Case Reports in Oncology (Apr 2021)

A Rare Case of Thyroid Carcinoma Showing Thymus-Like Differentiation in a Young Adult

  • Eri Kimura,
  • Keisuke Enomoto,
  • Masamitsu Kono,
  • Shunji Tamagawa,
  • Saori Takeda,
  • Naoko Kumashiro,
  • Shun Hirayama,
  • Takahito Kimura,
  • Muneki Hotomi

DOI
https://doi.org/10.1159/000514271
Journal volume & issue
Vol. 14, no. 1
pp. 671 – 675

Abstract

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Thyroid carcinoma showing thymus-like differentiation (CASTLE) is thought to originate from ectopic thymic tissue or remnants of the developing thymus within or adjacent to the thyroid. This case report describes a mass located on the left thyroid of a 28-year-old man. Fine-needle aspiration cytology revealed a number of lymphoid cells without atypia that were similar to those seen in a malignant lymphoma of the thyroid, and surgery was performed. Based on additional histopathological findings, the tumor was finally diagnosed as a CASTLE. It is difficult to diagnose this neoplasm using fine-needle aspiration cytology. However, it is possible to differentially diagnose CASTLE based on its histological features. CD5 is useful for diagnosing CASTLE with immunohistochemical staining.

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