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Objective To investigate ultrahistopathological features of symmetrical acrokeratoderma.Methods Biopsy specimens were obtained from skin lesions and perilesional normalappearing skin of 6 patients with symmetrical acrokeratoderma,as well as from normal skin of 3 healthy volunteers.Then,these skin specimens were subjected to transmission electron microscopy (TEM).Results TEM showed obviously thickened stratum corneum,irregular morphology of keratinocytes and discontinuous cornified envelope.Aggregation and abnormal arrangement of keratin filaments occurred in all epidermal layers.Many vacuoles of different sizes were observed in the transitional zone between the stratum corneum and stratum granulosum.Hypogranulosis,abnormal shape and different sizes of keratohyalin granules,and reduction of membrane-coating granules were found in the stratum granulosum.Increased melanocytes with a large number of stage Ⅳ melanosomes in the cytoplasm were observed in the basal layers.Moreover,there was infiltration of a few lymphocytes in the superficial dermis.Perilesional normal-appearing skin tissues showed similar but milder ultrastructural changes.Conclusion Abnormal metabolism of keratins,epidermal differentiation complex proteins and lipids may exist in skin lesions of symmetrical acrokeratoderma,which may contribute to epidermal thickening and impairment of skin barrier function.
RESUMEN
Objective To investigate the expressions of fatty acid-binding protein 5 (FABP5)and dihydroli-poamide dehydrogenase(DLD)in skin lesions of symmetrical acrokeratoderma(SAK), and to explore their significance. Methods Biopsy specimens were obtained from skin lesions on the wrists and perilesional skin of 9 patients with SAK, and from normal skin in the wrists of 9 healthy volunteers (control group). Reverse transcription PCR (RT-PCR)and immunohistochemical staining were performed to measure the expressions of FABP5 and DLD in these specimens. Results RT-PCR showed no significant differences in the mRNA expressions of FABP5 or DLD between lesional, perilesional and normal control skin specimens(both P > 0.05). Immunohistochemically, there was a significant increase in the extent and intensity of staining for FABP5 in SAK lesions. Concretely speaking, FABP5 was strongly expressed in the stratum corneum, granular and spinous layers in SAK lesions, but weakly expressed in the stratum corneum, granular and spinous layers in perilesional skin, and only in spinous and basal layers in normal control skin. The expression of DLD decreased in SAK lesions, and was observed only in the stratum corneum and spinous layer in a few cases of SAK. However, the full-thickness epidermis stained positive for DLD in perilesional skin, with the nuclei and cytoplasm both stained deep brown. Conclusion The overexpression of FABP5 in SAK lesions may participate in dysdifferentiation of keratinocytes, while the down-regulation of DLD expression suggests an imbalance in energy metabolism.