CELLULAR CLASSIFICATION

Approximately 85% of renal cell cancers are adenocarcinomas, for the most part of proximal tubular origin. Most of the remainder are transitional cell carcinomas of the renal pelvis, which are discussed in the PDQ summary on transitional cell cancer of the renal pelvis and ureter. Adenocarcinomas may be separated into clear cell and granular cell carcinomas, although the 2 cell types may occur together in some tumors. Some investigators have found that granular cell tumors have a worse prognosis, but this finding is not universal. The distinction between well-differentiated renal adenocarcinomas and renal adenomas can be difficult. The diagnosis is usually made arbitrarily on the basis of size of the mass, but size alone should not influence the treatment approach, since metastases can occur with lesions as small as 0.5 centimeters.
STAGE I RENAL CELL CANCER


Surgical resection is the accepted, often curative therapy for stage I renal cell cancer. Resection may be simple or radical. The latter operation includes removal of the kidney, adrenal gland, perirenal fat, and Gerota's fascia, with or without a regional lymph node dissection. Some, but not all, surgeons
believe the radical operation yields superior results. In patients who are not candidates for surgery, external radiation therapy or arterial embolization can provide palliation. In patients with bilateral stage I neoplasms (concurrent or subsequent), bilateral partial nephrectomy or unilateral partial nephrectomy with contralateral radical nephrectomy when technically feasible may be a preferred
alternative to bilateral nephrectomy with dialysis or transplantation.[1] There is increasing evidence that a partial nephrectomy is curative in selected cases. It is important to have a pathologist examine the gross specimen as well as the frozen section from the parenchymal margin of excision.[2]

Treatment options:

1. Radical nephrectomy.[3]

2. Simple nephrectomy.[3]

3. Partial nephrectomy (selected patients).[1,3]

4. External-beam irradiation (palliative).[3]

5. Arterial embolization (palliative).[3,4]

6. Clinical trials.
Improved understanding of the genetic basis of human renal cell carcinoma has
come from studies of families with a predisposition to develop renal carcinoma. This discusses von Hippel-Lindau disease, one inherited disorder that confers a predisposition to develop renal carcinoma. In addition to VHL, renal carcinoma is found in association with a constitutional chromosome 3;8 translocation, and with hereditary non polyposis colon carcinoma. Families have been described with several members affected with papillary renal carcinomas.

Identification of hereditary papillary renal carcinoma, a new hereditary cancer syndrome

The index patient with renal cell carcinoma was referred to the National Institutes of Health for consideration of experimental immunotherapy. The patient gave a family history of renal cell carcinoma. He reported that his father, brother, nephew and 2 uncles had renal cell carcinoma. Further study of this family demonstrated that 3 generations were affected with papillary renal cell carcinoma, an uncommon
histologic type of renal cell carcinoma.
Like VHL, the gross appearance of the kidneys from affected family members was striking. Multiple tumors of varying size were present in both kidneys of affected family members. Each renal tumor had a papillary growth pattern. The disorder was not linked to polymorphic markers on chromosome 3p (the site of the VHL gene) and there was no loss of heterozygosity at loci on 3p in renal tumors. No constitutional chromosomal alterations were detected in affected individuals; no germline VHL mutations were detected in affected individuals. The inherited disorder is this family appeared to be different from recognized hereditary cancer syndromes.

Characteristics of papillary renal carcinoma

Clear cell renal carcinomas comprise about 80% of sporadic renal cell carcinomas
while papillary renal carcinomas comprise about 5-10% of sporadic renal cell
carcinoma.
Karyotypes prepared from papillary renal carcinomas show characteristic genetic
changes distinct from those found in karyotypes prepared from clear cell renal
carcinomas. Papillary renal carcinomas show trisomy of chromosomes 7, 16 and
17, and in male patients, a loss of the Y chromosome.

Identification of 12 families with papillary renal carcinoma

Possibly family 150 was an isolated occurrence, a reflection of some as yet
unknown environmental factor. Alternatively, this family may represent a distinct
type of inherited cancer.  Papillary renal carcinomas were often detected incidentally in asymptomatic individuals or during screening of asymptomatic members of renal carcinoma families. Families with papillary renal
cell carcinoma have been identified in Spain, Sweden, Australia, the Netherlands,
the United States and Canada. The results suggest that the predisposition to develop papillary renal cell carcinoma may be inherited, and that hereditary papillary renal carcinoma constitutes a distinct class of inherited cancer.

Identification of renal tumors by computerized tomography in members of
papillary renal carcinoma

Renal tumors were detected by computerized tomography in asymptomatic
members of papillary renal carcinoma families; renal tumors were unusually
hypovascular and could be mistakenly identified as cysts unless measurements of
density were obtained. However, when region of interest density measurements
were obtained these lesions demonstrated a 15-30 unit increase in Hounsfield
density after intravenous contrast .
CT scan of familial papillary renal
carcinoma




Computerized tomography of the abdomen of an asymptomatic 34 years old member of an HPRC family. A renal tumor is present in the kidney (arrow).