Clear Cell Acanthoma/Pseudolymphoma: Clinical­ Dermatoscopic and Histological Correlation

Abstract

Introduction. Skin tumors make up the largest group due to the complex structure of this organ. Benign skin tumors are one of the most common pathologies that occupy an intermediate position at the interface of dermatol­ ogy, oncology and surgery, and their timely diagnosis and removal are important not only for these three specialties, but also for the general medical network. Differential diagnosis of such tumors is still an urgent problem, and a variety of diagnostic methods does not solve the problem. Today, the most affordable method of optical diagnostics of the skin is dermatoscopy, the non­invasiveness and simplicity of which made it indispensable in modern practice. The article describes dermatoscopic characteristics and their correlation with the data of pathomorphological stud­ ies in two cases from our own practice ­ clear cell acanthoma and pseudolymphoma. Both of these tumors are rare, benign, and present certain difficulties for diagnosis. The aim of the study. Analysis of available literature and the description of clinical cases from own practice. Мaterials and methods. Content analysis, method of system and comparative analysis, bibliosemantic method of studying of relevant scientific research were used. The search for sources was carried out in scientometric med­ ical information bases: PubMed­NCBI, Medline, CochraneLibrary, EMBASE, ResearchGate in accordance with the keywords: clear cell acanthoma, pseudolymphoma, dermatoscopy. Digital dermatoscopy images were obtained using a dermatoscope (DermLite DL3 dermatoscope) attached to a digital camera (Galaxy S­4 Samsung Corpora­ tion). For the immersion dermatoscopy ultrasound gel was used. All obtained images were estimated in accordance with the algorithm of G. Kittler. Results. Clear cell acanthoma is a rare benign epithelial tumor with unclear etiology. It is believed that the basis of its development is an impaired keratinocyte maturation. Some authors do not refer it to tumors, but consider that this is a local hyperplastic process. Clear cell acanthoma often develops in the elderly as a single node up to 2 cm in diam­ eter, usually found on the lower extremities, most commonly on the legs. Differential diagnosis should be carried out with dermatofibroma, lichenoid keratosis, basalioma, pyogenic granuloma. Differential diagnosis with irritated sebor­ rheic keratosis and non­pigmented melanoma is difficult. Dermatoscopic examination can be insufficient, the patho­ morphological conclusion is necessary for the final diagnosis. The pseudo­lymphoma of the skin is a reactive derma­ tosis, resembling lymphoma both clinically and histologically, but has a benign course and a tendency to spontaneous regression, therefore, for a differential diagnosis, dermatoscopy and pathological examination are necessary. Two cases from own practice were presented in the work; clearly distinguished pink hemispherical nodes were observed in both patients. During the dermatoscopic examination, two different tumors were diagnosed ­ clear cell acanthomas and pseudolymphomas, in both cases the dermatoscopic indicators corresponded to the pathological conclusion. Conclusions. An overview of modern literature and clinical cases from our own practice suggests that clinically similar single infiltrative skin lesions can be identified by previous dermatological studies. Careful clinical and dermatological monitoring provides additional benefits for better recognition of skin tumors, although unclear cases require a pathomorphological study.

Keywords

• clear cell acanthoma
• dermatoscopy
• pseudolymphoma