1/6. Atypical pityriasis rosea.Six cases of pityriasis rosea with atypical morphology and distribution of the eruption are reported. The eruption did not show a typical 'Christmas-tree' arrangement, confined to the trunk and proximal parts of the extremities. However, the histology of the eruption revealed dyskeratotic cells in the epidermis and extravasated erythrocytes in the dermis, which were recently reported as rather characteristic findings of this disease. prodromal symptoms, course and response to therapy were compatible with pityriasis rosea. Histological examination is important and helpful for the diagnosis of atypical cases.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |
2/6. pityriasis rubra pilaris: a clinico-pathological and therapeutic study with special reference to histochemistry, autoradiography, and electron microscopy.Five patients with pityriasis rubra pilaris (PRP) were analyzed by means of light and electron microscopy as well as by histochemistry and autoradiography. The results were compared with findings in psoriasis vulgaris. In PRP we found a moderate increase of the labeling index of epidermal cells, a highly increased labeling index of dermal infiltrating cells, and a mild spongiosis, and in the stratum granulosum, a decreased number of tonofilaments and an increased number of keratinosomes. The horny layer in PRP showed a pronounced histochemical and electron microscopical parakeratosis, even when histological parakeratosis was absent. In contrast with psoriasis vulgaris, there was no exocytosis of polymorphonuclear leucocytes into the epidermis, the papillomatosis index was normal, and there were no tortuous capillaries in the dermal papillae. The stratum granulosum was always present and sometimes thickened, showing electron microscopical changes different from those referred to in psoriasis. These changes point to a relatively distinct pattern of epidermal changes in PRP.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |
3/6. pityriasis rubra pilaris: epidermal cell kinetics.Epidermal proliferative kinetics were studied in a patient with pityriasis rubra pilaris. Elevated proliferative indices (flash labelling and mitotic indices) were apparent compared with normal epidermis and measurements of the birth rate indicate that the rate of epidermal cell production was similar to that found in psoriasis, and equalled 11.8 cells/1000 germinative cells/h; this suggests a cell cycle time of 60 h. Contemporaneous measurements of the rate of entry into dna synthesis showed values similar to the rate of entry into mitosis; hence there is no G2 cell loss as appears to occur in the hyperproliferative psoriatic epidermis.- - - - - - - - - - ranking = 2keywords = epidermis (Clic here for more details about this article) |
4/6. Familial pityriasis rubra pilaris.BACKGROUND: Familial pityriasis rubra pilaris is a rare autosomal dominant skin disorder. Four individuals from one family are described who demonstrate clinical features compatible with a diagnosis of familial pityriasis rubra pilaris. Results of light and electron microscopic, immunocytochemical, and biochemical analysis of skin biopsy specimens from three of these four individuals are presented. OBSERVATIONS: All affected individuals demonstrated erythematous scaly skin with follicular prominence and islands of sparing. Inheritance was consistent with an autosomal dominant trait. light and electron microscopic findings were compatible with those reported in sporadic cases of pityriasis rubra pilaris. Immunocytochemistry showed suprabasal staining with monoclonal antibody AE1. Immunoblot analysis revealed abnormal keratins with K6/16 expression, the possibility of an abnormal K14 or K16, and a 45-kd acidic keratin not normally expressed in epidermis. Because similar biochemical analyses have not been reported previously in other cases of pityriasis rubra pilaris (familial or sporadic), comparisons cannot be made. CONCLUSIONS: The observations suggest that the cutaneous abnormality in this family extends beyond clinical and morphological alterations to abnormalities in biochemical markers of epidermal differentiation.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |
5/6. dermatomyositis with a pityriasis rubra pilaris-like eruption: a little-known distinctive cutaneous manifestation of dermatomyositis.A pityriasis rubra pilaris-like eruption has been described in patients with dermatomyositis. These patients showed generalized follicular hyperkeratosis and diffuse thickening of the palms and soles. Histopathological findings consisted of keratotic plugging of the follicular infundibulum and features of erector pili myositis. We report on an 18-year-old woman with dermatomyositis. The diagnosis was established by characteristic enzymatic alterations, electromyographic pattern of myositis and the findings in a muscle biopsy, although the patient had no evidence of muscular weakness during a follow-up of 14 years. She developed an erythematosus and squamous eruption associated with diffuse palmoplantar keratoderma. Histopathological features consisted of a papillomatous epidermis with spicules of compact eosinophilic hyperkeratosis over the tips of papillae that were not related to hair follicles. pityriasis rubra pilaris-like eruption seems to be a characteristic although uncommon cutaneous manifestation in dermatomyositis.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |
6/6. The clinical and histomorphological features of pityriasis rubra pilaris. A comparative analysis with psoriasis.pityriasis rubra pilaris (PRP) is an idiopathic erythematous scaling eruption which can be difficult to distinguish from psoriasis. We explored the clinical features, including background medical illnesses and potential triggers in patients with PRP, and also its histomorphologic spectrum. patients with PRP were selected by natural language search of dermatopathology databases containing 250,000 cases accessioned over a 3-year period. A detailed medical history was obtained on each patient via office chart review and patient interviews. We compared the histologic findings in skin biopsies from patients with PRP to those of biopsies matched for site and age from control patients with psoriasis. Certain aspects of the clinical presentations encountered in the study group patients have not been previously emphasized, including eruptions compatible with a vesiculobullous disorder in 4 patients. Several patients had evidence of underlying iatrogenic or systemic immune dysregulatory states and certain triggers could be isolated such as emotional stress and prior exposure to microbial pathogens. Histomorphologic features predictive of PRP included follicular plugging, an increased granular cell layer, and acantholysis. While seen in a minority of biopsies of PRP, morphologic discriminators supportive of a diagnosis of psoriasis included neutrophils in the parakeratotic scale crust, and dermal papillae capillary ectasia with vessels lying in direct apposition to the epidermis. Other morphologic features were encountered in biopsies of PRP which have received little emphasis in the dermatopathology literature, including epithelial atrophy, significant dermal inflammation, the presence of eosinophils and plasma cells within the inflammatory infiltrates, an abnormal granular cell layer, and epidermolytic hyperkeratosis, albeit none were statistically signficant predictors of PRP over psoriasis. Nevertheless, their identification emphasizes the varied histologic spectrum of PRP. The almost ubiquitous finding of acantholysis and the presence of an abnormal granular cell layer in many biopsies of PRP suggests that abnormal keratins or defects in the retinol signalling pathway may be of pathogenetic importance.- - - - - - - - - - ranking = 1keywords = epidermis (Clic here for more details about this article) |