Procedure: Right radical nephrectomy.

Diagnosis: Chromophobe renal cell carcinoma. Histologic grade:  Grade 1. Tumor size: 4 x 5 x 6 cm. Tumor focality: Unifocal.  Sarcomatoid/Rhabdoid features:  Not identified. Necrosis:  Not identified. Tumor extension: Tumor limited to the kidney. Margins: Uninvolved by invasive carcinoma. Lymphovascular invasion:  Not identified. Regional lymph nodes: No lymph nodes submitted or found. Pathologic stage:  pT1b, pNx.

Additional pathologic findings in non-neoplastic kidney: Tubulointerstitial disease: Chronic pyelonephritis. Immunohistochemical study showed positivity of the tumor with antibody anti-CK7, CD117, CK8 and anti-RCC.  Immunostains with the antibody anti-CD10, CK (AE1/AE3), vimentin and CK20 were negative. The special stain with Hale's colloidal iron stain was positive in the tumor cells confirming the diagnosis of chromophobe renal cell carcinoma.

The renal lesion was picked up as an incidental finding on the initial MRI lumbar spine; however, unfortunately, it was not properly communicated with the referring physician (orthopedic surgeon) and not further investigated properly in a timely fashion. Furthermore it was overlooked by the sonographer on first ultrasound as the lower pole of the right kidney was partly obscured by the bowel gases. Ultimately, it was picked up on the follow-up renal ultrasound (16 months after the MRI lumbar spine) and then further investigated with CT urography. The patient was lucky enough that the lesion did not grow rapidly, was localized to the kidney only and was excised completely.