Journal of cutaneous pathology
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Case Reports
Histopathology of an adverse reaction to a eutectic mixture of the local anesthetics lidocaine and prilocaine.
A unique histopathologic reaction to the topical application of a eutectic mixture of the local anesthetics lidocaine and prilocaine (EMLA), used for topical anesthesia prior to biopsy in two children is described. Standard application of EMLA cream under occlusion for 1 h was given to both patients. ⋯ The epidermis was focally separated from the dermis in areas of basal vacuolar alteration. Electron microscopy performed in one case demonstrated the dermal-epidermal cleft to be secondary to alteration of the basal cells with condensation of the cytoplasm and cytologic degeneration similar to that seen in epidermolysis bullosa simplex.
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The hair follicle mites Demodex folliculorum and Demodex brevis and their role in the pathogenesis of rosacea have been the subject of much debate in the past. We studied the prevalence of Demodex mites in facial skin biopsies obtained from 80 patients with rosacea, 40 with facial eczematous eruption and 40 with lupus erythematosus discoides. The mite prevalence in the rosacea group (51%) was significantly higher than in the rest of the study population (eczema 28% and lupus discoides 31%). ⋯ We did not find any significant difference in mite counts of infested follicles between rosacea and the control group. A lympho-histiocytic cell infiltration was seen around the infested hair follicles. Our results suggest that Demodex mites may play a role in the inflammatory reaction in acne rosacea.
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The etiology and pathogenesis of idiopathic guttate hypomelanosis (IGH) are largely unknown. To investigate whether the pathologic alteration in IGH involves changes in melanocytic differentiation, cell number, or both, we studied nine lesions of IGH by immunoperoxidase, using monoclonal antibodies against the KIT receptor and a panel of melanocyte differentiation antigens (tyrosinase-related protein-1, tyrosinase, and gp100/pme117). ⋯ Double immunofluorescence labeling of lesions revealed only scattered cells with a less-differentiated phenotype, i.e. cells positive for KIT but having low or undetectable TRP-1. These results indicate that the pathogenesis of IGH involves an absolute decrease in the number of melanocytes; a block in melanocyte differentiation does not appear to be a major component of the process.
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It is important to differentiate the collodion baby from harlequin ichthyosis as the latter rarely survives past the first few days of life. Occasionally, babies share features of both disorders and defy a clinical diagnosis. We recently encountered such a baby who initially presented with harlequin-like features, but evolved into lamellar ichthyosis once the keratin cast was shed. ⋯ In harlequin ichthyosis, the marginal band is present at birth. It is suggested that electron microscopy can differentiate severe collodion baby from harlequin ichthyosis at birth using the absence of the marginal band. Previously reported features of harlequin ichthyosis, such as the presence of giant mitochondria and an abnormal formation of the marginal band in luminal villi of acrosyringeal eccrine duct, were absent in our case.
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We report 3 cases of severe burns in children in which eccrine squamous syringometaplasia (ESS) was found in skin biopsies taken 10 days after the trauma occurred. Microscopic examination showed partial or total necrosis of the epidermis, focal dermal necrosis and squamous metaplasia in eccrine ducts. These cases appear to be the first reported instances of ESS as an early consequence of severe burns.