The Impact of Next-generation Sequencing on Interobserver Agreement and Diagnostic Accuracy of Desmoplastic Melanocytic Neoplasms.

Next-generation sequencing (NGS) is increasingly being utilized as an ancillary tool for diagnostically challenging melanocytic neoplasms. It is incumbent upon the pathology community to perform studies assessing the benefits and limitations of these tools in specific diagnostic scenarios. One of the most challenging diagnostic scenarios faced by skin pathologists involves accurate diagnosis of desmoplastic melanocytic neoplasms (DMNs). In this study, 20 expert melanoma pathologists rendered a diagnosis on 47 DMNs based on hematoxylin and eosin sections with demographic information. After submitting their diagnosis, the experts were given the same cases, but this time with comprehensive genomic sequencing results, and asked to render a diagnosis again. Identification of desmoplastic melanoma (DM) improved by 7%, and this difference was statistically significant ( P <0.05). In addition, among the 15 melanoma cases, in the pregenomic assessment, only 12 were favored to be DM by the experts, while after genomics, this improved to 14 of the cases being favored to be DM. In fact, some cases resulting in metastatic disease had a substantial increase in the number of experts recognizing them as DM after genomics. The impact of the genomic findings was less dramatic among benign and intermediate-grade desmoplastic tumors (BIDTs). Interobserver agreement also improved, with the Fleiss multirater Kappa being 0.36 before genomics to 0.4 after genomics. NGS has the potential to improve diagnostic accuracy in the assessment of desmoplastic melanocytic tumors. The degree of improvement will be most substantial among pathologists with some background and experience in bioinformatics and melanoma genetics.

BRAF Mutated and Morphologically Spitzoid Tumors, a Subgroup of Melanocytic Neoplasms Difficult to Distinguish From True Spitz Neoplasms.

Drivers of Spitz neoplasms include activating point mutations in HRAS and Spitz-associated genomic fusions. It has become evident that some BRAF -mutated melanocytic neoplasms can morphologically mimic Spitz tumors (STs). These have been termed BRAF mutated and morphologically spitzoid (BAMS). In this study, 17 experts from the International Melanoma Pathology Study Group assessed 54 cases which included 40 BAMS and 14 true STs. The participants reviewed the cases blinded to the genomic data and selected among several diagnostic options, including BAMS, ST, melanoma, and other. A total of 38% of all diagnostic selections in the BAMS cases were for BAMS, whereas 32% were for ST. In 22 of the BAMS cases, the favored diagnosis was BAMS, whereas in 17 of the BAMS cases, the favored diagnosis was ST. Among the 20 cases in the total group of 54 with the highest number of votes for ST, half were BAMS. Of BAMS, 75% had a number of votes for ST that was within the SD of votes for ST seen among true ST cases. There was poor interobserver agreement for the precise diagnosis of the BAMS (kappa = 0.16) but good agreement that these cases were not melanoma (kappa = 0.7). BAMS nevi/tumors can closely mimic Spitz neoplasms. Expert melanoma pathologists in this study favored a diagnosis of ST in nearly half of the BAMS cases. There are BAMS cases that even experts cannot morphologically distinguish from true Spitz neoplasms.

Intravascular Lymphoma as a Cause of Recurrent Strokes - Case Report and Review of the Literature.

Background: Intravascular lymphoma is an uncommon cause of ischemic strokes. Because of its rarity and atypical pattern, most diagnoses are made post-mortem. Case study: We present a case of a 68-year-old male with multiple cardiovascular risk factors and recent SARS-CoV-2 infection who presented with recurrent strokes. Because of his stroke risk factors, he was initially managed with a sequentially escalating antithrombotic regimen. A malignant process was low on the differential at this point given his lack of systemic symptoms. When he continued to have new strokes despite these measures, including a spinal cord infarct, a broad workup was sent including for hypercoagulable states, vasculitis, and intravascular lymphoma. Eventually, a skin biopsy of a cherry angioma returned positive for lymphoma cells. He was treated with methotrexate followed by chemotherapy and rituximab. Unfortunately, he did not improve and was made comfort measures only by his family. Conclusion: This case illustrates the importance of considering intravascular lymphoma as a potential etiology of recurrent strokes, as early diagnosis and treatment are important for preventing irreversible neurological damage.

Revision of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis Classification Schema for Melanocytic Lesions: A Consensus Statement.

Importance: A standardized pathology classification system for melanocytic lesions is needed to aid both pathologists and clinicians in cataloging currently existing diverse terminologies and in the diagnosis and treatment of patients. The Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) has been developed for this purpose. Objective: To revise the MPATH-Dx version 1.0 classification tool, using feedback from dermatopathologists participating in the National Institutes of Health-funded Reducing Errors in Melanocytic Interpretations (REMI) Study and from members of the International Melanoma Pathology Study Group (IMPSG). Evidence Review: Practicing dermatopathologists recruited from 40 US states participated in the 2-year REMI study and provided feedback on the MPATH-Dx version 1.0 tool. Independently, member dermatopathologists participating in an IMPSG workshop dedicated to the MPATH-Dx schema provided additional input for refining the MPATH-Dx tool. A reference panel of 3 dermatopathologists, the original authors of the MPATH-Dx version 1.0 tool, integrated all feedback into an updated and refined MPATH-Dx version 2.0. Findings: The new MPATH-Dx version 2.0 schema simplifies the original 5-class hierarchy into 4 classes to improve diagnostic concordance and to provide more explicit guidance in the treatment of patients. This new version also has clearly defined histopathological criteria for classification of classes I and II lesions; has specific provisions for the most frequently encountered low-cumulative sun damage pathway of melanoma progression, as well as other, less common World Health Organization pathways to melanoma; provides guidance for classifying intermediate class II tumors vs melanoma; and recognizes a subset of pT1a melanomas with very low risk and possible eventual reclassification as neoplasms lacking criteria for melanoma. Conclusions and Relevance: The implementation of the newly revised MPATH-Dx version 2.0 schema into clinical practice is anticipated to provide a robust tool and adjunct for standardized diagnostic reporting of melanocytic lesions and management of patients to the benefit of both health care practitioners and patients.

Interobserver agreement in the histopathological classification of desmoplastic melanomas.

Desmoplastic melanoma is a subtype of melanoma characterised by amelanotic fusiform melanocytes dispersed in a collagenous stroma. Cell-poor and fibrous stroma-rich 'pure' variants have been distinguished from 'mixed' variants with areas of higher cell density and/or less desmoplastic stroma. This distinction is relevant because patients whose tumours display a pure phenotype have a lower risk for regional lymph node metastasis and distant recurrence. However, little is known about interobserver agreement among pathologists in the subclassification of desmoplastic melanoma. To address this issue, we conducted a study in which eleven dermatopathologists independently evaluated whole slide scanned images of excisions from 30 desmoplastic melanomas. The participating pathologists were asked to classify the tumours as pure or mixed. They were also asked to record the presence or absence of neurotropism and angiotropism. We found substantial interobserver agreement between the 11 dermatopathologists in the classification of tumours as pure versus mixed desmoplastic melanoma (kappa=0.64; p<0.0001). There was fair agreement between the 11 dermatopathologists in the evaluation of presence versus absence of neurotropism (kappa=0.26; p<0.0001), and slight agreement in the assessment of angiotropism (kappa=0.13; p<0.0001). The level of concordance in the subclassification of desmoplastic melanomas is encouraging for the acceptance of this prognostic parameter in the real-world practice of melanoma pathology.

Identification of fusions with potential clinical significance in melanoma.

Though uncommon in melanoma, gene fusions may have therapeutic implications. Next generation sequencing-based clinical assays, designed to detect relevant gene fusions, mutations, and copy number changes, were performed on 750 melanomas (375 primary and 375 metastases) at our institution from 2014-2021. These included 599 (80%) cutaneous, 38 (5%) acral, 11 (1.5%) anorectal, 23 (3%) sinonasal, 27 (3.6%) eye (uveal/ conjunctiva), 11 (1.5%) genital (vulva/penile), and 41 (5.5%) melanomas of unknown primary. Sixteen fusions (2%) were detected in samples from 16 patients: 12/599 (2%) cutaneous, 2/38 (5%) acral, 1/9 (11%) vulva, 1/23(4.3%) sinonasal; and 12/16 (75%) fusions were potentially targetable. We identified two novel rearrangements: NAGS::MAST2 and NOTCH1::GNB1; and two fusions that have been reported in other malignancies but not in melanoma: CANT1::ETV4 (prostate cancer) and CCDC6::RET (thyroid cancer). Additional fusions, previously reported in melanoma, included: EML4::ALK, MLPH::ALK, AGAP3::BRAF, AGK::BRAF, CDH3::BRAF, CCT8::BRAF, DIP2B::BRAF, EFNB1::RAF1, LRCH3::RAF1, MAP4::RAF1, RUFY1::RAF1, and ADCY2::TERT. Fusion positive melanomas harbored recurrent alterations in TERT and CDKN2A, among others. Gene fusions were exceedingly rare (0.2%) in BRAF/RAS/NF1-mutant tumors and were detected in 5.6% of triple wild-type melanomas. Interestingly, gene rearrangements were significantly enriched within the subset of triple wild-type melanomas that harbor TERT promoter mutations (18% versus 2%, p < 0.0001). Thirteen (81%) patients were treated with immunotherapy for metastatic disease or in the adjuvant setting. Six of 12 (50%) patients with potentially actionable fusions progressed on immunotherapy, and 3/6 (50%) were treated with targeted agents (ALK and MEK inhibitors), 2 off-label and 1 as part of a clinical trial. One patient with an AGAP3::BRAF fusion positive melanoma experienced a 30-month long response to trametinib. We show that, detecting fusions, especially in triple wild-type melanomas with TERT promoter mutations, may have a clinically significant impact in patients with advanced disease who have failed front-line immunotherapy.

From Churg-Strauss Syndrome to Eosinophilic Granulomatosis With Polyangiitis: A Historical Review of Nomenclature and Diagnostic Criteria.

ABSTRACT: Eosinophilic granulomatosis with polyangiitis (EGPA) is rare vasculitis syndrome that involves the skin and other organ systems manifesting as asthma, eosinophilia, and pulmonary infiltrates. The understanding of EGPA, previously known as Churg-Strauss Syndrome, has continued to evolve from its earliest documentation in the literature in 1951. Herein, we review key historical advances in the diagnosis, classification, and nomenclature of EGPA that have shaped our understanding of this protean disorder over time.

Sinonasal Mucosal Melanoma: An Update and Review of the Literature.

ABSTRACT: Primary sinonasal mucosal melanoma (SNMM) is an aggressive tumor with high metastatic potential and poor outcomes. Presenting symptoms are nonspecific, and the nasal cavity is the most common site of origin followed by the maxillary and ethmoid sinuses. Histopathologically, SNMMs are pleomorphic and predominantly composed of epithelioid cell type. Identifying these tumors requires a high index of suspicion for melanoma and the use of a panel of immunohistochemical markers when typical histopathological features are missing. Not infrequently, these tumors are undifferentiated and/or amelanotic. Currently, SNMM falls into 2 different staging systems proposed by the American Joint Committee on Cancer, one for carcinoma of the nasal cavity and sinuses and the other for head and neck melanoma. Although therapeutic standards do not exist, surgical resection with adjuvant radiotherapy and/or systemic therapy may offer the best outcome. Lymphadenectomy including possible parotidectomy and neck dissection should be considered in patients with regional lymph node metastasis. However, the role of elective lymph node dissection is controversial. Genetic profiling has identified a number of recurrent gene mutations that may prove useful in providing targets for novel, emerging biological treatments. In this article, we provide an update on clinicopathological features, staging, molecular discoveries, and treatment options for SNMM.

Combined tumor and immune signals from genomes or transcriptomes predict outcomes of checkpoint inhibition in melanoma.

Immune checkpoint blockade (CPB) improves melanoma outcomes, but many patients still do not respond. Tumor mutational burden (TMB) and tumor-infiltrating T cells are associated with response, and integrative models improve survival prediction. However, integrating immune/tumor-intrinsic features using data from a single assay (DNA/RNA) remains underexplored. Here, we analyze whole-exome and bulk RNA sequencing of tumors from new and published cohorts of 189 and 178 patients with melanoma receiving CPB, respectively. Using DNA, we calculate T cell and B cell burdens (TCB/BCB) from rearranged TCR/Ig sequences and find that patients with TMBhigh and TCBhigh or BCBhigh have improved outcomes compared to other patients. By combining pairs of immune- and tumor-expressed genes, we identify three gene pairs associated with response and survival, which validate in independent cohorts. The top model includes lymphocyte-expressed MAP4K1 and tumor-expressed TBX3. Overall, RNA or DNA-based models combining immune and tumor measures improve predictions of melanoma CPB outcomes.

Appropriate use criteria for ancillary diagnostic testing in dermatopathology: New recommendations for 11 tests and 220 clinical scenarios from the American Society of Dermatopathology Appropriate Use Criteria Committee.

BACKGROUND: Appropriate use criteria (AUC) provide patient-centered physician guidance in test selection. An initial set of AUC was reported by the American Society of Dermatopathology (ASDP) in 2018. AUC reflect evidence collected at single timepoints and may be affected by evolving evidence and experience. The objective of this study was to update and expand AUC for selected tests. METHODS: RAND/UCLA (RAND Corporation [Santa Monica, CA]/University of California Los Angeles) methodology used includes the following: (a) literature review; (b) review of previously rated tests and previously employed clinical scenarios; (c) selection of previously rated tests for new ratings; (d) development of new clinical scenarios; (e) selection of additional tests; (f) three rating rounds with feedback and group discussion after rounds 1 and 2. RESULTS: For 220 clinical scenarios comprising lymphoproliferative (light chain clonality), melanocytic (comparative genomic hybridization, fluorescence in situ hybridization, reverse transcription polymerase chain reaction, telomerase reverse transcriptase promoter), vascular disorders (MYC), and inflammatory dermatoses (periodic acid-Schiff, Gömöri methenamine silver), consensus by panel raters was reached in 172 of 220 (78%) scenarios, with 103 of 148 (70%) rated "usually appropriate" or "rarely appropriate" and 45 of 148 (30%), "appropriateness uncertain." LIMITATIONS: The study design only measures appropriateness. Cost, availability, test comparison, and additional clinical considerations are not measured. The possibility that the findings of this study may be influenced by the inherent biases of the dermatopathologists involved in the study cannot be excluded. CONCLUSIONS: AUC are reported for selected diagnostic tests in clinical scenarios that occur in dermatopathology practice. Adhering to AUC may reduce inappropriate test utilization and improve healthcare delivery.

Impact of Next-generation Sequencing on Interobserver Agreement and Diagnosis of Spitzoid Neoplasms.

Atypical Spitzoid melanocytic tumors are diagnostically challenging. Many studies have suggested various genomic markers to improve classification and prognostication. We aimed to assess whether next-generation sequencing studies using the Tempus xO assay assessing mutations in 1711 cancer-related genes and performing whole transcriptome mRNA sequencing for structural alterations could improve diagnostic agreement and accuracy in assessing neoplasms with Spitzoid histologic features. Twenty expert pathologists were asked to review 70 consultation level cases with Spitzoid features, once with limited clinical information and again with additional genomic information. There was an improvement in overall agreement with additional genomic information. Most significantly, there was increase in agreement of the diagnosis of conventional melanoma from moderate (κ=0.470, SE=0.0105) to substantial (κ=0.645, SE=0.0143) as measured by an average Cohen κ. Clinical follow-up was available in all 70 cases which substantiated that the improved agreement was clinically significant. Among 3 patients with distant metastatic disease, there was a highly significant increase in diagnostic recognition of the cases as conventional melanoma with genomics (P<0.005). In one case, none of 20 pathologists recognized a tumor with BRAF and TERT promoter mutations associated with fatal outcome as a conventional melanoma when only limited clinical information was provided, whereas 60% of pathologists correctly diagnosed this case when genomic information was also available. There was also a significant improvement in agreement of which lesions should be classified in the Spitz category/WHO Pathway from an average Cohen κ of 0.360 (SE=0.00921) to 0.607 (SE=0.0232) with genomics.

First Reported Case of Invasive Cutaneous Penicillium cluniae Infection in a Patient With Acute Myelogenous Leukemia: A Case Report and Literature Review.

Certain Penicillium species are emerging opportunistic pathogens. While these can be common causes of airborne contamination of clinical cultures, an increasing number of reports describe clinically significant disease in the immunocompromised population, particularly in patients with hematologic malignancy. The typical site of infection is respiratory, but disseminated infection is also reported with some frequency. Therefore, culture growth of Penicillium in respiratory and other clinical samples from immunocompromised patients requires thorough investigation with clinical correlation. Here we report a case of angioinvasive Penicillium cluniae infection of the right shin in a patient with acute myeloid leukemia and review reported cases of invasive Penicillium infection (excluding Talaromyces marneffei) in hematologic malignancy patients to characterize the emerging pathogen in this vulnerable population.

The significance of epidermal involvement in primary cutaneous gamma/delta (γδ) T-cell lymphoma: A systematic review and meta-analysis.

BACKGROUND: Primary cutaneous gamma/delta (γδ) T-cell lymphoma (PCGDTCL) is a rare, aggressive peripheral T-cell lymphoma. There is evidence that patients with epidermotropic PCGDTCL may have an improved prognosis compared with those with only dermal and/or subcutaneous involvement. METHODS: Systematic review of the literature and application of inclusion criteria yielded 48 manuscripts detailing the cases of 104 patients. RESULTS: Of the 104 patients, 57 were male (51.4%) and 47 were female (48.5%) Based on provided histopathologic descriptions, 57 cases (54.8%) had no epidermotropism, 47 cases (45.2%) patients demonstrated any degree of epidermotropism, and 25 cases were predominantly epidermotropic (25/104, 24%). Five-year overall survivals for patients with no epidermotropism, any epidermotropism, and predominantly epidermotropic presentation were 32.8%, 28.9%, and 40.0%, respectively (p = 0.40). The most commonly performed immunohistochemical markers were CD3, CD4, CD8, CD5, CD7, CD30, CD56, TCR beta, TCR γ, and TCR δ. There was no statistically significant difference in immunophenotype between groups. Lesion morphology was described in the majority of cases (85/104, 80.9%); most cases presented as a combination of nodules, plaques, and tumors (77.4%). Several cases had more atypical presentations, including "mycosis-fungoides-like" and ulcerated. CONCLUSION: In PCGDTCL, neither epidermotropism nor predominantly epidermotropic phenotype predict a better prognosis. In addition, the case report literature in dermatology and dermatopathology is rich and highly valuable.

Comparison of Shave and Punch Biopsy Utilization Among Dermatology Practices.

In 2019, the 2 Current Procedural Terminology (CPT) codes for skin biopsies were replaced with 6 new CPT codes to allow for technique specification and differential reimbursement. We sought to evaluate whether the concurrent decrease in reimbursement for shave biopsies and increase in reimbursement for punch biopsies led to utilization changes. We examined shave and punch biopsies submitted for pathologic examination at 3 academic centers in May 2018 and May 2019. We performed χ2 tests to evaluate for changes in the ratio of biopsy utilization over time, with subgroup analyses by practice setting and provider type. Totals included 11,785 (12.11% punch) and 11,291 (12.08% punch) biopsies submitted in May 2018 and May 2019, respectively. Our results demonstrate small yet important changes in biopsy use patterns within the context of recent reimbursement changes when analyzing academic and private practices separately. Although small in magnitude, this change in behavior may have a substantial impact when extrapolated to behavior across the nation.

Eosinophilic granulomatosis with polyangiitis: Cutaneous clinical and histopathologic differential diagnosis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, but severe systemic vasculitis that can affect skin and other organ systems. Diagnostic criteria have evolved, and many attempts have been made to classify the vasculitides based on clinical and/or histopathologic features, with an aim to develop standardized criteria. According to the EGPA Consensus Task Force recommendations, EGPA is a syndrome of asthma, eosinophilia, pulmonary infiltrates, and extrapulmonary vasculitis (such as cutaneous involvement with purpura). Histopathologic evidence of vasculitis in EGPA may be associated with eosinophilic infiltration and/or perivascular granulomatous inflammation. We review clinicopathologic criteria of this enigmatic vasculopathy.