Malignant onychopapilloma

Clinical, onychoscopic, nail clipping, and histopathological findings of malignant onychopapilloma

This report describes the clinical, onychoscopic, nail clipping, and histopathologic features of a malignant onychopapilloma. A 71-year-old male presented to our outpatient clinic for a stable, asymptomatic lesion on his left middle finger that had been present for 2 years. Prior nail clipping histopathology showed nail plate thinning with subungual abnormal onychocytes. Clinical examination revealed a 2-mm-wide streak of longitudinal xanthonychia extending to the proximal nail fold, with distal hyperkeratosis and onycholysis. Onychoscopy showed irregular longitudinal nail plate ridging with scattered punctate hemorrhagic foci. An excisional nail unit biopsy demonstrated cellular atypia of the nail bed epithelium, matrix metaplasia, longitudinal abnormal onychocytes, increased Ki-67 staining, and negative HPV immunoperoxidase staining, confirming the diagnosis of malignant onychopapilloma.

Diagnosis and management of longitudinal erythronychia: A clinical review by an expert panel

Longitudinal erythronychia (LE) is defined as a longitudinal red band of the nail(s) and is classified as localized (involvement of 1 nail) or polydactylous (involvement of more than 1 nail). The differential diagnosis is distinct for these classifications. The etiologies of localized longitudinal erythronychia are most frequently benign subungual neoplasms and less often malignancies. Polydactylous longitudinal erythronychia is typically secondary to regional or systemic diseases, including lichen planus and Darier disease. LE is a common but underrecognized clinical finding. Increased dermatologist awareness of the clinical characteristics and differential diagnosis for LE is necessary given the possibility for malignancy and associated systemic disease. In this clinical review, the clinical features, differential diagnosis, evaluation, and management of LE are described.

Three atypical/malignant onychopapillomas in a 52-case series with immunohistochemical study

BACKGROUND

Onychopapilloma (OP) is a benign tumor of the nail. Haneke reported one case of malignant OP in 2021. No systematic immunohistochemistry study has been conducted on OP. The aim of our study was to identify possible malignant OP in our series of OP and to describe the immunohistochemical expression of p16, p53, and Ki67 in typical and atypical/malignant ones.

METHODS

Ninety-one cases were available for pathological review. Immunohistochemical analysis could be performed on 52 cases.

RESULTS

In 88 of 91 cases, the diagnosis of OP was confirmed. Three atypical/malignant cases were observed. No OP expressed p16. A normal p53 expression was observed in two thirds of the cases, an abnormal increased p53 expression in one third, including the three atypical cases. A normal Ki67 expression was observed in 84% of the cases, an abnormal Ki67 expression with focal heterogeneous expression in the suprabasal layers in 6% and in all suprabasal cell layers in 10%, including the three atypical cases.

CONCLUSIONS

The diagnosis of atypical/malignant OP may be underestimated. The expression of Ki67 and p53 in these tumors differs from the expression observed in conventional OP. The absence of p16 expression confirms that human papillomavirus does not play a role in the etiopathogenesis of OP.

Ultrasound imaging of onychopapilloma: Evaluation of 43 cases

INTRODUCTION

Onychopapilloma is a benign tumor presenting as an isolated benign warty distal matrix and bed lesion in association with longitudinal erythronychia for which no underlying cause can be identified. Diagnosis might be challenging due to other, more severe, causes of erythronychia.

OBJECTIVES

This study aimed to investigate the clinical and sonographic features of onychopapilloma using high-frequency ultrasound.

METHODS

Between February 2022 and May 2023, a cross-sectional study was conducted, involving 39 patients displaying clinical features suggestive of onychopapilloma. These patients were selected at random and underwent examination using high-frequency ultrasound. High-frequency ultrasound assessments of the nail unit were carried out using 33 MHz and 24 MHz high-frequency linear transducers. An experienced radiologist performed the ultrasound scans while participants assumed an orthostatic seated position. Subsequently, the collected ultrasound images were independently evaluated by two radiologists specializing in nail injuries, ensuring a blinded assessment. This evaluation aimed to provide comprehensive insights into the imaging characteristics of onychopapilloma.

RESULTS

High-frequency ultrasound revealed oval or linear hyperechoic masses located in the middle of the nail plate, without vascularity or posterior acoustic shadowing. Nail plate irregularity, thickening, and nail bed indentation were observed in some cases. These findings demonstrate that high-frequency ultrasound can aid in the diagnosis and surgical planning of onychopapilloma, providing detailed visualization of the lesion and surrounding structures.

CONCLUSIONS

This imaging method could represent a potential tool to differentiate onychopapilloma from other nail conditions, especially malignant neoplasms. However, further research is needed to validate these findings and assess long-term outcomes.

Ultrasound Features of Onychopapilloma at High-Frequency and Ultra-High Frequency

OBJECTIVE

This study aimed to identify the sonographic features of pathologically confirmed onychopapilloma cases.

METHODS

High-frequency up to 24 MHz and ultra-high frequency-ultrasound up to 71 MHz examinations were performed and correlated with their clinical and pathologic presentations.

RESULTS

Twenty-two cases met the criteria. Clinical presentations revealed longitudinal erythronychia in 63.3% of cases. The ultrasound examinations identified a hypoechoic band in the nail bed (86.3%), nail plate abnormalities including upward displacement (68.2%) and thickening (68.1%), focal hyperechoic focal spots on the nail plate (50%) and irregularities of the ventral plate (33.3%). Color Doppler imaging showed no hypervascularity of the nail bed in all studies. These findings correlate with histological characteristics of onychopapilloma, including nail bed acanthosis, papillomatosis, and layered hyperkeratosis. Recurrence occurred in two cases after surgery, with tumors showing proximal extension in the matrix region on ultrasound not evident during clinical examination.

CONCLUSION

High-frequency and ultra-high-frequency can provide anatomical information in onychopapilloma that could enhance understanding and management.

Basic Concepts in Nail Pathology

ABSTRACT

Understanding nail pathology is complex for general pathologists and even for those dermatopathologists who do not receive many nail samples in their laboratories. In this article, we attempt to review some of the primary entities in nail pathology with the aid of modern interpretations of nail histology and embryology. We also provide diagrams that can aid in comprehending this field of pathology.

Update on nail unit histopathology

Histopathologic evaluation of the nail unit is an essential component in the diagnosis of nail unit disorders. This review highlights recent updates in nail unit histopathology and discusses literature covering a wide range of nail disorders including melanoma/melanocytic lesions, squamous cell carcinoma, onychomatricoma, onychopapilloma, onychomycosis, lichen planus, and other inflammatory conditions. Herein we also discuss recent literature on nail clipping histopathology, a useful and noninvasive diagnostic tool that continues to grow in popularity and importance to both dermatologists and dermatopathologists.

Diagnosis and surgical treatment of benign nail unit tumors

Little is known about benign non-melanocytic nail tumors, probably due to their low pathogenicity. They are commonly misdiagnosed as inflammatory or infective diseases. They have various features, depending on the type of tumor and its location in the nail apparatus. The typical sign of a tumor is the presence of a mass and/or secondary nail changes from damaged nail structures. In particular, if a single digit is affected by a dystrophic sign or a symptom is reported without any explanation, the presence of a tumor should always be ruled out. Dermatoscopy helps to enhance visualization of the condition and in many cases supports the diagnosis. It may also assist in identifying the right place to biopsy, but it never replaces surgery. Most common non-melanocytic nail tumors are analyzed in this paper, including glomus tumor, exostosis, myxoid pseudocyst, acquired fibrokeratoma, onychopapilloma, onychomatricoma, superficial acral fibromyxoma and subungual keratoacanthoma. The aim of our study is to review the main clinical and dermatoscopic characteristics of the most common benign non-melanocytic nail tumors, to correlate them with the histopathology and to advise practitioners of the best surgical management.

Clinical and histopathological features of onychopapilloma in an Australian setting: A case series of 50 patients

Onychopapilloma is an uncommon tumour of the nailbed and the distal nail matrix. To date, only 19 case reports and case series have been reported in the literature. This article includes literature review on all reported cases and provides the first case series of onychopapilloma in an Australian population, evaluating the clinical features and histopathological diagnosis of patients with onychopapilloma in an Australian subspecialty nail clinic.

Clinical and onychoscopic features of histopathologically proven onychopapillomas and literature update

BACKGROUND

Onychopapilloma is a benign tumor of the distal nail matrix and proximal nail bed with heterogeneous clinical presentations. It poses a diagnostic challenge because it could mimic subungual malignancies and inflammatory conditions. Clinical, onychoscopic, and histopathological clues play critical roles in diagnosis.

METHODS

We performed a retrospective chart review of onychopapilloma cases collected over 10 years, and characterized the clinical, onychoscopic, and histopathological features of onychopapilloma at an academic institution.

RESULTS

We obtained 17 biopsy-confirmed cases of onychopapilloma. Among our cases, we found manifestation of onychopapilloma as longitudinal erythronychia, longitudinal leukonychia, yellow-brown chromonychia, and longitudinal melanonychia. Long longitudinal or short splinter hemorrhages may be present. Distal fissuring with V-shaped notch, subungual keratotic mass, and onycholysis are other discernable features. Histopathological features include papillomatosis, epidermal hyperplasia, acanthosis of the distal nail bed, premature keratinization, matrix metaplasia, hyperkeratosis, and splinter hemorrhages; histopathological signs of malignancy were not observed in any of our cases.

CONCLUSIONS

Onychopapilloma has polymorphic clinical and morphological features. Onychoscopic and histopathological studies are important to help exclude malignant mimickers. Consider onychopapilloma in the differential diagnoses of a monodactylous longitudinal streak in the nail, especially on the left thumb of an adult female.