Related Experiment Video
Updated: May 27, 2026

Spontaneous Murine Model of Anaplastic Thyroid Cancer
Published on: February 3, 2023
Postoperative spindle cell nodule after thyroidectomy: a case mimicking recurrence with anaplastic transformation of
Sun Wook Kim1, Young Lyun Oh, Joon Young Choi
1Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Background:
Here, we report a case of a postoperative spindle cell nodule that mimicked recurrence with anaplastic transformation after thyroidectomy.
Methods:
The course of the disease is described. The mass was studied morphologically and immunohistochemically.
Results:
A 31-year-old woman underwent total thyroidectomy for papillary thyroid carcinoma. A mass suspected of recurrence was found 14 months later and caused dysphagia and dyspnea. An (18)F-fluorodeoxyglucose positron emission tomographic ((18)F-FDG-PET) scan showed a lesion with high uptake; however, a fine-needle aspiration biopsy (FNAB) was inconsistent with recurrent cancer. The mass was resected and was composed of elongated spindle cells, with eosinophilic cytoplasm within a myxoid background. Immunohistochemical staining was strongly positive for vimentin, focally positive for smooth muscle actin, desmin, and p53, and negative for cytokeratin AE1/AE3, Cam5.2, epithelial membrane antigen (EMA), and anaplastic lymphoma kinase (ALK-1).
Conclusion:
Although postoperative spindle cell nodules are rare after thyroid surgery, it should be considered in the differential diagnosis for recurrent masses at the operative site.
Related Concept Videos
Hyperthyroidism II: Pathophysiology
Goiter
Graves Disease II: Pathophysiology

