Phyllodes tumor metastatic to thyroid Hürthle cell adenoma

Area of Science:

• Oncology
• Pathology
• Endocrinology

Background:

• Malignant phyllodes tumors are rare breast neoplasms.
• Hürthle cell adenomas are benign thyroid neoplasms.

Observation:

• A patient with a history of malignant phyllodes tumor developed a thyroid mass.
• The thyroid mass exhibited distinct histological and immunophenotypic features.

Findings:

• The thyroid tumor was diagnosed as cystosarcoma phyllodes metastasis to Hürthle cell adenoma.
• Atypical spindle cells infiltrated Hürthle cell cords and follicles.

Implications:

• This case represents a novel instance of tumor-to-tumor metastasis from sarcoma to a thyroid neoplasm.
• Highlights the importance of comprehensive histopathological and immunohistochemical analysis in diagnosing metastatic disease.