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伴肉芽肿反应的原发性胸腺纵隔精原细胞瘤病例

已有 161 次阅读2020-5-7 22:23 |个人分类:TET学习|系统分类:医学科学| 胸腺肿瘤, 精原细胞瘤

伴肉芽肿反应的原发性胸腺纵隔精原细胞瘤。生殖细胞肿瘤(GCT)主要发生在性腺,但它们倾向于起源于中线结构,如纵隔、腹膜后、松果体和骶部区域,形成一组称为性腺外GCT的组织。前纵隔是原发性腺外GCT最常见的部位。原发性纵隔精原细胞瘤通常位于前纵隔,年轻男性多见。精原细胞瘤是继成熟畸胎瘤之后第二常见的纵隔GCT。

  Germ cell tumors (GCTs) occur primarily in the gonads; however, they have a predilection to arise from midline structures such as mediastinum, retroperitoneum, pineal gland, and sacral region forming a group designated as extragonal GCTs. Anterior mediastinum is the most common site for primary extragonadal GCTs. Primary mediastinal seminoma is usually located in the anterior mediastinum and affects young male. It constitutes 25% of all extragonadal GCTs. Seminoma is the second most common type of GCT of the mediastinum after mature teratoma.

  前纵隔最常见的肿瘤是胸腺,淋巴或生殖细胞起源。与异常甲状腺或甲状旁腺相关的肿块少见。纵隔GCTs可为良性(成熟畸胎瘤)或恶性,包括精原细胞瘤,非精原细胞瘤GCTs如胚胎癌、不成熟畸胎瘤、卵黄囊瘤、绒毛膜癌或混合GCT。

  The most common tumors found in the anterior mediatinal compartment are of thymic, lymphatic or germ cell origin. More rarely masses associated with aberrant thyroid or parathyroid are found. GCTs of the mediastinum can be benign (mature teratoma) or malignant including seminomas, and nonseminomatous GCTs such as embryonal carcinoma, immature teratoma, yolk sac tumor, choriocarcinoma, or mixed GCTs.

  精原细胞瘤和非精原细胞瘤GCT的起源存在争议。根据一种理论,它们是从性腺外卵黄囊生发细胞发展而来的,这些细胞沿着泌尿生殖嵴向性腺的正常迁移在纵隔被阻留了。另一种理论认为它们由于胸腺发育不良而起源于胸腺。纵隔精原细胞瘤常与胸腺相关。

  Some debate exists betwee n the origin of seminomatous and nonseminomatous GCTs. According to one theory, they develop from extragonadal yolk sac germinal cells whose normal migration along urogenital ridge to gonads was halted in the mediastinum.[4] Another theory suggests that they originate in the thymus due to its maldevelopment. Mediastinal seminoma is often associated with the thymus.

  原发性纵隔精原细胞瘤是一种少见但定义明确的疾病,常累及青年男性。患者表现为呼吸困难、咳嗽、发热、体重减轻,很少出现上腔静脉综合征。在大多数情况下,病变都是偶然发现,患者没有症状。

  Primary mediastinal seminoma is rare but well-defined disease which commonly affects young men. The diagnosis should be considered after exclusion of primary testicular tumor. The patients present with dyspnea, cough, fever, weight loss, and rarely superior vena cava syndrome.In most cases, these are detected incidentally, the patients being asymptomatic.

  组织形态学特征通常与性腺特征不可区分。很少有纵隔精原细胞瘤伴继发性改变的病例报告,这可能掩盖了我们病例中的实际诊断。这些变化包括反应性滤泡增生、大囊肿、上皮样肉芽肿和纤维化。我们的病例在镜下是一个诊断难题,因为只有局部区域显示肿瘤细胞,这些细胞被炎症细胞掩盖,并伴有花斑样肉芽肿反应。

  The histomorphological features are usually indistinguishable from its gonadal counterpart. There are few case reports of mediastinal seminoma accompanied by secondary changes which may conceal the actual diagnosis as was seen in our case. These changes include reactive follicular hyperplasia, large cysts, epithelioid granulomas, and fibrosis. Our case was a diagnostic dilemma on microscopic examination as there were only focal areas showing neoplastic cells which were being masked by inflammatory cells along with florid granulomatous reaction.

  纵隔精原细胞瘤与转移性黑色素瘤、胸腺瘤、胸腺癌、霍奇金病和间变性大细胞淋巴瘤的鉴别诊断需要借助免疫组织化学(IHC)等辅助技术,尤其是当原发肿瘤的形态学变得模糊时。

  Mediastinal seminomas need to be differentiated from metastatic melanoma, thymoma, thymic carcinoma, Hodgkin disease, and anaplastic large cell lymphoma by use of ancillary techniques like immunohistochemistry (IHC), especially if the morphology of the original tumor is getting obscured.

  很多这些疾病也报道有明显的肉芽肿反应。IHC用完整的抗体组来识别肿瘤细胞的表型。本病例的诊断是在IHC显示肿瘤细胞对PLAP、CD117和D2-40呈强阳性后确定的。D2-40在纯精原细胞瘤中呈弥漫膜阳性,在胚胎癌中呈阳性染色,因此不能排除胚胎癌。此外,D2-40不是生殖细胞瘤的特异性标记物,因为它在间皮细胞、淋巴管内皮细胞及其肿瘤中都有表达。D2-40在皮肤腺嘌呤类肿瘤、肾上腺皮质肿瘤、滑膜肉瘤、胚胎癌等也呈阳性,因此与Oct3/4+SOX2相比,它作为生殖细胞肿瘤鉴别诊断标志物的应用受到限制。然而,PLAP仅在精原细胞瘤中呈不同程度的阳性,是本病例鉴别诊断的良好指标。我们中心没有Oct3/4和SOX2标记。

  Many of these entities have also been reported with exuberant granulomatous reaction.[9] The complete panel of antibodies was used for IHC to discern the phenotype of the neoplastic cells. The diagnosis of the present case was established after IHC showed tumor cells to be strongly positive for PLAP, CD117, and D2-40. D2-40 gives diffuse membrane positivity in pure seminoma as well as positive staining in embryonal carcinoma hence embryonal carcinoma cannot be excluded by this marker. Besides D2-40 is not specific marker for Germinoma as it shares expression in mesothelial cells, lymphatic endothelium, and its neoplasm. D2-40 is also positive in adenxal tumors of the skin, adrenal cortical tumors, synovial sarcoma, embryonal carcinoma, etc., thus limiting its utility as a differential diagnostic marker in germ cell tumors as compared to Oct3/4 plus SOX2. However, PLAP is variably positive only in seminoma and was a good marker for differential diagnosis in our case. Oct3/4 and SOX2 markers were unavailable at our center.

  纵隔精原细胞瘤可发生转移。只有30-40%患者的肿瘤局限于胸腺。最常见侵犯肺部和其他胸内结构。治疗包括联合手术和放化疗。小肿瘤可以尝试完全切除,术后放射治疗40-45gy即可治愈。众所周知,以顺铂为基础的化疗可以诱导精原细胞瘤患者的完全反应。我们的患者在化疗的同时也对手术有反应,目前正在进行MDTC的OPD随访。这个病例强调了获得足够活检标本的重要性。

  Metastasis in mediastinal seminomas is known to occur. Only 30–40% of patients are found to have localized disease. The most common behavior is an invasion into lungs and other intrathoracic structures. Treatment includes a combination of surgery and chemo-radiotherapy. Small tumors can be attempted for complete resection and postoperative radiotherapy of 40–45 Gy is curative. Cisplatin-based chemotherapy is known to induce complete response in patients with seminoma.Our patient responded to surgery along with chemotherapy and is presently on OPD follow-up at MDTC. This case highlights the importance of obtaining an adequate biopsy specimen.

  因此,作为一种具有良好预后的可治疗肿瘤,早期正确诊断纵隔精原细胞瘤是至关重要的。继发性改变不应作为诊断的误区,并且在报告小型活检时应保持足够的警惕。病理专家对原发性病变的高度怀疑和对继发性病变的认识有助于早期诊断。

  Thus, being a treatable tumor with a good prognosis early and correct diagnosis of mediastinal seminoma is of paramount importance. Secondary changes should not act as a deterrent in diagnosis and one should be vigilant enough while reporting on a small biopsy. A high index of suspicion by an astute pathologist and awareness of the secondary changes which can mask the primary lesion can help to clinch the diagnosis early.

  由于一些纵隔肿块,如淋巴瘤,无法通过手术治疗,因此通常尝试针芯或微创活检进行诊断。这些小的活检可能不能代表真正的病变,只能描绘出周围的继发性变化,如在本例中所见。

  As some mediastinal masses such as lymphoma are not treated surgically, a diagnosis is often attempted on needle core or minimally invasive biopsies. These small biopsies may not be representative of the true lesion and depict only the peripheral secondary changes as was seen in our case.

图1:(a)正位胸片示肺门区轻度分叶的纵隔肿块。 (b)胸部CT增强显示前纵隔不均质肿块,未侵犯大血管

Figure 1: (a) Frontal chest radiograph showing a mildly lobulated mediastinal mass at the region of pulmonary bay. (b) Contrast enhanced computed tomography chest shows a heterogenous well-defined mass in the anterior mediastinum, not invading the great vessels

图2:大体标本显示多结节棕褐色卵形纵隔肿物,包膜不完整,外围边缘稍不规则,呈锐角; 切面质实,橡胶状坚硬

Figure 2: Gross specimen shows nonencapsulated multinodular tan-brown ovoid mediastinal mass with slightly irregular to sharp peripheral margins; the cut surface is solid and rubbery firm in consistency

图3:(a)纵隔肿块的镜下(×10)显示肉芽肿呈花斑样散在到融合。(b)高倍镜下可见肿瘤细胞散布在肉芽肿周围。 恶性细胞呈大多面体形态,胞质丰富,胞浆薄,核膜突出,核仁内可见粗大的染色质团,核膜明显,核仁呈骨架状突起。(c) CD117免疫染色显示精原细胞瘤细胞膜强阳性。

Figure 3: (a) Microscopic examination of the mediastinal mass (×10) shows florid discrete to confluent granulomas. (b) Higher magnification shows tumor cells interspersed and rimming these granulomas. The malignant cells appear to be of large polyhedral shape with abundant thin cytoplasm and round to oval vesicular nucleus with coarse clumped chromatin encircling clear areas in nucleoplasm, prominent nuclear membrane, and skein-like prominent nucleolus. (c) Immunostaining with CD117 shows strong membranous positivity in the seminoma cells

参考文献:Gupta D, Rath A, Rathi KR, Singh G. Primary thymic mediastinal seminoma with florid granulomatous reaction. Indian J Pathol Microbiol. 2016 Jul-Sep;59(3):351-4. doi: 10.4103/0377-4929.188113. PubMed PMID: 27510675.


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发表评论 评论 (2 个评论)

回复 hyc3140 2020-5-21 19:10
恶性生殖细胞瘤与侵袭性胸腺瘤、胸腺癌及淋巴瘤难以鉴别Mediastinal seminoma mimicking invasive
thymoma on 18F-FDG PET/CT
回复 hyc3140 2020-5-21 19:22
对比分析CT和MRI及DWI在诊断胸腺恶性生殖细胞瘤的价值

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