Spatial transcriptomics of a giant pilomatricoma.

Pilomatricomas (PMs) are common benign adnexal tumors that show a predilection for the head and neck region and are characterized at the molecular level by activating mutations in the beta-catenin (CTNNB1) gene. Giant PMs are a rare histopathological variant, according to the World Health Organization, which are defined by a size greater than 4 cm and are reported to show upregulation of yes-associated protein compared to PMs of typical 1-3 cm size. We describe the case of a 67-year-old man with an 8 cm giant PM involving his temporal scalp, whose PM we characterized by 10X spatial gene expression analysis. This revealed five total transcriptomic clusters, including four distinct clusters within the giant PM, each with a unique transcriptional pattern of hair follicle-related factors, keratin gene expression, and beta-catenin pathway activity.

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.

Guidelines of care for the management of actinic keratosis.

BACKGROUND: Actinic keratoses (AK) are rough scaly patches that arise on chronically ultraviolet-exposed skin and can progress to keratinocyte carcinoma. OBJECTIVE: This analysis examined the literature related to the management of AK to provide evidence-based recommendations for treatment. Grading, histologic classification, natural history, risk of progression, and dermatologic surveillance of AKs are also discussed. METHODS: A multidisciplinary Work Group conducted a systematic review to address 5 clinical questions on the management of AKs and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach for assessing the certainty of the evidence and formulating and grading clinical recommendations. Graded recommendations were voted on to achieve consensus. RESULTS: Analysis of the evidence resulted in 18 recommendations. LIMITATIONS: This analysis is based on the best available evidence at the time it was conducted. The pragmatic decision to limit the literature review to English language randomized trials may have excluded data published in other languages or limited identification of relevant long-term follow-up data. CONCLUSIONS: Strong recommendations are made for using ultraviolet protection, topical imiquimod, topical 5-fluorouracil, and cryosurgery. Conditional recommendations are made for the use of photodynamic therapy and diclofenac for the treatment of AK, both individually and as part of combination therapy regimens.

Guidelines of care for the management of actinic keratosis: Executive summary.

BACKGROUND: Actinic keratoses (AK) are rough scaly patches that arise on chronically ultraviolet-exposed skin and can progress to keratinocyte carcinoma. Treatment options for AK include topical medications, photodynamic therapy, cryosurgery, and laser ablation. OBJECTIVE: This executive summary provides a synopsis of the 18 evidence-based recommendations for the treatment of AK detailed in the Guidelines of Care for the Management of Actinic Keratosis. METHODS: A multidisciplinary workgroup conducted a systematic review to address 5 clinical questions on the management of AKs and applied the Grading of Recommendations Assessment, Development and Evaluation approach for assessing the certainty of the evidence and formulating and grading clinical recommendations. Graded recommendations were voted on to achieve consensus. RESULTS: Analysis of the evidence resulted in 18 recommendations, suggesting there are several effective treatments available for AK. LIMITATIONS: The analysis informing the recommendations was based on the best available evidence at the time it was conducted. The results of future studies may necessitate a revision of current recommendations. CONCLUSIONS: Strong recommendations are presented for using ultraviolet protection, topical imiquimod, topical 5-fluorouracil, and cryosurgery. Conditional recommendations are presented for the use of photodynamic therapy and diclofenac for the treatment of AK, both individually and as part of combination therapy regimens.

Impact of clinical photographs on the accuracy and confidence in the histopathological diagnosis of mycosis fungoides.

BACKGROUND: The histopathological diagnosis of MF is challenging, and there is significant overlap with benign inflammatory processes. Clinical features may be relevant in the assessment of skin biopsies. METHODS: We provided photomicrographs to board-certified dermatopathologists and one hematopathologist with and without accompanying clinical photographs and assessed accuracy and confidence in diagnosing MF. RESULTS: We found that access to clinical photographs improved diagnostic accuracy in both MF and non-MF (distractors); the degree of improvement was significantly higher in the non-MF/distractor category. Across all categories, diagnostic confidence level was higher when clinical images were available. CONCLUSION: These findings suggest that clinical images are useful in making an accurate diagnosis of MF, and may be particularly helpful in ruling it out when an inflammatory disorder is clinically suspected.

Number of skin biopsies needed per malignancy: Comparing the use of skin biopsies among dermatologists and nondermatologist clinicians.

BACKGROUND: There are too few board-certified dermatologists to treat all patients with skin disease. Primary care physicians often serve at the frontline of skin cancer screening. OBJECTIVE: To compare biopsy use among dermatologist physicians, dermatology advanced practice professionals (APPs), primary care physicians (PCPs), and other nondermatology clinicians. METHODS: Pathology reports, requisition forms, and clinical notes of skin biopsies submitted to our institution during the study period were reviewed. Skin biopsies for inflammatory conditions, cosmetic or functional purposes, and re-excisions were excluded. The number needed to biopsy (NNB) was calculated as the number of biopsied lesions divided by histologically proven skin cancers. RESULTS: The NNB by clinician type was 2.82 for dermatology physicians, 4.69 for APPs, 4.55 for nondermatology PCPs, and 6.55 for other nondermatology clinicians (P < .001). The NNB was significant between clinician groups for nonmelanoma skin cancer (dermatology physicians, 2.00; APPs, 2.71; PCPs, 2.36; and other nondermatology clinicians, 3.47; P < .001) but not for melanoma (dermatology clinicians, 14.33; APPs, 20.78; PCPs, 27.80; and other nondermatology clinicians, 53.56; P = .061). LIMITATIONS: The NNB represents a measure of use but gives no insight into the number of malignant lesions that go unbiopsied and, therefore, undiagnosed. The prevalence of skin cancer varies among dermatology and nondermatology practices. The results are not generalizable to all practice settings. CONCLUSIONS: Dermatology physicians had the lowest NNB of all clinician groups. PCPs performed similarly to dermatology APPs.

Basomelanocytic Neoplasms: A Report of Two Similar Tumors With Divergent Treatments.

Basomelanocytic neoplasms are tumors consisting of elements of both basal cell carcinoma and melanoma. These tumors are exceedingly rare and present a unique challenge as to how the melanoma component should be classified. Due to the paucity of cases, there are no clear-cut evidence-based guidelines as to how these tumors should be staged and which treatment options provide the optimal outcome. We present 2 separate patients with similar cases of colonizing basomelanocytic tumors that were treated in drastically different ways, highlighting the differing approaches to treatment. We discuss theses treatment modalities and the challenges inherent to diagnosing and treating basomelanocytic neoplasms.

Discordance between histologic and visual assessment of tissue viability in excised burn wound tissue.

The regenerative capacity of burn wounds, and the need for surgical intervention, depends on wound depth. Clinical visual assessment is considered the gold standard for burn depth assessment but it remains a subjective and inaccurate method for tissue evaluation. The purpose of this study was to compare visual assessment with microscopic and molecular techniques for human burn depth determination, and illustrate differences in the evaluation of tissue for potential regenerative capacity. Using intraoperative visual assessment, patients were identified as having deep partial thickness or full thickness burn wounds. Tangential excisions of burn tissue were processed with hematoxylin and eosin to visualize tissue morphology, lactate dehydrogenase assay to ascertain cellular viability, and Keratin-15 and Ki67 to identify epidermal progenitor cells and proliferative capacity, respectively. RNA from deep partial and full thickness burn tissue as well as normal tissue controls were submitted for RNA sequencing. Lactate dehydrogenase, Keratin-15, and Ki67 were found throughout the excised burn wound tissue in both deep partial thickness burn tissues and in the second tangential excision of full thickness burn tissues. RNA sequencing demonstrated regenerative capacity in both deep partial and full thickness burn tissue, however a greater capacity for regeneration was present in deep partial thickness compared with full thickness burn tissues. In this study, we highlight the discordance that exists between the intraoperative clinical identification of burn injury depth, and microscopic and molecular determination of viability and regenerative capacity. Current methods utilizing visual assessment for depth of injury are imprecise, and can lead to removal of viable tissue. Additionally, hematoxylin and eosin microscopic analysis should not be used as the sole method in research or clinical determination of depth, as there are no differences in staining between viable and nonviable tissue.

Insulinoma-associated 1: A novel nuclear marker in Merkel cell carcinoma (cutaneous neuroendocrine carcinoma).

Merkel cell carcinoma (MCC) is a rare, clinically aggressive, cutaneous neuroendocrine (NE) neoplasm. As a tumor with small, round, blue cells, the histologic differential diagnosis for MCC can include melanoma, metastatic small cell carcinoma (SCC), nodular hematopoietic tumors, basal cell carcinoma (BCC), atypical variants of squamous carcinoma and the uncommon occurrence of primary cutaneous Ewing sarcoma. In cases with atypical histology or without the classic immunophenotype, the diagnosis can be challenging. Ultimately, immunohistochemistry (IHC) is essential to the definitive diagnosis of MCC and in difficult cases, the diagnosis may hinge entirely on the immunophenotype of the tumor cells. Insulinoma-associated 1 (INSM1) is a transcription factor expressed in tissues undergoing terminal NE differentiation. As a nuclear protein tied to both differentiation and the cell cycle, INSM1 may offer additional utility in comparison to traditional, cytoplasmic markers of NE differentiation.

Photosensitive lichenoid skin reaction to capecitabine.

BACKGROUND: Capecitabine is an oral prodrug of fluorouracil, which is a common agent used in the management of many solid tumor malignancies. Dermatologic reaction is common with various chemotherapy agents but is not commonly reported in the use of capecitabine. When adverse reactions of rashes occur, the offending agent is typically removed. We report here an unusual case of photosensitive lichenoid rash due to capecitabine which is managed conservatively without major alteration in treatment. CASE PRESENTATION: Seventy-three year old female with a diagnosis of stage IV breast cancer undergoing management with capecitabine presents with a rash during the summer months that is biopsy proven to be lichenoid photosensitive rash with likely offending agent being capecitabine. Her treatment was initially held despite having response to treatment, started on topical steroids after evaluation by dermatology. Given her response to treatment, drug was resumed with instructions to use sun precaution, sunscreen, and to complete course of topical steroids until rash resolution. CONCLUSION: Drug-related rashes tend to lead to disruptions or alterations in treatments of malignancies, despite responses. Given the wide use of capecitabine in many different solid tumors, it is important to recognize this photosensitive related skin rash and to initiate appropriate precautions of sun safety and topical steroids to allow minimal disruptions in therapy and continue use of capecitabine.

Improving the histologic characterization of burn depth.

BACKGROUND: Visual assessment of burn wound appearance is the standard of care to determine the depth of thermal injury but often incorrectly predicts wound healing potential. Histologic evaluation of hematoxylin and eosin (H&E) stained burn tissue is prone to subjectivity and is challenging for the novice. Lactate dehydrogenase (LDH) staining may offer a simplified and consistent technique to identify burn tissue viability. METHODS: Thirty tissue samples were obtained from 6 patients undergoing surgical excision for clinically determined deep partial thickness or full thickness burns. Tissues were stained with H&E or LDH. Each specimen was scored by 3 individuals with varying levels of skill in histologic interpretation using a standardized checklist at 2 distinct time points. RESULTS: Agreement within raters was highest for the expert rater and lowest for the novice; however, the LDH stained tissue method had improved agreement for an experienced burn surgeon and novice. Agreement between raters was greater for the LDH stained samples which were determined to have greater viability than the corresponding H&E section in 100% of samples scored by the expert and in 80% for the novice clinician. CONCLUSION: LDH staining offers a more consistent measure of tissue viability that can be used by experienced and novice clinicians.

Multiple Adult Xanthogranulomas Associated With Cutaneous Lymphoid Hyperplasia and Lupus Erythematosus.

A 50-year-old woman presented to our clinic for evaluation of numerous recurrent, pruritic papules on her upper extremities. She reported a 2- to 3-year history of up to eight unique lesions on the bilateral upper arms that would initially appear as firm papules before gradually softening and flattening out, leaving residual pink macules (Figure 1A). Her medical history was notable for mild hyperlipidemia. On presentation, she had several erythematous papules with overlying telangiectasias scattered throughout her bilateral upper arms. One lesion of concern over the left deltoid had been present for 5 months without signs of regression (Figure 1B). Pathology of this and a similar lesion showed histiocytes forming Touton giant cells with foamy cytoplasm consistent with a xanthogranuloma (AXG). Results from immunoperoxidase stains were negative for factor XIIIa and CD1a, diffusely positive for CD68, and focally positive for S100 (Figure 2).

Successful Treatment of Metastatic Primary Cutaneous Adnexal Carcinoma With a PD-1 Inhibitor.

SUMMARY: Standard of care treatment for metastatic cutaneous adnexal carcinomas is not well established. In this case report, we highlight the successful use of anti-programmed cell death protein 1 (anti-PD-1) therapy in treating a patient with low tumor mutation burden, microsatellite stable, high programmed death-ligand 1 (PD-L1) gene expression, metastatic primary cutaneous adnexal carcinoma with significant radiographic, and circulating tumor DNA response with durable benefit. Immune checkpoint inhibitors hold promise as a future treatment option in rare instances of metastatic disease from primary skin adnexal carcinoma. Further studies are needed to identify better immune checkpoint inhibitor predictive biomarkers for rare, advanced-stage non-melanoma skin cancers.

Delayed Injection Site Reaction to Fremanezumab for Chronic Migraine Treatment.

INTRODUCTION: Fremanezumab is a humanized monoclonal antibody administered through a subcutaneous injection. It is used for treatment of migraines, and occasional injection site reactions have developed after usage. CASE PRESENTATION: This case report describes a nonimmediate injection site reaction on the right thigh of a 25-year-old female patient after starting treatment with fremanezumab. The injection site reaction presented as 2 warm, red annular plaques 8 days following a second injection of fremanezumab and about 5 weeks following the first injection. She was prescribed a 1-month course of prednisone that relieved her symptoms of redness, itching, and pain. DISCUSSION: Similar nonimmediate injection site reactions have been reported before, but this particular injection site reaction was significantly more delayed. CONCLUSIONS: Our case illustrates that injection site reactions to fremanezumab can be delayed after the second dose and may require systemic therapy to alleviate symptoms.

Diffuse Large B-Cell Lymphoma, Not Otherwise Specified (DLBCL NOS) Presenting as Multiple Subcutaneous Nodules: An Unusual Cutaneous Presentation of Systemic Disease.

Diffuse large B-cell lymphoma, not otherwise specified (DLBCL NOS) is the most common lymphoid malignancy in the Western world and classically presents as a rapidly enlarging nodal or extranodal mass. Cutaneous involvement by systemic DLBCL NOS is an infrequent clinical presentation, encountered in only 1.5-3.5% of cases, while disseminated cutaneous disease with multiple subcutaneous nodules at the time of diagnosis is unusual and can present a diagnostic challenge. The differential diagnosis when encountering a high-grade B-cell malignancy at a cutaneous site is broad and includes primary cutaneous follicle center lymphoma (PCFCL), primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT), high-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL-MYC/BCL2), and other potential entities which must all be carefully considered before rendering a final diagnosis. In this report, we describe the case of a 69-year-old man who was seen at our hospital due to generalized weakness and was found to have multiple subcutaneous nodules representing disseminated DLBCL NOS. The case was complicated by concurrent monoclonal B-cell lymphocytosis involving the bone marrow.