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Background: Keratoacanthoma (KA) is a benign neoplasm that affects mainly photodamaged skin. It is locally destructive and may rarely spread. Surgery is not always suitable and usually disfiguring. Thus, non-operative modalities represent good alternatives. Objective: To assess and compare the efficacy of intralesional methotrexate (MTX) and 5-flurouracil (5-FU) in the treatment of KA. Patients and methods: Randomized controlled trial included 20 patients with biopsy proven KA divided into 2 equal groups; group (A) received intralesional MTX, 25 mg/ml and group (B) received intralesional 5-FU, 50 mg/ml every 2 weeks till complete clearance or for a maximum 5 sessions. Results: In the MTX group, complete clearance was observed in 7 patients (70%) compared to 8 patients (80%) in the 5- FU group with no statistically significant difference. However, the median number of injections needed to achieve complete response in the MTX group was 3 sessions versus only 2 sessions in the 5-FU group. Limitations: the small sample size due to the relatively low incidence of KAs in our population. Conclusion: Intralesional therapy is a good alternative to surgery in selected cases of KA. Both drugs showed comparable efficacy, but 5-FU may give faster results, hence increasing patient satisfaction and compliance. [ABSTRACT FROM AUTHOR]

In December 2020, a major vaccination program against COVID-19 commenced in Europe with vaccines such as Pfizer's mRNABNT162b2 (Comirnaty®). Subsequent reports of immediate and delayed skin reactions emerged. This study presents a case of a 64-year-old male who developed multiple keratoacanthomas approximately two weeks after receiving a second booster dose of the Pfizer vaccine. The patient, who had significant medical history of hypertension and diabetes, presented with erythematous, crateriform lesions on his limbs. A physical examination and histopathological analysis confirmed the diagnosis of Generalized Eruptive Keratoacanthoma (GEKA). Treatment involved cemiplimab I.v. 350 mg administered every three weeks. Within two months, the patient showed significant improvement, with the disappearance of all lesions. Dermoscopy and histopathological exams supported the GEKA diagnosis, which is a rare variant of multiple keratoacanthomas. This case suggests a potential immune-mediated mechanism triggered by the COVID-19 vaccine, leading to the rapid development of keratoacanthomas. Treatment with cemiplimab showed promise, highlighting the potential of immune checkpoint inhibitors in managing multiple keratoacanthomas. Further research is needed to explore the efficacy and safety of such treatments. [ABSTRACT FROM AUTHOR]

Keratoacanthoma diagnosis is challenging, and therefore, this publication contributes to the current literature by presenting epidemiological data and describing clinical and histopathological characteristics and the treatment decision. A 69-year-old Caucasian male patient presented with a well-delimited exophytic growth nodule in the lower lip measuring 10 millimeters with circular shape, firm consistency, pink color, and rough surface. The clinical suspicion was squamous cell carcinoma. An incisional biopsy and histopathological analysis were performed, which revealed fragments of oral mucosa lined by hyperparakeratinized stratified squamous epithelium with a center filled with keratin, corneal pearls, pseudoepitheliomatous hyperplasia, and areas of epithelial dysplasia. The diagnosis of keratoacanthoma was determined. Surgical resection was performed, completely removing the lesion, and histopathological analysis confirmed the diagnosis of keratoacanthoma. The fact that the patient was male, over 45 years old, and Caucasian agrees with the epidemiology of the population most affected by keratoacanthoma. The histopathology of the case corroborates the classic characterization, mainly the central depression filled with keratin. The treatment chosen was surgical resection with a small margin of safety, according to the current literature. Keratoacanthomas are more common in males aged over 45 years and in Caucasian individuals. The main etiology is sun exposure without protective measures. It presents as an exophytic nodule with a firm consistency, rough surface, and center filled with keratin. Histopathology is characterized by a crateriform structure, dyskeratosis, and the presence of corneal pearls. The most indicated treatment is surgical resection.

Background: Tattooing is a widespread practice and has increased in popularity over time. Many lesions have been described in relation to tattoos, including malignant tumors. Objectives: The primary goal of this review is to determine whether the frequency of published cases of skin cancers within tattoos has been increasing over time. Methods: Our review is in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and reporting criteria. The databases MEDLINE via PubMed, Embase via Elsevier, and Scopus via Elsevier were searched from inception to February 23, 2023. No data or publication date limits were imposed. Results: Our review identified 160 cases of cutaneous tumors arising within tattoos. An increase in published cases over time was observed. Most reported tumors developed within red tattoo pigment (36.9%), with the largest contribution by squamous cell carcinoma and keratoacanthoma lesions. Limitations: There was a lack of consistency of information in published case reports which limited the scope of our analysis. Small sample size was also a limitation of this review. Conclusions: With the increased popularity of tattoos, it is helpful to continue reporting cases of cutaneous malignancies within tattoos. Awareness of the frequency and severity of tumors within tattoos may be communicated to the public.

Keratoacanthomas (KAs) are a type of skin tumor that rapidly grow (Bosch-Amate et al., 2022). A form of KAs was first identified in 1889 (Jeon et al., 2011). These types of lesions can be challenging to differentiate from cutaneous squamous cell skin carcinoma both through histopathology and clinically (Higgins et al., 2015; Ko et al., 2012; Mei et al., 2022). Adding to the complexity, there are no current evidence- based guidelines for treatment of KAs. Although KAs can be self-resolving, the persistence and growth of the KA is unpredictable (Bettoli et al., 2023; Ko et al., 2012). Treatment of KAs with surgical excision or Mohs are typically considered first line due to the possibility of misdiagnosis and invasion into local tissue (Ambur et al., 2022). Dependent upon the location and size of the KA, comorbidities, patient preference, and other considerations, surgical treatment may notbethe most ideal treatment (Kissetal., 2019). Therearemany nonsurgical options including intralesional injections of methotrexate, fluorouracil, corticosteroid, bleomycin, or interferonalpha (Kissetal., 2019). Ionizingradiation, systemicagents, destructive therapy, topical imiquimod, and topical fluorouracil are also possibilities for treatment of KAs (Ambur et al., 2022). EventhoughconditionsofKAswere first identifiedover 100years ago, more research is needed to be able to accurately diagnose and appropriately treat KAs (Tisack et al., 2021). [ABSTRACT FROM AUTHOR]

Context.--Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis. Objective.--To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis. Data Sources.--Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center. Conclusions.--In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Histopathologic overlap between cutaneous squamous cell carcinoma (cSCC) and its indolent mimics likely leads to the overdiagnosis of cSCC. Objective: To perform a pilot study of the p53 immunohistochemical scoring system developed on vulvar squamous lesions in cSCC. Methods: The consistency and reliability of p53 immunostaining using a scoring system developed on vulvar cases, as compared with TP53 genomic sequencing, was studied in an initial cohort of 28 cutaneous cases. p53 labeling was further assessed in an additional 63 cases of atypical squamous lesions, including 20 atypical squamous lesions classified by the authors as benign, 22 cases diagnosed as cSCC without high‐risk features, and 21 cases of high‐risk cSCC (cSCC‐HR). Results: The concordance of p53 labeling and TP53 sequencing was 82.1%. Four positive patterns of p53 mutation were identified: basal, parabasal/diffuse, null, and cytoplasmic. p53 positivity in atypical, benign squamous lesions (10%) was significantly lower than that of low‐risk cSCC (63.6%, p = 0.0004) or cSCC‐HR (90.5%, p < 0.0001). p53 positivity in low‐risk cSCC versus cSCC‐HR was not statistically significant (p = 0.07). Conclusion: p53 Labeling may be a helpful biomarker to support the diagnosis of cSCC and distinguish cSCC from atypical but benign mimics. [ABSTRACT FROM AUTHOR]

Abstract is missing (Corrigendum) This Corrigendum relates to the following article: https://doi.org/10.2340/actadv.v104.13381

Keratoacanthoma (KA) is a common, low-grade, rapidly growing cutaneous squamous cell carcinoma that presents as an enlarging crateriform nodule, which may spontaneously involute but rarely metastasizes. Immunosuppression, ultraviolet light, viral infection, surgical procedures, and trauma are associated with their development. Overall, tattoo-induced squamous cell neoplasms are infrequently described in the literature. Carcinogenesis is hypothesized to result from trauma caused by the tattooing procedure or a foreign body reaction to the pigment. However, the pathogenesis has not been clearly deffned. While most commonly associated with red ink, to date, very few cases of KA forming within black, blue, or multicolored ink tattoos are reported. Herein, we describe a case of KA arising within areas of blue and black pigment in a decorative ink tattoo. [ABSTRACT FROM AUTHOR]

Background There are case reports in the medical literature showing some patients has recurrent keratoacanthoma in selected region and given different names such as chronic keratoacanthoma serpiginous, eruptive keratoacanthoma centerifugum and involuting keratoacanthoma. Objective To report seven patients with keratoacanthoma who had recurrent relapsing and involuting keratoacanthoma in selected body regions and to suggest a covering reprehensive name for this specific medical condition. Methods This is cross sectional descriptive study that was carried out during the period from 2013- 2020 where all patients with keratoacanthoma were collected and among them the recurrent involuting keratoacanthoma were isolated. Full demographic and clinical examination was done. Skin biopsies were performed for histopathological evaluation. Results Forty-five patients with keratoacanthoma were described with Fitzpatrick skin type III, IV among them seven (15.5%) male patients with chronic involuting relapsing keratoacanthoma (CIRKA) were detected, their ages ranged from 25-60 years with a mean of 50 years with negative family history. All had chronic picture with a round of 3-4 years duration. Patients gave story of old and new lesions appearing on the sites. The sites of lesions were on the dorsa of hands in three patients with one patient had in addition chest involvement. While the other four patients had their lesions on the legs apart of one patient had in addition lesions on the face. In all patients, the lesions on the sun exposed sites including face, hands and legs. Also, all patients and on all sites showed different stages of lesion maturation, early umblicated papules and nodules, then small and large plaques, and large tumor size some with characteristic keratoacanthoma with crateriform. All patients had grouping of their lesions in well selected sites. In addition some had atrophic areas which were the sites of involution. Histopathological evaluation demonstrated a picture of keratoacanthoma in all patients. Conclusion All patients showed features of recurrent involuting relapsing keratoacanthoma on well-defined areas. The histopathology was that of keratoacanthoma and all cases are not part of syndrome. As literature described this entity by different names; hence we suggest the name chronic relapsing involuting keratoacanthoma (CIRKA) as representative new informative name. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In December 2020, a major vaccination program against COVID-19 commenced in Europe with vaccines such as Pfizer’s mRNABNT162b2 (Comirnaty®). Subsequent reports of immediate and delayed skin reactions emerged. This study presents a case of a 64-year-old male who developed multiple keratoacanthomas approximately two weeks after receiving a second booster dose of the Pfizer vaccine. The patient, who had significant medical history of hypertension and diabetes, presented with erythematous, crateriform lesions on his limbs. A physical examination and histopathological analysis confirmed the diagnosis of Generalized Eruptive Keratoacanthoma (GEKA). Treatment involved cemiplimab I.v. 350 mg administered every three weeks. Within two months, the patient showed significant improvement, with the disappearance of all lesions. Dermoscopy and histopathological exams supported the GEKA diagnosis, which is a rare variant of multiple keratoacanthomas. This case suggests a potential immune-mediated mechanism triggered by the COVID-19 vaccine, leading to the rapid development of keratoacanthomas. Treatment with cemiplimab showed promise, highlighting the potential of immune checkpoint inhibitors in managing multiple keratoacanthomas. Further research is needed to explore the efficacy and safety of such treatments.

Simple Summary: Cutaneous squamous cell carcinoma (cSCC) is the second most frequent cancer in humans, and it is especially common in fragile, elderly people. Surgery is the standard treatment for cSCC but intralesional treatments can be an alternative in those patients who are either not candidates or refuse to undergo surgery. Classic intralesional treatments, including methotrexate or 5-fluorouracil, have been implemented, but there is now a landscape of active research to incorporate intralesional immunotherapy and oncolytic virotherapy into the scene, which might change the way we deal with cSCC in the future. In this review, we focus on intralesional treatments for cSCC (including keratoacanthoma), from classic to very novel strategies. Cutaneous squamous cell carcinoma (cSCC) is the second most frequent cancer in humans and has the potential to progress locally, metastasize, and cause death in a subset of patients. cSCC is especially common in the elderly, and it will probably represent a major health concern in the near future. Surgery is the standard treatment for cSCC, but intralesional therapies can sometimes be considered for certain patients and under certain circumstances. The choice of intralesional treatment depends on the patient′s characteristics and the clinician′s previous experience and expertise. Here we are reviewing intralesional treatments for cSCC and keratoacanthoma (KA). We have started with some classic drugs, such as methotrexate and 5-fluorouracil, bleomycin, interferon, and cryosurgery, but also comment on electrochemotherapy. Finally, we have focused on novel therapies, some of which are under development, and future perspectives, including intralesional immunotherapy and oncolytic viruses. [ABSTRACT FROM AUTHOR]

While the gold standard treatment for cutaneous squamous cell carcinomas (cSCCs) is surgical removal, there is a risk of infection, cosmetic and functional deficits. Intralesional 5‐fluorouracil (5‐FU) has been shown to be a potential non‐surgical treatment modality for cSCCs in the literature. The aim was to investigate the safety and feasibility of using intralesional 5‐FU to treat cSCCs. A literature review was conducted and a retrospective case series analysed patients who commenced intralesional 5‐FU treatment for at least one cSCC between 1 January 2018 and 1 January 2019 at a private clinic in Orange, Australia. Inclusion criteria include: at least one cSCC was treated; only intralesional 5‐FU was used; and treatment was ceased due to complete or inadequate remission, or adverse effects. There were 15 patients (7 female, 8 male, 60–99 years) and 20 out 21 cSCC lesions (82.6%) cleared while one lesion (4.3%) recurred. Six lesions (26.1%) ulcerated, four lesions became infected (17.4%) and one patient had an allergic reaction. The average number of treatments required for clearance was four (range 1–35), and the average 5‐FU dose used was 75 mg (range 50–150 mg). Across 25 studies, 656 out of 708 lesions cleared (92.66%). Adverse effects were self‐limiting and mostly well‐tolerated. Intralesional 5‐FU is an affordable and non‐invasive non‐surgical treatment modality that appears feasible to use for cSCCs and has a relatively low treatment‐associated morbidity. Future clinical trials can help develop a protocol to guide clinicians in its use. [ABSTRACT FROM AUTHOR]

Beyond established anti-programmed cell death protein 1/programmed cell death ligand 1 immunotherapy, T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain (TIGIT) and its ligand CD155 are promising novel inhibitory immune checkpoint targets in human malignancies. Yet, in cutaneous squamous cell carcinoma, evidence on the collective expression patterns of these inhibitory immune checkpoints is scarce. Complete tumour sections of 36 cutaneous squamous cell carcinoma, 5 cutaneous metastases and 9 keratoacanthomas, a highly-differentiated, squamoproliferative tumour, with disparately benign biologic behaviour, were evaluated by immunohistochemistry for expression of programmed cell death ligand 1 (Tumor Proportion Score, Immune Cell Score), TIGIT, CD155 and CD8+ immune infiltrates. Unlike keratoacanthomas, cutaneous squamous cell carcinoma displayed a strong positive correlation of programmed cell death ligand 1 Tumor Proportion Score and CD115 expression (p

Keratoacanthoma is an epithelial tumour derived from hair follicles. Clinical and histopathological features of keratoacanthoma can resemble that of squamous cell carcinoma. Different treatment alternatives have been described over the years including intralesional methotrexate injection. We present an interesting case of treatment of solitary keratoacanthoma lesion on the nose with intralesional methotrexate as non-surgical therapy. [ABSTRACT FROM AUTHOR]

This report describes the case of a 72-year-old female patient admitted to the ophthalmology clinic for a large roundoval 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. [ABSTRACT FROM AUTHOR]

Immune-related adverse reactions primarily involve the skin and the endocrine, digestive, and respiratory systems. In the endocrine system, these adverse effects mainly include hypophysitis, thyroiditis, hypoadrenalism, and rarely, diabetes mellitus. The most common symptoms in the skin are pruritus, rash, and infrequently, eruptive keratoacanthoma. Here, we report a case of a 67-year-old woman who developed eruptive keratoacanthoma of the skin 6 weeks after beginning treatment with a bispecific antibody (PM8001), targeting both programmed cell death receptor 1 and transforming growth factor β, as well as type I diabetes mellitus--induced ketoacidosis after 13 weeks. The type I diabetes appeared to stabilize after insulin treatment, and the keratoacanthoma gradually resolved after drug discontinuation. This case report describes a case of the effects of PM8001 immunotherapy on the endocrine glands and skin, together with a review of the relevant literature, and summarizes the different clinical characteristics of rare immune-related adverse events resulting from PM8001 immunotherapy to provide a reference for their early detection, diagnosis, and treatment. [ABSTRACT FROM AUTHOR]

Tumors developed in 2 old women presented with pathological findings similar to seborrheic keratosis, although the clinical feature of tumor showed typical keratoacanthoma. In addition to these two cases, we compared the pathological findings of a total of four cases, one case each of keratoacanthoma and seborrheic keratosis, which were clinically and histopathological typical. These two cases and the typical keratoacanthoma showed cell apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and infiltration of cytotoxic T cells. The keratoacanthoma in the decompensated stage may be histologically similar to seborrheic keratosis. TUNEL staining can help in the diagnosis of fading keratoacanthoma.

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.

The article focuses on a case study of keratoacanthoma centrifugum marginatum (KCM), a rare variant of keratoacanthoma, emphasizing its clinical presentation and histopathological features. It discusses the challenges in diagnosis, including the consideration of differential diagnoses such as deep fungal infections, and highlights the efficacy of intralesional methotrexate as an alternative treatment option to surgery for KCM.

We report a case of a 72-year-old man who underwent surgical excision of a keratoacanthoma centrifugum marginatum (KCM) located on the left forearm. It is an uncommon variant of keratoacanthoma, which can assume large dimensions (up to 20 cm) and does not tend to spontaneous regression. The lesion is usually single, with raised borders, and has progressive centrifugal growth associated with central healing and atrophy. Due to its rarity and lack of pathognomonic histopathological features, KCM can be a diagnostic challenge for dermatologists and pathologists.

Introduction: Individuals with melanin-rich skin account for the majority of the world's population. However, literature data regarding dermoscopic characteristics of skin cancer in skin of color (SoC) are scarce. The dermoscopic characteristics of cutaneous tumors might differ among skin types due to heterogeneity in composition and pigmentation. Objectives: To summarize literature data on the dermoscopic findings of skin neoplasms according to the skin color and race. Methods: The literature search was performed using the PubMed database up to December 30, 2022, and was conducted with the use of terms referring to dermoscopy, race (Caucasians, Hispanics, Asians, and Black/African), and skin cancer types (basal cell carcinoma [BCC], squamous cell carcinoma [SCC], keratoacanthoma, Bowen disease, and melanoma). Results: In total, 30 race-specific records were included. Nine SoC records for BCCs (2 BCC studies in Hispanics, 1 BCC study in Black individuals, and 6 BCC studies in Asians), 9 SoC records for SCCs ( 1 SCC study in Hispanics ,1 SCC study in Black individuals and 7 SCCs in Asian population), and 8 SoC records for melanoma (2 melanoma studies in Hispanics, 1 in Blacks, and 5 in Asians) were compared with 4 records that involved only a Caucasian population, according to their participant section as well as with studies on dermoscopy characteristics without focusing on race origins and phototype of the patient. Conclusion: Based on a review of studies including Caucasians, Hispanics, Asians and Blacks /Africans, SoC patients present with more frequent and unique dermatoscopy features of skin cancers.

A 59-year-old male working as a construction worker presented with an acute, rapidly growing dorsal hand mass after a direct, sharp penetrating injury to the hand. He was taken to the operating room for an excision biopsy and local flap coverage. Final pathology reports demonstrated well-differentiated squamous cell carcinoma, keratoacanthoma (KA) type. KA is common but has a varied presentation. The diagnosis and management are controversial but typical recommendations are wide excision for a tissue diagnosis and postoperative surveillance. Here, we present a rare report of an acute posttraumatic keratoacanthoma of the hand and a review of the literature.

Little is known about patient-specific risk factors for skin neoplasia in individuals with Lynch syndrome (LS). Identify clinical factors associated with development of skin neoplasms in LS. Clinical data were systematically collected on a cohort of LS carriers (confirmed pathogenic germline variants in MLH1 , MSH2 , MSH6 , PMS2 , or EPCAM) age ≥18 undergoing clinical genetics care at Dana-Farber Cancer Institute from January 2000 to March 2020. Multivariable logistic regression was performed to evaluate clinical factors associated with skin neoplasia. Of 607 LS carriers, 9.2% had LS-associated skin neoplasia and 15.0% had non-LS-associated skin neoplasia; 58.2% (353/607) had documentation of prior dermatologic evaluation; 29.7% (38/128) with skin neoplasms lacked a history of visceral LS-associated malignancy. LS-associated skin neoplasms were significantly associated with male sex, age, race, MLH1 pathogenic germline variants, MSH2/EPCAM pathogenic germline variants, and personal history of non-LS skin neoplasms. Non-LS-associated skin neoplasms was significantly associated with age, number of first- and second-degree relatives with non-LS-associated skin neoplasms, and personal history of LS-associated skin neoplasms. Single-institution observational study; demographic homogeneity. Skin neoplasms are common in individuals with LS. We identified clinical factors associated with LS- and non-LS-associated skin neoplasms. Regular dermatologic surveillance should be considered for all LS carriers. [ABSTRACT FROM AUTHOR]

Keratoacanthoma (KA) and squamous cell carcinoma (SCC) are rare side effects of programmed cell death ligand-1 (PD-L1) inhibitors that can disrupt therapy. There is no consensus on optimal treatment. We investigated the management strategy and factors influencing pathophysiology. An institutional cancer registry and literature search were used for this retrospective study. Only PD-L1-induced KA and SCC cases were included. Pathology specimens were stained with immune markers and management strategies were analyzed. Four cases were identified at our institution. Immunohistochemistry of atypical keratinocytes revealed PD-1/PD-L1 positivity, high p53, and low bcl-2 for all cases with differential expression of CD44 and beta-catenin for KA versus SCC. Nivolumab was continued or temporarily held with complete resolution. In addition, a literature search identified 30 additional cases of KA/SCC after PDL-1 inhibitor use. The most common treatment was excision/destruction followed by topical and/or intralesional corticosteroids. Therapy was definitely withheld in 22% of KA patients and in 9% of SCC cases. The expression of PD-L1 by atypical keratinocytes helps to explain the effects of nivolumab on the development of cutaneous neoplasms. The expression of immune markers provides mechanistic insights into pathophysiology. Management may be achieved with conservative therapy and without treatment interruption. [ABSTRACT FROM AUTHOR]

Keratoacanthomas are rapidly growing neoplasms of squamous epithelium. Despite their benign nature, they are often difficult to distinguish from squamous cell carcinoma and require excision. In cases in which excision is not successful or not desired, intralesional treatments may be considered. However, limited research exists on individual therapeutic efficacy. We present a 68-year-old man who developed multiple eruptive keratoacanthomas around the wound edge of a previous keratoacanthoma excision. Considering previous excisional failure, intralesional 5-fluorouracil was used as a treatment modality. Injections every 3-4 weeks over a course of 12 weeks induced clinical keratoacanthoma clearance with excellent cosmetic results. This case showcases that weekly intralesional 5-fluorouracil injections, as was the standard mode of treatment in previous case reports, may not be necessary. This less frequent injection strategy is more convenient for the patient and may lead to fewer treatments and less medication necessary. Although a case-by-case basis is needed for any alternative approach to keratoacanthoma treatment, this report is useful for the practicing clinician in showing that 5-fluorouracil may be efficacious in these difficult-to-treat patients.

A 57-year-old man presented with a pigmented papule, 0.4 cm in diameter, on the left lower eyelid. Skin biopsy revealed a basal cell carcinoma, which was excised through a wide excision followed by a full-thickness skin graft (FTSG). Two weeks after the surgery, an erythematous nodule developed in the lower margin of the graft recipient site. The nodule size increased rapidly over 2 weeks, becoming dome-shaped with a central hyperkeratotic plug. A diagnosis of keratoacanthoma (KA) was made, and surgical excision was performed. Histological findings revealed a large, well-differentiated squamous tumor with a central keratin-filled crater and buttress. The human papilloma virus (HPV) genotyping results were negative. Risk factors for KA include trauma, old age, exposure to ultraviolet (UV) radiation, immunosuppression, and HPV infection. KA has most often been reported to develop at the donor site. Although the pathogenesis of KA is unclear, trauma is believed to act as a second insult to a preceding oncogenic insult, such as exposure to UV radiation, resulting in a koebnerization. Herein, we report a case of solitary KA at a FTSG recipient site. This report presents information that may provide guidance during dermatologic surgeries.

Skin cancer is the most common malignancy in the world, and the majority of cases affect the skin of the head and neck. The face is a particularly emotive area for patients who often present with a lesion that is causing them concern. This article reviews the identification, diagnosis and principles of management of non-melanoma skin cancer of the head and neck. There are many lesions of the skin which are benign and mimic skin cancer. The differential of head and neck skin lesions and how to determine their nature is discussed. The vast majority of non-melanoma skin cancer are basal cell carcinoma, followed by squamous cell carcinoma. These and the other types of non-melanoma skin cancer are described and illustrated. Current methods of clinical identification, diagnosis and evaluation of skin cancers are clarified, and contemporary treatment paradigms are presented. [ABSTRACT FROM AUTHOR]

Anti-PD-1 immunotherapy agents are known to cause cutaneous side effects in up to 42% of patients with melanoma, infrequently including eruptive keratoacanthomas (de Golian et al., 2016, p. 57). Although traditionally documented with pembrolizumab use, increasing reports of eruptive keratoacanthomas with nivolumab use are emerging in the literature (Bednarek et al., 2018, pp. e28–e29). We present a similar case of a 74-year-old woman with melanoma of the right upper extremity with metastases to the lung. She received her first infusion of nivolumab and, within 2 weeks, developed a pruritic rash on the right arm. Within 1 month, the rash spread to all extremities and would blister, scale, and slough off. Punch biopsy of the right lower extremity revealed squamous proliferation suspicious for eruptive keratoacanthoma secondary to nivolumab therapy. The patient continued nivolumab and was referred to dermatology to monitor. [ABSTRACT FROM AUTHOR]

Keratoacanthoma‐like squamous cell carcinoma (KA‐like SCC) is a malignant classification of KA. We report here a case of surgical combined with 5‐aminolevulinic acid‐photodynamic therapy (ALA‐PDT) to treat KA‐like SCC in an elderly male with successful tumor removal. The tumor resection was performed before ALA‐PDT. One week later, the lesion site was further treated with 20% ALA for 3 h when it was unknown whether the tumor was resected entirely or not. The irradiation was performed with a 633 nm light‐emitting diode lamp at 100 mW/cm2 for 200 J/cm2 after wiping off the ALA cream. Two sessions of ALA‐PDT were performed at a 2 weeks interval. One month after ALA‐PDT, the surgical trace of the lesion was found to have disappeared entirely, with a little scab, and the cancer did not recur. After 1 year of follow‐up, there was no recurrence. The combination with surgery and ALA‐PDT may provide a new idea for the treatment of KA‐like SCC for a wide range of patients. [ABSTRACT FROM AUTHOR]

Simple Summary: Tumors of the skin are one of the most commonly observed neoplasms in captive lizards. The current study characterizes keratoacanthoma, a previously undescribed skin tumor, in five male lizards (one bearded dragon, one veiled chameleon, and three panther chameleons) with an average to high age. In all lizards, keratoacanthomas presented as cystic nodules with a central keratin pearl that was predominantly located at the body wall. In all chameleons, a multicentric distribution was observed. Following surgical removal of the keratoacanthomas in all lizards, a follow-up period of one to two years was established. While the skin neoplasia reappeared in the bearded dragon and the veiled chameleon, no recurrence was seen in the panther chameleons. Keratoacanthoma constitutes a rather benign histologic variant of squamous cell carcinoma, representing a non-invasive but rapidly growing skin neoplasia that may be associated with the inappropriate use of ultraviolet lighting in the captive environment. In addition, panther chameleons may show a species predisposition as well as a tendency to develop multicentric keratoacanthomas. The present study delivers pertinent results for the diagnosis, prevention, and treatment of keratoacanthomas in lizards. The present study describes the clinical behavior as well as the histopathologic and immunohistochemical characteristics of keratoacanthomas (Kas) in three different saurian species. While Kas presented as two dermal lesions in a bearded dragon (Pogona vitticeps), multicentric Kas were observed in three panther chameleons (Furcifer pardalis) and a veiled chameleon (Chamaeleo calyptratus). Macroscopically, Kas presented as dome-shaped skin tumors with a centralized keratinous pearl and a diameter ranging from 0.1–1.5 cm. In all lizards, Kas were predominantly located at the dorsolateral body wall, and KA of the eyelid was additionally observed in three out of four chameleons. Histologically, KAs presented as relatively well-defined, circumscribed epidermal proliferations that consisted of a crateriform lesion containing a central keratinous pearl with minimally infiltrating borders. In all KAs, a consistent immunohistochemical pattern was observed, with the expression of cyclooxygenase-2, E-cadherin, and pan-cytokeratin. A follow-up period of one to two years was established in all lizards. While no recurrence was observed in the panther chameleons, recurrence of a single keratoacanthoma was observed in the bearded dragon after one year, and in the veiled chameleon, multicentric keratoacanthomas reappeared during a follow-up period of two years. We describe KA as a previously unrecognized neoplastic entity in lizards that constitutes a low-grade, non-invasive but rapidly growing skin tumor that may show a multicentric appearance, especially in chameleons. As previously postulated for dermal squamous cell carcinomas (SCC), artificial ultraviolet lighting may play an important role in the oncogenesis of KAs in lizards. Although dermal SCCs in lizards show similar predilection sites and gross pathologic features, our results suggest that KA should be considered as a histologic variant of SCC that represents a rather benign squamous proliferation in comparison to conventional SCCs. Early diagnosis of KA and reliable discrimination from SCCs are essential for the prognosis of this neoplastic entity in lizards. [ABSTRACT FROM AUTHOR]

Cutaneous metastases are rarely the initial manifestation of a previously undiagnosed malignancy and keratoacanthoma-like lesions are a notoriously unusual presentation pattern of cutaneous dissemination of a primary tumor. Herein, we report a 40-year-old woman presenting to our dermatology department with multiple keratoacanthoma-like scalp nodules. Subsequent investigation determined it to be the first manifestation of a disseminated endometrial epithelioid trophoblastic tumor, eventually causing the patient's death. Epithelioid trophoblastic tumor, a rare form of gestational trophoblastic disease, is a recently described neoplasm whose cutaneous metastasis has not been previously reported in the literature.

Abstract Keratoacanthoma‐like squamous cell carcinoma (KA‐like SCC) is a malignant classification of KA. We report here a case of surgical combined with 5‐aminolevulinic acid‐photodynamic therapy (ALA‐PDT) to treat KA‐like SCC in an elderly male with successful tumor removal. The tumor resection was performed before ALA‐PDT. One week later, the lesion site was further treated with 20% ALA for 3 h when it was unknown whether the tumor was resected entirely or not. The irradiation was performed with a 633 nm light‐emitting diode lamp at 100 mW/cm2 for 200 J/cm2 after wiping off the ALA cream. Two sessions of ALA‐PDT were performed at a 2 weeks interval. One month after ALA‐PDT, the surgical trace of the lesion was found to have disappeared entirely, with a little scab, and the cancer did not recur. After 1 year of follow‐up, there was no recurrence. The combination with surgery and ALA‐PDT may provide a new idea for the treatment of KA‐like SCC for a wide range of patients.

A 57-year-old man presented with a pigmented papule, 0.4 cm in diameter, on the left lower eyelid. Skin biopsy revealed a basal cell carcinoma, which was excised through a wide excision followed by a full-thickness skin graft (FTSG). Two weeks after the surgery, an erythematous nodule developed in the lower margin of the graft recipient site. The nodule size increased rapidly over 2 weeks, becoming dome-shaped with a central hyperkeratotic plug. A diagnosis of keratoacanthoma (KA) was made, and surgical excision was performed. Histological findings revealed a large, well-differentiated squamous tumor with a central keratin-filled crater and buttress. The human papilloma virus (HPV) genotyping results were negative. Risk factors for KA include trauma, old age, exposure to ultraviolet (UV) radiation, immunosuppression, and HPV infection. KA has most often been reported to develop at the donor site. Although the pathogenesis of KA is unclear, trauma is believed to act as a second insult to a preceding oncogenic insult, such as exposure to UV radiation, resulting in a koebnerization. Herein, we report a case of solitary KA at a FTSG recipient site. This report presents information that may provide guidance during dermatologic surgeries. [ABSTRACT FROM AUTHOR]