Perrin Christophe, Baran Robert, Balaguer Thierry, Chignon-Sicard Bérangère, Cannata Giuseppe E, Petrella Tony, Michiels Jean-François
Laboratoire Central d'Anatomie Pathologique, Hôpital Pasteur, University of Nice, Nice, France.
Am J Dermatopathol. 2010 Feb;32(1):1-8. doi: 10.1097/DAD.0b013e3181af8516.
To further define the clinicopathological spectrum of onychomatricoma (OM). We report the clinical feature, histological, and immunophenotypic characteristics of 19 cases of OM diagnosed between 2002 and 2007. The characteristic histologic appearance of OM is sometimes difficult to grasp because of 3 main factors: the anatomic particularities of the nail apparatus, the often fragmented aspect of the tissue specimen, and the choice of the section planes, which strongly modified the morphologic appearances observed. To prevent these difficulties, we built a tridimensional model using serial, transverse, and longitudinal sections. This reconstitution gives us a better understanding of the apparent diversity of the morphologic aspects observed in linking them to the anatomic site of the tumor. OM of the matrix is characterized by a thick nail plate with porch roof. OM of the ventral aspect of the proximal nail fold (PNF) is characterized by a nail plate without porch roof, exhibiting either a woodworm-like appearance or multiple cavities. In this second category, the fibrous base becomes elongated in shape, taking the shape of the anatomic contour of the PNF. The stroma gives rise to numerous fibroepithelial digitations. This pattern is different from the classical OM visualized in longitudinal sections, which appears as a single and large fibroepithelial tumor, that is, the multiple distal epithelial digitations arranged along a transversal plane are not seen. In the PNF variant, the characteristic clinical signs of OM fail to appear. We individualize 3 misleading clinical variants: tumor with a verrucous surface that is located in the lateral nail fold, as a band pattern suggesting wart or Bowen disease; a total dystrophy of the nail unit mimicking a squamous cell carcinoma; and pseudofibrokeratoma type. In the OM located on the ventral matrix, 3 new specific histologic variants were noted: pleomorphic OM, OM with a predominantly collagenous stroma, and superficial acral fibromyxoma-;like OM. OM is a benign tumor with a broader morphologic spectrum than previously thought. When the nail plate is not available, the immunohistochemistry can aid diagnosis by highlighting the peculiar immunophenotyping of OM, which expresses CD34 but not CD99, epithelial membrane antigen, S-100 protein, actin, and desmin.
为进一步明确甲母质瘤（OM）的临床病理谱。我们报告了2002年至2007年间确诊的19例OM的临床特征、组织学及免疫表型特征。由于三个主要因素，OM的特征性组织学表现有时难以把握：甲器的解剖特殊性、组织标本常呈碎片化外观以及切片平面的选择，这些因素会显著改变所观察到的形态学表现。为避免这些困难，我们利用连续的横切面和纵切面构建了一个三维模型。这种重建使我们能更好地理解所观察到的形态学方面的明显多样性，并将它们与肿瘤的解剖部位联系起来。甲母质的OM表现为甲板增厚呈门廊屋顶状。近端甲襞（PNF）腹侧的OM表现为无门廊屋顶的甲板，呈蛀虫样外观或有多个腔隙。在这第二类中，纤维性基底形状拉长，呈PNF的解剖轮廓形状。间质产生许多纤维上皮指状突起。这种模式不同于纵切面上所见的经典OM，经典OM表现为单个大的纤维上皮肿瘤，即沿横向平面排列的多个远端上皮指状突起不可见。在PNF变异型中，OM的特征性临床体征未出现。我们确定了3种具有误导性的临床变异型：位于侧甲襞、表面呈疣状的肿瘤，呈带状模式提示疣或鲍温病；甲单元完全营养不良，类似鳞状细胞癌；以及假纤维角化瘤型。在位于腹侧甲母质的OM中，发现了3种新的特异性组织学变异型：多形性OM、以胶原性间质为主的OM以及浅表性肢端纤维黏液瘤样OM。OM是一种良性肿瘤，其形态谱比以前认为的更广泛。当没有甲板时，免疫组化可通过突出OM独特的免疫表型来辅助诊断，OM表达CD34但不表达CD99、上皮膜抗原、S - 100蛋白、肌动蛋白和结蛋白。
