Reversible renal hypertension due to renal hygroma.

A hygroma of the left kidney was found at surgery in a thirty-five-year-old woman, who presented with anemia, hypertension, and a left abdominal mass. There was a very high sedimentation rate and fine needle aspiration yielded bizarre cells which raised the possibility of malignancy. Compression of the kidney by the cystic structure probably interfered with renal blood flow and was responsible for the elevated blood pressure which receded to normal after removal of the cyst and the left kidney.