American Urological Association - Other Rare and Unclassified Renal Carcinomas
Other Rare and Unclassified Renal Carcinomas
Thyroid-like follicular carcinoma of the kidney
- Exceedingly rare, resembles well-differentiated thyroid follicular tumors.
- Characterized by tumor follicles filled with inspissated colloid-like materials.
- All cases negative for thyroid markers (thyroglobulin- and TTF1-); metastatic thyroid primary carcinoma should be excluded before making the diagnosis.
Unclassified Renal Carcinomas
- Primary renal carcinoma that does not fit to any of the known RCC types.
- Mixture of RCC types (image A). (Except low-grade clear cell papillary RCC and TFE3 carcinoma with mixed clear cell and papillary growth).
- Renal carcinoma with florid or pure sarcomatoid change that the original tumor is no longer identifiable (image B).