One hundred fifty yolk sac tumors (YSTs) of the ovary in patients from 1 to 61 (mean: 21.5) years of age are described; 75% of the patients were in the second and third decades and only 1 was above 50 years of age. The clinical manifestations were typically related to a fast-growing adnexal mass; endocrine manifestations (hirsutism) were present in only 2 cases. The tumors were all unilateral and 70% were ≥15 cm; an associated dermoid cyst was present in 20 cases. The tumors were solid and cystic in 57% of the cases, 25% were multicystic, and 18% uniformly solid. The solid tissue was typically tan to pink or yellow and often friable with hemorrhage and necrosis; smaller solid neoplasms were sometime uniformly yellow. The most common histologic pattern was reticular composed of an irregular meshwork of spaces that was conspicuous in 68% of the neoplasms but present to at least a minor degree in all of them. That appearance almost always merged with small to large cysts that were prominent in about 40% of tumors. In 25% of the tumors, cysts sometimes associated with a cellular stroma (the polyvesicular pattern), were present but conspicuous in only half these cases. One third of the tumors had a labyrinthine pattern, 22% glands, and 6% a festoon pattern. Papillae with a central blood vessel (Schiller-Duval bodies) were seen in one-third of the tumors but were numerous in only 5% of them. Nonspecific appearing papillae were seen in 10% of the tumors. A solid growth of cells with pale cytoplasm was seen in one-third of the tumors but was conspicuous in only half of that subset. The solid appearance was typically reminiscent of that of dysgerminoma, but lacked the septa and lymphocytic infiltrate of that neoplasm. Nine tumors had a component of cells with scant cytoplasm resulting in a blastema-like appearance and 3 had cells with abundant clear cytoplasm. Cords and clusters of cells were common but did not dominate the microscopic appearance. The stroma typically had a nonspecific collagenous to edematous appearance. Stromal luteinization was seen in 12 tumors; in 5 this was likely due to the patient being pregnant. Two tumors had minor foci of cells that resembled hepatocytes. Hyaline bodies were seen in most of the tumors and were often conspicuous. The neoplastic cells typically had modest amounts of lightly staining cytoplasm and only mild nuclear pleomorphism. Cells lining cysts were often flattened sometimes resulting in a deceptively innocuous appearance. Many of the tumors (mostly consultation cases), caused diagnostic difficulty; tumors in the differential diagnosis included clear cell carcinoma, embryonal carcinoma, Sertoli-Leydig cell tumor, and juvenile granulosa cell tumor. The patient age and marked elevation of the serum alpha-fetoprotein level (if measured) is helpful in many of these considerations. The overtly malignant gross appearance of most YSTs contrasts with certain other tumors in the differential and the association of some YSTs with dermoid cyst and many clear cell carcinomas with endometriosis may be helpful. The vast majority of ovarian YSTs are dominated microscopically by merging of reticular and cystic patterns which, although focally mimicked by other neoplasms, are in general characteristic, and distinctive features of other neoplasms are absent. Immunohistochemistry, particularly for alpha-fetoprotein and glypican 3, and lack of staining for various markers of other neoplasms is helpful but overlap exists and these results must be considered in the context of the overall clinical, gross, and microscopic features. YSTs dominated by hepatoid and glandular features are rare and their categorization as YSTs should be done cautiously if thoroughly sampled tumors show no evidence of classic features of YST emphasized herein and first elaborated by the Danish investigator Gunnar Teilum whose seminal observations have stood the test of time.

描述了 150 例卵巢卵黄囊肿瘤 (YST)，患者年龄为 1 至 61（平均：21.5）岁；75%的患者年龄在二十三岁，只有1人年龄在50岁以上。临床表现通常与快速生长的附件肿块有关；仅 2 例出现内分泌表现（多毛症）。肿瘤均为单侧，70%≥15 cm；20 例患者存在相关的皮样囊肿。57% 的病例肿瘤为实性囊性，25% 为多囊性，18% 为均匀实性。实体组织通常呈棕褐色至粉红色或黄色，并且常常因出血和坏死而易碎；较小的实体肿瘤有时呈均匀黄色。最常见的组织学模式是由不规则的空间网状结构组成的网状，在 68% 的肿瘤中很明显，但在所有肿瘤中至少有轻微程度的存在。这种外观几乎总是与小到大的囊肿合并，这些囊肿在约 40% 的肿瘤中很突出。在 25% 的肿瘤中，存在有时与细胞间质（多泡模式）相关的囊肿，但只有一半的病例很明显。三分之一的肿瘤呈迷宫状，22% 呈腺体状，6% 呈花彩状。三分之一的肿瘤中可见带有中央血管的乳头（席勒-杜瓦尔小体），但只有 5% 的肿瘤中乳头数量较多。10% 的肿瘤中可见非特异性乳头状突起。在三分之一的肿瘤中观察到细胞质呈浅色的固体生长，但只有一半的肿瘤亚群中的细胞生长很明显。固体外观通常让人想起无性细胞瘤，但缺乏该肿瘤的隔膜和淋巴细胞浸润。9 个肿瘤的细胞成分缺乏细胞质，导致胚基样外观，3 个肿瘤的细胞具有丰富的透明细胞质。细胞索和细胞簇很常见，但并不主导微观外观。基质通常具有非特异性胶原至水肿的外观。在 12 个肿瘤中观察到间质黄素化；5 这可能是由于患者怀孕了。两个肿瘤具有类似肝细胞的小细胞灶。大多数肿瘤中可见透明体，并且常常很明显。肿瘤细胞通常具有适量的浅色细胞质和仅轻度的核多形性。囊肿内壁的细胞常常变平，有时会产生看似无害的外观。肿瘤较多（多为会诊病例），造成诊断困难；鉴别诊断中的肿瘤包括透明细胞癌、胚胎癌、支持-间质细胞瘤和幼年颗粒细胞瘤。患者年龄和血清甲胎蛋白水平显着升高（如果测量）对于许多这些考虑都有帮助。大多数 YST 的明显恶性外观与某些其他肿瘤在鉴别上形成鲜明对比，一些 YST 与皮样囊肿和许多透明细胞癌与子宫内膜异位症的关联可能会有所帮助。绝大多数卵巢YST在显微镜下以网状和囊性模式的融合为主，尽管与其他肿瘤有局灶性模仿，但具有一般特征，并且不存在其他肿瘤的独特特征。免疫组织化学，特别是对于甲胎蛋白和磷脂酰肌醇蛋白聚糖3，以及其他肿瘤的各种标记物缺乏染色是有帮助的，但存在重叠，必须在整体临床、大体和微观特征的背景下考虑这些结果。以肝样和腺体特征为主的 YST 很少见，如果彻底取样的肿瘤没有显示本文强调的 YST 经典特征的证据，则应谨慎进行 YST 分类，该特征由丹麦研究者 Gunnar Teilum 首先阐述，其开创性观察经受了时间的考验。