Title: Carcinoma showing thymus-like differentiation (CASTLE) – A Rare Extra-Thyroid Disease

Authors: Dr Lakshmi JS, Dr Pushpaja K Ullattil, Dr Shabin K Sidhique, Mrs Sreedevi E, Mrs Regina LS

 DOI: https://dx.doi.org/10.18535/jmscr/v9i7.10

Abstract

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant tumor occurs in soft tissues of neck or thyroid gland. It accounts for 0.1% to 0.15% of all thyroid cancers. Immuno-staining with CD5 is a useful marker for differentiating from other malignancy of thyroid.

Case report: A 72-year-old female presented with painless neck swelling which on examination was firm to hard mass at left level III region extending inferiorly up to medial supraclavicular fossa. Imaging showed a solid conglomerate lymph-nodal mass and biopsy reported as poorly differentiated neoplasm. IHC markers confirmed the diagnosis of CASTLE disease. She underwent left modified radical neck dissection along with left hemithyroidectomy and Adjuvant radiation therapy. Now at 8 years of follow-up, no evidence of disease recurrences.

Thus, being a rare entity, early diagnosis and prompt treatment plays an important role in the outcome.

Keywords: Castle disease, thymus like differentiation, thyroid neoplasm, long-term follow-up, extra-thyroidal disease.

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Corresponding Author

Dr Lakshmi JS

Senior Resident, Department of Radiation Oncology, Government Medical College (GMC), Kottayam