Mesoblastic nephroma of adulthood: report of three cases

Mesoblastic nephroma is an uncommon congenital tumor of infancy that rarely occurs in adults. We report three patients (two were female, one was male) who had mesoblastic nephroma of adulthood and who presented at 45, 64, and 66 years of age with hematuria, flank mass, and pain. All underwent nephrectomy without postoperative adjuvant therapy. The tumors were solitary yellow-tan masses with solid and cystic areas involving the renal cortex (three cases) with extension into the renal pelvis and calyces (two) and ureter (one). Microscopically, all consisted of uniform spindle cell proliferations with entrapped dilated renal tubules. Focal necrosis was present in two, but no atypia or mitoses were identified in any case