Objective: To investigate the clinicopathological characteristics, differential diagnosis and prognosis of nodal nevi (NN). Methods: Eighteen cases of NN diagnosed at Fudan University Shanghai Cancer Center, Shanghai, China from 2009 to 2019 were collected. The clinicopathological characteristics and follow-up data were retrospectively analyzed. Histopathologic evaluation and immunohistochemical studies were carried out. The Vysis Melanoma FISH Probe Kit, combined with 9p21(CDKN2A) and 8q24(MYC) assays were performed in 2 cases. Results: There were 2 males and 16 females in the case series. The age of the patients ranged from 36 to 70 years (average 48.2 years). Fifteen cases located in axillary lymph nodes, 1 in inguinal lymph node, 1 in cervical lymph node, and 1 in external iliac lymph node. NN was found in only one lymph node in each case. Histologically, the nevus cell aggregates were found in capsule of lymph nodes in all cases. Nevus cells grew along the capsule into trabeculae in 8 cases, with 3 of them scattered in parenchyma. In one of these 8 cases, nevus cell aggregates massively occupied the parenchyma of the lymph node. The largest lesions in the 18 NN cases measured from 0.2 to 6.5 mm. All of the NN cases were classified as conventional nevi. The majority of the cases were composed of uniform nevus-like cells and identical to cutaneous pigmented nevi without atypia, necrosis, or mitosis. In the NN case that massively occupied parenchyma, some areas had abundant nevus cells and displayed atypical cytologic features, including increased nucleo-cytoplasmic ratio, small nucleoli, and occasional mitotic figures. Immunohistochemistry was performed in 13 cases. All of them were positive for S-100, SOX10, Melan A, and p16. HMB45 showed weak staining in rare cells of only one case out of 13 cases. Ki-67 labeling index <1% was found in all 13 cases. Additionally, the results of FISH assay were both negative. All patients were followed up for 13 to 129 months (median 31.5 months). Except that one patient died of the salivary gland carcinoma, the other patients all survived without tumor during the follow-up period. Conclusions: NN is a benign melanocytic lesion in lymph node. It is important to distinguish NN from metastatic melanoma when nevus cells occur in parenchyma and subcapsular sinus of lymph nodes, or show some atypical cytologic features. The morphology of bland nevus cells in capsule and trabeculae is a valuable clue. Besides, immunohistochemical profiling and FISH assay are helpful in the differential diagnosis.
目的： 探讨淋巴结内痣的临床病理学特征、鉴别诊断要点及预后。 方法： 收集2009到2019年间复旦大学附属肿瘤医院诊断的18例淋巴结内痣，回顾性分析其临床病理学特征及随访资料。常规行HE和免疫组织化学染色进行组织病理形态学观察。其中2例行第一代黑色素瘤4色荧光原位杂交（FISH）及9p21（CDKN2A）、8q24（MYC）基因检测。 结果： 患者男性2例，女性16例，年龄36~70岁（平均年龄48.2岁）。淋巴结内痣发生部位分别为腋窝淋巴结15例，腹股沟淋巴结1例，颈部淋巴结1例，髂外淋巴结1例。所有病例均仅累及单个淋巴结。镜下观察，18例淋巴结被膜上均可见痣细胞聚集，8例同时沿着被膜伸入小梁中，其中3例呈小灶状散在分布于实质内，另有1例痣细胞呈团块状大量占据淋巴结实质。所有病例最大病灶的直径范围为0.2~6.5 mm。18例淋巴结内痣的组织学类型均为普通痣，绝大多数病例细胞学形态类似良性的皮肤色素痣细胞，缺乏明显的不典型性、坏死和核分裂象。仅1例占据实质的淋巴结内痣中可见少部分富于细胞区域呈现不典型特征，包括核质比增加、出现小核仁以及偶见核分裂象。13例样本的免疫组织化学检测显示S-100蛋白、SOX10、Melan A和p16均为阳性，仅1例HMB45有少数细胞弱阳性，所有病例Ki-67阳性指数<1%。2例痣细胞巢团累及实质内的淋巴结内痣FISH检测结果为阴性。所有患者均获得随访，随访时间13~129个月（中位时间31.5个月）。1例淋巴结内痣患者因涎腺癌全身转移死亡，其余所有患者均无瘤生存。 结论： 淋巴结内痣是一种良性的淋巴结内黑色素细胞增生性病变。当淋巴结内痣累及淋巴结实质及被膜下窦时，或偶尔出现细胞不典型性时，需要与转移性黑色素瘤鉴别。寻找被膜或小梁上形态温和的痣细胞巢团，以及借助免疫组织化学染色和FISH检测，可以帮助明确诊断。.