Perrin Christophe, Cannata Giuseppe Emilio, Bossard Celine, Grill Jean Marie, Ambrossetti Damien, Michiels Jean-François
Laboratoire Central d'Anatomie Pathologique, Hôpital Pasteur, University of Nice, France.
Am J Dermatopathol. 2012 Feb;34(1):54-9. doi: 10.1097/DAD.0b013e31822c3d8b.
Among the tumors of the epidermal appendages, only rare tumors have been proved as differentiating in the direction of the nail. Beside onychomatricoma, we report a new matrical tumor of the nail: onychocytic matricoma (acanthoma of the nail matrix producing onychocytes). The main differential diagnosis of onychocytic matricoma is seborrheic keratosis. However, if attention is paid to the nature of the different layers of the tumor and the peculiar microanatomy of the nail matrix, the differentiation is not difficult. Onychocytic matricoma is a localized (monodactylous) longitudinal melanonychia which is slightly raised. The term pachymelanonychia is used to define the 2 clinical features of the tumor. Pachyonychia indicate a localized thickening of the nail plate, and melanonychia indicate its longitudinal pigmented band. Onychocytic matricoma is composed of a basal compartment with a varying admixture of prekeratogenous cells and keratogenous cells. Endokeratinization originating in the deep portion of the tumor and nests of prekeratogenous and keratogenous cells in concentric arrangement are a characteristic feature. Three major patterns can be identified as follows: acanthotic, papillomatous, keratogenous type with retarded maturation. Given the peculiar thickening of the nail plate observed both in pigmented onychomatricoma and onychocytic matricoma, the term pachymelanonychia longitudinal could be proposed to specify clinically these 2 lesions, which the clinician sometimes mistakes for melanoma.
在表皮附属器肿瘤中，仅有罕见肿瘤被证实可向甲方向分化。除甲母质瘤外，我们报告一种新的甲母质肿瘤：甲母质细胞痣（产生甲母质细胞的甲母质棘皮瘤）。甲母质细胞痣的主要鉴别诊断是脂溢性角化病。然而，如果关注肿瘤不同层次的性质以及甲母质独特的微观解剖结构，鉴别并不困难。甲母质细胞痣是一种局限性（单指）纵向黑甲，略隆起。厚甲黑甲这一术语用于定义该肿瘤的两个临床特征。厚甲指甲板局限性增厚，黑甲指其纵向色素带。甲母质细胞痣由一个基底部分组成，含有不同比例的角质形成前细胞和角质形成细胞。起源于肿瘤深部的内角质化以及角质形成前细胞和角质形成细胞呈同心排列的巢状结构是其特征性表现。可识别出三种主要模式如下：棘皮瘤型、乳头瘤型、成熟延迟的角质形成型。鉴于在色素性甲母质瘤和甲母质细胞痣中均观察到甲板的特殊增厚情况，可提出纵向厚甲黑甲这一术语来在临床上明确这两种病变，临床医生有时会将其误诊为黑色素瘤。
