Keratocystoma of the parotid gland: A report of two cases of an unusual pathologic entity
Keratocystoma of the parotid gland: A report of two cases of an unusual pathologic entity
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DOI：
10.1097/01.mp.0000026053.67284.a3
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发表时间：
2002-09-01
期刊：
影响因子：
7.5
通讯作者：
Ebihara, Y
中科院分区：
文献类型：
--
作者：
Nagao, T;Serizawa, H;Ebihara, Y
由纯鳞状细胞组成的良性唾液腺肿瘤非常罕见，并且不包括在世界卫生组织的分类中。我们已经看到两个良性腮腺肿瘤的特点是多囊性空间分层鳞状衬里和局灶性实性上皮巢。Seifert等最近将这种情况描述为脉络膜瘤;然而，我们在此提出了一个新的名称，角化囊肿，因为它独特的组织学特征，为这个独特的肿瘤组。这些肿瘤发生在18岁和38岁的男性腮腺肿瘤扩大。两者的大体和组织学特征基本相似，但存在一些差异。囊肿的上皮衬里通过角化不全或角化矫正途径表现出明显的角化，但未形成颗粒细胞层。上皮的分层总是有规律地从外基底层到内角化细胞层。外层局部有芽状突起。在某些区域，被基底膜包围的固体鳞状细胞岛被封闭在胶原基质内。这些囊实性结构随机分布，没有明确的小叶结构。所有肿瘤细胞均具有均匀、淡黄色的细胞核和丰富的嗜酸性胞浆。观察到散在的有丝分裂像，仅限于外上皮层，未显示异常模式。腮腺导管上皮向肿瘤细胞的转化是明显的。存在针对角蛋白材料的异物反应病灶。细胞角蛋白的免疫反应再次证实了肿瘤细胞鳞状分化的性质。Ki-67阳性细胞沿着肿瘤上皮的外基底层分布。α-平滑肌肌动蛋白和S-100蛋白的检测结果完全阴性。两例患者分别在腮腺次全切除术后3年和2年没有复发的证据，没有任何额外的治疗。我们认为这种病变是一种良性囊性肿瘤，而不是恶性肿瘤或假瘤性化生。重要的是要认识到这种特殊的良性肿瘤确实起源于唾液腺。
Benign salivary gland tumors composed of purely squamous cells are quite unusual and are not included in the World Health Organization classification. We have seen two benign parotid gland tumors characterized by multicystic spaces with stratified squamous linings and focal solid epithelial nests. Seifert et al. recently described such a case as a choristoma; we, however, herein propose a new designation, keratocystoma, for this unique tumor group, because of its distinctive histological features. These tumors occurred in men aged 18 and 38 years with enlarging parotid gland tumors. Both had largely similar gross and histological features, with some variations. The epithelium lining of the cysts showed apparent keratinization through a parakeratotic or orthokeratotic pathway without forming a granular cell layer. Stratification of the epithelium was always regularly oriented from the outer basal to the inner keratotic cell layer. Focally, the outer layer had bud-like protrusions. In some areas, solid squamous cell islands surrounded by basement membrane were enclosed within the collagenous stroma. These cystic and solid structures were randomly distributed, showing no definite lobular architecture. All of the tumor cells had uniform, bland nuclei and abundant eosinophilic cytoplasm. Scattered mitotic figures were observed, limited to the outer epithelial layer, and showed no abnormal patterns. Transformation from the parotid ductal epithelium to the tumor cells is evident. Foci of foreign-body reactions against keratin materials were present. Immunoreactivities for cytokeratins reconfirmed the nature of squamous differentiation of the tumor cells. Ki-67-positive cells were confined along the outer basal layer of the tumor epithelium. Tests for alpha-smooth muscle actin and S-100 protein were completely negative. Both patients had no evidence of recurrence 3 and 2 years after subtotal parotidectomy, respectively, without any additional therapy. We believe that this lesion represents a benign cystic neoplasm rather than a malignant tumor or pseudoneoplastic metaplastic condition. It is important to recognize that this peculiar benign tumor does originate from the salivary gland.