Low‐grade metaplastic carcinoma of the thymus

Yoneda, Satoshi; Marx, Alexander; S, Heimann; Shirakusa, T; Kikuchi, Masahiro; Müller-Hermelink, H. K.

doi:10.1046/j.1365-2559.1999.00691.x

Cited by 41 publications

(40 citation statements)

References 32 publications

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“…3689). Like almost all published cases, [17][18][19] the current cases were clinically benign and were not associated with MG. One other "WHO-unclassifiable" case was a "micronodular thymoma with lymphoid B-cell hyperplasia". 20 Like most previously published cases, 20 -22 the current case of "micronodular thymoma" was not associated with MG and was clinically benign although microinvasion (Stage II) was present.…”

Section: Discussionsupporting

confidence: 68%

“…17 The reproducibility rate of thymoma subtyping according to the WHO criteria was more than 90%. This high degree of reproducibility was similar to the rates reported previously for the histogenetic classification.…”

Section: Discussionmentioning

confidence: 96%

“…First, the study showed that 97.5% of all thymomas were classified by H&E-stained sections (Table 3). Only five cases were not covered unequivocally by the WHO classification: three cases exhibited features of the recently described "thymoma with pseudosarcomatous stroma," 19 which has also been called "low-grade metaplastic carcinoma of the thymus" 17 and is probably a novel thymoma entity (Muller-Hermelink, 2000, patient no. 3689).…”

Section: Discussionmentioning

confidence: 99%

“…Only five tumors (2.5%) could not be classified. Theses cases comprised three low-grade metaplastic carcinomas, 17,18 alternatively called "thymoma with pseudosaromatous stroma", 19 one micronodular thymoma with lymphoid B-cell hyperplasia, 20 and one Type AB thymoma in combination with a classical carcinoid tumor (Table 3). Of the 39 cases classified as B2, 30 contained no histologic components of other thymoma subtypes, 3 cases contained small admixtures (Ͻ 10%) of AB, and 6 cases showed areas of B3 comprising 10 -30% of the tumor.…”

Section: Clinical Datamentioning

confidence: 99%

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New WHO histologic classification predicts prognosis of thymic epithelial tumors

Chen

Marx

Chen

et al. 2002

Cancer

353

276

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BACKGROUNDIn 1999, a World Health Organization (WHO) committee published histologic criteria for distinct thymoma entities (labeled as Type A, AB, B1, B2, B3 thymomas) and for the heterogeneous group of thymic carcinomas, collectively called Type C thymomas. Whether WHO‐defined histologic thymoma subtypes are of independent prognostic relevance has yet to be proved.METHODSTwo hundred thymomas from the Shanghai Chest Hospital with a mean follow‐up time of 15 years (range, 1–246 months) were studied for the relevance of WHO histologic subtype and other factors (stage, therapy, and myasthenia gravis [MG]) for survival.RESULTSIn order of frequency, 68 patients (34.0%) had Type AB, 39 (19.5%) had Type B2, 36 (18.0%) had Type C, 27 (13.5%) had Type B3, 17 (8.5%) had Type B1, and 8 (4.0%) had Type A thymoma. Five cases (2.5%) were rare thymomas not mentioned in the WHO classification. Survival data showed significant differences among the histologic subtypes (log rank test: P < 0.001). Among patients with Type A and AB thymomas, none died of tumor; of the Type B1 thymoma patients, only one (5.9%) died at 22 months. Type B2, B3, and C thymomas had a significantly worse prognosis with 5‐year survival rates of 75.0%, 70.0%, and 48.0%, respectively. Ninety‐six patients (48.0%) were in Masaoka Stage I, 26 (13.0%) were in Stage II, 65 (32.5%) were in Stage III, and 13 (6.5%) were in Stage IV. Stage was highly significant in predicting survival (log rank, test P < 0.001). The association between histologic subtype and invasive behavior (stage) was statistically significant (P < 0.001). However, histology was an independent predictive factor of survival in Stage I and II thymomas: Type B2, B3, and C thymomas had a worse prognosis than Type A, AB, and B1 thymomas (log rank test: P < 0.003). Thirty patients (15.0%) presented with MG. MG was significantly more frequent in Type B2 and B3 than in Type A, AB, and B1 thymomas (P < 0.01). On multivariate analysis, MG had no adverse effect on survival (P = 0.17). Radiation or chemotherapy improved patients' survival at 5 and 10 years in Type B2, B3, and C thymomas (log rank test: P < 0.003).CONCLUSIONSTumor stage is the most important determinant of survival in thymoma patients, but the WHO histologic subtype is an independent prognostic factor in Stage I and II thymomas, among which WHO Type A, AB, and B1 thymomas form a low‐risk group. Patients with high‐risk thymomas might profit from novel adjuvant radiochemotherapy regimens. Cancer 2002;95:420–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10665

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Section: Discussionsupporting

confidence: 68%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Clinical Datamentioning

confidence: 99%

See 2 more Smart Citations

New WHO histologic classification predicts prognosis of thymic epithelial tumors

Chen

Marx

Chen

et al. 2002

Cancer

353

276

View full text Add to dashboard Cite

show abstract

“…Periodic acid-Schiff and reticulin stains highlighted a delicate envelope of epithelial complexes, but reticulin fibres did not surround individual cells. Using immunohistochemistry, the neoplastic epithelial cells were reactive for cytokeratins (5,6,8,17) and alpha-smooth muscle actin (a-SMA, Fig. 2), but non-reactive for desmin, myoglobin, myogenin, S-100 protein, glial fibrillary acid protein (GFAP) and CD20.…”

mentioning

confidence: 99%