Renal metastasis from thyroid carcinoma: a case report

Area of Science:

• Oncology
• Nephrology
• Endocrinology

Background:

• Renal metastases from thyroid carcinoma are exceptionally rare, accounting for approximately 3% of all kidney metastases.
• The English literature documents only 23 reported cases of renal thyroid carcinoma metastasis.

Observation:

• A 77-year-old male presented with gross hematuria.
• CT imaging revealed a 5 x 3 cm mass in the right kidney, located cortico-sinusally.
• Gross and microscopic examination showed a lobulated mass with papillary and follicular proliferation, containing colloid-like material.

Findings:

• Immunohistochemical staining for thyroglobulin and thyroid transcription factor-1 confirmed the thyroid origin of the renal mass.
• The findings supported the diagnosis of a renal metastasis of thyroid carcinoma.

Implications:

• Renal metastasis of thyroid carcinoma should be considered in the differential diagnosis of unilateral renal masses, even without a history of thyroid surgery.
• Distinguishing metastatic thyroid carcinoma from primary renal tumors like thyroid-like follicular carcinoma is critical.
• Immunohistochemistry plays a vital role in accurate diagnosis and subsequent patient management.