Clinical and functional significance of WHO classification on human thymic epithelial neoplasms: A study of 146 consecutive tumors

Meinoshin Okumura, Shinichiro Miyoshi, Yoshitaka Fujii, Yukiyasu Takeuchi, Hiroyuki Shiono, Masayoshi Inoue, Kenjirou Fukuhara, Yoshihisa Kadota, Hisashi Tateyama, Tadaaki Eimoto, Hikaru Matsuda

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138 Citations (Scopus)

Abstract

We examined the clinical and functional significance of histologic classification of thymic epithelial neoplasms proposed by the World Health Organization (WHO), based on an analysis of 146 consecutive tumors derived from 141 patients and 47 normal thymuses derived from children ranging in age from 1 to 9 years. Invasive tumors were seen in 12.5%, 38.6%, 40.0%, 69.4%, 80.0%, and 100% of type A, AB, B1, B2, B3, and C primary tumors, respectively. All of six recurrent or metastatic lesions were type B2 tumors. Myasthenia gravis was associated in 0%, 6.8%, 40.0%, 55.6%, 10.0%, and 0% in patients with type A, AB, B1, B2, B3, and C tumors, respectively. The average number (xl06) of tumor-associated CD4+CD8+ cells present in 1 g of tumor tissue was 1.5, 391.1, 1041.7, 333.9, 24.5, and 0.2 in type A, AB, B1, B2, B3, and C, respectively, and it was 1168.2 in the normal thymuses. Thus, type B1 tumor retained the function to induce CD4+CD8+ double-positive cells at a level comparable to that of the normal thymic cortical epithelial cells, followed by type AB and type B2 tumors. Type A and B3 tumors had this function at a barely detectable level, and type C tumor was nonfunctional. WHO histologic classification was shown to reflect the clinical features and the T-cell-inducing function of thymic epithelial tumors.

Original languageEnglish
Pages (from-to)103-110
Number of pages8
JournalAmerican Journal of Surgical Pathology
Volume25
Issue number1
DOIs
Publication statusPublished - Jan 2 2001

Keywords

  • CD4CD8 cells
  • Myasthenia gravis
  • Thymic carcinoma
  • Thymoma
  • Thymus

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

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    Okumura, M., Miyoshi, S., Fujii, Y., Takeuchi, Y., Shiono, H., Inoue, M., Fukuhara, K., Kadota, Y., Tateyama, H., Eimoto, T., & Matsuda, H. (2001). Clinical and functional significance of WHO classification on human thymic epithelial neoplasms: A study of 146 consecutive tumors. American Journal of Surgical Pathology, 25(1), 103-110. https://doi.org/10.1097/00000478-200101000-00012