intraepithelial neoplasia (PeIN) or invasive carcinoma. We evaluated 200 patients and designed a topographical approach for the histological evaluation focusing in alterations of the following anatomical layers: squamous epithelium, lamina propria, dartos, and corpus spongiosum. We documented the quantity and topographical location of stromal lymphocytes. The prevalent lesions found were epithelial hyperplasia, atrophy, PeIN, basal cell vacuolization, lamina propria sclerosis, and variable patterns of lymphocytic infiltration. Various unique patterns of stromal sclerosis were described: perivascular, globular, linear, and solid fibrosis/hyalinization; any of them were found to be diagnostic for LS. The variation in the topography and density of lymphocytes was determinant for the identification of LS morphological variants: lichenoid, band-like, lymphocytic depleted, and mixed. A major finding was the identification of the variant designated as lymphocytic depleted LS, which we considered as the morphological prototype of LS associated with penile neoplasia. The detailed description of this complex lesion presented in this study may help pathologists in practice to identify and better define LS. The identification of the special variants suggests a role of the stromal lymphocytes in the process of carcinogenesis. Confirmation of the observations with more studies is necessary to determine the significance of these findings.

Clinical and molecular characterization of virus-positive and virus-negative Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin caused by either the integration of Merkel cell polyomavirus (MCPyV) and expression of viral T antigens or by ultraviolet-induced damage to the tumor genome from excessive sunlight exposure. An increasing number of deep sequencing studies of MCC have identified significant differences between the number and types of point mutations, copy number alterations, and structural variants between virus-positive and virus-negative tumors. However, it has been challenging to reliably distinguish between virus positive and UV damaged MCC. METHODS: In this study, we assembled a cohort of 71 MCC patients and performed deep sequencing with OncoPanel, a clinically implemented, next-generation sequencing assay targeting over 400 cancer-associated genes. To improve the accuracy and sensitivity for virus detection compared to traditional PCR and IHC methods, we developed a hybrid capture baitset against the entire MCPyV genome and software to detect integration sites and structure. RESULTS: Sequencing from this approach revealed distinct integration junctions in the tumor genome and generated assemblies that strongly support a model of microhomology-initiated hybrid, virus-host, circular DNA intermediate that promotes focal amplification of host and viral DNA. Using the clear delineation between virus-positive and virus-negative tumors from this method, we identified recurrent somatic alterations common across MCC and alterations specific to each class of tumor, associated with differences in overall survival. Finally, comparing the molecular and clinical data from these patients revealed a surprising association of immunosuppression with virus-negative MCC and significantly shortened overall survival. CONCLUSIONS: These results demonstrate the value of high-confidence virus detection for identifying molecular mechanisms of UV and viral oncogenesis in MCC. Furthermore, integrating these data with clinical data revealed features that could impact patient outcome and improve our understanding of MCC risk factors.