Metaplastic Thymoma: Report of 4 Cases

Kang, Gyu-Hong; Yoon, Nara; Han, Joungho; Kim, Young Eun; Kim, Tae Sung; Kim, Kwhanmien

doi:10.4132/koreanjpathol.2012.46.1.92

Cited by 16 publications

(11 citation statements)

References 12 publications

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“…2B ), and metaplastic thymoma were found in two, one, one, and one patient, respectively. One patient with WHO type B1 thymoma and a patient with metaplastic thymoma have previously been reported [ 2 , 16 ]. There were three patients with CASTLE ( Fig.…”

Section: Resultsmentioning

confidence: 99%

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Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

Noh

Ahn

et al. 2014

Cancer Res Treat

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PurposeThe purpose of this study is to assess the clinicopathologic features, treatment outcomes, and role of adjuvant radiation therapy (RT) in cervical thymic neoplasm involving the thyroid gland or neck.Materials and MethodsThe medical and pathologic records of eight patients with cervical thymic neoplasm were reviewed retrospectively. All patients underwent surgical resection, including thyroidectomy or mass excision. Adjuvant RT was added in five patients with adverse clinicopathologic features. The radiation doses ranged from 54 Gy/27 fractions to 66 Gy/30 fractions delivered to the primary tumor bed and pathologically involved regional lymphatics using a 3-dimensional conformal technique.ResultsEight cases of cervical thymic neoplasm included three patients with carcinoma showing thymus-like differentiation (CASTLE) and five with ectopic cervical thymoma. The histologic subtypes of ectopic cervical thymoma patients were World Health Organization (WHO) type B3 thymoma in one, WHO type B1 thymoma in two, WHO type AB thymoma in one, and metaplastic thymoma in one, respectively. The median age was 57 years (range, 40 to 76 years). Five patients received adjuvant RT: three with CASTLE; one with WHO type B3; and one with WHO type AB with local invasiveness. After a median follow-up period of 49 months (range, 11 to 203 months), no recurrence had been observed, regardless of adjuvant RT.ConclusionAdjuvant RT after surgical resection might be worthwhile in patients with CASTLE and ectopic cervical thymoma with WHO type B2-C and/or extraparenchymal extension, as similarly indicated for primary thymic epithelial tumors. A longer follow-up period may be needed in order to validate this strategy.

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Section: Resultsmentioning

confidence: 99%

“… EPE, extraparenchymal extension; F, female; M, male; CASTLE, carcinoma showing thymus-like differentiation. a) Previously reported [ 2 ], b) Previously reported [ 16 ]. …”

Section: Figmentioning

confidence: 99%

Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

Noh

Ahn

et al. 2014

Cancer Res Treat

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“…The epithelial cells of metaplastic thymoma constantly express p40/p63; therefore, it can be speculated that epithelial cells differentiate into the thymic epithelium. 4,5 Thymomas derived from the medullary epithelium, such as type A thymoma, often lack infiltration by numerous immature lymphocytes. 1 Metaplastic thymomas lack immature lymphocytes, suggesting that metaplastic thymoma likely originates from the medullary epithelium.…”

Section: Discussionmentioning

confidence: 99%

Malignant Transformation of Metaplastic Thymoma into High-Grade Sarcomatoid Carcinoma: A Case Report

Piao

Chen

et al. 2021

Int J Surg Pathol

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The correlation of histogenesis between metaplastic thymoma and thymic sarcomatoid carcinoma is unclear. We report a case of metaplastic thymoma transformed into high-grade sarcomatoid carcinoma. A 64 × 54 × 32 mm anterior mediastinal mass in a 61-year-old woman microscopically consisted mainly of classic metaplastic thymoma, with the center dominated by high-grade sarcomatoid carcinoma. In some areas, both epithelial and spindle cell components of the metaplastic thymoma showed increased cellular atypia, mitotic activity, and focal necrosis and gradually transformed into the polygonal/pleomorphic and spindle cell components of sarcomatoid carcinoma. Immunohistochemically, the characteristics of the polygonal/pleomorphic sarcomatoid cells were similar to those of the epithelial component of metaplastic thymoma, while the spindle sarcomatoid cells were more similar to the spindle cells component of metaplastic thymoma. The Ki-67 index was less than 5% in the metaplastic thymoma areas but up to 70% in the sarcomatoid carcinoma area. Radical operation and postoperative radiotherapy were performed. Multifocal relapses at the pleura occurred 13 months after surgery.

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“…To our knowledge, only rare cases of metaplastic thymoma have been reported in Asian population ( 5 , 6 ), whereas about a total of 30 cases have been described separately in the English literatures ( 7 , 8 ). The genomic alterations driving metaplastic thymoma have not previously been defined in any guidance or classification and hence little is known about its molecular characteristics.…”

Section: Introductionmentioning

confidence: 98%

YAP1-MAML2 Fusion as a Diagnostic Biomarker for Metaplastic Thymoma

Zhao

Xiang

et al. 2021

Front. Oncol.

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BackgroundMetaplastic thymoma is a very rare tumor with only a few case reports documented in literature. Hence, its molecular features have not been well explored.Material and MethodsSeventeen specimens of metaplastic thymoma were sequenced and retrospectively analyzed by fluorescence in situ hybridization (FISH) and immunohistochemistry in the study. In addition, seven cases of micronodular thymoma with lymphoid stroma and nine cases of type A thymoma were also investigated.ResultsAmong these metaplastic thymomas, fifteen cases showed classical histological features, and two cases displayed characteristic micronodular-like growth patterns. DNA and RNA based next-generation sequencing identified and confirmed highly recurrent Yes Associated Protein 1 (YAP1) - Mastermind Like Transcriptional Coactivator 2 (MAML2) translocation (13/17, 76.5%) in metaplastic thymoma but not in micronodular thymoma with lymphoid stroma (0/7, 0%) and type A thymoma (0/9, 0%). In addition, six nonsense mutations were also detected in the metaplastic thymoma. FISH in microdissection specimens indicated that both epithelioid and spindle cell components harbored YAP1-MAML2 gene rearrangements.ConclusionsOur study explored the genetic alterations in epithelioid and spindle cell components in metaplastic thymoma. Furthermore, YAP1-MAML2 gene rearrangements emerged as a potential diagnostic biomarker helpful for distinguishing metaplastic thymoma from type A and micronodular thymoma with lymphoid stroma.

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Metaplastic Thymoma: Report of 4 Cases

Cited by 16 publications

References 12 publications

Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

Potential Role of Adjuvant Radiation Therapy in Cervical Thymic Neoplasm Involving Thyroid Gland or Neck

Malignant Transformation of Metaplastic Thymoma into High-Grade Sarcomatoid Carcinoma: A Case Report

YAP1-MAML2 Fusion as a Diagnostic Biomarker for Metaplastic Thymoma

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