SMALL RENAL PARENCHYMAL NEOPLASMS - FURTHER OBSERVATIONS ON GROWTH

PURPOSE: To determine the growth rate and behavior of small (less than or equal to 3.5-cm diameter) incidentally detected renal parenchymal neoplasms. MATERIALS AND METHODS: Forty renal parenchymal tumors in 37 adult patients (mean age, 65.5 years) were observed with computed tomography (CT) and ultrasound for 1.75-8.5 years (mean, 3.25 years). Surgical removal was performed of 26 tumors proved and graded at pathologic examination. Fourteen tumors with CT criteria of neoplasm are being followed up. RESULTS: The overall growth rate of neoplasms was 0-1.1 cm/y (mean, 0.36 cm/y). Thirty tumors grew 0.5 cm/y or less and 19 grew very slowly (less than or equal to 0.35 cm/y). No patient developed metastatic disease. Nine (24%) had multiple neoplasms. CONCLUSION: Most small, incidentally discovered, well-marginated renal parenchymal neoplasms grow slowly and are not an immediate threat to a patient's life. Watchful waiting might be appropriate instead of surgical removal, especially in patients who are elderly or may not survive surgery.