Case of medullary thyroid carcinoma with desmoid‐type fibromatosis

• Published in: Pathology international Vol. 70; no. 6; pp. 364 - 369
• Main Authors: Cho, Yoon Ah, Oh, Young Lyun
• Format: Journal Article
• Language: English
• Published: Australia Wiley Subscription Services, Inc 01-06-2020
• Subjects: Adult; Amyloid; beta‐catenin; Carcinoma, Neuroendocrine - pathology; Cell proliferation; Chromatin; Computed tomography; Cytoplasm; desmoid‐type fibromatosis; Endocrine disorders; Epithelial cells; Fibromatosis, Aggressive - pathology; Genetics; Head and neck; Hemorrhage; Humans; Male; medullary thyroid carcinoma; Necrosis; Nucleoli; Pathogenesis; Radiation; Stroma; Thyroid; Thyroid cancer; Thyroid carcinoma; Thyroid Neoplasms - pathology; Tumors; beta-catenin; desmoid-type fibromatosis; medullary thyroid carcinoma
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1111/pin.12926

A 36‐year‐old man was admitted to hospital for a right thyroid nodule incidentally discovered on a chest computed tomography scan for a rib fracture. He had no history of radiation to the head and neck, no known family history of endocrine disease, and no medical or surgical history. A 17 × 10 mm, well‐demarcated, multinodular, whitish nodule with neither necrosis nor hemorrhage was found in the right thyroid. Microscopically, the tumor consisted of epithelial cell nests with oval, plasmacytoid or polygonal cells with speckled chromatin, inconspicuous nucleoli and granular cytoplasm. The surrounding stroma showed amyloid deposition and prominent spindle cell proliferation with myxoid substance. Epithelial cell nests showed an immunoreactive pattern for typical medullary thyroid carcinoma (MTC), and the spindle cell stroma showed nuclear expression of beta‐catenin. This may be the first report on histopathologic findings of MTC with desmoid‐type fibromatosis. Further studies are necessary to discover the clinicopathologic characteristics and pathogenesis of this rare type of tumor.