[A case of transitional cell carcinoma in a pyelocaliceal diverticulum].

A 63-year-old man visited our hospital because of painless macrohematuria. Drip infusion pyelography and retrograde pyelography revealed a space-occupying lesion with extravasation of contrast medium to upper caliceal system. A computed tomographic study revealed an intrarenal solid moiety and further more, arteriography showed the arterial encasement and fine neovascularity of the lesion. On gross section of the extirpated kidney, a cystic cavity measuring 3 by 3 cm existed at the upper pole and apparently channeled to the upper caliceal system. Small stones were found in the cystic cavity. Histopathologically, the wall of the cavity was covered with layered squamous cells and a part of the wall developed metaplasic transitional cell carcinoma proliferation which invaded into the renal parenchyma and renal pelvis, as well.