Naevus trichilemmocysticus – the first paediatric case of a newly delineated organoid naevus

Abstract

EditorRecently, an organoid naevus combining filiform hyperkeratoses and trichilemmal cysts in Blaschko-linear distribution has been delineated as a distinct entity. 1 The authors provided evidence that the same rare type of naevus had been described in a few previous instances without perceiving its originality. 2-5 Here, we would like to point out the so-called naevus trichilemmocysticus or trichilemmal cyst naevus by reporting the first paediatric case.A 13-year-old boy had hyperkeratotic skin lesions arranged in a linear pattern on the left upper part of the body since birth. At the age of 3 years, cysts began to develop within the involved areas.

Nevus trichilemmocysticus

“…Additionally, comedo‐like plugs have been described . Few cases with similar morphology have also been described in the past but were not labeled as nevus trichilemmocysticus …”

“…Nevus trichilemmocysticus is a rare organoid nevus described since 2007 in few case reports (Table ) . It is characterized by the congenital presence of hyperkeratotic verrucous linear lesions in generalized distribution all over the body following Blaschko's lines.…”

“…Biopsy from filiform lesions has been reported to show epidermal acanthosis, papillomatosis, with deep invaginations filled with orthokeratotic plug while the rest of the area shows parakeratotic columns and absent granular layer reminiscent of cornoid lamella . Histopathology of the nodulocystic lesion has shown features of a trichilemmal cyst, characterized by the cyst wall lined by a flat stratified epithelium, abrupt keratinization without any granular layer, and lumen containing compact orthokeratotic keratin.…”

“…Extracutaneous features like skeletal abnormalities have been observed in few patients, which included frontal bossing and joint pain . These additional systemic features would qualify the nevi as nevus trichilemmocysticus syndrome .…”

Naevus Spinofiliformis

“…However, spinous filiform projections in epidermal naevus have been described in earlier case reports as shown in Table 1 . [ 1 3 4 5 6 ]…”