<unk> s are diagnosed by biopsy or excision. It is important to correctly diagnose them as, radiologically, they may mimic the appearance of a renal cell carcinoma that is<unk> . Pathologic diagnosis High magnification micrograph of a<unk>  showing the characteristic simple epithelium with hobnail morphology, and the ovarian-like stroma. H&E stain. The characteristics of<unk> s are: *Cysts lined by a simple epithelium with a hobnail morphology, i.e. the nuclei of the cyst lining epithelium bulges into the lumen of the cysts, *Ovarian-like stroma that has a: *Spindle cell morphology, and has a *Basophilic cytoplasm.<unk> s have an immunostaining pattern like ovarian stroma; they are positive for: *Estrogen receptor (ER), *Progesterone receptor (PR) and *CD10. Differential diagnosis incidences and prognoses.<unk>  is seen at bottom right in pie chart.<unk>  partially differentiated nephroblastoma<unk>  standard nephroblastoma<unk>  Wilm's tumor)<unk>  mesoblastic<unk> <unk>  renal cell carcinoma *other renal cysts
Cystic nephroma
Renal medullary fibroma
Mesoblastic nephroma
Medullary sponge kidney
Renal cyst
Renal anaplastic sarcoma
Ectopic kidney
Multicystic dysplastic kidney