Linear and whorled naevoid hypermelanosis in a patient with trisomy 4 mosaicism

Clinical characteristics of 47 children with pigmentary mosaicism: A cross-sectional study

BACKGROUND

Pigmentary mosaicism (PM), also known as Blaschkoid dyspigmentation, is a rare pigmentary anomaly. Although several case reports have been published describing extracutaneous manifestations associated with PM, there are very few studies on the clinical characteristics of patients with PM.

AIM

To describe the clinical characteristics of patients with PM.

PATIENTS AND METHODS

This descriptive cross-sectional study was conducted among 47 children examined by a dermatologist and a pediatrician. The pattern and location of the PM, type of pigmentation and extracutaneous manifestations were documented.

RESULTS

The most common pattern of PM was narrow-band PM, followed by broad-band and checkerboard patterns. The trunk was the most affected region, followed by the legs and arms. PM manifested as hypopigmentation in 51.1% of cases, as hyperpigmentation in 27.6%, and as hypo/hyperpigmentation in 21.2%. Accompanying diseases were present in 40.4% of patients: neuropsychiatric diseases were the most common, followed by endocrinological or hematological diseases and growth/developmental delay.

CONCLUSION

PM has been associated with several extracutaneous findings but there is still some debate whether these associations reflect different PM phenotypes or whether they are simply coincidental. Our study suggests that extracutaneous involvement in PM patients is frequent, thus warranting careful examination of PM patients.

Clinical Approach to Linear Hyperpigmentation: A Review Article

Linear hyperpigmentation is an unusual anatomical configuration in clinical dermatology. Owing to its rarity, consensus on the most effective method of classification is lacking. While linear hyperpigmentation generally follows Blaschko's lines, this is not universal. Clinical findings such as adherence to Blaschko's lines, associated morphological findings (including other cutaneous lesions), and systemic manifestations can be used to further characterize and diagnose variants of the disorder. Early detection of any underlying disease is vital, especially in cases with effective management, because the disorder may make it difficult to manage hyperpigmentation. Herein, we introduce a logical clinical diagnostic approach that represents a useful tool for dermatologists to efficiently evaluate patients presenting with linear hyperpigmentation. A simplified systematic and evidence-based approach is useful for this clinical condition owing to the heterogeneous causes and lack of specific diagnostic tools.

Pigmentary mosaicism: a review of original literature and recommendations for future handling

Background

Pigmentary mosaicism is a term that describes varied patterns of pigmentation in the skin caused by genetic heterogeneity of the skin cells. In a substantial number of cases, pigmentary mosaicism is observed alongside extracutaneous abnormalities typically involving the central nervous system and the musculoskeletal system. We have compiled information on previous cases of pigmentary mosaicism aiming to optimize the handling of patients with this condition. Our study is based on a database search in PubMed containing papers written in English, published between January 1985 and April 2017. The search yielded 174 relevant and original articles, detailing a total number of 651 patients.

Results

Forty-three percent of the patients exhibited hyperpigmentation, 50% exhibited hypopigmentation, and 7% exhibited a combination of hyperpigmentation and hypopigmentation. Fifty-six percent exhibited extracutaneous manifestations. The presence of extracutaneous manifestations in each subgroup varied: 32% in patients with hyperpigmentation, 73% in patients with hypopigmentation, and 83% in patients with combined hyperpigmentation and hypopigmentation. Cytogenetic analyses were performed in 40% of the patients: peripheral blood lymphocytes were analysed in 48%, skin fibroblasts in 5%, and both analyses were performed in 40%. In the remaining 7% the analysed cell type was not specified. Forty-two percent of the tested patients exhibited an abnormal karyotype; 84% of those presented a mosaic state and 16% presented a non-mosaic structural or numerical abnormality. In patients with extracutaneous manifestations, 43% of the cytogenetically tested patients exhibited an abnormal karyotype. In patients without extracutaneous manifestations, 32% of the cytogenetically tested patients exhibited an abnormal karyotype.

Conclusion

We recommend a uniform parlance when describing the clinical picture of pigmentary mosaicism. Based on the results found in this review, we recommend that patients with pigmentary mosaicism undergo physical examination, highlighting with Wood’s light, and karyotyping from peripheral blood lymphocytes and skin fibroblasts. It is important that both patients with and without extracutaneous manifestations are tested cytogenetically, as the frequency of abnormal karyotype in the two groups seems comparable. According to the results only a minor part of patients, especially those without extracutaneous manifestations, are tested today reflecting a need for change in clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0778-6) contains supplementary material, which is available to authorized users.