Onychocytic Matricoma: A Clinical, Dermoscopic, and Pathological Analysis of 14 Cases.

ABSTRACT: Onychocytic matricoma (OCM) is a benign neoplasm of the nail matrix. Only 18 cases of this tumor have been reported in the literature to date. We retrospectively analyzed the clinical features of 14 patients with OCM. The most common clinical feature was longitudinal xanthopachyonychia (n = 9), followed by longitudinal leukopachyonychia (=3) and longitudinal pachymelanonychia (n = 2). The most common clinical findings identified following dermoscopy and analysis at high magnification of classical photographs were free-edge thickening of the nail plate without pitting (n = 14), longitudinal ridging (n = 7), round white clods (n = 7), white dots (n = 7), and filiform hemorrhages (n = 7), followed by oval and linear white clods (n = 5), fuzzy lateral border (n = 5), and red-purple blood clods (n = 3). Nail clipping histopathology showed a thickened nail plate with multiple, small, round-to-oval spaces. The tumor expressed immunopositivity for LEF-1. Dermoscopy of the nail plate and nail clipping histology provides useful information with regards to the differential diagnosis with subungual squamous cell carcinoma and nail melanoma. Ex vivo-in vivo correlation facilitates a better dermoscopic assessment of this unique underrecognized disease. However, the differential diagnosis between OCM and onychocytic carcinoma requires biopsy of the tumor. LEF-1 as an onychogenic marker can be used to resolve the differential diagnosis between OCM and subungual longitudinal acanthoma/seborrheic keratosis.

Tumor of follicular infundibulum - reappraisal in a series of 28 patients with critical review of the literature.

BACKGROUND AND OBJECTIVES: Tumor of follicular infundibulum (TFI) has been described as a neoplasm - isolated and multiple - and in association with other lesions. Its histopathologic definition is controversial. PATIENTS AND METHODS: We present a histopathologically analyzed series of 28 patients with TFI features. This has been supplemented by a search in MEDLINE on the literature on this subject. The corresponding figures given in these articles have been discussed and analyzed. RESULTS: Patients comprised 16 women and twelve men. TFI features were seen in five patients with nevus sebaceous, two trichofolliculomas, one dilated pore Winer, eight viral warts, one dermatofibroma, six seborrheic keratoses, three actinic keratoses, one invasive squamous cell carcinoma, and one basal cell carcinoma in association with a squamous cell carcinoma/actinic keratosis. After study of the literature especially of solitary cases of TFI, we interpret such cases mostly as variants of seborrheic keratoses with variable degree of infundibular, isthmic and/or sebaceous differentiation with or without regression. CONCLUSIONS: We regard TFI as an epithelial growth pattern which may occur in hamartomatous, inflammatory, infectious, reactive, or neoplastic conditions, in most solitary forms likely best classified within the histopathological spectrum of seborrheic keratoses.

Acantoma de células claras. Estudio clínico de 70 pacientes / Clear Cell Acanthoma: A Series of 70 Cases

Antecedentes y objetivo El acantoma de células claras (ACC) es una lesión poco frecuente caracterizada histológicamente por la presencia de acantosis epidérmica a expensas de queratinocitos de citoplasma claro. Aunque se han descrito muchos casos clínicos de forma individual, se han publicado pocas series de pacientes con ACC. Nuestro objetivo fue analizar las características clínicas del ACC en nuestra población. Material y métodos Estudio retrospectivo de los pacientes con ACC diagnosticados en el Hospital Universitario de Bellvitge en Barcelona, España, entre 1995-2021. Se revisaron las historias clínicas para obtener los siguientes datos: edad, sexo, localización, número de lesiones, diámetro, tiempo de evolución, características clínicas de los tumores, diagnóstico clínico de sospecha y el tratamiento realizado Resultados Setenta pacientes con ACC fueron incluidos en el estudio (30 mujeres y 40 varones, edad media 62 años, DE 13). La mediana del tiempo de evolución fue de dos años, rango intercuartílico (RIQ) 4 y la del diámetro 6 mm, RIQ 5. Una paciente presentó lesiones múltiples. Las lesiones se localizaron en las extremidades inferiores en 57 pacientes (81%), en la cara posterior del tronco en ocho (11%), la cara anterior del tronco en cuatro (5%) y en las extremidades superiores en uno (1%). Se planteó el diagnóstico clínico de ACC en 40% de los pacientes atendidos por dermatólogos. Conclusiones El aspecto clínico característico del ACC es el de una lesión cupuliforme eritematosa con punteado vascular y collarete epidérmico. La proporción de ACC diagnosticados clínicamente ha mejorado respecto a series antiguas, quizás por un mayor conocimiento clínico de la entidad y un mayor uso de la dermatoscopia (AU)

Background and objective Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. Material and methods Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. Results Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5) mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. Conclusions CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy (AU)

[Translated article] Clear Cell Acanthoma: A Series of 70 Cases / Acantoma de células claras. Estudio clínico de 70 pacientes

Background and objective Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. Material and methods Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. Results Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5)mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. Conclusions CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy (AU)

Antecedentes y objetivo El acantoma de células claras (ACC) es una lesión poco frecuente caracterizada histológicamente por la presencia de acantosis epidérmica a expensas de queratinocitos de citoplasma claro. Aunque se han descrito muchos casos clínicos de forma individual, se han publicado pocas series de pacientes con ACC. Nuestro objetivo fue analizar las características clínicas del ACC en nuestra población. Material y métodos Estudio retrospectivo de los pacientes con ACC diagnosticados en el Hospital Universitario de Bellvitge en Barcelona, España, entre 1995-2021. Se revisaron las historias clínicas para obtener los siguientes datos: edad, sexo, localización, número de lesiones, diámetro, tiempo de evolución, características clínicas de los tumores, diagnóstico clínico de sospecha y tratamiento realizado. Resultados Setenta pacientes con ACC fueron incluidos en el estudio (30 mujeres y 40 varones, edad media: 62 años, DE: 13). La mediana del tiempo de evolución fue de 2 años, rango intercuartílico (RIQ): 4 y la del diámetro 6mm, RIQ: 5. Una paciente presentó lesiones múltiples. Las lesiones se localizaron en las extremidades inferiores en 57 pacientes (81%), en la cara posterior del tronco en 8 pacientes (11%), la cara anterior del tronco en 4 pacientes (5%) y en las extremidades superiores en un paciente (1%). Se planteó el diagnóstico clínico de ACC en el 40% de los pacientes atendidos por dermatólogos. Conclusiones El aspecto clínico característico del ACC es el de una lesión cupuliforme eritematosa con punteado vascular y collarete epidérmico. La proporción de ACC diagnosticados clínicamente ha mejorado respecto a series antiguas, quizás por un mayor conocimiento clínico de la entidad y un mayor uso de la dermatoscopia (AU)

Clear Cell Acanthoma: A Series of 70 Cases. / Acantoma de células claras. Estudio clínico de 70 pacientes.

BACKGROUND AND OBJECTIVE: Clear cell acanthoma (CCA) is an uncommon lesion histologically characterized by the presence of epidermal acanthosis with keratinocytes containing clear cytoplasm. Although many single cases of CCA have been described, few case series have been published. The aim of this study was to describe the clinical characteristics of CCA in our practice setting. MATERIAL AND METHODS: Retrospective study of patients diagnosed with CCA at Hospital Universitario de Bellvitge in Barcelona, Spain, between 1995 and 2021. We conducted a chart review to record age, sex, number and location of lesions, diameter, time since onset, clinical characteristics, suspected clinical diagnosis, and treatment. RESULTS: Seventy patients (30 women and 40 men) with a mean (SD) age of 62 (13) years were diagnosed with CCA during the study period. Median (interquartile range) time since onset was 2 (4) years and median lesion diameter was 6 (5) mm. One woman had multiple lesions. Lesions were located on the lower extremities in 57 patients (81%), the posterior aspect of the trunk in 8 (11%), the anterior aspect of the trunk in 4 (5%), and the upper extremities in 1 (1%). CCA was clinically suspected in 40% of patients seen by dermatologists. CONCLUSIONS: CCA presents as an erythematous, dome-shaped lesion with pinpoint vessels and an epidermal collarette. The accuracy of clinical diagnosis has improved relative to earlier series, possibly due to a better clinical understanding of this lesion and a greater use of dermoscopy.

Diagnostic utility of SOX10 immunostaining in benign lichenoid keratosis: A study of 21 cases.

BACKGROUND: Benign lichenoid keratosis (BLK) is a cutaneous lesion that can clinically mimic malignancy and may represent regression of a pre-existing lesion. BLK may show epidermal pseudo-nests prompting evaluation for a melanocytic lesion. False positivity of MART-1/Melan-A immunostaining in pseudonests has been showed; however, the value of SRY-related HMG-box 10 (SOX10) staining in BLK with features suspicious for a melanocytic proliferation has not been previously reported. METHODS: Twenty-one cases of BLK from 2015 to 2020 were identified. Slides were reviewed and SOX10 immunohistochemistry was performed on each case. Subsequently, Melan-A immunohistochemical staining was performed on all cases. RESULTS: In 10 cases (47.6%), unexpected SOX10 staining was seen in rare to numerous small, single cells in the epidermis above the basal cell layer. No malignancy was identified. Of the 10 cases, 8 (80%) showed suprabasal SOX10 staining did not show similar suprabasal Melan-A staining; 2 (20%) cases showed scattered suprabasal cells positive for Melan-A. CONCLUSION: SOX10 immunostaining in BLK can highlight scattered cells in the epidermis (not easily noticeable on routine stain). Performing SOX10 immunostain alone on BLK can prompt a misdiagnosis of a melanocytic lesion and should be done with caution.

Condyloma and coincidental epidermodysplasia verruciformis acanthoma positive for human papillomavirus-14 and -21.

Epidermodysplasia verruciformis (EDV) is a rare genodermatosis that predisposes individuals to persistent infection with ß-human papillomavirus (HPV) genotypes. The term EDV acanthoma may be applied to lesions with incidental findings of EDV-defining histopathological features without clinical signs of EDV. We report a case of HPV-14- and -21-positive EDV acanthoma arising in association with condyloma in a female patient with a history of low-grade squamous intraepithelial lesion of the cervix positive for high-risk HPV (non-16/18), chronic kidney disease, and systemic lupus erythematosus. The patient had no family or personal history of EDV, but the patient was on immunosuppressive therapy with mycophenolate mofetil and prednisone. A biopsy specimen from one of the perianal lesions revealed histopathologic changes consistent with EDV in the setting of condyloma. Molecular testing showed HPV-14 and -21, which supported the coexistence of condyloma with EDV acanthoma.

A conscious minimally invasive approach to remove follicular cysts and infundibular keratinizing acanthomas in five dogs.

Follicular cysts and infundibular keratinizing acanthomas are common benign cutaneous lesions in dogs. Current treatment options include surgical excision under general anaesthesia, cryotherapy, carbon dioxide laser and retinoids, each with potential disadvantages. We describe a conscious, minimally invasive, surgical excision procedure with high success rate and no complications in five dogs.

Les kystes folliculaires et les acanthomes kératinisant infundibulaires sont des lésions cutanées bénignes fréquentes chez le chien. Les options de traitement actuelles comprennent l'exérèse chirurgicale sous anesthésie générale, la cryothérapie, le laser au dioxyde de carbone et les rétinoïdes, chacun présentant des inconvénients potentiels. Nous décrivons une procédure d'exérèse chirurgicale consciente, peu invasive, avec un taux de réussite élevé et aucune complication chez cinq chiens.

Los quistes foliculares y los acantomas queratinizantes infundibulares son lesiones cutáneas benignas comunes en perros. Las opciones de tratamiento actuales incluyen la escisión quirúrgica bajo anestesia general, crioterapia, láser de dióxido de carbono y retinoides, cada uno con posibles desventajas. Describimos un procedimiento de escisión quirúrgica consciente, mínimamente invasivo, con una alta tasa de éxito y sin complicaciones en cinco perros.

Cistos foliculares e acantomas infundibulares queratinizantes são lesões cutâneas benignas em cães. As opções terapêuticas existentes atualmente são excisão cirúrgica sob anestesia geral, crioterapia, laser de dióxido de carbono e retinoides, cada um com desvantagens potenciais. Nós descrevemos aqui um procedimento de excisão cirúrgica minimamente invasivo, consciente, com um grande potencial de sucesso e sem complicações em cinco cães.

Follicular Porokeratoma: Report of a New Variant of Porokeratoma (Porokeratotic Acanthoma) and Literature Review.

ABSTRACT: Porokeratoma is a rare type of epidermal acanthoma, of which 22 cases have been published in the literature. It is characterized by the presence of multiple cornoid lamellae embedded within a single verrucous or keratotic nodule. Despite this histologic feature being shared with porokeratosis, the etiopathogenesis of porokeratoma and its relationship with porokeratosis remain unclear. We report a new case of porokeratoma involving hair follicles, a finding that has been reported in only one of the previously published cases. Analogous to follicular porokeratosis, a form of porokeratosis involving hair follicles, we have termed this lesion "follicular porokeratoma." A review of all 23 published cases (including the present case) is also provided.

Dermoscopic findings and histopathological correlation in large cell acanthoma.

Since large cell acanthoma (LCA) has many overlapping clinical and histopathological features with other epidermal pigmented tumours, an additional method to differentiate it would be of great clinical significance. A retrospective study was performed on 33 lesions (26 patients) to identify distinct dermoscopic findings of LCA and to describe dermoscopic-histopathological correlations. The results revealed that dermoscopy significantly aids in the distinction of LCA from other epidermal tumours included in the differential diagnosis. Yellow opaque homogeneous background, brown dots, and moth-eaten border are common findings, and prominent skin markings and short white streaks are additional distinguishing features. Several important findings that are common in other diseases are rare in LCA.

Update from the 5th Edition of the World Health Organization Classification of Head and Neck Tumors: Tumours of the Oral Cavity and Mobile Tongue.

The fifth chapter of the upcoming fifth edition of the 2022 World Health Organization Classification of Tumours of the Head and Neck titled Tumours of the oral cavity and mobile tongue, has had some modifications from the 2017 fourth edition. A new section "Non-neoplastic Lesions", introduces two new entries: necrotizing sialometaplasia and melanoacanthoma. The combined Oral potentially malignant disorders and Oral epithelial dysplasia section in the 2015 WHO has now been separated and submucous fibrosis and HPV-associated dysplasia are also discussed in separate sections. Carcinoma cuniculatum and verrucous carcinoma are described in dedicated sections, reflecting that the oral cavity is the most common location in the head and neck for both these entities which have distinct clinical and histologic features from conventional squamous cell carcinoma. This review summarizes the changes in Chapter 5 with special reference to new additions, deletions, and sections that reflect current clinical, histological, and molecular advances.

Multiple eruptive clear cell acanthomas successfully treated with CO2 laser ablation.

Clear cell acanthoma (CCA) is a rare, benign epidermal lesion of clear glycogen-containing keratinocytes. The exact etiology is unknown. Although CCA usually appear as solitary lesions, cases of multiple CCAs have also been described. The rare eruptive CCA variant describes cases with more than 30 lesions.Current therapeutic evidence for the management of multiple CCAs is limited. CO2 laser remains the most widely used laser in clinical practice. However, literature describing its effectiveness on CCA is sparse, and previous reports have described its use for a maximum of three lesions. To our knowledge, this is the first report of successful CO2 laser treatment of the multiple eruptive CCA variant with an excellent cosmetic outcome.Our case adds to the evidence that CO2 laser is an effective treatment for this condition. Particularly in those patients with refractory or multiple eruptive CCAs, or for those who may not tolerate repeated courses of cryotherapy, or who are concerned about scarring and cosmetic outcome.

Comparative study of treatment methods for benign lichenoid keratosis of the face.

Benign lichenoid keratosis is one of the most common skin lesions that develop on the faces of middle-aged women. This study aimed to find an effective treatment method for benign lichenoid keratosis. A total of 49 patients, who had a positive diagnosis during 2010-2018, were enrolled in the study. An Investigator's Global Assessment of the lesion was done using the 5-point visual analog scale to evaluate treatment efficacy. After excluding subjects who did not have a follow-up photograph, 38 subjects were given an Investigator's Global Assessment score. Combination therapy using laser and a topical agent was useful in the management of benign lichenoid keratosis on the face. Ablative laser was effective for immediate improvement of the lesion, whereas non-ablative laser was also useful and showed several benefits over ablative laser. Optimal treatment should be decided after considering the patient's preference, compliance with treatment regimen, and skin type.

Pilomatrical Acanthoma: An Extremely Rare Intraepidermal Variant of Pilomatricoma.

ABSTRACT: Pilomatrical differentiation can be observed in a variety of benign and malignant tumors, with the most common prototype being pilomatricoma. Pilomatricoma often presents in the deep dermis or subcutis, and the sole involvement of epidermis is extremely rare. In our current case series, specimens from 5 patients were included with an average age of 68 years. All lesions presented as solitary verrucous or keratotic papules on the extremities, with 1 lesion having a prominent horn. All lesions have a variable mixture of basaloid matrical cells and shadow cells, and all lesions express ß-catenin (strong nuclear and cytoplasmic), lymphoid enhancer-binding factor 1 within the matrical component, and pleckstrin homology-like domain family A member 1. The histomorphology and immunoprofile of all lesions are of pilomatrical differentiation, confined to the level of the epidermis. Based on these findings and analogous to the terminology used for other benign intraepidermal proliferations (hidroacanthoma simplex and epidermolytic acanthoma), we propose the term "pilomatrical acanthoma" for these rare lesions.