Effective treatment of linear Darier's disease with topical retinoids: case report and review of the literature.

Darier's disease is a rare genodermatosis caused by a defect in ATP2A2 gene located on chromosome 12q23-23 (1). This somatic mutation rarely occurs in the postzygotic phase of embryogenesis, leading to cutaneous mosaicism for the disease. The mosaic form of Darier's disease is also called linear Darier's disease and clinically presents with linear, zosteri-form or localized patterns located on Blaschko's lines. A case of linear Darier's disease successfully treated with topical 0.1% tretinoin therapy is presented. A 62-year-old male patient presented to dermatology department for scaly eruption on the back for over a month. The patient had undergone Whipple's operation (pancreatoduodenosplenectomy) for pan-creatic adenocarcinoma 3 months before. Dermato-logic examination revealed unilateral follicular hy-perkeratotic papules in an oblique linear configuration over the patient's back. Some keratotic papules coalesced to form plaques, which were located on Blaschko's lines (Fig. 1). The remaining dermatologic examination of the hair, nails and mucosa was unremarkable. A punch biopsy performed from one of the papules showed focal suprabasilar acantholysis accompanied by dys-keratotic keratinocytes both in the stratum spinosum and stratum corneum. Dyskeratotic cells in the stratum spinosum showed pyknotic nuclei and enlarged homogeneous eosinophilic cytoplasm, whereas ba-sophilic elongated nuclei were observed in dyskera-totic cells of the stratum corneum (Fig. 2). They were consistent with corps ronds and grains previously described in dyskeratotic dermatoses and particularly in Darier's disease (2). With these histopathologic findings , the diagnosis of Darier's disease was made. The clinical presentation composed of localized plaques parallel to Blaschko's lines led to the definitive diagnosis of linear Darier's disease. Topical 0.1% tretinoin twice daily was prescribed and total improvement was accomplished after a month (Fig. 3). Darier's disease is a rare autosomal dominant genodermatosis which is caused by a defect in AT-P2A2 gene on chromosome 12q23-23.1 (1). This gene's product is a protein which functions as a sarco/endo-plasmic reticulum calcium pumping ATPase isoform 2 (SERCA2) and mutation of this protein leads to loosening of the cell-cell adhesions by causing defect in the formation or maturation of the tonofilament-des-mosome complex (3). The disrupted adhesion results in separation of the cells contributing particular focal suprabasilar acantholysis and dyskeratosis in kerati-nocytes known as corps ronds and grains histopatho-logically (2). The clinical findings in Darier's disease include keratotic, crusted red-brownish papules distributed over the seborrheic areas such as the trunk, scalp margins, face and lateral aspects of the face. The papules generally coalesce to form large verrucous plaques. …