Mediastinal seminoma presenting as a neck mass falsely diagnosed as anaplastic thyroid carcinoma: A case report

Germ cell tumors can occur in the mediastinum. They account for about 20% of tumors at this location. The majority are located in the anterior mediastinum and usually occur in young adult males. Extension of mediastinal germ cell tumors into the neck with mass formation is a very rare and unusual event. Herein, we report a case of a 34 year old male who presented with a progressively enlarging neck mass. Fine Needle Aspiration (FNA) was performed as initial evaluation and showed cellular smears comprising atypical large cells with prominent irregular nucleoli and moderate amount of cytoplasm with lymphocytic infiltrate and some epithelioid granulomas in the background. The mass was misdiagnosed initially on the cytology smears as anaplastic thyroid carcinoma. The subsequent tissue core biopsy showed sheets and nests of atypical cells admixed with ill‐defined granulomatous inflammation. By immunohistochemistry, the tumor cells were immunoreactive with SALL4, PLAP and OCT3/4, compatible with malignant germ cell tumor, seminomatous type. It is very rare for patients with primary mediastinal seminoma to present initially with a neck mass. Fine Needle Aspiration (FNA) of this “neck mass” can lead to misinterpretation of findings due to similarities in cytological features between malignant germ cell tumors and other undifferentiated malignant neoplasms and the diagnosis, therefore, can be very challenging.     

Case report: Different metastatic components from anaplastic thyroid carcinoma in mediastinal and neck lymph nodes simultaneously diagnosed by FNA

Anaplastic thyroid carcinoma (ATC) is a rare but aggressive form of undifferentiated thyroid carcinoma which arises from previously well‐differentiated thyroid carcinomas, such as papillary carcinoma or follicular carcinoma. We report on an interesting case of ATC found in an enlarging neck mass with metastatic papillary carcinoma found in mediastinal lymph nodes sampled by endoscopic bronchial‐ultrasound guided‐ fine‐needle aspiration, due to the incidental finding of a lung mass by CT scan. Divergent morphologies on cytology preparations were resolved by immunohistochemistry, which aided in the identification of both sites of malignancy and the common thread between them. The eventual palliative resection demonstrated the various components including undifferentiated thyroid carcinoma, papillary carcinoma, and background lymphocytic thyroiditis. Diagn. Cytopathol. 2014;42:694–699. © 2013 Wiley Periodicals, Inc.     

Cell proliferation marker MCM2, but not Ki67, is helpful for distinguishing between minimally invasive follicular carcinoma and follicular adenoma of the thyroid

AIMS: To compare cell proliferation markers, minichromosome maintenance protein 2 (MCM2) and Ki67, in minimally invasive follicular carcinoma (MIFC) and follicular adenoma (FA) of the thyroid and among MIFCs with different diagnostic criteria. METHODS AND RESULTS: Twenty-two MIFCs and 20 FAs were immunohistochemically stained for MCM2 and Ki67. The MIFCs were subdivided into six Group 1 tumours with both capsular and vascular invasions, seven Group 2 tumours with vascular invasion only and nine Group 3 tumours with capsular invasion only. The MCM2 and Ki67 indices were calculated, counting more than 1000 tumour cells in the most frequently positive areas. In total and Groups 1-3 MIFCs and in FAs, the average MCM2 index was 26.7 +/- 11.0, 28.4 +/- 8.6, 26.3 +/- 14.8, 25.9 +/- 8.4 and 10.7 +/- 4.5, respectively, whereas the average Ki67 index was 2.07 +/- 1.65, 1.93 +/- 2.02, 2.49 +/-1.38, 1.84 +/- 1.5 and 1.78 +/- 0.92, respectively. There was a significant difference in the MCM2 index, but not in the Ki67 index, between each category of MIFCs and FA (P < 0.01). However, neither the MCM2 index nor the Ki67 index showed a statistically significant difference among the subgroups of MIFC. CONCLUSIONS: MCM2, but not Ki67, is a helpful marker for differentiating MIFC from FA. The tumour cell proliferative activity supports the histological criteria based on diagnosing MIFC by either capsular or vascular invasion only.     

Immunohistology of anaplastic thyroid carcinoma. A study of 43 cases

Forty-three cases of large cell anaplastic thyroid carcinoma were examined with various antisera. Four histological patterns were identified: spindle cell, giant cell, trabecular and squamous. In 38 cases the epithelial origin was demonstrated with various epithelial markers: 11 cases stained positively for thyroglobulin, 19 for T3 and/or T4, 35 for fat globule membrane antigens, 28 for keratin, 29 for lactoferrin, and one for calcitonin. Five cases were negative for all epithelial markers but could not be characterized further since, except for vimentin, they did not have mesenchymal markers. The immunohistochemical proof of the epithelial nature of anaplastic thyroid tumours is given by staining with anti-keratin and anti-fat globule membrane antigen. In addition the detection of lactoferrin seems useful, but not that of thyroglobulin which was present in only 4% of the spindle cell tumours and in 32-56% of the other histological types. Thirty carcinomas were positive for vimentin; the co-expression of vimentin and epithelial markers seems frequent in thyroid anaplastic carcinomas.     

Paucicellular variant of anaplastic thyroid carcinoma: report of two cases

The paucicellular variant of anaplastic carcinoma is an infrequent type of thyroid tumor. It was described as a tumor characterized by very low cellularity and prominent fibrosis, probably secondary to extensive infarction. These features could lead to an erroneous diagnosis of Riedel’s thyroiditis. In this paper, we report the clinical and pathological features of two new cases of this unusual entity. Tumor cells were negative for thyroglobulin immunostaining and positive for keratins and p53. Although the number of reported cases is small, the cumulative data on these two cases and the previously reported ones lead us to suggest that the paucicellular variant may occur in younger patients than the conventional anaplastic thyroid carcinoma and that the tumor may be associated with a less aggressive tendency to local progression and metastasis.     

Tumor-to-tumor metastasis to a thyroid follicular adenoma as the initial presentation of a colonic adenocarcinoma

The incidence of thyroid involvement by metastatic disease from distant organs ranges from an average of 3.1% in surgical series to 5.3% in autopsy series. However, the metastasis of one tumor into another (traditionally referred to as 'tumor-to-tumor metastasis') is distinctly uncommon. Typically, they are identified as new manifestations or necropsy findings of a known, pre-existing donor tumor. Herein is described the case of a 59-year-old woman whose thyroid nodule (a follicular adenoma) was resected and found to contain foci of a well-differentiated adenocarcinoma with a morphologic and immunohistochemical profile consistent with origination from the lower gastrointestinal tract. Subsequent diagnostic work-up revealed a sigmoid colon tumor with metastases to the liver. This is, to the authors' knowledge, the first reported example of a colon adenocarcinoma whose initial clinical manifestation was a metastasis to a thyroid neoplasm and only the third reported example of a colonic adenocarcinoma metastatic to a thyroid tumor. In a review of previously reported examples of tumor-to-tumor metastases involving a thyroid neoplasm as the recipient, the following features were present in the majority: (i) multifocality of the metastatic tumor aggregates; (ii) a total lack of, or only minimal amounts of reaction (desmoplastic, inflammatory or myxoid) of the recipient tumor to the metastatic deposits; and (iii) retention of the histopathologic characteristics of the donor tumor in the metastatic deposits. In general, strikingly divergent morphologic features in an otherwise typical thyroid neoplasm should elicit a differential diagnosis that takes into consideration the possibility of metastasis.     

Cytology of anaplastic giant cell carcinoma of the thyroid with osteoclast-like giant cells--a case report

Anaplastic carcinoma of the thyroid is known for its highly aggressive behaviour and rapid spread. While the giant cell variant is a well recognized morphologic pattern, the presence of osteoclast-like giant cells is a rare occurrence. We report a case of anaplastic carcinoma of the thyroid with focal presence of osteoclast-like giant cells occurring in an elderly male patient, diagnosed on aspiration cytology.     

甲状腺非典型腺瘤中DAPI核染色、Ki-67表达及意义

目的 探讨4',6-二脒基-2-苯基吲哚(4',6-diamidino-2-phenylindole,DAPI)细胞核染色、Ki-67在甲状腺非典型腺瘤(atypical thyroid adenoma,ATA)中的表达及临床意义.方法 采用免疫组化EnVision两步法和免疫荧光染色法分别检测ATA、甲状腺滤泡癌(follicular thyroid carcinoma,FC)中Ki-67增殖指数及DAPI核染色情况.结果 DAPI在低、高核级ATA组织中的阳性率分别为12.50％ (2/16)、16.13％(5/31),两组相比差异无统计学意义(x2=0.01,P＞0.05);其在对照组FC中的阳性率为85.71％(6/7),两组相比差异有统计学意义(x2=13.17,P＜0.01);Ki-67在低、高核级ATA组织中的阳性率分别为6.25％(1/16)、6.45％(2/31),二者相比差异无统计学意义(x2 =0.36,P＞0.05);而在对照组FC中的阳性率为85.71％ (6/7),二者相比差异有统计学意义(x2=22.19,P＜0.01);Ki-67、DAPI表达与ATA患者年龄、结节数量、肿块大小无关.结论 联合检测Ki-67和DAPI可能对ATA与FC的鉴别诊断有一定价值.Ki-67、DAPI与ATA核级别、患者年龄、肿块大小和结节数量无关.     

Hyalinizing trabecular adenoma of the thyroid: Its unusual cytoplasmic immunopositivity for MIB1

The monoclonal antibody Ki-67 reacts with a human nuclear cell proliferation-associated antigen that is expressed in all active parts of the cell cycle and is well established as a marker of cell proliferation. However, the Ki-67 method requires fresh frozen material. Recently, MIB1 has been reported to give an immunohistochemical staining pattern identical to Ki-67 on paraffin-embedded tissue sections, frozen sections and cytological samples_? This proliferation-associated antigen is apparently localized in the nucleus. Recently, we performed immunohistochemical staining using the monoclonal MIB1 antibody upon a variety of tumors and non-neoplastic conditions of the thyroid. Tumor cells of hyalinizing trabecular adenoma revealed an intense cytoplasmic immunopositivity for MIB1. In contrast, cytoplasmic immunostaining for MIB1 was negative in all other thyroid tumors and non-neoplastic lesions. Because of this unusual staining pattern, we repeated the staining of all cases and found the results to be reproducible. Therefore, we believe that positive cytoplasmic immunostaining for MIB1 is a characteristic finding of hyalinizing trabecular adenoma and is useful in differentiating it from other thyroid tumors.     

Warthin tumor-like variant of papillary thyroid carcinoma: A case with dedifferentiation (anaplastic changes) and aggressive biological behavior

Warthin tumor-like variant of papillary thyroid carcinoma is uncommon and approx 80 cases have been reported in the literature. This tumor is often associated with a favorable prognosis. In this report, a Warthin tumor-like variant of the papillary thyroid carcinoma, 5-cm in maximum dimension, underwent anaplastic changes in a 74-yr-old woman. The tumor was positive for CD15 and EMA, and a high proliferative index was noted in the anaplastic area. The patient developed distant metastases after operation and died of the disease 18 mo after the operation. The present case is the first reported case of Warthin tumor-like variant of papillary thyroid carcinoma with anaplastic changes.     

Immunohistochemical detection of epithelialmesenchymal transition associated with stemness phenotype in anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is a highly aggressive neoplasm resistant to radiation and chemotherapy. Epithelial-mesenchymal transition (EMT) generating cells with stem cell characteristics have been reported to be associated with chemoradioresistance in cultured cells. However, EMT and stem cell properties in ATC have not been fully investigated. In this study, we retrieved 2 thyroidectomy specimens of ATC with coexisting well differentiated thyroid carcinomas (DTCs) including one papillary carcinoma (PTC) and one follicular carcinoma (FTC). We used im-munohistochemistry to examine the expression of stem cell markers (nestin, CD133 and CD44) and a marker for EMT (E-cadherin). Intense expressions of nestin, CD133 and CD44, and no expression of E-cadherin were observed in both ATCs. In contrast, the PTC and FTC, and non-neoplastic thyroid tissue in both cases were negative for nestin and positive for E-cadherin. The expressions of CD133 and CD44 were variable in the PTC, FTC, and non-neoplastic thyroid tissue and were at a lower level of expression of these markers in the overall pattern. The results confirmed EMT, demonstrated the stem cell phenotype in ATC, and revealed the difference in expression of these markers between ATC and DTCs/non-neoplastic thyroid tissue. Nestin may be the most specific marker for stemness in ATC by immuno-histochemial staining. The results warrant future studies on a large series of cases in order to gain the understanding of the tumor biology and to provide molecular basis for restoring the sensitivities to clinical therapies.     

New evidence for tumour embolism as a mode of metastasis

The demonstration that a significant proportion of patients with renal carcinomas of the clear cell type have tumour cell clumps or aggregates in venous outflow from the kidney has interest from two viewpoints. Firstly, the association of this occurrence with high VEGF‐A production by the cancer seems to suggest a novel mode of ‘budding’ invasion where nests of tumour cells enter the dilated and mechanically fragile new vessels supplying the cancerous growth. Secondly, with the association of fragment occurrence and metastatic development, the entrance of clumps into the circulation indicates that epithelial–mesenchymal transition (EMT) is not an obligatory step for the disseminatory behaviour of all cancers. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.