Clinico-pathological correlation of linear dermatoses along the lines of Blaschko: An observational study

Several epidemiological studies have described linear dermatoses; however, only few studies have correlated linear dermatoses along Blaschko’s lines with the histopathological findings. The aims of this study were to investigate the clinical patterns of various linear dermatological lesions along Blaschko’s lines and investigate the correlations between these dermatological lesions and their histopathological features. Patients who attended our dermatology out-patient department with linear dermatoses along the Blaschko’s lines were included in the study. Detailed history was obtained, clinical examination was performed, and a final provisional clinical diagnosis was noted. Subsequently, biopsy of the lesions was performed for histopathological examination. Of 62 patients who presented with linear lesions along the Blaschko’s lines, 45 patients underwent biopsy and histopathological examination. Of 45 patients who underwent biopsy, clinico-pathological correlation was observed in 100% of those diagnosed with lichen striatus and linear morphea, 89% of those diagnosed with hypomelanosis of Ito, 80% of those diagnosed with linear epidermal nevus, 75% of those diagnosed with lichen planus, and 67% of those diagnosed with nevus depigmentosus. The importance of correlation of linear lesions with their histopathological features in dermatology cannot be over emphasized. However, 100% correlation may be wishful thinking, and a correlation can help choose the appropriate line of management. Our results highlight this discrepancy and add to the knowledge on linear dermatosis.

Life-long Skin Eruptions along Blaschko’s Lines in a 27-year-old Woman

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Bilateral Systematised Epidermolytic Epidermal Nevus

Verrucous epidermal nevi (VEN) are benign congenital hamartomas consisting of keratinocytes. Histological examination mostly exhibits hyperkeratosis, acanthosis, papillomatosis and, rarely, the features of epidermolytic hyperkeratosis (EHK). We report a case of a 6-year-old boy who presented at Aga Khan University Hospital, Karachi, Pakistan with bilaterally symmetrical linear epidermal nevi following Blaschko’s lines and showing epidermolytic hyperkeratosis on histology. The patient was treated with topical keratolytics and emolients which led to considerable improvement. To the best of the authors’ knowledge, this is the first report of VEN from Pakistan. KEYWORDS Verrucous Epidermal Nevus; Mosaicism; Epidermolytic Hyperkeratoses; Hamartoma; Case Report; Pakistan.

Nevus Comedonicus, a Rare Case : Dermoscopic and Histopathological Findings

Nevus comedonicus is an extremely rare adnexal hamartoma of pilosebaceous apparatus, with approximately 200 cases reported in the literature so far. It appears as cluster of adjacent honeycomb-like dillated follicular openings with firm pigmented keratin plugs resembling comedones.The comedones oftentimes arranged in linear pattern paralled to Blaschko’s lines. We report a case of a 5-year-old boy with open brown to black comedones in a linear pattern localized on the back of the left thigh that appearing since birth. Pain, itch and discharge were not obtain. There were some episodes of infection, due to manual removal done by his mother which left some hypertrophic scars. Dermoscopic examination revealed the distinctive pattern consisting of pigmented, sharply demarcated keratin plugs of 1-3 mm in diameter, some open pores, multiple structurless, various shades of brown homogenous circular areas surrounding the plugs. Histopathological examination showed an aggregation of dilated follicular infundibulum with laminated keratinous material plugging. This case report prove that dermoscopy examination, a simple non-invasive diagnostic tool is very helpful in diagnosing nevus comedonicus. We recommend this tool to differentiate the diagnosis of other rare epidermal nevi while histopathological examination should be performed only in uncertain cases.

A clinical study on linear dermatoses at a teriary care teaching hospital in Davangere

<p class="abstract"><strong>Background:</strong> Skin lesions present with innumerable patterns like discoid, petaloid, arcuate, annular, polycyclic, livedo, reticulate, target, stellate, digitate, linear, serpiginous and whorled. Most of the linear lesions follow the Blaschko’s lines. Aim was to study the incidence of linear dermatoses, the age and sex incidence, various types of clinical presentation, various sites of distribution and their clinical correlation. </p><p class="abstract"><strong>Methods:</strong> Detailed history including family history, History of disease documented with clinical examination. After counselling and after recording their consent for the test, skin biopsy along with routine investigations was done wherever needed and the results were evaluated. <strong></strong></p><p class="abstract"><strong>Results:</strong> Lichen striatus was seen in 29.91% followed by linear herpes zoster in 24.7%, linear lichen planus in 18.22%, linear verrucous epidermal nevus in 14.01%, segmental vitiligo in 3.73%, nevus depigmentation in 2.33% and others. Maximal cases were asymptomatic and reported for cosmetic reason. Intense itching was the main reason to bring the lichen planus patients and few cases of the lichen striatus patients for treatment. </p><p class="abstract"><strong>Conclusions:</strong> Lichen striatus was found to be more common, female preponderance. Majority of patients showed unilateral distribution more on the extremities. Histopathological correlation shows the importance of histopathology which ultimately changes the management in any given condition.</p><p> </p>

De novo mutations in the X-linked TFE3 gene cause intellectual disability with pigmentary mosaicism and storage disorder-like features

IntroductionPigmentary mosaicism (PM) manifests by pigmentation anomalies along Blaschko’s lines and represents a clue toward the molecular diagnosis of syndromic intellectual disability (ID). Together with new insights on the role for lysosomal signalling in embryonic stem cell differentiation, mutations in the X-linked transcription factor 3 (TFE3) have recently been reported in five patients. Functional analysis suggested these mutations to result in ectopic nuclear gain of functions.Materials and methodsSubsequent data sharing allowed the clustering of de novo TFE3 variants identified by exome sequencing on DNA extracted from leucocytes in patients referred for syndromic ID with or without PM.ResultsWe describe the detailed clinical and molecular data of 17 individuals harbouring a de novo TFE3 variant, including the patients that initially allowed reporting TFE3 as a new disease-causing gene. The 12 females and 5 males presented with pigmentation anomalies on Blaschko’s lines, severe ID, epilepsy, storage disorder-like features, growth retardation and recognisable facial dysmorphism. The variant was at a mosaic state in at least two male patients. All variants were missense except one splice variant. Eleven of the 13 variants were localised in exon 4, 2 in exon 3, and 3 were recurrent variants.ConclusionThis series further delineates the specific storage disorder-like phenotype with PM ascribed to de novo TFE3 mutation in exons 3 and 4. It confirms the identification of a novel X-linked human condition associated with mosaicism and dysregulation within the mechanistic target of rapamycin (mTOR) pathway, as well as a link between lysosomal signalling and human development.