DP16 Trichilemmocysticus naevus: a rare birthmark treated successfully with erbium ablative laser

Abstract We report a rare case of 58-year-old woman with naevus trichilemmocysticus. The patient presented to tertiary dermatology centre longstanding skin changes her trunk. had been apparent since childhood and became more prominent in teens. Examination showed linear Blaschkoid distribution subtle hyperpigmentation warty follicular prominence the left submammary region, extending upper back, where comedones cystic papules were also noted. Histopathology confirmed presence cysts containing keratin, lined by trichilemmal-type squamous epithelium, representing trichilemmal cysts. overlying epidermis appeared normal. Given childhood, it was thought that this most likely represented Tantcheva-Poor et al. described named as type organoid naevus-type lesion 2007 (Tantcheva-Poor I, Reinhold K, Krieg T, Happle R. Trichilemmal cyst nevus: new complex epidermal nevus. J Am Acad Dermatol 2007; 57:S72–7). Only seven cases have identified reported literature. These characterized multiple filiform hyperkeratoses distribution. Most involve extensive areas present disfiguring lesions. Histology reports confirm acanthosis deep invaginations filled massive orthokeratosis, parakeratotic columns an absent granular layer (isthmic or differentiation) keratosis sebaceous ducts acrosyringia. Our is currently undergoing successful treatment erbium laser under local anaesthesia, order improve texture appearance birthmark. This has achieved ablation level papillary dermis, focal deeper each cyst, followed use meibomian curette for enucleation.