Clear cell renal tumors Flashcards
SDH-deficient renal cell carcinoma
Characteristic flocculent cytoplasmic vacuoles with a pale eosinophilic, wispy or bubbly appearance and low grade nuclei (at least focally), but may have high grade areas.
The tumor often has a diffuse acinar pattern with a central scar. Tumor cells have lightly granular cytoplasm and distinctive cytoplasmatic inclusions containing flocculent material. Nuclei are centrally placed, low grade, round to oval with inconspicuous nucleoli. Immunostain for SDHB is negative in tumor cells in contrast to strong coarse granular staining in endothelial cells.
Most patients have a germline mutation, most often in SDHB.
IHC: SDHB neg, CK7 neg, CAIX neg, RCC neg, CD117 neg,
Multilocular cystic neoplasm of low malignant potential
Multiloculated cysts lined by a simple lining of WHO/IUSP grade 1-2 cells, with no solid components greater than 1mm. (solid areas greater than 1mm make clear cell RCC the preferred diagnosis)
Molecularly, a lot of overlap with clear cell RCC, however this morphology is distinguished due to its substantially better overall prognosis. When strict criteria are applied, there are no metastases or even recurrences.
Mucinous tubular and spindle cell carcinoma
Uncommon renal cell carcinoma characterized by epithelioid/cuboidal and spindled cells in a myxoid, mucinous stroma. Nuclear features are ISUP/WHO grade 1-2. Often these components are very intermixed and at intermediate power you only have a vague impression of streaming or spindling.
