A case report of differentiated thyroid cancer presenting as a renal mass

Abstract

The kidney is an unconventional site for thyroid metastasis. As of the writing of this article, only about 30 cases have been reported. It presents like a renal mass. We are reporting a man with thyroid carcinoma presenting with distant metastasis to the kidney. He had complaints of abdominal pain and haematuria. Initial imaging suggested a left renal mass. A diagnosis of renal cell carcinoma was made and a nephrectomy was performed. Histopathology revealed it to be a metastasis from cancer of the thyroid gland. Subsequently, an ultrasound of the thyroid gland was performed, which showed a malignant appearing thyroid nodule. Correlative bone scan showed uptake at multiple skeletal sites. Total thyroidectomy was done and it was found to be papillary thyroid cancer. Subsequently, high dose radioactive iodine was administered. The patient was followed up and has recently found to have metastasis to the brain and is undergoing radiotherapy.

Keywords: Differentiated thyroid cancer; Papillary thyroid cancer; Renal metastasis.

Figure 1

CT scan showing left renal mass along with the destruction of the right pedicle of the D12 vertebra

Figure 2

Coronal section of the CT showing renal left renal mass involving upper and mid pole

Figure 3

A renal mass with neoplastic lesion composed of colloid filled follicles lined with neoplastic cells displaying overlapping nuclei with grooves (A). Strong positive staining of thyroglobulin (B)

Figure 4

The whole-body ^99mTc-MDP bone scan of the patient revealing metastasis in the proximal end of the left clavicle, lateral border of the left scapula, D9 and L2 vertebrae and mid-shaft of right femur

Figure 5

Post therapeutic whole body I-131 scan of the patient revealing multiple iodine avid metastases

Figure 6

MRI revealing a large metastatic lesion in the right frontal lobe