Dermoscopic features of primary cutaneous amyloidosis in skin of colour: A retrospective analysis of 48 patients from South India

Dermatoscopy of primary localised cutaneous amyloidosis - A cross-sectional study in a setting of South Asian public dermatology department

Background

Amyloidosis, deposition of misfolded protein in body, is a fairly common condition. The deposition of misfolded proteins in skin which occurs in absence of systemic comorbidities, namely Primary Cutaneous Amyloidosis (PCA) is also a well-known entity in skin of colour patients of Asian subcontinent. Primary Cutaneous Amyloidosis is usually diagnosed with good clinical acumen and typical clinical phenotype and involved site. Dermoscope has been used as an adjunct non-invasive tool to confirm cases with diagnostic uncertainty and in those in whom biopsy is deferred. Typical dermoscopic features of PCA helps differentiate it from other pigmentary dermatoses and avoids unwanted invasive biopsies and investigations especially in resource poor settings with financial constraints.

Objectives

This study aims to identify and corroborate clinically, typical dermoscopic features in PCA in 42 patients which includes Macular Amyloidosis (MA) and Papular Amyloidosis (PA) predominantly in skin of colour patients from government based hospital of a south east Asian country.

Materials and methods

Patients with classic clinical features of PCA were selected. Primary Cutaneous Amyloidosis was subclassified into MA or PA and their corresponding clinically corroborative dermoscopic features were enlisted respectively. All patients (treatment naïve and previously treated), who consented to participate in the study were included. Patients were diagnosed based on the prototypical clinical features. Dermoscopy was done using DermLite III DL3N Polarised and Fluid Dermoscope w/PigmentBoost Brand (3Gen, DermLite LLC, San Juan Capistrano, CA, USA) and images were obtained to create digital dermoscopy system by attaching camera-equipped mobile device via an optional connection kit (Redmi Note 11, MIUI version 13.0.5, CHINA) and the findings were enlisted concurrently.

Results

In this study of dermoscopic findings of PCA, 42 patients were evaluated for their clinical lesions along with its corroboration with the dermoscopic features. Macular Amyloidosis was seen in 30 patients and 12 patients had typical cutaneous phenotypic and dermoscopic feature of PA. The most common dermoscopic finding seen in patients with MA was shiny to dull white, circular or oval central hub surrounded with halo of light brown dots. Most common configuration of brownish pigmentation around central hub was fine streak type. Also eccrine clues were seen in some cases of MA, which was a unique finding. Similarly in the PA subtype, the central hub was replaced by scar like structureless translucent white area surrounded by brownish black dot like structures, especially in those with large and thick plaques.

Conclusion

Dermoscopic findings of PCA and their clinical corroboration is a much-needed aspect in treating patients with pigmentary disorders and in those with skin of colour, especially in developing countries. Utilization of dermoscope in clinical settings of low income countries and in government based hospitals will decrease the add on economic burden of invasive diagnostic modalities like biopsy and other inadvertent tests done to rule out pigmentary conditions.

Primary Localized Cutaneous Amyloidosis in Central Europe: A Retrospective Monocentric Study on Epidemiology and Therapy

Amyloid deposits can be the cause of many chronic diseases. Primary localized cutaneous amyloidosis (PLCA) is a chronic dermatologic condition with amyloid deposits in the papillary dermis. The most common types of the keratinocyte-derived form of PLCA include macular (MA), lichen (LA), and biphasic (BA) amyloidosis. The estimated prevalence of PLCA in the Asian population is 0.98/10,000, which is higher than in the European population; thus, epidemiologic data on PLCA in the Caucasian population are limited. We performed a retrospective single-center study analyzing epidemiologic characteristics of a Central European PLCA population. Epidemiologic data regarding age, sex, skin phototype (Fitzpatrick scale I-VI), disease duration, comorbidities, history of atopy, and family history of PLCA were collected. Clinical characteristics, localization of PLCA lesions, applied therapies and treatment outcomes were also analyzed. Dermoscopic characteristics were also evaluated. A total of 41 patients diagnosed with PLCA were included, with 22 presenting with macular, 18 with lichen, and 1 with biphasic amyloidosis. The male/female ratio was 16/25, and mean age at diagnosis was 54.6 ± 15.2 years (range 27-87 years). The mean age at the onset of PLCA was 53 ± 16.1 years (range 19-79 years) in MA, 46.7 ± 18.2 years (range 14-73 years) in LA, and 26 years in BA. The interscapular region in MA and the extensor surface of the lower extremities in LA proved to be localization-related areas. In our center, a wide range of therapeutic options was applied, with the most prescribed being topical corticosteroids in all types of PLCA. We presented a retrospective, monocentric study on the epidemiology of PLCA in the Central European region. By examining the medical data of a significant number of PLCA patients, we compared our epidemiologic data with that of the Asian PLCA population. Due to the rarity of the condition, further randomized controlled trials and guidelines are needed to improve therapeutic outcomes.

Lichen Amyloidosis on the Scalp: A Case Report

Lichen amyloidosis (LA) is one form of primary cutaneous amyloidosis, presented as discrete, lichenoid papules with itching, commonly involving the extensor surfaces of extremities. Scalp involvement is rarely reported in the literature. In this study, we reported a case of LA over the crown and vertex areas of the scalp. The lesions subsided with topical clobetasol propionate/all-trans retinoic acid compound ointment treatment for 2 months and achieved significant improvement.

Dermoscopic Features of Lichen Amyloidosis in Caucasians-A Case Series and Literature Review

Primary cutaneous amyloidosis (PCA) is characterized by the extracellular deposition of amyloid in the skin without systemic involvement. It comprises several clinical variants, the most common of which are macular amyloidosis (MA) and lichen amyloidosis (LA). PCA is frequently observed in Asians, while it is considered to be very rare in Caucasians. In the latter population, the condition often poses a diagnostic challenge. Dermoscopy has already been proved to be a useful, non-invasive diagnostic tool in various non-neoplastic skin diseases. In the paper, we present three Caucasian patients (skin phototypes I–II) with histologically confirmed LA. Under dermoscopy, central white hubs with grayish-brown dots and globules were observed in all three cases. Vascular structures were present in two cases and had the morphology of red globules and thick, unfocused branching lines intersecting the white hubs. A comprehensive review of the literature retrieved twelve papers presenting the dermoscopic features of PCA, including five articles on the dermoscopy of LA. The vast majority of these studies have been conducted on the Asian population, and there is a lack of data on the dermoscopic findings for patients with skin type I or II. The literature review revealed that MA and LA share several dermoscopic similarities (the presence of a white central hub and grayish dots), but also display distinct features. Compared to the dermoscopic features of LA in darker skin phototypes, our patients presented less pronounced pigmentation and more evident vascular structures. Nevertheless, further studies are needed in order to reliably evaluate the dermoscopic features of PCA in various ethnicities.