Metze D, Rütten A
Department of Dermatology, University of Münster, Germany.
J Cutan Pathol. 1999 Aug;26(7):339-52. doi: 10.1111/j.1600-0560.1999.tb01855.x.
Axillary granular parakeratosis is a recently described condition presenting with erythematous hyperkeratotic papules and plaques. We report on nine women and one man with eruptions not only localized to the axillae. Biopsy specimens were investigated by histology, immunohistochemistry, electron microscopy, immuno-electron microscopy, and in situ hybridization. In general, the epidermis was hyperplastic and showed a well preserved stratum granulosum. In the upper dermis a discrete perivascular CD4+ T-cell infiltrate was found, CD1+ dendritic cells were absent from the epidermis. The distribution pattern of the epidermal keratins (keratin 5/14, 1/10) and the expression of involucrin was regular. The horny layer was excessively thickened and parakeratotic. The nuclear remnants showed marginal chromatin condensation and were reactive for the nick-end labeling technique using TdT-mediated dUTP-biotin. The corneocytes were characteristically replete with basophilic granules which showed both ultrastructural features of keratohyalin granules and immunoreactivity for filaggrin. Loricrin was expressed irregularly in small L-granules. Granular parakeratotic cells revealed regular development of a cornified envelope while cell membranes and desmosomes remained undegraded. In conclusion, our studies on granular parakeratosis suggest a basic defect in processing of profilaggrin to filaggrin that results in a failure to degrade keratohyalin granules and to aggregate keratin filaments during cornification. Associated abnormalities of the cell surface structures and dysregulation of cornified envelope components may account for the retention hyperkeratosis. Further studies are necessary to clarify the etiology of this unique, acquired disorder of keratinization that localizes to intertriginous areas and body folds.
腋窝颗粒状角化不全是一种最近才被描述的疾病，表现为红斑性角化过度丘疹和斑块。我们报告了10例患者（9名女性和1名男性），其皮疹不仅局限于腋窝。对活检标本进行了组织学、免疫组织化学、电子显微镜、免疫电子显微镜和原位杂交检查。总体而言，表皮增生，颗粒层保存良好。在上层真皮中发现了离散的血管周围CD4 + T细胞浸润，表皮中不存在CD1 + 树突状细胞。表皮角蛋白（角蛋白5/14、1/10）的分布模式和兜甲蛋白的表达是正常的。角质层过度增厚且角化不全。核残余物显示边缘染色质凝聚，并且对使用TdT介导的dUTP生物素的缺口末端标记技术有反应。角质形成细胞的特征是充满嗜碱性颗粒，这些颗粒既显示透明角质颗粒的超微结构特征，又对丝聚蛋白有免疫反应性。兜甲蛋白在小L颗粒中表达不规则。颗粒状角化不全细胞显示角质包膜正常发育，而细胞膜和桥粒未降解。总之，我们对颗粒状角化不全的研究表明，前丝聚蛋白加工成丝聚蛋白存在基本缺陷，这导致在角质化过程中无法降解透明角质颗粒和聚集角蛋白丝。细胞表面结构的相关异常和角质包膜成分的失调可能是导致潴留性角化过度的原因。需要进一步研究以阐明这种独特的、后天性角化异常疾病的病因，该疾病局限于擦烂部位和身体褶皱处。
