Melanocytoma of the eyelid: Case report and introduction of new nomenclature.

Purpose: The term melanocytoma was recently proposed for intermediate-stage melanocytic lesions with specific histopathologic and molecular genetic features. Prior studies have demonstrated a heightened potential for these intermediate lesions to spread to regional lymph nodes, with decreased likelihood for distant spread, when compared to melanomas. Observations: Herein we present a case of a 28-year-old male who presented with a recurrent right lower eyelid margin combined cutaneous and palpebral conjunctival pigmented lesion, ultimately classified as a melanocytoma, to highlight this new nomenclature, characteristic histopathologic and genetic findings, and prognostic implications. Conclusions: Ophthalmologists should be aware of this new cutaneous histopathologic classification system and apply to the periorbital region to improve melanocytic lesion management and surveillance.

Noninvasive virtual biopsy using micro-registered optical coherence tomography (OCT) in human subjects.

Histological hematoxylin and eosin-stained (H&E) tissue sections are used as the gold standard for pathologic detection of cancer, tumor margin detection, and disease diagnosis. Producing H&E sections, however, is invasive and time-consuming. While deep learning has shown promise in virtual staining of unstained tissue slides, true virtual biopsy requires staining of images taken from intact tissue. In this work, we developed a micron-accuracy coregistration method [micro-registered optical coherence tomography (OCT)] that can take a two-dimensional (2D) H&E slide and find the exact corresponding section in a 3D OCT image taken from the original fresh tissue. We trained a conditional generative adversarial network using the paired dataset and showed high-fidelity conversion of noninvasive OCT images to virtually stained H&E slices in both 2D and 3D. Applying these trained neural networks to in vivo OCT images should enable physicians to readily incorporate OCT imaging into their clinical practice, reducing the number of unnecessary biopsy procedures.

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.

Treatment With Ataluren for Wound Healing and Health Complications in a Patient With Junctional Epidermolysis Bullosa.

This case report describes an 11-year-old boy with widespread chronic wounds, frequent corneal erosions, dental caries, a tracheostomy, and failure to thrive.

Immunotherapy for keratinocyte cancers. Part I: Immune-related epidemiology, risk factors, pathogenesis, and immunotherapy management of keratinocyte cancers.

The important role of the immune system in the surveillance and control of keratinocyte cancers (KCs), namely squamous and basal cell carcinomas, is increasingly appreciated, as new immunotherapies have recently become available. As the field of immunotherapy is rapidly evolving, this review synthesizes key concepts and highlights important cellular components within the immune system responsible for attacking KCs. We review the most current data on the epidemiology, risk factors, and immunotherapy management for KCs. Patients will seek advice from dermatologists to help explain why immunotherapies work for KCs and whether they might be appropriate for different clinical scenarios. Collaboration with medical colleagues across different disciplines to evaluate KCs for response to immunotherapy and early recognition of immune-related adverse events will help to optimize patient outcomes.

Isolated Sixth Nerve Palsies in a Child With Familial Hemophagocytic Lymphohistiocytosis Type 2.

ABSTRACT: A previously healthy 2-year-old boy presented with a left sixth cranial nerve palsy. There was a family history of multiple sclerosis and optic neuritis. Neuroimaging showed multiple foci of T2/FLAIR hyperintense signal abnormality in both cerebral hemispheres and in the brainstem. The initial diagnosis was suspicious for demyelinating disease. However, there was no clinical improvement after a course of corticosteroids, and there was no change in his follow-up MRI. He later developed bilateral sixth nerve palsies, with esotropia addressed with bilateral medial rectus botulinum toxin injections. A brain biopsy was planned. However, his 3-month-old sister was separately admitted for fever and pancytopenia. She had markedly elevated ferritin, D-dimer, triglycerides, sIL-2R, CXCL9, and IL-18 and low fibrinogen. Her bone marrow biopsy showed hemophagocytosis. Genetic testing of both siblings revealed biallelic mutations in the PRF1 locus. The final diagnosis of familial hemophagocytic lymphohistiocytosis Type 2 was made. Both siblings underwent chemotherapy. The boy's sixth nerve palsies and MRI abnormalities resolved. Both siblings then went on to undergo bone marrow transplant.

Two cases of mycosis fungoides with large cell transformation with KMT2A rearrangements.

Cutaneous T-cell lymphomas (CTCL) are a clinically and molecularly heterogeneous class of lymphomas of the skin-homing T cell, and their genetic profiles are not fully characterized. Previously, rearrangements of the Lysine Methyltransferase 2A (KMT2A) gene have been identified as driver mutations only in acute leukemias. KMT2A plays a role in epigenetic regulation, and cancers with such rearrangements are responsive to epigenetic therapy including hypomethylating agents. Here, we report two cases of CTCL with novel genetic profiles. KMT2A rearrangements were identified in two aggressive cases of mycosis fungoides with large cell transformation. A KMT2A::DSCAML1 gene rearrangement was seen in Case 1, while a KMT2A::MAPRE1 fusion was identified in Case 2. These cases demonstrate that KMT2A rearrangements can be found in primary CTCLs rather than solely acute leukemias, illustrating the importance of correlating molecular findings with clinical and histologic features in diagnosis. Additionally, this finding suggests that the subset of CTCLs driven by aberrancy of the KMT2A pathway may be responsive to therapy with hypomethylating agents or menin inhibitors, as seen in acute leukemias.

Livedoid vasculopathy.

Livedoid vasculopathy is a painful thrombo-occlusive vascular disorder characterized by spontaneous thrombosis in medium-size arterioles, which causes localized hypoxia and skin ulceration. As livedoid vasculopathy is rare, case reports are the primary means of expanding collective knowledge about its presentation and response to various therapies.

LY6D marks pre-existing resistant basosquamous tumor subpopulations.

Improved response to canonical therapies requires a mechanistic understanding of dynamic tumor heterogeneity by identifying discrete cellular populations with enhanced cellular plasticity. We have previously demonstrated distinct resistance mechanisms in skin basal cell carcinomas, but a comprehensive understanding of the cellular states and markers associated with these populations remains poorly understood. Here we identify a pre-existing resistant cellular population in naive basal cell carcinoma tumors marked by the surface marker LY6D. LY6D+ tumor cells are spatially localized and possess basal cell carcinoma and squamous cell carcinoma-like features. Using computational tools, organoids, and spatial tools, we show that LY6D+ basosquamous cells represent a persister population lying on a central node along the skin lineage-associated spectrum of epithelial states with local environmental and applied therapies determining the kinetics of accumulation. Surprisingly, LY6D+ basosquamous populations exist in many epithelial tumors, such as pancreatic adenocarcinomas, which have poor outcomes. Overall, our results identify the resistant LY6D+ basosquamous population as an important clinical target and suggest strategies for future therapeutic approaches to target them.

Clinical and Pathological Characteristics and Outcomes Among Patients With Subcutaneous Panniculitis-like T-Cell Lymphoma and Related Adipotropic Lymphoproliferative Disorders.

Importance: There is a knowledge gap about subcutaneous panniculitis-like T-cell lymphoma (SPTCL) owing to its rarity and diagnostic difficulty, resulting in an absence of well-documented large case series published to date. Objective: To generate consensus knowledge by a joint multi-institutional review of SPTCL and related conditions. Design, Setting, and Participants: This retrospective clinical and pathological review included cases initially diagnosed as SPTCL at 6 large US academic centers. All cases were reviewed by a group of pathologists, dermatologists, and oncologists with expertise in cutaneous lymphomas. Through a process of group consensus applying defined clinical and pathological diagnostic criteria, the cohort was classified as (1) SPTCL or (2) adipotropic lymphoproliferative disorder (ALPD) for similar cases with incomplete histopathological criteria for SPTCL designation. Exposures: Cases of SPTCL diagnosed between 1998 and 2018. Main Outcomes and Measures: The main outcome was disease presentation and evolution, including response to therapy, disease progression, and development of hemophagocytic lymphohistiocytosis. Results: The cohort of 95 patients (median [range] age, 38 [2-81] years; female-to-male ratio, 2.7) included 75 cases of SPTCL and 20 cases of ALPD. The clinical presentation was similar for both groups with multiple (61 of 72 [85%]) or single (11 of 72 [15%]) tender nodules mostly involving extremities, occasionally resulting in lipoatrophy. Hemophagocytic lymphohistiocytosis (HLH) was only observed in SPTCL cases. With a mean follow-up of 56 months, 60 of 90 patients (67%) achieved complete remission with a median (range) of 3 (1-7) cumulative therapies. Relapse was common. None of the patients died of disease progression or HLH. Two patients with ALPD eventually progressed to SPTCL without associated systemic symptoms or HLH. Conclusions and Relevance: In this case series of patients initially diagnosed as having SPTCL, results showed no evidence of systemic tumoral progression beyond the adipose tissue. The SPTCL experience in this study confirmed an indolent course and favorable response to a variety of treatments ranging from immune modulation to chemotherapy followed by hematopoietic stem cell transplantation. Morbidity was primarily associated with HLH.