Clinical case of neonatal rare skin condition

Abstract

Objectives: The 41 week gestation, 4080 g female infant was born by vaginal delivery from meconium tained waters in 03.10.2022. Apgar scores were 10 and 10. After birth, the infant looked clinically healthy. However, on the right shin's skin was covered with blisters, some of them filled with clear fluid, some – with hemorrhagic fluid. The rightshin was swollen, lymphostatic. Results: Multidisciplinary meeting with attendness of neonatologists, paediatric oncohematologist, paediatric surgeon, genetic, dermatovenerologist was held. It was decided to perform some testing: (1) Labtests: rapid plasma reagin (RPR), agglutination assay (TP-PA) were NEGATIVE. Peripheral blood count – without changes. (2) MRI: rightshin's structural changes similar to venous of lymphatic malformation.(3) Neurosonogram: choroid plexus cysts, cerebellar vermis hypoplasia(4) Ultrasound of abdominal cavity organs: small bilateral ovarian cysts. (5) Skin biopsy - congenital smooth muscle hamartoma. Discussion: Congenital smooth muscle hamartoma (CSMH) is a rare cutaneous hamartomatous lesion most often located on the lumbosacral area or proximal limbs and characterized by a disorganized proliferation of smooth muscle fibres of arrector pili presenting usually as a localized skin-coloured or hyperpigmented plaque (up to 10 cm in diameter) with prominent vellus hairs or less commonly by multiple skin-coloured papules that can coalesce to form irregularly shaped plaques. Extensive congenital smooth muscle hamartomas may show hypertrichotic and skin-coloured to lightly hyperpigmented patches in association with excessive skin folds and follicular dimpling (sometimes called Michelin baby syndrome). A positive pseudo-Darier sign (temporary induration or piloerection after rubbing) is present in 80% of the patients. It is a rare asymptomatic benign skin defect detected in newborns and young children. Treatment is unnecessary, only considering from a cosmetic point of view. This clinical case shows the importance of having a multidisciplinary command working with rare skin diseases in paediatric population.