Necrotizing Infundibular Crystalline Folliculitis-A Case Report of a Rare Entity and Review of the Literature.

ABSTRACT: Necrotizing infundibular crystalline folliculitis (NICF) is a rare distinct entity that was introduced in 1999. It typically presents with numerous eruptive waxy papules on the forehead and/or the upper back in adults in their fifth to seventh decade of life. The pathogenesis is unknown to date, but yeast and bacterial infection of the follicular ostia seems to contribute to the development. More recently, NICF has occasionally been observed as a side effect of targeted antitumoral therapy. Histopathologically, NICF is characterized by dilated follicular ostia filled with pale filamentous and birefringent material enclosed by parakeratotic columns of the epidermis and accompanied by a mild superficial inflammatory infiltrate of the dermis. This case report is about a 58-year-old male patient presenting with multiple eruptive keratotic papules on his forehead. Histopathology revealed all classic features of NICF. The case represents a classic example of NICF and is compared with previously published cases that are comprehensively summarized in this article.

Approach to Chilblains During the COVID-19 Pandemic [Formula: see text].

Coronavirus disease (COVID-19) chilblains is a well-reported cutaneous pattern of severe acute respiratory syndrome coronavirus (SARS-CoV-2). Through this narrative review, we provide an evidence-based overview of idiopathic and secondary chilblains, distinguishing features of COVID-19 chilblains, and a systematic clinical approach to history, examination, investigations, and treatment. In the absence of cold or damp exposure, COVID-19 should be considered as a cause of acute chilblains. The timing of onset of COVID-19 chilblains relative to active SARS-CoV-2 viremia remains unclear. Patients with suspected COVID-19 chilblains should thus follow public health guidelines for COVID-19 testing and self-isolation.

Invasive melanoma in a 5-year-old Canadian patient: A case report.

Atypical Spitzoid lesions pose a distinct challenge in classification as they may comprise a mixture of both classic benign nevus and cutaneous melanoma characteristics. Immunostaining and molecular analysis, such as comparative genomic hybridization, can assist in narrowing the differential diagnosis. We present a case of a 5-year-old male with an atypical Spitzoid lesion on his back. Initial histopathology revealed a relatively symmetric lesion with mitotic figures and poor maturation of melanocytes with descent into the dermis. Immunohistochemistry demonstrated a loss of p16, and array comparative genomic hybridization revealed a loss of chromosome 9, supporting a diagnosis of invasive melanoma arising in conjunction with a remnant of a conventional melanocytic nevus. This case is the first in Canada to demonstrate the use of array comparative genomic hybridization for diagnosing melanoma in a young paediatric patient.

Granulomatous Tumoral Melanosis Associated With Pembrolizumab Therapy: A Mimicker of Disease Progression in Metastatic Melanoma.

Immune checkpoint inhibitor therapy has revolutionized the treatment of advanced melanoma, with these agents significantly improving survival for patients with metastatic disease. With the increasing use of these agents, the number of adverse reactions secondary to their use has also increased. Sarcoidosis and sarcoid-like reactions are one such immune checkpoint inhibitor-related adverse event. We report a case of sarcoid-like granulomatous tumoral melanosis in a patient on the programmed cell death-1 (PD-1) receptor inhibitor pembrolizumab for metastatic melanoma. This is, to our knowledge, the first reported case of a sarcoidal form of tumoral melanosis in a patient on anti-PD-1 therapy. We postulate that this reflects tumor regression in response to pembrolizumab-induced immune activation, with concomitant therapy-triggered induction of a sarcoid-like reaction. These findings and the literature review presented herein should alert clinicians and pathologists to the possibility of regressed lesions with sarcoid-like features presenting as mimickers of disease progression in patients undergoing immunotherapy for advanced melanoma.

Non-Healing Perianal Ulcers in a Healthy Elderly Male: An Unusual Case of Perforating Dermatosis.

BACKGROUND: Perforating dermatoses are a rare group of dermatologic conditions characterized by transepidermal elimination of dermal material that can be primary or acquired secondary to systemic disease. OBJECTIVE: We present an atypical case of perforating dermatosis resembling elastosis perforans serpiginosa (EPS) presenting with perianal ulcers in an elderly male with no systemic disease or medications and outline his successful treatment course. CONCLUSIONS: Perianal ulcers in an otherwise healthy individual is an unusual presentation for perforating disorders but should be considered in cases not responding to traditional treatment options.

Practical Strategies to Improve the Clinical Utility of the Dermatopathology Report.

CONTEXT: -Dermatologists and subspecialty dermatopathologists, working together over many years, develop a common understanding of clinical information provided on the requisition and of terminology used in the pathology report. Challenges arise for pathologists without additional subspecialty training in dermatology/dermatopathology, and for any pathologist reporting skin biopsies for nondermatologists such as general practitioners or surgeons. OBJECTIVE: -To provide practical strategies to improve efficiency of dermatopathology sign-out, at the same time providing the clinician with clear diagnostic and prognostic information to guide patient management. DATA SOURCES: -The information outlined in this review is based on our own experiences with routine dermatopathology and dermatology practice, and review of English-language articles related to the selected topics discussed. CONCLUSIONS: -Using generic diagnoses for some benign lesions, listing pertinent negatives in the pathology report, and using logical risk management strategies when reporting on basal cell carcinoma, partial biopsies, or specimens with incomplete clinical information allow the pathologist to convey relevant and useful diagnostic information to the treating clinician.

Pathologic complete response to intralesional interleukin-2 therapy associated with improved survival in melanoma patients with in-transit disease.

PURPOSE: Melanoma patients with in-transit disease have a high mortality rate despite various treatment strategies. The aim of this study was to validate the role of intralesional interleukin (IL)-2, to understand its mechanism of action, and to better understand factors that may influence its response. METHODS: We retrospectively collected the clinicopathological data of 31 consecutive patients who presented to a tertiary care cancer center for treatment of in-transit melanoma with intralesional IL-2. Kaplan-Meier survival curves and multivariable Cox regression analysis were performed. Immunohistochemistry (IHC) was used to better understand the immune response to localized IL-2 therapy. Targeted next-generation sequencing was performed to genomically characterize the tumors. RESULTS: Ten patients (10/31, 32 %) achieved a pathologic complete response (pCR), 17/21 (55 %) had a partial response, and 4/21 (19 %) had progressive disease on treatment. pCR to IL-2 therapy was associated with overall survival (log-rank p = 0.004) and improved progression-free survival (PFS) [adjusted hazard ratio (HR) 0.11; 95 % CI 0.02-0.47; p = 0.003). A higher CD8+ T cell infiltrate was identified in in-transit lesions with a pCR compared with the other lesions (mean IHC score 3.78 vs. 2.61; p = 0.01). Patients with an elevated CD8+ infiltrate demonstrated an improved PFS (unadjusted HR 0.08; 95 % CI 0.01-0.52; p = 0.008). CONCLUSIONS: Thirty-two percent of patients achieved pCR with intralesional IL-2 therapy and had a significantly improved PFS compared with the rest of the cohort, which may be explained by a systemic CD8+ T-cell response.

Fibrolipomatous Hamartoma of the Nerve Arising in the Neck: A Case Report With Review of the Literature and Differential Diagnosis.

We report an unusual case of a fibrolipomatous hamartoma that arose in a nuchal nerve. Typically, fibrolipomatous hamartoma, otherwise known as a neural fibrolipoma or lipomatosis of nerve, arises in the median nerve, brachial plexus, cranial nerves, or plantar nerves. The differential diagnosis is broad and includes benign and malignant spindle cell lesions, such as spindle cell lipoma, perineurioma, and myxoid liposarcoma. We were able to identify the lesion based on the typical histology, including triphasic composition with spindle cell, neural, and adipocytic components and whorled architecture. Because of the atypical location in the neck, detailed immunohistochemical staining was performed. The lesional spindle cells were negative for SMA, CD10, CD68, EMA, S100, PGP9.5, CD34, CD56, and beta-catenin. Colloidal iron stain highlighted marked intralesional mucin deposition. This detailed immunohistochemical profile is a useful diagnostic aid and to our knowledge has not been previously described.

Utilization and utility of immunohistochemistry in dermatopathology.

Immunohistochemistry (IHC) is considered a valuable ancillary tool for dermatopathology diagnosis, but few studies have measured IHC utilization by dermatopathologists or assessed its diagnostic utility. In a regionalized, community-based dermatopathology practice, we measured IHC utilization (total requests, specific antibodies requested, and final diagnosis) over a 12-month period. Next, we assessed diagnostic utility by comparing a preliminary "pre-IHC" diagnosis based on routine histochemical staining with the final diagnosis rendered after consideration of IHC results. The dermatopathology IHC utilization rate was 1.2%, averaging 3.6 stains requested per case. Melanocytic, hematolymphoid, and fibrohistiocytic lesions made up 23%, 18%, and 16%, respectively, of the total cases requiring IHC. S100 and Melan A were the most frequently requested stains, ordered on 50% and 34% of IHC cases, respectively. The utility study revealed that IHC changed the diagnosis in 11%, confirmed a diagnosis, or excluded a differential diagnosis in 77%, and was noncontributory in 4% of cases. Where IHC results prompted a change in diagnosis, 14% were a change from a benign to malignant lesion, whereas 32% changed from one malignant entity to another. IHC is most commonly used in cutaneous melanocytic and hematolymphoid lesions. In 11% of dermatopathology cases in which IHC is used, information is provided that changes the H&E diagnosis. Such changes may have significant treatment implications. IHC is noncontributory in only a small percentage of cases.

Large cell neuroendocrine carcinoma arising in a sessile serrated adenoma: a novel observation.

A 68-year-old woman underwent polypectomy of 2 right-sided colonic polyps identified by screening colonoscopy. Histologic examination of both polyps showed features of sessile serrated adenoma. The larger polyp harbored an invasive tumor composed of large, high-grade cells arranged in nests and cords without tumoral mucin production. Immunohistochemistry demonstrated synaptophysin, cdx-2, cytokeratin 7, and cytokeratin 20 positivity. Both invasive carcinoma and sessile serrated adenoma showed a decreased expression level to focal negative expression of hMLH-1 by immunohistochemistry. Combined morphologic and immunohistochemical features favored large cell neuroendocrine carcinoma arising in a sessile serrated adenoma. Specific carcinoma subtypes and special histologic features (eg, tumor-infiltrating lymphocytes) have been previously reported in carcinomas arising from sessile serrated adenomas. Large cell neuroendocrine carcinoma has not yet been reported in association with sessile serrated adenomas, with this case suggesting a rare but potentially novel end point for the microsatellite instability pathway.