Cystic renal cell carcinoma: pathological features, survival and implications for treatment.

OBJECTIVES

To assess the incidence, clinicopathological features, prognosis and therapeutic options of cystic renal cell carcinoma (CRCC).

PATIENTS AND METHODS

The clinical records and nephrectomy specimens from 206 patients with renal cell carcinoma (RCC) were reviewed after a minimum follow-up of 5 years. The mode of presentation, tumour size, growth pattern, nuclear grade, cytoplasmic appearance and pathological stage at presentation were compared with the outcome, as measured by disease-free and overall survival of the patients.

RESULTS

From the 206 patients with RCC, 25 (12%) were classified as having CRCC; most of these cases (96%) occurred in male patients, as opposed to 64% in the remaining patients RCC (P = 0.0029). The clinical features at diagnosis were similar in both groups, although asthenia, anorexia and weight loss were uncommon in patients with CRCC (P = 0.045). Nuclear grade and pathological stage were usually lower in those with CRCC than in those with RCC (P = 0.0071 and P = 0.0033, respectively). Survival was significantly longer in patients with CRCC (P = 0.0342).

CONCLUSIONS

CRCC is a type of RCC that is usually identified at earlier stages, has a slower growth rate, and is therefore associated with a better prognosis and longer survival than conventional RCC. The differential diagnosis between CRCC, cystic multilocular nephroma and cysts with a superimposed infectious or haemorrhagic process can be extremely difficult in imaging studies, and even in intra-operative frozen-section analysis. Because of this, and with the better prognosis of CRCC, a conservative surgical approach would be the treatment of choice whenever technically feasible.