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.