Diagnosis: darier’s disease
Darier’s disease, also called Darier-White disease or keratosis follicularis, is a genodermatosis that affects 1 in 55,000 to 100,000 persons.1 It is inherited in an autosomal dominant fashion, resulting from a mutation in chromosome 12q23-q24.1, which encodes the gene ATP 2A2, which in turn encodes a SERCA2 (sarco/endoplasmic reticulum calcium)-ATPase pump. This defect results in instability of desmosomes.2-4
With Darier’s disease, skin lesions are often present in the second decade of life but rarely appear in adulthood. The clinical findings are described as yellowish, greasy hyperkeratotic papules coalescing to warty plaques in a seborrheic distribution on the face, scalp, flexures, and groin. The nails can have red and white alternating longitudinal bands, as well as a V-shaped nicking at the distal nail plate, with resultant splitting and subungual hyperkeratosis. Oral and anogenital mucosa can have a cobblestone appearance. Some families have had associated cases of schizophrenia and mental retardation.1,5
The histologic findings on skin biopsies of Darier’s disease show acantholysis (loss of epidermal adhesion) and dyskeratosis (abnormal keratinization) as the 2 main features.
Laboratory tests: biopsy confirms diagnosis
Biopsy of a characteristic papule from the patient’s back revealed diffuse acantholytic dyskeratosis, which confirmed the clinical diagnosis of Darier’s disease.
Two types of dyskeratotic cells are present: corps ronds and grains. Corps ronds, found in the stratum spinosum, are characterized by an irregular eccentric pyknotic nucleus, a clear perinuclear halo, and a brightly eosinophilic cytoplasm. Grains are mostly located in the stratum corneum; they consist of oval cells with elongated cigar-shaped nuclei. The patient declined genetic testing.