[Pathology] Atlas of Unusual Types of Thymoma

[Pathology] Atlas of Unusual Types of Thymoma, Atlas of Unusual Types of Thymoma, Unusual Types of Thymoma, Atlas of Mediastinal Pathology

There are certain types of thymoma that do not fit into any of the WHO categories and have been assigned to the classification of “unusual thymomas.” Some of them, such as micronodular, sclerosing, and metaplastic, actually representunusual variants of spindle-cell thymoma (discussed previously). A few other rare types of thymomas have also been described, including rhabdomyomatous thymoma and plasma cell-rich thymoma.

Fig. 2.77 Rhabdomyomatous thymoma shows islands of epithelial

cells containing clusters of large, round cells with small nuclei and

abundant eosinophilic cytoplasm  

Fig. 2.78 Higher magnification of a rhabdomyomatous thymoma

shows that the large cells with abundant eosinophilic cytoplasm have

features of rhabdomyocytes, with small hyperchromatic nuclei and

abundant eosinophilic cytoplasm. These cells stain positive for desmin

and also show nuclear positivity with the transcription factors MyoD1

and myogenin  

Fig. 2.79 Plasma cell-rich thymoma is a rare type characterized by a

dense plasma cell infi ltration of the stroma. This fi nding is paradoxical

in thymoma because the lymphoid cell population in these tumors is

normally composed of immature T lymphoblasts  

Fig. 2.80 Higher magnification from plasma cell-rich thymoma showing 

a monotonous population of mature plasma cells in the stroma,

adjacent to the island of thymic epithelial cells. The plasma cells

showed polytypic kappa/lambda distribution  

 Suggested Reading

Chalabreysse L, Roy P, Cordier J-F, Loire R, Gamondes JP, ThivoletBejui F. Correlation of the WHO schema for the classification of thymic epithelial neoplasms with prognosis: a retrospective study of 90 tumors. Am J Surg Pathol. 2002;26:1605–11.

Choi WWL, Lui YH, Lau WH, Crowley P, Khan A, Chan JK. Adenocarcinoma of the thymus: report of two cases, including a previously undescribed mucinous subtype. Am J Surg Pathol. 2003;27:124–30.

Hasserjian RP, Klimstra DS, Rosai J. Carcinoma of the thymus with clear cell features: report of eight cases and a review of the literature. Am J Surg Pathol. 1995;19:835–41.

Kalhor N, Suster S, Moran CA. Spindle cell thymoma with prominent papillary and pseudopapillary features: A clinicopathologic study of 10 cases. Am J Surg Pathol. 2011;35:372–7.

Koga K, Matsuno Y, Noguchi M, Mukai K, Asamura H, Goya T, Shimosato Y. A review of 79 thymomas: modification of staging system and reappraisal of conventional division into invasive and non-invasive thymoma. Pathol Int. 1994;44:359–67.

Matsuno Y, Morozumi N, Hirosashi S, Shimosato Y, Rosai J. Papillary carcinoma of the thymus. Report of four cases of a new microscopic type of thymic carcinoma. Am J Surg Pathol. 1998;22:873–80.

Moran CA, Suster S. Mucoepidermoid carcinomas of the thymus. Clinicopathologic study of 6 cases. Am J Surg Pathol. 1995;19:826–34.

Moran CA, Suster S. Thymoma with prominent cystic and hemorrhagic changes and areas of necrosis and infarction. A clinicopathologic study of 25 cases. Am J Surg Pathol. 2001;25:1086–90.

Moran CA, Suster S. Ancient (sclerosing) thymomas. A clinicopathologic study of 10 cases. Am J Clin Pathol. 2004;121:867–71.

Moran CA, Suster S. Thymic carcinoma: current concepts and histologic features. Hematol Oncol Clin North Am. 2008;22:393–407.

Moran CA, Kalhor N, Suster S. Invasive spindle cell thymomas (WHO type A): a clinicopathologic correlation of 41 cases. Am J Clin Pathol. 2010;134:793–8.

Pan CC, Chen WY, Chiang H. Spindle cell and mixed spindle/lymphocytic thymomas: an integrated clinicopathologic and immunohistochemical study of 81 cases. Am J Surg Pathol. 2001;25:111–20.

Rieker RJ, Hoegel J, Morresi-Hauf A, Hofmann WJ, Blaeker H, Penzel R, Otto HF. Histologic classification of thymic epithelial tumors: comparison of established classifications schemes. Int J Cancer. 2002;98:900–6.

Shimosato Y, Kameya T, Nagai K, Suemasu K. Squamous cell carcinoma of the thymus: an analysis of 8 cases. Am J Surg Pathol. 1997;1:109–21.

Snover DC, Levine GD, Rosai J. Thymic carcinoma: five distinctive histological variants. Am J Surg Pathol. 1982;6:451–70.

Suster S, Rosai J. Thymic carcinoma: a clinicopathologic study of 60 cases. Cancer. 1991;67:1025–32.

Suster S, Rosai J. Cystic thymomas: clinicopathologic study of 10 cases. Cancer. 1992;69:92–7.

Suster S, Moran CA. Primary thymic epithelial neoplasms with combined features of thymoma and  thymic carcinoma. A clinicopathologic study of 22 cases. Am J Surg Pathol. 1996;20:1469–80. 

Suster S, Moran CA, Chan JKC. Thymoma with pseudosarcomatous stroma. Report of an unusual histologic variant of thymic epithelial neoplasms that may simulate carcinosarcoma. Am J Surg Pathol. 1997;21:1316–23.

Suster S, Moran CA. Thymic carcinoma: spectrum of differentiation and histologic types. Pathology. 1998;30:111–22. 

Suster S, Moran CA. Thymoma, atypical thymoma and thymic carcinoma. A novel conceptual approach to the classifi cation of neoplasms of thymic epithelium. Am J Clin Pathol. 1999a;111:826–33.

Suster S, Moran CA. Spindle cell carcinoma of the thymus. Clinicopathologic and immunohistochemical study of 15 cases of a novel form of thymic carcinoma. Am J Surg Pathol. 1999b;23:691–700.

Suster S, Moran CA. Micronodular thymoma with lymphoid B-cell hyperplasia. Clinicopathologic and immunohistochemical study of 18 cases of a distinctive morphologic variant of thymic epithelial

neoplasm. Am J Surg Pathol. 1999c;23:955–62.

Suster S, Moran CA. Primary thymic epithelial neoplasms: spectrum of differentiation and histologic features. Semin Diagn Pathol. 1999d;16:2–17.

Suster S. Thymic carcinoma: update of current diagnostic criteria and histologic types. Semin Diagn Pathol. 2005;22:198–212. 

Suster S, Moran CA. Thymoma classification: current status and future trends. Am J Clin Pathol. 2006;125:542–54.

Suster S, Moran CA. Classification of thymoma: the WHO and beyond. Hematol Oncol Clin North Am. 2008;22:381–92. 

Suster S, Moran CA. The mediastinum. In: Weidner N, Cote R, Suster S, Weiss LM, editors. Modern surgical pathology. 2nd ed. Philadelphia: W.B. Saunders; 2009. p. 454–516.

Travis WD, Brambilla E, Burke AP, Marx A, Nicholson AG. Pathology and genetics. Tumors of the lung, pleura, thymus, and heart. In: World Health Organization classification of tumors. Lyon: IARC

Press; 2015.

Wu T-C, Kuo T-T. Study of Epstein-Barr virus RNA (EBER-1) expression by in-situ hybridization in thymic epithelial tumors of Chinese patients in Taiwan. Hum Pathol. 1993;24:235–8.

This is only a part of the book : Atlas of Mediastinal Pathology  of authors: Saul Suster. If you want to view the full content of the book and support author. Please buy it here: https://www.amazon.com/Atlas-Mediastinal-Pathology-Anatomic/dp/149392673X