Metastatic leiomyosarcoma of the thyroid: A rare entity

Area of Science:

• Oncology
• Pathology
• Endocrinology

Background:

• Thyroid gland metastases from non-thyroidal primary cancers are uncommon clinical findings.
• Renal cell carcinoma, colorectal, lung, and breast cancers are the most frequent sources of thyroid metastases.

Observation:

• A 64-year-old woman presented with neck swelling four years post-hysterectomy for uterine leiomyosarcoma.
• Fine needle aspiration cytology initially suggested undifferentiated thyroid carcinoma.

Findings:

• Histopathological analysis post-thyroidectomy confirmed metastatic leiomyosarcoma to the thyroid.
• Immunohistochemistry revealed positive myogenic markers and negative epithelial markers, aiding diagnosis.
• Metastatic leiomyosarcoma can mimic primary thyroid malignancies like anaplastic or medullary thyroid carcinoma.

Implications:

• This case highlights the importance of considering metastatic disease in thyroid nodules, especially with a prior cancer history.
• A multidisciplinary approach involving pathologists, surgeons, and radiologists is crucial for accurate diagnosis.
• Distinguishing metastatic leiomyosarcoma from primary thyroid cancers is vital for appropriate patient management.