Keratoacanthoma and Cutaneous Squamous Cell Carcinoma With PD-1 and PD-L1 Inhibitor Use.

This cross-sectional study assesses risk of dermatological immune-related adverse events associated with immunotherapy for cancer.

Spontaneous resolution of eruptive papules following ablative laser resurfacing-Case report and review of laser-associated eruptive keratoacanthomas.

BACKGROUND: Keratoacanthomas (KAs) following laser treatment are a rare, but well-described entity. AIM: Herein, we describe a case of eruptive keratoacanthoma (KA) following laser resurfacing treatment and aim to better characterize laser-associated KAs. METHODS: A literature search was performed on PubMed reviewing laser-associated KAs including various characteristics: epidemiology, history of skin cancer, location, and number, type of laser, as well as the management and outcome. RESULTS: Fractional ablative was the most common type of laser triggering KAs, and most cases presented within the first month following treatment. The majority of cases of laser-induced KA had a prior history of a malignant or premalignant skin neoplasm. Laser-induced KAs were treated using modalities similar to KAs arising in other contexts. CONCLUSION: Clinicians need to be knowledgeable and prepared to understand, and manage complications following laser treatments, as rare as they may be, including KAs.

Multiple Keratoacanthoma-like Syndromes: Case Report and Literature Review.

Keratoacanthoma (KA) is a fast-growing skin tumor subtype that can be observed as a solitary lesion or rarely as multiple lesions in the context of rare genetic syndromes. Syndromes with multiple keratoacanthoma-like lesions have been documented as multiple self-healing squamous epithelioma (Ferguson-Smith syndrome), eruptive keratoacanthoma of Grzybowski, multiple familial keratoacanthoma of Witten and Zak Muir-Torre syndrome, and incontinentia pigmenti. The treatment approach of those entities is challenging due to the numerous lesions, the lesions' undefined nature, and the co-existence of other malignant skin tumors. Herein, we report a case of a 40-year-old woman who developed multiple treatment-resistant Ferguson-Smith-like keratoacanthomas with a co-existing large and ulcerated invasive squamous cell carcinoma and microcystic adnexal carcinoma on the scalp. Multiple keratoacanthomas on her extremities were successfully treated with oral acitretin (0.5 mg/kg/day) in combination with topical Fluorouracil (5-FU) 5%, while excision and plastic surgery restoration were performed to treat the ulcerated cancer lesion on her scalp. Due to the interesting nature of this rare syndrome, we performed a literature review including case reports and case series on multiple-KA-like lesions syndromes and focusing on diagnosis and therapy approaches. We also conducted a comparison of patient reports, which included assessing the clinical appearance of the lesions and evaluating the success and progress or the failure of various treatment approaches that were implemented.

A rapidly growing nodule on the face during pregnancy.

It is well known that adnexal skin tumors can simulate other cutaneous neoplasia and that various types of benign and malignant skin tumors can develop or modify during pregnancy. Here, we report a case of trichoblastoma mimicking a keratoacanthoma arising in a nevus sebaceous during pregnancy. Given its unique clinical and dermoscopic features, this case highlights the pivotal role of clinicopathological correlation in the diagnosis of adnexal tumors with an atypical clinical presentation.

Mosaic Muir Torre Syndrome: Keratoacanthoma as a Piece of the Puzzle.

ABSTRACT: Lynch syndrome is an inherited condition, which increases the risk of numerous visceral malignancies and cutaneous tumors such as keratoacanthomas and sebaceous tumors. It is typically identified by immunohistochemistry of tissue taken from tumors or through genetic testing with next-generation sequencing. Diagnosing Lynch syndrome becomes more complex when the individual is mosaic for the relevant pathogenic variant. There are very few cases of this reported in the medical literature. It is even more unusual for the diagnosis to be made based on testing of a keratoacanthoma lesion. We report a case where immunohistochemistry of a keratoacanthoma helped make a diagnosis of mosaic Lynch syndrome. We will explore how mosaicism should be considered when a phenotype is strong, even if next-generation sequencing reports no pathogenic or likely pathogenic variant and how lesions such as keratoacanthomas can have a role in the early detection and treatment of future malignancies.

Multiple Eruptive Keratoacanthomas Secondary to Nivolumab Immunotherapy.

Immune checkpoint inhibitors are increasingly being utilized for the treatment of advanced neoplastic disease and have been associated with wide-ranging cutaneous adverse effects. Though exceedingly rare, eruptive keratoacanthomas have been associated with the use of immune checkpoint inhibitors such as pembrolizumab and nivolumab, whose molecular target is the programmed cell death protein 1. Herein, we detail a case of numerous eruptive keratoacanthomas arising in a patient one month after initiation of nivolumab for recurrent metastatic oropharyngeal squamous cell carcinoma. Treatment with multiple rounds of intralesional corticosteroids and a several-month course of oral acitretin resulted in partial improvement. Subsequent treatment with intralesional 5-fluorouracil demonstrated near-complete resolution of the keratoacanthomas without discontinuation of nivolumab. Although eruptive keratoacanthomas secondary to immune checkpoint inhibitors are exceptionally rare, physicians should be aware of this cutaneous adverse effect as their use becomes more widespread.

Aberrant p16, p53 and Ki-67 immunohistochemistry staining patterns can distinguish solitary keratoacanthoma from cutaneous squamous cell carcinoma.

Keratoacanthoma (KA) is widely considered a benign, usually self-resolving, neoplasm distinct from cutaneous squamous cell carcinoma (cSCC), while some consider KA to be indistinguishable from cSCC. Published studies indicate utility for p16, p53, Ki-67 immunostaining and elastic van Gieson (EVG) in the assessment of KA and cSCC. We compared clinical features and staining patterns for p16, p53, Ki-67 and EVG in fully excised KA, cSCC with KA-like features (cSCC-KAL) and other cSCC (cSCC-OTHER). Significant differences between KA, cSCC-KAL and cSCC-OTHER were found for head and neck location (20%, 86%, 84%), and duration <5 months (95%, 63%, 36%). KA shows both a mosaic pattern for p16 (>25-90% of neoplasm area) and peripheral graded pattern for p53 (up to 50% moderate and strong nuclear staining) in 92% compared with 0% of cSCC-KAL and 0% of cSCC-OTHER. In contrast, a highly aberrant pattern (usually null) for one or both p16 and p53, was present in 0% of KA, 83.8% of cSCC-KAL and 90.9% of cSCC-OTHER. Abnormal distribution of Ki-67 beyond the peripheral 1-3 cells was uncommon in KA (4.2%) and common in cSCC-KAL (67.6%) and cSCC-OTHER (88.4%). Moderate to striking entrapment of elastic and collagen fibres was present in the majority of KA (84%), cSCC-KAL (81%) and cSCC-OTHER (65%). KA are clinically distinct neoplasms typically of short duration occurring preferentially outside the head and neck and generally lacking aberrations of p16, p53 and Ki-67, compared with cSCC that have high rates of aberrant or highly aberrant p16, p53 and Ki-67, but EVG lacked specificity.

Distinguishing Keratoacanthoma from Well-Differentiated Cutaneous Squamous Cell Carcinoma Using Single-Cell Spatial Pathology.

Keratoacanthoma (KA) is a common keratinocyte neoplasm that is regularly classified as a type of cutaneous squamous cell carcinoma (cSCC) despite demonstrating benign behavior. Differentiating KA from well-differentiated cSCC is difficult in many cases due to the substantial overlap of clinical and histological features. Currently, no reliable discriminating markers have been defined, and consequently, KAs are often treated similarly to cSCC, creating unnecessary surgical morbidity and healthcare costs. In this study, we used RNA sequencing to identify key differences in transcriptomes between KA and cSCC, which suggested divergent keratinocyte populations between each tumor. Imaging mass cytometry was then used to identify single-cell tissue characteristics, including cellular phenotype, frequency, topography, functional status, and interactions between KA and well-differentiated cSCC. We found that cSCC had significantly increased proportions of Ki67+ keratinocytes among tumor keratinocytes, which were dispersed significantly throughout non-basal keratinocyte communities. In cSCC, regulatory T-cells were more prevalent and held greater suppressive capacity. Furthermore, cSCC regulatory T-cells, tumor-associated macrophages, and fibroblasts had significant associations with Ki67+ keratinocytes as opposed to avoidances with KA, indicating a more immunosuppressive environment. Our data suggest that multicellular spatial features can serve as a foundation to enhance the histological discrimination of ambiguous KA and cSCC lesions.

Dilute Intralesional 5-Fluorouracil for the Treatment of Squamous Cell Carcinomas and Keratoacanthomas: A Case Series.

BACKGROUND: Intralesional 5-fluorouracil (5-FU) is a promising, yet sparsely studied alternative to surgical treatment for nonmelanoma skin cancer (NMSC).1 Previous studies of intralesional 5-FU have reported concentrations ranging from 30 to 50 mg/mL. To the best of our knowledge, this case series represents the first reported use of intralesional 5-FU 10.0 mg/mL and 16.7 mg/mL for NMSC. METHODS: A retrospective chart review identified 11 patients who received intralesional 5-FU 10.0 mg/mL and 16.7 mg/mL for 40 cutaneous squamous cell carcinomas and 10 keratoacanthomas. We describe the characteristics of these patients and calculate the clinical clearance rate of dilute intralesional 5-FU therapy for NMSC at our institution. RESULTS: Dilute intralesional 5-FU successfully treated 96% (48/50) of the study lesions, providing complete clinical clearance in 82% (9/11) of patients across a mean follow-up time of 21.7 months. All patients tolerated their treatments well with no reported adverse effects or local recurrences. DISCUSSION: The use of more dilute preparations of intralesional 5-FU for NMSC may be a means of reducing cumulative dose and dose-dependent adverse reactions while maintaining clinical clearance. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.5058.

Ungual Keratoacanthoma With Features of Regression.

ABSTRACT: Ungual keratoacanthoma (UKA) is an infrequent tumor. Different from keratoacanthoma in other parts of the skin, UKA rarely regresses, and grows aggressively with common destruction of the subjacent phalanx. Reported cases of UKA with features of regression are exceptional, and even dermatopathologists with reputed experience in nail pathology admit to having seen very few cases. We herein report a case of a 77-year-old man who presented a painful subungual lesion on the second finger of the right hand. An x-ray showed evidence of erosion of the subjacent distal phalanx. The patient was highly concerned about the lesion and rejected conservative treatment preferring amputation of the distal phalanx. The histopathologic examination revealed a UKA with features of regression.

Surgical management of periocular squamous cell carcinoma: case report.

This report describes the case of a 72-year-old female patient admitted to the ophthalmology clinic for a large round-oval tumor with a long-standing keratotic lesion on her lower eyelid, without extending to the free margin of the eyelid. The tumor was excised with a margin in non-tumorous tissue, the nearest being 1 mm away from the tumor at the 12 o'clock position. The surgical process was complicated by the patient's treatment with the anticoagulant rivaroxaban, resulting in increased bleeding during surgery. The histopathological evaluation showed characteristics indicative of a well-differentiated squamous cell carcinoma, more specifically, the keratoacanthoma type. Consequently, it was necessary to extend the excision at the 12 o'clock position by an additional 3 mm. The procedure involved extensive removal of the impacted area and subsequent reconstruction with advancement flaps, supported by histological examination to ensure total excision. In cases of squamous cell carcinoma on the eyelid, multiple sequential excisions are often required to ensure complete removal within safe histological margins, achieving desirable functional and esthetic results.

Treatment of Reactive Keratoacanthomas with Acitretin Following Multiple Excisions and Mohs Surgery for Recurrent Squamous Cell Carcinoma.

Surgical intervention is seen as the gold standard in the treatment of Squamous cell carcinoma. Yet, in cases of recurrence, repeated surgical procedures may unwittingly foment the rise of reactive keratoacanthomas at the surgical margins or edge of a newly placed skin graft.