Clinicopathologic features, demographics, disease burden, and therapeutics in alopecic sarcoidosis: a case series and systematic review.

Background: Alopecic sarcoidosis is an uncommon cutaneous manifestation of sarcoidosis. Scarring and nonscarring alopecic sarcoidosis have been reported; however, information on the epidemiology, systemic disease associations, and treatment efficacy is limited. Objective: To address these gaps, we conducted a retrospective chart review and systematic literature review of alopecic sarcoidosis cases. Methods: Full-text English publications from PubMed, Scopus, and Google Scholar from inception to August 2023 were analyzed. Treatment evidence quality was assessed using the modified Oxford Centre for Evidence-Based Medicine rating scale. Three patients with biopsy-proven alopecic sarcoidosis were included as a case series, all demonstrating systemic sarcoidosis and 2 requiring multiple therapies. Among 1778 search results, 60 articles representing 77 cases of alopecic and scalp sarcoidosis were included. Patients were categorized into 4 distinct alopecic subgroups. Black patients constituted the majority of all subgroups. Results: Extracutaneous sarcoidosis burden was high across all alopecic subgroups, with ocular disease appearing overrepresented. Topical and oral corticosteroids were the main treatments. Though scarring alopecia patients had poor outcomes despite receiving immunomodulators/cx, limited data suggest potential efficacy of tumor necrosis factor-alpha inhibitors. Limitations: This study has a small sample size. Conclusion: Our findings underscore the importance of evidence-based strategies for improving alopecic sarcoidosis management. Prompt diagnosis and systemic evaluation, especially for scarring alopecia, are essential for timely intervention to optimize patient outcomes.

Papule Protruding Into the Nasal Cavity.

An 18-year-old male with no significant medical history presented for evaluation of a nasal papule that was asymptomatic without any associated pain, pruritus, or bleeding with no changes for a year. What is your diagnosis?

Quantitative multiplex immunohistochemistry reveals inter-patient lymphovascular and immune heterogeneity in primary cutaneous melanoma.

Introduction: Quantitative, multiplexed imaging is revealing complex spatial relationships between phenotypically diverse tumor infiltrating leukocyte populations and their prognostic implications. The underlying mechanisms and tissue structures that determine leukocyte distribution within and around tumor nests, however, remain poorly understood. While presumed players in metastatic dissemination, new preclinical data demonstrates that blood and lymphatic vessels (lymphovasculature) also dictate leukocyte trafficking within tumor microenvironments and thereby impact anti-tumor immunity. Here we interrogate these relationships in primary human cutaneous melanoma. Methods: We established a quantitative, multiplexed imaging platform to simultaneously detect immune infiltrates and tumor-associated vessels in formalin-fixed paraffin embedded patient samples. We performed a discovery, retrospective analysis of 28 treatment-naïve, primary cutaneous melanomas. Results: Here we find that the lymphvasculature and immune infiltrate is heterogenous across patients in treatment naïve, primary melanoma. We categorized five lymphovascular subtypes that differ by functionality and morphology and mapped their localization in and around primary tumors. Interestingly, the localization of specific vessel subtypes, but not overall vessel density, significantly associated with the presence of lymphoid aggregates, regional progression, and intratumoral T cell infiltrates. Discussion: We describe a quantitative platform to enable simultaneous lymphovascular and immune infiltrate analysis and map their spatial relationships in primary melanoma. Our data indicate that tumor-associated vessels exist in different states and that their localization may determine potential for metastasis or immune infiltration. This platform will support future efforts to map tumor-associated lymphovascular evolution across stage, assess its prognostic value, and stratify patients for adjuvant therapy.

Characterization of Immunosuppressive Myeloid Cells in Merkel Cell Carcinoma: Correlation with Resistance to PD-1 Pathway Blockade.

PURPOSE: Merkel cell carcinoma (MCC) is a highly immunogenic skin cancer. Although essentially all MCCs are antigenic through viral antigens or high tumor mutation burden, MCC has a response rate of only approximately 50% to PD-(L)1 blockade suggesting barriers to T-cell responses. Prior studies of MCC immunobiology have focused on CD8 T-cell infiltration and their exhaustion status, while the role of innate immunity, particularly myeloid cells, in MCC remains underexplored. EXPERIMENTAL DESIGN: We utilized single-cell transcriptomics from 9 patients with MCC and multiplex IHC staining of 54 patients' preimmunotherapy tumors, to identify myeloid cells and evaluate association with immunotherapy response. RESULTS: Single-cell transcriptomics identified tumor-associated macrophages (TAM) as the dominant myeloid component within MCC tumors. These TAMs express an immunosuppressive gene signature characteristic of monocytic myeloid-derived suppressor cells and importantly express several targetable immune checkpoint molecules, including PD-L1 and LILRB receptors, that are not present on tumor cells. Analysis of 54 preimmunotherapy tumor samples showed that a subset of TAMs (CD163+, CD14+, S100A8+) selectively infiltrated tumors that had significant CD8 T cells. Indeed, higher TAM prevalence was associated with resistance to PD-1 blockade. While spatial interactions between TAMs and CD8 T cells were not associated with response, myeloid transcriptomic data showed evidence for cytokine signaling and expression of LILRB receptors, suggesting potential immunosuppressive mechanisms. CONCLUSIONS: This study further characterizes TAMs in MCC tumors and provides insights into their possible immunosuppressive mechanism. TAMs may reduce the likelihood of treatment response in MCC by counteracting the benefit of CD8 T-cell infiltration. See related commentary by Silk and Davar, p. 1076.

Acute regression of a melanocytic neoplasm.

Immune-mediated regression of melanocytic neoplasms is predominantly lymphocytic, driven by CD8+ anti-tumoral T-cells and, rarely, natural killer cells. Histopathologic features of regression include effacement of the epidermis, replacement of tumor cells by a fibrotic stroma, varying degrees of chronic inflammation (usually lymphocytes) and melanophages, as well as vascular ectasia and angioplasia. The understanding of regression and the complex immune response in melanoma has led to the development of targeted immunotherapy in melanoma. Here, we report a case of near-complete regression of a melanocytic neoplasm associated with neutrophilic and eosinophilic inflammation, suggesting a non-traditional pathway of regression that has yet to be explored.

Tumoral melanosis mimicking residual melanoma in the setting of talimogene laherparepvec treatment.

Talimogene laherparepvec (T-VEC) has become an increasingly popular treatment option for surgically non-resectable, recurrent melanoma, usually of cutaneous metastases. The complete response (CR) rate has been reported to be ~20% with a median of ~9 months to achieve it. In real-world practice, decrease of tumor size often occurs rapidly within the first 2-3 months, while improvement of the pigmentation takes several more months. Such clinical observation of lasting pigmentation could be explained by tumorous melanosis-a histopathological term referring to the presence of a melanophage-rich inflammatory infiltrate without remaining viable tumor cells. Herein, we report six patients with metastatic cutaneous melanoma who were treated with T-VEC. Biopsies were performed after observing clinical responses in the injected tumors. Pathological evaluation demonstrated non-viable or absent tumor tissue with tumorous melanosis in all cases. To accurately assess response to therapy and potentially decrease unnecessary additional T-VEC treatments, serial biopsy of 'stable' lesions should be considered to assess the presence or absence of viable tumor.

Cutaneous Ganglioneuromas With Overlying Epidermal Hyperplasia: A Case Series Presentation and Proposal of Potential Etiopathogenesis.

ABSTRACT: Cutaneous ganglioneuromas (GNs) are exceptionally uncommon tumors, and many reported cases describe association with overlying epidermal hyperplasia that may be interpreted as seborrheic keratosis (SK) or SK-like proliferation. We report 5 cases of cutaneous GN in adult patients; all of which were discovered incidentally in the immediate vicinity of epidermal hyperplasia. A review of the literature demonstrates the current-although likely imperfect-understanding of the etiopathogenesis of both SK and GN in the skin. We explore the putative pathophysiologies of other common, well-characterized skin lesions and, taking them into account, provide rationale for the coexistence of cutaneous GN with overlying SK and SK-like epidermal changes. However, we ultimately acknowledge a dilemma of causality and, given the rarity of their co-occurrence, objectively question whether occasional cameo appearances by GN lying subjacent to SK and SK-like hyperplasia may be due merely to chance.

Neoantigen-specific CD4+ T cells in human melanoma have diverse differentiation states and correlate with CD8+ T cell, macrophage, and B cell function.

CD4+ T cells that recognize tumor antigens are required for immune checkpoint inhibitor efficacy in murine models, but their contributions in human cancer are unclear. We used single-cell RNA sequencing and T cell receptor sequences to identify signatures and functional correlates of tumor-specific CD4+ T cells infiltrating human melanoma. Conventional CD4+ T cells that recognize tumor neoantigens express CXCL13 and are subdivided into clusters expressing memory and T follicular helper markers, and those expressing cytolytic markers, inhibitory receptors, and IFN-γ. The frequency of CXCL13+ CD4+ T cells in the tumor correlated with the transcriptional states of CD8+ T cells and macrophages, maturation of B cells, and patient survival. Similar correlations were observed in a breast cancer cohort. These results identify phenotypes and functional correlates of tumor-specific CD4+ T cells in melanoma and suggest the possibility of using such cells to modify the tumor microenvironment.

Molecular Mechanisms of Cutaneous Squamous Cell Carcinoma.

Non-melanoma skin cancers are cutaneous malignancies representing the most common form of cancer in the United States. They are comprised predominantly of basal cell carcinomas and squamous cell carcinomas (cSCC). The incidence of cSCC is increasing, resulting in substantial morbidity and ever higher treatment costs; currently in excess of one billion dollars, per annum. Here, we review research defining the molecular basis and development of cSCC that aims to provide new insights into pathogenesis and drive the development of novel, cost and morbidity saving therapies.

A novel GAB2::BRAF fusion in cutaneous non-Langerhans-cell histiocytosis with systemic involvement.

Several mutations and gene fusions involved in the mitogen-activated protein kinase (MAPK) pathway have been reported in histiocytic neoplasms including Langerhans cell histiocytosis and non-Langerhans-cell histiocytosis (NLCH). We identified a GAB2::BRAF fusion in a cutaneous lesion from a 22-year-old woman who presented with central diabetes insipidus and red/brown papules on her face, oral mucosa, axilla, and groin. Skin biopsy showed a CD68+, S100-, and CD1a- histiocytic proliferation consistent with NLCH, best clinically classified as xanthoma disseminatum. Next-generation sequencing identified a GAB2::BRAF fusion involving exon 2 of GAB and exon 10 of BRAF. This case implicates a novel fusion in the MAPK signaling pathway, not previously reported in histiocytic neoplasms, as a possible driver of NLCH. Our findings underscore the utility of performing molecular studies on skin biopsy specimens with NLCH to help identify potential targets for therapy.

PRAME immunohistochemistry is useful in the diagnosis of oral malignant melanoma.

OBJECTIVES: While the incidence of cutaneous melanoma has dramatically increased in recent years, oral malignant melanoma (OMM) remains a rare form of noncutaneous melanoma with poor survival. PRAME (PReferentially expressed Antigen in MElanoma) is reported to have diagnostic and some prognostic utility in cutaneous melanomas and some head and neck malignancies. We sought to explore the diagnostic utility of PRAME in OMM. METHODS: A total of ten specimens from eight unique cases of OMM were identified from the Oral Pathology Biopsy Service (OPBS) at University of Washington School of Dentistry between 2005 and 2019. For all cases, standard histology and immunohistochemistry stains were performed, including a stain against PRAME. The diagnoses were reviewed and confirmed by two pathologists. Clinical and epidemiologic features were described. RESULTS: Patient ages ranged from 55 to 82. The group consisted of five males and three females. All eight cases were located on the hard palate. Six cases represented invasive melanoma while two were early melanoma in situ. PRAME immunohistochemistry was successfully performed on seven of eight cases: six were positive (86%), one was negative (14%) and one case lacked sufficient tissue for staining. CONCLUSIONS: Our results suggest that PRAME immunohistochemistry may be useful in the diagnosis of OMM, including early melanoma in situ. Further studies with clinical follow-up and a larger number of cases are needed to explore prognostic value as well as the ability to distinguish between benign, intermediate and malignant melanocytic proliferations of the oral cavity.

A case of endocrine mucin-producing sweat gland carcinoma with distant metastasis.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare cutaneous adnexal neoplasm typically arising on the face of older individuals, most commonly around the eyelids. Histopathologic features include a circumscribed proliferation of low-grade epithelioid cells with areas of cystic and cribriform growth, foci of intracytoplasmic and extracellular mucin, and coexpression of endocrine, neuroendocrine, and cytokeratin markers by immunohistochemistry. Given histopathologic and immunohistochemical similarities, EMPSGC is often likened to solid papillary carcinoma of the breast and endocrine ductal carcinoma in situ, and is thought by many to represent a forme fruste of mucinous carcinoma of the skin. To date, the vast majority of reported cases of EMPSGC have been described as having indolent behavior, with no cases of distant metastasis yet reported. Here we report a unique case of EMPSGC that recurred over several years following standard surgical excision and Mohs micrographic surgery, with subsequent metastasis to the parotid gland and axial skeleton.

Metastatic Melanoma With Features of Desmoplastic Melanoma in a Patient With Primary Cutaneous Superficial Spreading Melanoma With Epithelioid Features.

ABSTRACT: The synchronous incidence of 2 different subtypes of melanoma is very rare. Desmoplastic melanoma (DM) can be a diagnostic challenge because of its frequent appearance as a dermal banal spindle cell proliferation. We present a case of a 30-year-old man who developed an irregular, purple, tender plaque measuring 2.5 cm on the right pretibial region. Wide excision of the right leg lesion showed superficial spreading melanoma with epithelioid cells and no spindle cell component. Sentinel lymph node (SLN) biopsy showed an atypical melanocytic proliferation involving one inguinal lymph node with subcapsular and intraparenchymal components. There were spindled tumor cells in lymph node capsule with hyperchromatic nuclei, which were nested within desmoplastic stroma, and were S100- and SOX10-positive and MART1- and HMB-45 negative; in addition to epithelioid tumor cells, which were S100-, SOX10-, and MART1-positive. Multiple discontinuous foci, subcapsular atypical melanocytes, and extracapsular extension helped in excluding capsular nevus. These findings were consistent with DM. Herein, we present an unusual case of primary cutaneous superficial spreading melanoma of the right leg with a predominantly epithelioid morphology that developed metastases to the SLN. The metastasis exhibited divergent differentiation, including both epithelioid morphology identical to the primary, but with additional features of DM that were nonoverlapping with the primary lesion.