Thyroid collision tumor with renal metastasis as first symptom: a case report / 中华泌尿外科杂志

ABSTRACT

A 62-year-old female patient was admitted to the hospital with a mass in the left kidney finding during medical check-up by color doppler imaging 1 day before admission. Unenhanced and contrast enhanced CT of urinary tract showed a mass on the inferior pole of left kidney. The left kidney cancer was diagnosed preoperatively and a left radical nephrectomy was performed laparoscopically. Postoperative diagnosis was thyroid-like follicular carcinoma of the left kidney and suspected derived from thyroid tumors by metastasis. Color doppler and CT examination of thyroid confirmed a mass in the right thyroid. Thyroid fine needle aspiration confirmed follicular carcinoma of the right thyroid, and follicular carcinoma of the right thyroid was diagnosed subsequently. The patient underwent radical resection of thyroid cancer according to the intraoperative frozen-section pathological results, and postoperative pathological diagnosis confirmed follicular carcinoma of the right thyroid and papillary carcinoma of the left thyroid. I 131 radio-iodine therapy and L-thyroxine tablets were administered based on the postoperative diagnosis of thyroid collision tumor. Seven months after surgery, the follow-up CT scan revealed no recurrence or metastases for renal area. Nine months later, no thyroid carcinoma recurrence was observed and no significant abnormality was detected in I 131 image. The composition of collision tumor is complicated and origin is unknown. Thyroid collision tumor with kidney metastasis is extremely rare, and the prognosis is better than primary renal carcinoma. The diagnosis depends on pathological examination.