Metastatic type-2 papillary renal cell carcinoma responded to interleukin-2 therapy: case report

This report documents a case of metastatic papillary renal cell carcinoma (PRCC) which successfully responded to interleukin-2 (IL-2) therapy. A 59-year-old male presented with a left renal mass measuring 3.0 cm in diameter and a right adrenal mass measuring 5.0 cm in diameter. He underwent a left partial nephrectomy and a right adrenalectomy. The histological findings revealed pT1bN1M1 type-2 PRCC and metastatic renal cell carcinoma in the right adrenal gland. The patient was given interferon-α (IFN-α) after the operation for 3 months. A CT scan revealed a metastatic nodule measuring 6.0 cm in diameter near the surface of the liver at 4 months after the opereation. The patient was given interleukin-2 (IL-2), 7 × 10⁵ units/day intravenously, for 3 days per week. A CT scan revealed this hepatic nodule to have decreased in size from 6.0 to 4.0 cm after 4 months of IL-2 therapy. However, a new metastatic nodule measuring 6.0 cm in diameter was found which came in contact with the spleen. Next, the patient was given an increased dose of IL-2 from 7 × 10⁵ to 1.4 × 10⁶ units/day intravenously, for 3 days per week. At 9 months of follow-up after the dose escalation, a CT scan revealed a dramatic decrease in the size of these two metastatic nodules to 1.5 and 0.5 cm, respectively. This is a very rare case in that it represents a type-2 PRCC which dramatically responded to low-dose IL-2 therapy.