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.

Differential Immunoexpression of Inhibitory Immune Checkpoint Molecules and Clinicopathological Correlates in Keratoacanthoma, Primary Cutaneous Squamous Cell Carcinoma and Metastases.

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 < 0.001) with significantly higher programmed cell death ligand 1 Tumor Proportion Score (p < 0.001) and CD155 expression (p < 0.01) in poorly differentiated G3-cutaneous squamous cell carcinoma compared with keratoacanthomas. TIGIT+ infiltrates were significantly increased in programmed cell death ligand 1 Immune Cell Score positive primary tumours (p = 0.05). Yet, a strong positive correlation of TIGIT expression with CD8+ infiltrates was only detected in cutaneous squamous cell carcinoma (p < 0.01), but not keratoacanthomas. Providing a comprehensive overview on the collective landscape of inhibitory immune checkpoint expression, this study reveals associations of novel inhibitory immune checkpoint with CD8+ immune infiltrates and tumour differentiation and highlights the TIGIT/CD155 axis as a potential new target for cutaneous squamous cell carcinoma immunotherapy.

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.

Intralesional methotrexate as non-surgical therapy for giant keratoacanthoma on the nose.

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.

Xeroderma Pigmentosum: Part Two: Treatment of Skin Tumors with Topical Podophyllin 25% in Benzoin.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease; relatively mild XP patients are sometimes designated as having pigmented xerodermoid or xerodermoid pigmentosum (XP-V), a variant of XP. It is commonly associated with many long-standing skin conditions and tumors, including malignancies, management of which is necessary to prevent the progress of the disease. The objective of the study was to evaluate an innovative therapeutic treatment, beyond surgery, surgical excision, cryotherapy, electrocautery and curettage, or Mohs surgery, for the management of skin tumors in XP.This was a prospective therapeutic interventional study comprising 50 patients with XP-V. Age of subjects ranged from 2 to 50 years, with a mean age of 18 years. Several measures were evaluated in part one of this study, and a number of others (as reviewed in part one) were successful in prophylaxis of skin tumors in XP as well as in treating earlier stigmata of XP; however, these measures were notably less successful in treating well-developed skin tumors in XP patients, and 18 of the 50 patients evaluated in part one had well-developed tumors (total 22 lesions) refractory to treatments. Podophyllin 25% in 100-mL tincture of benzoin was applied topically to lesions until complete resolution was documented in 18 patients with XP complications, such as keratoacanthoma (KA), basal cell carcinoma, or squamous cell carcinoma. Topical podophyllin 25% in benzoin was a less destructive alternative treatment for skin cancer and KA in XP patients.

NITROSAMINE CONTAMINATION WITHIN CARDIAC MULTIMEDICATION - SARTANS (VALSARTAN), CALCIUM CHANNEL BLOCKERS (AMLODIPINE AND NIFEDIPINE), AND ANTIARRHYTHMICS (PROPAFENONE) AS A SIGNIFICANT FACTOR IN THE DEVELOPMENT AND PROGRESSION OF MULTIPLE KERATINOCYTIC CANCERS: ADVANCEMENT ROTATION FLAP FOR KERATOACANTHOMA OF THE UPPER LIP AND UNDERMINING SURGERY FOR BCC OF THE SHOULDER AS AN OPTIMAL DERMATOSURGICAL APPROACH.

The data on the polycontamination of multimedication in polymorbid patients with a heterogeneous class of carcinogens/nitrosamines, NDSRIs (classified according to the FDA regulation to the companies of 2023 to those with a carcinogenic potency between 1 and 5), are one of the most important steps to clarify the concept of skin cancer nitrosogenesis/ pathogenesis. The FDA is the first regulatory institution in the world to courageously declare that a problem exists and should be addressed. The main and currently unexplained and somewhat controversial issue lies in 1) the sporadic nature of polycontamination in different geographical regions, and 2) the lack of official data from the established international, but also regional pharmaceutical market regulators on the results of the checks conducted for nitrosamine contamination of the respective batches. It is this that leads scientists to the idea of (albeit seemingly) speculative but entirely possible controlled contamination of the production in certain geographical regions. This (hypo)thesis is supported, albeit indirectly, by the fact that: a recent regional check for possible contamination of sartans in a particular geographical region was not indicative of the presence of any nitrosamines/NDSRIs. But this fact is indicative of several extremely important things: 1) contamination is not ubiquitous, its genesis is heterogeneous; 2) contamination could be completely avoided at production level in certain geographical regions; 3) ˝controlled contamination˝ or carelessness of a heterogeneous nature should be excluded by the relevant regulators. Regular inspection and certification of medicinal products in relevant geographical regions to exclude contamination with nitrosamines/NDSRIs would be the surest method to protect public health globally. The initial parameters of the restrictive processes for the availability of nitrosamines in medicines have been established by the most powerful regulator globally in the face of the FDA, with the hope being that manufacturers will find a short-term solution to the problem. We report another patient who simultaneously developed 2 cutaneous tumors under potentially/actually nitrosamine contaminated drugs such as: beta blockers- atenolol, calcium antagonists- nifedipine/amlodipine, sartans- valsartan and antiarrhythmics- propafenone. One of the tumors was localized in the upper lip area (keratoacanthoma) and the other in the right shoulder area (basal cell carcinoma). Successful surgical treatment of the tumors was performed in the form of upper lip advancement rotation flap and elliptical excision of the second lesion. The evolution/growth rate of the tumors in relation to the potential mutagens/carcinogens heterogeneous in their potency contained in the drugs is commented.

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.