Renomedullary Interstitial Cell Tumor

**Semantic type:** Neoplastic Process

**Definition:** A benign, asymptomatic kidney tumor arising from renomedullary interstitial cells. It is often found incidentally at the time of nephrectomy in adults. These tumors are either single or multiple and usually measure 1-10 mm in diameter. Microscopically the tumor cells are small, stellate, or spindled cells, embedded in a faintly basophilic stroma reminiscent of renal medullary stroma. (WHO 2016)

**Synonyms:** - Fibroma of Renal Medulla - Kidney Fibroma - Medullary Fibroma - Renal Hamartoma - Renomedullary interstitial cell tumor