Cases
60-year-old man with sudden weight loss   

History and images

Our appreciation is extended to Dr. Abdul Abid, University of Texas Medical Branch, for contributing this case.

History: A 60-year-old man presented with sudden weight loss and hematuria. An ultrasound of the abdomen and pelvis revealed a right-sided kidney mass. A subsequent magnetic resonance imaging (MRI) exam demonstrated a heterogeneously enhancing mass arising from the mid/upper pole measuring 12 cm in the greatest dimension. A nephrectomy was performed. Gross and microscopic images are presented.

Click the images to enlarge.
What is the most likely diagnosis based on morphology and histology?
Microphthalmia transcription factor (MiTF) translocation renal cell carcinoma
Clear cell carcinoma with eosinophilic features
Low-grade oncocytic tumor
Chromophobe renal cell carcinoma

Which immunohistochemical stains would help with the diagnosis?
Cytokeratin 7 (CK 7), cluster of differentiation 10 (CD10), and transcription factor (TFE)
CK 7, CD117, and E-cadherin
Paired box gene 8 (PAX8), carbonic anhydrase IX (CA-IX), and CD10
PAX8, CA-IX, and alpha methyacyl CoA racemase (AMACR)