Renin in angiolymphoid hyperplasia with eosinophilia. Its possible effect on vascular proliferation.

A hypertensive man became normotensive after the surgical removal of two subcutaneous masses of angiolymphoid hyperplasia with eosinophilia. To demonstrate that angiolymphoid hyperplasia with eosinophilia is a renin-producing pathologic condition, Bowie stain for juxtaglomerular cell granules and immunohistochemistry for human renin were used. Bowie stain was positive in cells showing cytoplasmic granules similar to those found in the juxtaglomerular cells of the kidney. Immunohistochemical staining using antiserum against human renin showed the presence of renin-containing cells. This staining was not seen after substitution of the specific renin antiserum by preimmune serum, by the renin antiserum preabsorbed with pure human renin, or with plasma from a patient with high-plasma renin activity. Renin-containing cells were located in areas surrounding vascular structures and were apparently neither endothelial, mast, nor lymphoid cells. Six of eight additional cases of angiolymphoid hyperplasia with eosinophilia were positive for renin-containing cells. Renin has been described in several other histologically highly vascularized tumors. Since a product of renin, angiotensin II, has been found to have angiogenic properties, it is possible to postulate that renin, through angiotensin II, may stimulate the proliferation of vessels and, therefore, may be involved in the pathogenesis of angiolymphoid hyperplasia with eosinophilia.