Rare source of hypertension, these tumors arise from the juxtaglomerular apparatus.
Most patients are young adults (teens and 20's).
Male > female.
All patients have had hypertension with increased serum renin (hypertension does not respond to antihypertensive therapy).
Elevated aldosterone and hypokalemia may also be present.
Gross: Single, small yellow to gray-white nodules in the cortex.
Histology: Quite variable:
Typically composed of bland-looking round or polygonal cells with eosinophilic cytoplasm (image A).
Numerous capillaries or branching blood vessels. (Solid growth around vessels of JCT cells resembles glomus tumor or "glomoid growth")
Cells form irregular cords with a loose connective tissue stroma.
Electron microscopy: secretory granules containing renin (rhomboid shaped crystals)(image B).
Immunohistochemistry: diffuse renin+, CD34+.
Typically behave in a benign fashion (rare metastasis).
Surgical excision generally curative - not only of the tumor, but of the hypertension.