Adult xanthogranuloma diagnosed on reflectance confocal microscopy

Reflectance Confocal Microscopy Can Help Differentiate Adult Xanthogranulomatous Disease from Xanthelasma-A Case Report

Background: Adult xanthogranulomatous disease (AXD) is a rare histiocytic disorder with systemic potential, while xanthelasma palpebrarum (XP) is a common xanthoma often linked to lipid disorders. Differentiating these conditions is challenging due to overlapping features. Reflectance confocal microscopy (RCM), a non-invasive imaging tool, offers high-resolution visualization of skin structures and may aid diagnosis. Methods: We present a 71-year-old woman with periocular lesions. RCM was used to evaluate the lesions, identifying cellular and structural features. The findings were confirmed through histopathology, followed by surgical excision. Postoperative monitoring utilized RCM and LC-OCT. Results: RCM identified Touton giant cells, foamy histiocytes, and fibrosis, helping to distinguish xanthogranuloma from xanthelasma. Histopathology confirmed the diagnosis, and the patient underwent successful lesion excision without complications. Conclusions: This case underscores RCM's utility as a diagnostic adjunct for differentiating AXD from XP in sensitive regions like the periocular area. The combined use of RCM and LC-OCT enhances monitoring for recurrence. While histopathology remains the diagnostic gold standard, RCM shows promise as a non-invasive tool, warranting further research to validate its role and develop standardized clinical protocols.

Analysis of the characteristics of reflectance confocal microscopy images of xanthogranuloma and xanthoma

BACKGROUND

Both xanthogranuloma and xanthoma clinically manifest as yellowish skin lesions. Historically, the gold standard for diagnosis was skin histopathological examination. Currently, the advent of reflectance confocal microscopy (RCM) offers additional diagnostic support for these diseases by revealing their microscopic features, thereby enhancing the theoretical foundation for diagnosis.

OBJECTIVE

This study aimed to elucidate the distinctive characteristics of RCM images in xanthogranuloma and xanthoma, assess their diagnostic value, and investigate the relationship between RCM and histopathological features, ultimately boosting diagnostic accuracy.

METHODS

RCM and histopathological examinations were conducted on 13 patients with xanthogranuloma and 12 with xanthoma, recruited from our Dermatology Clinic between August 2022 and November 2023. The study involved analyzing RCM image features and correlating them with histopathological findings.

RESULTS

The RCM images of 13 xanthogranuloma and 12 xanthoma cases showed similar features. Xanthogranuloma predominantly exhibited epidermal atrophy and thinning in 6 cases (46.15%). Additionally, in 69.23% of cases, scattered small mononuclear inflammatory cells were infiltrated in the superficial and middle dermis layers. Medium to high refractive cells, predominantly vacuolated and resembling foam, were observed in 61.54% of cases. All cases demonstrated high refractive cells with distinct target-shaped, disc-shaped, horseshoe-like, and flower-ring structures. Concordance rates with histopathological examinations were 69.23, 92.31, 92.31, and 100%, respectively. Regarding xanthoma, epidermal atrophy and thinning occurred in two cases (16.67%), and mononuclear inflammatory cell infiltration was observed in 25% of cases. High refractive cells with the previously mentioned shapes were present in 100% of cases, though only 16.67% displayed these characteristics exclusively. The concordance rates were 66.67, 91.67, 100, and 91.67%, respectively.

CONCLUSION

RCM imaging of xanthogranuloma and xanthoma presents distinctive, highly consistent features with their histopathology, offering valuable insights for clinicians in diagnosing and differentiating these conditions.

Multicentric Reticulohistiocytosis with Dermatomyositis-Like Features: A Case Report with Dermoscopy and Reflectance Confocal Microscopy Findings

Multicentric reticulohistiocytosis is an insidious-onset, non-Langerhans-cell histiocytosis affecting joints and skin. Early diagnosis is important to prevent destructive arthritis and disease-related complications. Reflectance confocal microscopy (RCM) is a technique that allows the visualization of the epidermis and superficial dermis non-invasively on a horizontal plane with quasi-histologic images of the skin. RCM features of non-Langerhans cell histiocytosis including Rosai-Dorfman disease, adult xanthogranuloma (AXG) and, juvenile xanthogranuloma (JXG) have been reported. However, RCM features of MRH have not previously been described. Herein, we present the RCM features of a case of MRH with dermoscopic and histopathologic features. This article is protected by copyright. All rights reserved.

Line-field confocal optical coherence tomography of xanthogranuloma: Correlation with vertical and horizontal histopathology

Line‐field confocal optical coherence tomography (LC‐OCT) is a new noninvasive technique for a real‐time, vertical, and horizontal imaging of the skin at cellular resolution. A 47‐year‐old female presented with a 6‐month history of an asymptomatic yellowish papule. LC‐OCT evaluation was able to show the diagnostic microscopic features of xanthogranuloma and showed an excellent correlation with vertical and horizontal histopathological sections by revealing enlarged dermal papillae containing multiple, bright roundish giant cells, corresponding to foamy histiocytes, and giant cells characterized by a dark center surrounded by a highly hyper‐refractile peripheral ring, corresponding to Touton cells. LC‐OCT may represent a valid, noninvasive alternative to histopathological examination in clinically atypical cases of xanthogranuloma.

Dermoscopic Patterns in Juvenile Xanthogranuloma Based on the Histological Classification

Background: Several dermoscopic features of juvenile xanthogranuloma (JXG) have been previously described in single cases or small case series and need to be further verified in a large sample.

Objective: We aimed to investigate the dermoscopic patterns of JXG in a large case series and the correlations of these with clinical features of different histopathological subtypes of JXG.

Methods: Patients who underwent dermoscopic evaluation and had a histopathological diagnosis of JXG were recruited. Histological findings, including stage and Ki67 proliferative index and the dermoscopic features of each lesion were recorded.

Results: Forty-one patients with JXG were included. The male to female ratio was 1.28: 1 and the median age of onset was 11 months (range: 0–95 months). Fourteen lesions were histologically categorized in the early stage, 17 in the developed stage, and 10 in the late stage. The “setting sun” pattern was observed in 35 lesions (85.4%) and “clouds” of paler yellow areas in 26 lesions (63.4%). The frequency of the “setting sun” pattern was higher in the early and developed stages (30/31) than in the late stage (5/10) (P = 0.002), while that of “clouds” of paler yellow areas was not significantly different between each stage. Branched linear vessels were detected in the early (11/14) and developed stage (6/17), but not in the late stage. The mean Ki67 index of the lesions with linear vessels was 11.8% (range: 2–40%), which was higher than that of lesions without linear vessels (mean index: 5%, range: 1–30%) (P = 0.005). The pigment network and whitish areas were only detected in 6 and 5 lesions in the late stage, respectively. The whitish areas presented either as streak or stellate shape. The pigment network exhibited either in a centric or a peripheral pattern.

Conclusions: The “setting sun” pattern is the characteristic dermoscopic features of JXG in the early and developed stages, while whitish areas and pigment network are the characteristic patterns in the late stage. Linear vessels present as branched patterns and mostly occur in the early stage with a high proliferative index, indicating rapid growth. The whitish areas and pigment network may present in various patterns. Dermoscopy is a useful adjunctive tool in the diagnosis and staging of JXG.

Diffuse (Generalized) Plane Xanthoma Misdiagnosed as Carotenoderma: Usefulness of Reflectance Confocal Microscopy

Diffuse (generalized) plane xanthoma is a rare normolipemic xanthomatosis, frequently associated with multiple myeloma and monoclonal gammopathy. Its clinical presentation is well described, and in most cases, clinical suspicion is immediate. Rarely, it can clinically present with a diffuse and uniform yellowish discoloration, and in this context, several investigations are required to identify the correct diagnosis. We describe a case characterized by progressive diffuse yellow-orange discoloration lasting about 3 years and classified as carotenoderma in which reflectance confocal microscopy addressed the diagnosis and drove the correct selection of the biopsy site. Definitive diagnosis of diffuse (generalized) plane xanthoma was confirmed later by histological examination.

Multiple xanthogranulomas in an adult patient: clinical, dermoscopic, reflectance confocal microscopy and histopathological features

A case of multiple xanthogranulomas located bilaterally on arms, armpits, legs, trunk, abdomen, scalp, neck and plantar surfaces in a 25-year-old man is reported. The patient was evaluated by polarised light dermoscopy and reflectance confocal microscopy (RCM) that showed peculiar aspects. In particular, dermoscopy showed a homogeneous orange-yellowish hue that is related to the histopathological presence of foamy histiocytes and Touton giant cells; the last typically appeared at RCM as peculiar giant cells surrounded by highly refractive ring due to the cytoplasm rich of lipids. Laboratory investigations, including routine haematological examination, liver and renal function tests, serum lipid and sugar levels were normal. The patient started isotretinoin 20 mg once daily. After 6 months, some lesions flattened, leading to yellowish or hyperpigmented macules, but new lesions raised up.