Dermoscopic features of clear cell acanthoma

Reflectance Confocal Microscopy and Dermoscopy for the Diagnosis of Solitary Hypopigmented Pink Lesions: A Narrative Review

Diagnosing solitary pink skin lesions poses a significant challenge due to the scarcity of specific clinical and dermoscopic criteria. Several benign lesions, such as cherry angioma, clear cell acanthoma, dermal nevus, keloid, hypertrophic scar, and Spitz nevus, often exhibit similar clinical and dermoscopic features. This similarity extends to some malignant lesions, including basal cell carcinoma, actinic keratosis, and amelanotic melanoma, making differentiation difficult. Recent studies highlight the enhanced diagnostic accuracy of reflectance confocal microscopy (RCM), which offers increased sensitivity and specificity compared to dermoscopy alone for diagnosing skin cancer. This study aims to summarize the application of dermoscopy and RCM in distinguishing between benign and malignant pinkish-reddish skin lesions. The integration of RCM with traditional dermoscopic techniques improves the ability to accurately identify and differentiate these lesions. However, it is crucial to note that for any suspicious lesions, a final diagnosis must be confirmed through surgical excision and histopathological evaluation. This comprehensive approach ensures accurate diagnosis and appropriate treatment, highlighting the importance of combining advanced imaging techniques in clinical practice.

Non-Invasive Diagnosis of a Facial Tumor Using Dermoscopy and Successful Treatment with 595 nm Pulsed Dye Laser

Clear cell acanthoma (CCA) is an uncommon, benign epithelial tumor presenting as a well-defined, slow-growing solitary nodule. The diagnosis of CCA is usually based on clinical and histopathological evaluation of the tumor. However, when such type of benign tumor occurs on an exposed area, a biopsy is not always the best diagnostic option since it may leave scar. The recent advent of dermoscopy has offered an accurate and non-invasive method to diagnose CCA without resorting to skin biopsy. A 40-year-old male presented with a shiny, erythematous-to-brown, flattened nodule on the left cheek. Dermoscopic examination revealed a 'string of pearls' vascular pattern, a characteristic dermoscopic feature of CCA. Under the clinical and dermoscopic impression of CCA, a 595 nm pulsed dye laser (PDL) therapy targeting the vascular tissue in the superficial dermis of the lesion was chosen for a minimally invasive treatment. After repeated sessions of PDL, an optimal cosmetic outcome was achieved and no recurrence was recorded during the follow-up period. Herein, we report a case of presumed CCA which was successfully diagnosed and treated by utilizing non-invasive modalities.

Clear cell acanthoma

Clear cell acanthoma is a rarely diagnosed tumor with variable clinical morphology that is usually only recognized by its histopathological features. The primary lesion is a red papule a few millimeters in diameter that often occurs as a single lesion on the lower extremities. In dermoscopy, resemblance of the vessels to a string of pearls is a largely specific finding of clear cell acanthoma. In contrast to the initially uncharacteristic clinical findings, histopathology of clear cell acanthomas is characterized by a typical compact, well-demarcated acanthosis consisting of pale-staining, PAS-reactive keratinocytes. As etiology and pathogenesis are both unclear, nosology of clear cell acanthoma is also controversial, with an ongoing debate as to its classification as cutaneous neoplasia or reactive inflammatory dermatosis.

Differences in dermoscopic findings between early and mature clear cell acanthoma

Clear cell acanthoma (CCA) is a rare benign epidermal tumor that is difficult to diagnose by visual inspection. Conversely, its diagnosis by dermoscopy is relatively easy owing to the characteristic serpiginous arrangement of coiled vessels, sometimes described as the "string-of-pearls" formation. However, in few published reports, the dermoscopic diagnosis of mature CCA has been reported. Here, we report the histopathological and detailed dermoscopic findings of two CCA cases. Between these, one case was of early (~6 months) CCA exhibiting the characteristic vascular string-of-pearls formation, whereas the other was of a more mature (~10 years) CCA; although the latter case showed combined thick and thin white intersecting lines with large coiled vessels and/or red clods, it had the string-of-pearls formation. Thus, regardless of CCA maturity, the string-of-pearls formation was present. We propose that the combination of combined thick and thin white intersecting lines along with the vascular string-of-pearls formation reflecting large coiled vessels and/or red clods on dermoscopy is a diagnostic clue to mature CCA.