Dermoscopy of squamous cell carcinoma: from actinic keratosis to invasive forms

When performing the dermoscopy of squamous cell carcinoma and its precursors we differentiate among keratin-related, vascular, and pigment-related criteria. Non-pigmented actinic keratoses are characterized by the "strawberry pattern". Pigmented actinic keratosis shows a significant dermatoscopic overlap with lentigo maligna, but the presence of pigmented scales, erythema, and prominent follicles favors its diagnosis. Bowen's disease is characterized by clustered glomerular vessels, white-yellowish scales, and brown or grey dots arranged in lines in its pigmented variant. Finally, dermoscopy allows us to detect invasive squamous cell carcinoma in its early stages and differentiate it from its precursors. Furthermore, its presentation may vary depending on the degree of differentiation, with keratin-associated criteria predominating in well-demarcated tumors, while the atypical vascular pattern will predominate in poorly differentiated tumors.

Reactive Keratoacanthoma Following Treatment with 5-Fluorouracil

Keratoacanthoma (KA) is an epidermal cell tumor with a central keratin plug known to be a variant of keratinocyte carcinoma (KC). KAs typically arise from ultraviolet (UV)-damaged skin and thus are particularly prevalent on extremities. KAs can also be a consequence of local skin trauma. 5-fluorouracil (5-FU) is a topical therapy used to treat early KC, as well as actinic keratoses (AKs). In this paper, we describe the unique cases of two elderly female patients who were treated with 5-FU for AKs of the lower extremities but developed severe inflammatory reactions and reactive KAs to the topical therapy.

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.

Squamous carcinogenesis: potential truncal mutations

Squamous carcinogenesis is incompletely understood, but more recent genetic studies support that the order of acquired mutations is important. This paper will review more recent genetic studies with an emphasis on the potential truncal mutations, mutations critical to the trunk of the cancer evolutionary tree, in actinic keratosis, squamous cell carcinoma in situ, cutaneous squamous cell carcinoma, keratoacanthoma, and keratoacanthoma-like squamous proliferation.

Post-traumatic keratoacanthoma of the hand: A case report

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.

Non-melanoma skin cancer of the head and neck

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.

Diagnostic Utility of TUNEL Staining for Degenerative Keratoacanthoma Requiring Pathologic Differentiation from Seborrheic Keratosis

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.

Interventional treatment of keratoacanthoderma: a case report

This current case report describes a 56-year-old male patient with a skin mass on his lip that had been growing for 1 year. The pathological findings demonstrated that the epidermis was characterized by hyperkeratosis, hyperplasia and hypertrophy and was formed in the shape of a crater. The skin on both ends had developed into a ball-like growth that resembled a volcanic cone. There was invasive growth of heterotype squamous epithelium and a small number of inflammatory cells infiltrating the dermis. Immunohistochemistry demonstrated an increase in P16 (the focus, +) and the hot spot Ki-67 index. The diagnosis was of tumour-like hyperplasia, malignancy and moderate-to-severe dysplasia confirming that it was keratoacanthoma. The patient underwent surgical resection and was discharged from hospital, but the tumour returned. Paclitaxel and cisplatin were administered intraoperatively and bilateral lingual artery perfusion chemoembolization was undertaken six times. This procedure led to an excellent postoperative recovery and discharge from hospital. Tumour therapy was regarded as successful. The patient's medical history included acute lymphoblastic leukaemia L1 and long-term immunosuppressant use. After a 6-month period of follow-up, he died from systemic organ failure as a consequence of having too many ailments.

An Updated Review of the Therapeutic Management of Keratoacanthomas

Objective

Keratoacanthomas are fast-growing cutaneous neoplasms that can be difficult to distinguish from squamous cell carcinoma, both clinically and histologically. The uncertain behavior of these neoplasms creates a challenge in management, and treatment choice often varies significantly between cases. The objective of this review is to discuss the most common and up-to-date treatment modalities used in the management of keratoacanthomas.

Methods

A literature search was performed using PubMed to access and review relevant keratoacanthoma treatment modalities published within the last 40 years. Keywords searched included "keratoacanthoma," "Grzybowski syndrome," "Ferguson-Smith syndrome," "Witten-Zac syndrome," and "Muir-Torre" syndrome.

Results

Our search resulted in 3,408 articles, of which 67 articles were ultimately included in this review.

Conclusion

Although surgical removal with excision or Mohs micrographic surgery remains the standard of therapy, there are many alternative therapeutic modalities that can be utilized.

An Updated Review of the Therapeutic Management of Keratoacanthomas

OBJECTIVE

Keratoacanthomas are fast-growing cutaneous neoplasms that can be difficult to distinguish from squamous cell carcinoma, both clinically and histologically. The uncertain behavior of these neoplasms creates a challenge in management, and treatment choice often varies significantly between cases. The objective of this review is to discuss the most common and up-to-date treatment modalities used in the management of keratoacanthomas.

METHODS

A literature search was performed using PubMed to access and review relevant keratoacanthoma treatment modalities published within the last 40 years. Keywords searched included "keratoacanthoma," "Grzybowski syndrome," "Ferguson-Smith syndrome," "Witten-Zac syndrome," and "Muir-Torre" syndrome.

RESULTS

Our search resulted in 3,408 articles, of which 67 articles were ultimately included in this review.

CONCLUSION

Although surgical removal with excision or Mohs micrographic surgery remains the standard of therapy, there are many alternative therapeutic modalities that can be utilized.

Lower lip recurrent keratoacanthoma: A case report

BACKGROUND

This paper introduces a case of recurrent keratoacanthoma (KA). KA is a self-healing disease. Recurrence after surgical resection is rare. In this case, the local application of retinoic acid ointment after the second operation achieved a good prognosis after 2 years of follow-up.

CASE SUMMARY

A 76-year-old male patient was admitted to the hospital for "lower lip rupture and scab for 3 mo". Treatment: A rectangular incision was made in the healthy tissue about 3 mm outside the periphery of the lower lip mass, and a modified Bernard sliding flap was designed to completely remove the mass. Pathology showed (lower lip) KA. When the patient returned 6 mo after surgery, the middle mucosa of the lower lip had a bulge with a diameter of about 0.5 cm. The boundary was still clear, the surface was ulcerated. A recurrence of lower lip KA was suspected and a fan-shaped incision was performed in the healthy tissue about 5 mm outside the lesion to completely resect. Pathological showed lower lip KA had recurred. Topical application of tretinoin cream was applied once a day for 3 mo. The lower lip wounds were clean at the 2-year postoperative follow-up and the mucosa was normal.

CONCLUSION

Adjuvant retinoic acid treatment after KA surgical resection can achieve good results.

Successful treatment of a giant keratoacanthoma-like squamous cell carcinoma in the eyebrow using surgery combined with photodynamic therapy: A case report

Keratoacanthoma (KA)-like squamous cell carcinoma (SCC) is inclined to be diagnosed as KA due to its resemblance to KA in appearance. A giant facial KA-like SCC has aggressive growth and malignant metastasis, and seriously affects health and aesthetics. Prompt and appropriate treatment is extremely crucial and is a great challenge. Herein, we report a case of surgery combined with 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the successful management of a giant KA-like SCC in the left eyebrow of an elderly woman, providing reference for more efficient disposal of such cases in clinic.

Differences in the mitochondrial microsatellite instability of Keratoacanthoma and cutaneous squamous cell carcinoma

Keratoacanthoma (KA) is a common cutaneous neoplasm which often resembles typical squamous cell carcinoma (SCC) in both its clinical and historical presentation. Several studies have attempted to identify methods for distinguishing between KA and SCC, however, none of these have proven to play any obvious roles in these tumors. Given this we went on to evaluate mitochondrial microsatellite instability (mtMSI) in KA and SCC in an effort to understand these tumors better. DNA was isolated from paired normal and tumoral tissues donated by 57 KA patients and 43 SCC patients. MtMSI was then analyzed using eight microsatellite markers and was observed in 2 (3.5%) of the 57 KA patients and 8 (18.6%) of the 43 SCC patients, respectively. MtMSI was also shown to affect different locations depending on tumor type. In KA patients, mtMSI was detected at mitochondrial D514 D-loop and presented with (CA) n repeats, in contrast, all of the SCC patient experienced mtMSI at the D310 with (C)n repeats of the D-loop region. These differences in location were found to be significant, which may support the hypothesis that KA and SCC have different pathogenetic pathways. Our results also suggest that mtMSI may be a candidate for developing novel differential diagnostic methods for KA and SCC.

Multiple Keratoacanthomas after a Recent Tattoo: A Case Report

We report on a 39-year-old man who presented with seven skin lesions on the right thigh 3 weeks after receiving a large tattoo which included red and black pigments. Initially, the lesions grew fast, later their growth stabilized. Histopathology showed well-circumscribed symmetric tumors with a central keratin-filled crater along with further trademarks of a keratoacanthoma. The patient had previously had multiple tattoos with no history of similar lesions. PCR analysis of one of the lesions revealed the presence of human papillomavirus 6. All lesions were excised with a safety margin. A 3-month follow-up revealed no further lesions.

Grzybowski's Generalized Eruptive Keratoacanthomas in a Patient with Terminal Kidney Disease-An Unmet Medical Need Equally Ameliorated by Topical Imiquimod Cream and Lapacho Tea Wraps: A Case Report

Introduction

Development of singular keratoacanthoma (KA) is generally considered a benign condition as it has a tendency to regress spontaneously in spite of histological similarity to squamous cell carcinoma. Most KAs undergo excision to rule out differential diagnoses. Several alternative treatment modalities (keratinolytic, ablative, immunomodulating, antiproliferative, or targeted therapy) have been described in the past with varying success, underlining the therapeutic challenges associated with large or multiple lesions. Isomorphic response (Koebner phenomenon) may limit the efficacy of ablative options, and comorbidity may limit the use of systemic treatments. Less aggressive topical immunomodulatory treatment options represent an alternative with varying therapeutic success.

Case Report

Here, we describe the clinical course of a 51-year-old male patient with terminal kidney disease who suffered from the rare benign pruritic condition of Grzybowski’s generalized eruptive keratoacanthomas (GEKA) and experienced a significant reduction of lesions and symptoms upon topical therapy with imiquimod 5% cream and lapacho tea dressings alike.

Conclusions

Very little is known about the potential antiinflammatory or antiproliferative effects on the epidermis of the popular phytotherapeutic agent lapacho tea. More studies are warranted considering both the etiology and treatment of GEKA and topical use of phytotherapeutics in dermatology in general. Management of large or multiple KAs remains challenging.

Case for diagnosis. A pruritic eruption of keratotic papules over the face and neck

Generalized eruptive keratoacanthoma of Grzybowski is a rare variant of multiple keratoacanthomas counting with about 40 cases reported. It is a chronic and progressive disease for which none of the described therapeutic options has been entirely satisfactory. We report a case of an 83-year-old female who presented with a 3-month history of extremely pruritic, multiple, skin-coloured to erythematous to brownish, millimetric papules, with a keratotic centre. Histological examination of an incisional biopsy was consistent with the diagnosis of keratoacanthoma. The patient started acitretin 25 milligrams daily with a complete resolution of pruritus and regression of numerous lesions.

Intralesional methotrexate in dermatology: Diverse indications and practical considerations

Intralesional methotrexate (IL-MTX) is a long-established treatment, which is arguably underutilized by dermatologists. We describe the underlying evidence base and practical considerations for its broad range of cutaneous indications, including in cutaneous oncology (keratoacanthomas, squamous cell carcinomas, lymphomas), inflammatory dermatology (nail psoriasis, plaque psoriasis, pyoderma gangrenosum, cutaneous Crohn's disease, amyloidosis), cutaneous infections (viral warts) and for treatment of filler complications. In certain circumstances, IL-MTX can be more efficacious and less invasive than other treatments, with fewer adverse effects. Dermatologists should consider using IL-MTX for a range of recalcitrant cutaneous conditions, particularly for those patients not amenable to surgery or systemic therapy.

Intralesional Methotrexate for the Treatment of Advanced Keratinocytic Tumors: A Multi-Center Retrospective Study

Introduction

Keratinocyte tumors (KT) are frequently observed. Surgery is the treatment gold standard. In some cases, a surgical approach might not be the best option. Radiotherapy (RT) and systemic treatments can frequently cause side effects or be contraindicated. Intralesional methotrexate (MTX) can be a conservative yet effective alternative. We decided to evaluate the effectiveness and safety of intralesional chemotherapy with MTX for the treatment of squamous cell carcinoma (SCC), keratoacanthoma (KA), and basal cell carcinoma (BCC).

Methods

All patients had a histologically confirmed diagnosis of BCC, SCC, or KA and no indication to surgery or RT. MTX was injected subcutaneously proceeding from the periphery of the lesion toward the center. Different protocols in terms of dose, frequency, and length of treatment were used to compare them. Treatment efficacy was evaluated in terms of tumor size reduction. Patients were divided into three groups: responders (improvement of more than 50%), partial responders (< 50%), and non-responders (no improvement or worsening). All data were analyzed using the chi-squared test (χ²).

Results

Thirty-five patients were included. Twenty-one patients suffered from SCC, 12 from KA, and 2 from BCC. KA showed a higher response rate than SCC and BCC. For AK, 92% of patients had a complete resolution; 8% were partial responders. For SCC, 47.6% of cases were responders and 14.3% partial responders, while 38% non-responders. All BCCs showed no improvement. A treatment protocol of weekly injections, performed for 4 to 6 weeks, was the most efficient. Doses of 25 mg/ml per session seemed to be most effective. About one third of our patients developed side effects with mild anemia being the most frequent.

Conclusions

For selected cases, intralesional MTX can be a safe and effective option for the treatment of KT, especially in case of KA and, to a lesser extent, SCC.

Photodynamic therapy for keratoacanthoma on the upper lip

BACKGROUND

Keratoacanthoma (KA) is a cutaneous neoplasm, which is similar to squamous cell carcinoma (SCC) clinically, cytologically, and histopathologically. Surgical resection is the first choice for treating KA, but it may be impractical when a KA is located in a cosmetically sensitive area.

OBSERVATION

We describe a patient with a nodule on the right upper lip. We performed a surgical biopsy to obtain a histopathological diagnosis. Specimen analysis revealed a diagnosis of KA. As the tumor was located in the upper lip, a direct resection may require a flap to reconstruct the lip shape; instead, a noninvasive field approach using photodynamic therapy (PDT) was initiated. After five sessions of treatment, the lesion disappeared, and there was no scar.

CONCLUSIONS

Although there is no consensus on using PDT to treat KA, we provide a case report on the effective use of PDT in the treatment of KAs. PDT can be an alternative treatment option when KA is located in a particular anatomic site.

Tumor immunotherapy - A lot to learn from Keratoacanthoma

Dysfunctionalinty and exhaustion of T cells in the tumor microenvironment is a harsh reality of anti-tumor immune response where tumor cells can escape it. A considerable effort is going on in the field of research that tries to harness the power of T cells against cancer cells to design new anti-cancer immunotherapeutic designs. All these efforts are getting a setback due to the fact that T cells become dysfunctional in tumors while expressing exhaustion markers, so it is necessary to understand from the perspective of cancer itself that what is lacking in tumor-specific T cells in tumor microenvironment so they are getting evaded. Keratoacanthoma is a compelling case of a tumor where auto-regression is happening and many molecular mechanisms can be attributed to this fact. One of the possibilities is having non-exhausting T cells and a highly conducive environment for anti-tumor immune response. In this hypothesis, I am proposing a detailed strategy to decipher this peculiar type of possible immune response in keratoacanthoma and how it can be idolized to create successful anti-cancer T cell immunotherapies.

[Complications related to tattoo practice]

Complications related to tattoo practice. Tattooing can result in a wide variety of complications, whose prevalence and incidence remain still unclear. Hypersensitivity reactions (or allergies) to tattoo pigments are currently the most common complication on a tattoo, however are not predictable. Infections are nowadays directly related to the lack of asepsis and hygiene during the tattooing procedure or during the healing phase. Patients with a known cutaneous disease should be warned of a potential risk of localization of their disease to the tattoo. Patients with chronic conditions and/or impaired immunity should discuss with their physician about the possibility and when to have a tattoo. Laser removal is the gold standard for tattoo removal and include Q-switched, picoseconds and CO2 lasers. However, a complete disappearance of the tattoo is not always possible.

Myriad facades of keratocanthoma: Benignity VS malignancy

Keratoacanthoma (KA) is a self-limiting benign epithelial neoplasm. It occurs predominantly on sun-exposed areas of the body and is believed to arise from hair follicle. It shows a unique behavior in being clinically benign and microscopically malignant. Earlier it was considered as a pseudomalignant lesion but now it is believed to be pseudobenign in nature. The most common concern is related to its nosological position at the border of malignancy and benignity. We hereby report a rare case of keratoacanthomatous type of squamous cell carcinoma in an elderly female showing aggressive nature of the lesion. The various terminologies used for KA in the past have also been tabulated.

Cutaneous keratinocyte cancers of the head and neck: Epidemiology, risk factors and clinical, dermoscopic and reflectance confocal microscopic features

Keratinocyte cancers are the most common malignancy among people with European ancestry, and are very common on sun-exposed areas of the head and neck. Incidence is directly correlated with latitude and annual ultraviolet radiation incidence, although there are a number of other environmental, occupational and genetic risk factors, and keratinocyte cancers become more common at middle age. Basal cell carcinomas (BCC) are the most common, comprising 80% of keratinocyte cancers, but have a very low rate of metastases and low mortality. Squamous cell carcinomas (SCC) make up 20% of keratinocyte cancers, and have relatively infrequent metastases, at 5-16%. While there are no precursor lesions for BCC, SCC represents the final stage in a spectrum of cellular atypia and dysplasia, from actinic keratoses to in situ SCC to invasive SCC. Dermoscopy is a well-established diagnostic tool for keratinocyte cancers, and reflectance confocal microscopy is emerging as another useful diagnostic tool, particularly on functionally and cosmetically sensitive sites like the face.

No Association between Merkel Cell Polymavirus Infection and Keratoacanthoma in Korean Patients

Objectives:

Keratoacanthoma (KA) is a relatively common benign tumor and resembles squamous cell carcinoma (SCC). The definitive cause of KA remains unclear, but trauma, ultraviolet light, chemical carcinogens, human papillomavirus, genetic factors, and immunocompromised status have been implicated as etiologic or triggering factors. Merkel cell polyomavirus (MCPyV) is suspected to cause the majority of cases of Merkel cell carcinoma (MCC). MCPyV-DNA was found significantly more frequently in MCC and only found in about one fourth of KAs. In a recent study, MCPyV was found in Korean patients with MCC. The aim of this study was to determine the presence of MCPyV in Korean patients with KA.

Methods:

Paraffin-embedded tissue samples were analyzed for the presence of MCPyV-DNA by polymerase chain reaction (PCR). A total of 105 KA samples were analyzed.

Results:

A study of MCPyV has not been reported about KA in Korean cases. In the present study the MCPyV was not detected with KA in the Korean patients.

Conclusions:

This supports that KA and MCPyV are not related to each other and MCVyP is not a major factor in the pathogenesis of KA.

Malignant transformation of a conjunctival keratoacanthoma requiring enucleation

PURPOSE

We report a rare case of rapid transformation of a conjunctival keratoacanthoma (KA) into a highly aggressive squamous cell carcinoma requiring enucleation. To our knowledge, this is the second such case reported in the literature.

METHODS

Case report.

RESULTS

A 73-year-old man presented with a recurrent conjunctival lesion in the right eye. A slit lamp examination revealed a hyperkeratotic lesion in the limbar conjunctiva adhered to deep planes but with no ocular involvement. An incisional biopsy was performed because an area of scleromalacia was observed underlying the lesion. Histological findings were consistent with conjunctival KA. One week later, a raised lesion was observed invading the anterior chamber. Histological examination of another excisional biopsy specimen indicated conjunctival squamous cell carcinoma. The right eye was enucleated. Histological analysis confirmed intraocular tumor invasion. Complete clinical remission was observed over one year of follow up.

CONCLUSIONS

Although conjunctival keratoacanthoma is normally benign, it is important to correctly differentiate between KA and squamous cell carcinoma, and closely monitor the eye after surgery because of the rare possibility of recurrence or conversion to squamous cell carcinoma. Immunohistochemistry could help in the diagnosis and management of dubious cases.

Patterns of LC3A Autophagy Protein Expression in Keratoacanthomas

To investigate the expression patterns of autophagy marker light chain protein 3 (LC3A) in keratoacanthoma (KA). KAs are generally regarded as benign but malignant behavior, including rare metastases, may occur. 85 KAs were assessed for the LC3A autophagic protein by immunohistochemistry. Diffuse cytoplasmic staining and a "stone-like structure" (SLS) characterized positive expression. Thirty-four out of 85 KAs (40%) had diffuse cytoplasmic LC3A immunostaining (percentage of positive cells ranging from 5 to 60%). In contrast, only 4 of the 85 KAs (4.7%) expressed SLSs. Only one SLS was detected per histologic section of each tumor. The p53 oncoprotein was encountered in all cases with expression ranging from 1 to 90% of cells (median 30%). The Ki-67 index was expressed in 63 cases (74% of cases; range 1-50% of cells; median value 5%). Neither of these two parameters nor diffuse cytoplasmic LC3A staining was significantly correlated with SLS expression or lack thereof. Expression of SLSs, a hallmark of malignancy, was found in 4.7% of KAs. Further study is necessary to determine whether this fraction represents the exceptional cases that harbor latent malignant potential.

Rapidly Growing and Aggressive Cutaneous Squamous Cell Carcinomas in a Patient Treated with Ruxolitinib

Ruxolitinib is a Janus kinase (JAK)1 and JAK2 inhibitor approved for the treatment of myelofibrosis and for polycythemia patients who are resistant or intolerant to hydroxyurea. We report a 72 year-old man patient with polycythemia vera who developed multiple cutaneous squamous cell carcinomas (cSCCs) with keratoacanthoma-like histological features while on treatment with ruxolitinib. Similar lesions have been reported in an isolated patient who also received ruxolitinib. Our case confirms that ruxolitinib may induce eruptive cSCCs with characteristic clinical and histological features that differentiate them from conventional non-drug induced lesions. Moreover, we performed a mutational panel analysis of the tumors. The lack of specific mutations in these tumors suggests an impairment of immunosurveillance in the origin of the cutaneous lesions. Frequent and thorough dermatological examinations in patients receiving ruxolitinib with a history of photodamage, skin cancer and/or previous hydroxyurea intake is thus recommended.

Intralesional Methotrexate for the Treatment of Keratoacanthoma: The Neapolitan Experience

Introduction

Keratoacanthomas are cutaneous neoplasms known for their rapid growth and spontaneous regression over a long time period. Their treatment can be difficult because of the potentially large field size and number of lesions. Intralesional methotrexate constitutes an effective, nonsurgical treatment of keratoacanthomas, as proven by our experience.

Methods

We treated 11 elderly patients affected by keratoacanthoma with intralesional methotrexate. The injections were performed weekly, followed by 10 mg of folic acid to be taken 24 h later.

Results

All our patients underwent complete resolution of the lesions after 4–8 injections, without side effects.

Conclusion

Intralesional methotrexate seems to be an effective and safe nonoperative treatment modality for keratoacanthoma, especially when it arises in anatomic areas difficult to treat with surgery, in elderly debilitated patients, and in those refusing surgery.

Efficacy and Safety of Intralesional Methotrexate in the Treatment of a Large Keratoacanthoma of the Dorsal Hand in a 99-Year-Old Woman

Several case reports and retrospective studies have demonstrated that intralesional methotrexate (MTX) could be a very effective and safe alternative treatment of keratoacanthoma (KA). Here, we report a rapid clinical efficacy of two intralesional MTX injections (total dose 40 mg) that were performed 1 week apart in the treatment of a large KA lesion of the dorsal hand in a 99-year-old woman. The lesion, with a 3-cm major axis diameter and a thickness of 2 cm with a central ulceration had rapidly appeared on the right dorsal hand. A 3-mm punch biopsy confirmed the diagnosis of a well-differentiated KA-type spinous cellular carcinoma. Due to the presence of comorbidities (arterial hypertension and atrial fibrillation) and chronic treatment with antihypertensive and oral anticoagulant drugs, treatment with intralesional MTX was proposed to the patient. Two intralesional MTX injections of 20 mg each were performed 1 week apart. A very fast resolution of the lesion was observed after the first injection. A week after the second injection a full resolution of the skin lesion was observed, with a nearly complete resolution of the central ulceration. The treatment was very well tolerated. No local or systemic side effects were observed. This case report confirms that intralesional MTX could be considered an effective and safe treatment of KA also in very old subjects.

Successful Treatment of a Keratoacanthoma with Electrochemotherapy: A Case Report

Introduction

Few studies have evaluated the efficacy of intralesional bleomycin injection combined with electroporation for the treatment of cutaneous tumors. However, the phenomenon that electroporation can enhance the cytotoxicity of bleomycin in vivo by 300–700 fold has been intensely investigated.

Case Presentation

Keratoacanthoma in an 86-year-old patient was treated with intralesional bleomycin combined with electroporation. Treatment consisted of local application of shorty and intense electric pulses followed by local injection of bleomycin. Electroporation was always well tolerated by the patient, with no significant complaints, and the tumor had completely regressed by day 71 of the follow-up.

Conclusion

The results suggest that intralesional bleomycin injection combined with electroporation could represent a valid alternative therapeutic approach for the treatment of keratoacanthomas.

Carcinogenicity assessment of the Hedgehog pathway inhibitor, vismodegib in Tg.rasH2 mice and Sprague-Dawley rats

Vismodegib (also known as GDC-0449) is a novel small molecule inhibitor of the Hedgehog (Hh) signaling pathway currently approved for the treatment of metastatic or locally advanced basal cell carcinoma (BCC) in humans. Its tumorigenic potential was assessed in dedicated carcinogenicity studies in rasH2 transgenic (Tg.rasH2) mice and Sprague Dawley (SD) rats. Tumorigenicity potential of vismodegib was identified in rats only and was limited to benign hair follicle tumors, including pilomatricomas and keratoacanthomas at exposures of ≥0.1-fold and ≥0.6-fold, respectively, of the steady-state exposure (AUC_0-24h) of the recommended human dose. No malignant tumors were identified in either species. Overall, the totality of pharmacology and nonclinical safety data (lack of genotoxicity, in vitro secondary pharmacological binding, and immunoregulatory effects, and limited effects on the endocrine system) suggests that the development of the benign hair follicle tumors may be related to pharmacologically-mediated disruption of hair follicle morphogenesis, although the exact mechanism of tumorigenesis is unclear. Hair follicle tumors have not been reported in vismodegib-treated patients. The relevance of this finding in rats to patients is uncertain.

Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a malignant neoplasm of the skin characterized by an aberrant proliferation of keratinocytes. Cutaneous SCC is the second most common malignancy globally, and usually arises in the chronically sun-damaged skin of elderly white individuals. From a pathologist's perspective, it is important to differentiate cSCC from the benign and reactive squamoproliferative lesions and identify the high-risk features associated with aggressive tumor behavior. In this article, we provide an up-to-date overview of cSCC along with its precursor lesions and important histologic variants, with a particular emphasis on the histopathologic features and molecular pathogenesis.

Expression of PD-L1 in keratoacanthoma and different stages of progression in cutaneous squamous cell carcinoma

BACKGROUND

Programmed cell death 1 (PD-1) and its ligands (PD-L1) play a major role in the immune responses of a variety of cancers.

OBJECTIVES

To investigate the expression of PD-L1 in different progression forms of cutaneous squamous cell carcinoma (cSCC) and keratoacanthoma (KA).

METHODS

We performed immunohistochemical staining of 21 KA, 26 actinic keratoses (AK), 20 Bowen´s diseases (BD), and 26 high-risk cSCC. The staining patterns were assessed using the tumour proportion score and staining intensity evaluation. Immunohistology scores were statistically analysed.

RESULTS

PD-L1 expression of tumour cells as well as tumour-infiltrating cells (TILs) was significantly higher in KA and cSCC when compared to AK and BD (P = 0.00028 and P = 0.00033, respectively). We observed a very strong positive correlation between the PD-L1 protein expression of tumour cells of KA and the PD-L1 protein expression of TILs (r = 0.97; P < 0.0001). A similar correlation was also found for cSCC (r = 0.86; P < 0.0001). The percentage of PD-L1 + tumours was 33.3% for KA and 26.9% for cSCC. Similarly, the percentage of PD-L1 + TILs in KA and cSCC was 33.3 and 34.6%, respectively.

CONCLUSIONS

PD-L1 is differently expressed in cSCC and closely related non-melanoma skin cancer. cSCC exhibit PD-L1 expression in a fourth of cases, indicating that PD1/PD-L1 inhibitors might be beneficial in a proportion of patients with an inoperable or metastatic cSCC. Unlike AK and BD, TILs and tumour cells of KA and cSCC present very similar PD-L1 expression profiles indicating a common immune escape mechanism.

Relationship between Human Papilloma Virus and Subungual Keratoacanthoma: Two Case Reports and the Outcomes of Surgical Treatment

Subungual keratoacanthoma (SUKA) is a rare form of keratoacanthoma, with the majority of the lesions appearing as rapidly growing, painful hyperkeratotic masses located under the distal nail plate of the thumb. In some cases, SUKA causes damage to the underlying bone. The first case presented here was treated by surgical excision alone, and human papilloma virus (HPV) type 6 was detected in the tissue samples. The second case was treated by surgical excision plus curettage; however, HPV was not detected, and tumor cells were not found in the curettage material. There was near complete improvement in both the clinical appearance and the distal phalanx destruction, with no recurrence at the final follow-up in either patient (30 and 14 months, respectively). Overall, simple excision alone or in combination with curettage seemed to be sufficient in the treatment of SUKA; however, the etiopathogenetic role of HPV in SUKA remains controversial, as in its classical form.

Late-Onset Multiple Self-Healing Squamous Epithelioma Ferguson-Smith Recurrence Induced by Radiotherapy

We report the case of a woman in her 60s with confirmed multiple self-healing squamous epitheliomas (MSSE) Ferguson-Smith. After recurrences following surgery and radiotherapy, the patient was successfully treated with minimal surgical intervention combined with intralesional injections of triamcinolone acetate. The histological comparison between mature and regressed keratoacanthomas (KA) revealed an increased inflammatory infiltrate with numerous plasmacytoid dendritic cells in the regressed KA in comparison to the mature one, speaking in favor of an inflammation-mediated regression process. Corticosteroids injection in MSSE may have paradoxical effects with action on the proliferation phase rather than the inflammatory regression phase of the KA. Our case confirms previous reports showing that radiotherapy may exacerbate MSSE and should be avoided. Intralesional triamcinolone acetate injection is a safe and easy to use method also effective for multiple lesions. Our case underlines the difference between squamous cell carcinoma and KA, responding differently to therapies like imiquimod or radiotherapy.

Frequent detection of human polyomavirus 6 in keratoacanthomas

BACKGROUND

The recent discovery of the Merkel cell polyomavirus and its consistent association with Merkel cell carcinoma has drawn attention to the numerous recently discovered polyomaviruses and their possible involvement in the etiopathogenesis of non-melanoma skin cancer (NMSC). Data on the recently discovered human polyomavirus 6 (HPyV6) and its role in NMSC are sparse and in part controversial.

METHODS

In the present study we tested a large number (n = 299) of NMSC specimens for the presence of human polyomavirus 6 (HPyV6) by DNA PCR and HPyV6 fluorescence in situ hybridization (FISH). In detail, 59 keratoacanthomas (KA), 109 basal cell carcinomas (BCC), 86 squamous cell carcinomas (SCC) and 45 trichoblastomas (TB) were tested for the presence of HPyV6.

RESULTS

HPyV6 DNA PCR and subsequent sequence analysis revealed that 25 KAs (42.3 %), 23 BCCs (21.1 %), 8 SCCs (9.3 %) and 10 TBs (22.2 %) were HPyV6 positive. The presence of HPyV6 DNA was visualized and validated on the single cell level within the histomorphological context by HPyV6 fluorescence in situ hybridization.

CONCLUSIONS

The high frequency of HPyV6 DNA in 42.3 % of KA possibly points to a role for HPyV6 in the etiopathogenesis of KAs. Although the detection rate of HPyV6 DNA in BCCs and TBs is within the previously reported detection range in normal skin, it does not exclude a possible role for HPyV6 in the carcinogenesis in a significant subset of these skin tumors.

Penis keratoacanthoma transforming into squamous cell carcinoma: a rare case

Keratoacanthoma is variously regarded as a benign epithelial tumor, characterized by a rapid-growing and solitary flesh-colored nodule with a central keratin plug on the sun-exposed skin. Under certain circumstances, it can transform into squamous cell carcinoma. In this paper, we present a case of a 50-year-old man with a 2.5 × 3 × 2.2 cm mass on his penis stub-end. The patient was treat with a partial penectomy after further expert discussions and histopathology the lesion demonstrated penis keratoacanthoma. He received a partial penectomy again and the pathological result revealed squamous cell carcinoma this time. This case indicates that undergoing a partial penectomy on initial diagnosis of a penile tumor secondary to penile keratoacanthoma should be considered because of its high malignant potency. To our best knowledge, this is the first study to describe the malignant conversion of penis keratoacanthoma.

Pseudoepitheliomatous Hyperplasia: Relevance in Oral Pathology

Pseudoepitheliomatous hyperplasia (PEH), a neglected entity by oral pathologist possesses utmost importance in the field of research. Of all the investigative challenges, PEH, a reactive epithelial proliferation is seen secondary to lesions with infectious, inflammatory, reactive, and degenerative origin. Small sized samples, incomplete excision, improper orientation, and dense inflammatory changes render diagnostic confront to the oral pathologist in exclusion of frankly invasive malignant lesions like squamous cell carcinoma from lesions exhibiting PEH. The diagnosis can occasionally be difficult as they mimic other lesions also, on clinic-pathological assessment. Thus, this article gives an insight regarding the various concepts of etiopathogenesis, histopathology, differential diagnosis, and malignant potential of PEH. A combined effort of a clinician and pathologist benefits every patient to rule out malignancy and render appropriate treatment as the only local conservative approach is essential to remove PEH associated lesions.

A clinical, histopathological and immunohistochemical approach to the bewildering diagnosis of keratoacanthoma

Keratoacanthoma (KA) is a comparatively common low-grade tumor that initiates in the pilo-sebaceous glands and pathologically mimics squamous cell carcinoma (SCC). Essentially, strong debates confirm classifying keratoacanthoma as a variant of invasive SCC. The clinical behavior of KA is hardly predictable and the differential diagnosis of keratoacanthoma and other conditions with keratoacanthoma-like pseudocarcinomatous epithelial hyperplasia is challenging, both clinically and histopathologically. This article aims to illustrate and explicate some of these complicated issues by presenting two cases of KA and a relevant review of literature. It also targets the clinical, histopathologic, and immuno-histochemical features of these two cases. Both presented lesions of this study had appeared on the vermilion border of the lower lip and no vascular or perineural invasion was observed. The results of the immuno-histochemical survey, particularly in staining with marker CD30, confirmed the differential diagnosis of keratoacanthoma from keratoacanthoma-like pseudocarcinomatous proliferations which was consequent to the CD30(+) lymphoid infiltration. Histopathological and immunohistochemical investigation is necessary to disprove the invasive biologic behavior of keratoacanthoma and also to refute all conditions with keratoacanthoma-like pseudocarcinomatous epithelial hyperplasia.

Keratoacanthoma accompanied by multiple lung squamous cell carcinomas developing in a renal transplant recipient

Keratoacanthoma (KA) is a benign keratinocytic neoplasm that spontaneously regresses after 3–6 months and shares features with well-differentiated squamous cell carcinoma (SCC). An increased incidence of both KA and non-melanoma skin tumor, including SCC, is seen among immunosuppressed, organ-transplant recipients. In this report we describe a case of KA accompanied by multiple lung SCCs developing in a renal transplant recipient.

Pattern of TGFbeta receptor 1 expression differs between kras-mutated keratoacanthomas and squamous cell carcinomas of the skin

PURPOSE

Increasing evidence indicates that TGFbeta- and EGFR-signaling is involved in the pathogenesis of keratoacanthoma (KA) and squamous cell carcinoma (SCC) of the skin. We analyzed the expression pattern of TGFbeta-signaling components and screened for mutations in tgfbetaR1, egfr, kras and braf in KAs and SCCs.

METHODS

Immunohistochemical analysis of TGFbeta1, TGFbetaR1, TGFbetaR2 and phospho-SMAD2/3 was performed on skin tumors (29 KAs, 30 well and 31 moderately differentiated SCCs). Mutation screening in hotspot regions of tgfbetaR1, egfr, kras and braf was performed through pyrosequencing of tumor DNA.

FINDINGS

Expression of TGFbeta1, TGFbetaR1 and p-SMAD2/3 was increased in tumors as compared to surrounding skin. In KAs characteristic strong discontinuous membranous TGFbetaR1 expression pattern frequently associated with kras mutation was noted. SCCs showed continuous TGFbetaR1 expression, stronger p-SMAD2/3 expression and less frequent kras mutations. In tumors at sun-exposed sites stronger TGFbetaR1 expression was noted. One SCC showed tgfbetaR1 mutation, but no other mutations were found.

CONCLUSION

Although tgfbetaR1 germline mutations cause inherited KAs and our finding of strong discontinuous membranous expression in KAs suggests accumulation of functionally altered protein, we found no tgfbetaR1 mutations or influence on TGFbeta-signaling, but frequent kras mutations in this subgroup of KAs. Characteristic TGFbetaR1 expression pattern in KA can facilitate histopathologic distinction from SCC.

Intralesional methotrexate for the treatment of keratoacanthoma: retrospective study and review of the korean literature

Background

Although intralesional methotrexate (MTX) is an effective, nonsurgical treatment of keratoacanthoma (KA), there have not been many reports of on the MTX treatment for KA in Korea.

Objective

The purpose of this study was to evaluate the clinical efficacy of the intralesional MTX for the treatment of KA in Korean patients.

Methods

We retrospectively studied seven patients with KA who received intralesional injection of MTX in our department. The efficacy was evaluated based on the physician assessment. Our review also included the cases of KA treated with intralesional MTX in Korean patients from the previous reports. We then analyzed the therapeutic regimens in the Korean patients by comparing them with the Caucasian patients.

Results

We identified 11 cases of Korean KA patients treated with an intralesional MTX, including seven from our institution and four from the Korean literature. Ten of the 11 patients (91%) showed a complete resolution with an intralesional MTX. No adverse events were observed during the treatment and the follow-up periods. No recurrence was found during the follow-up. In therapeutic analysis, the Korean patients required 2 to 7 injections (mean 4.6 injections) to achieve a tumor resolution with the mean time to clearing at 7.6 weeks.

Conclusion

Intralesional MTX can be an effective and safe non-operative treatment modality for most Koreans with KA.