What happened, in summary

A woman in her late 60s had Stage IV lung adenocarcinoma with malignant pleural effusion and liver metastasis. She started carboplatin, pemetrexed, and pembrolizumab, then continued maintenance pemetrexed plus pembrolizumab. During treatment, her kidney function gradually worsened. Pemetrexed was stopped first, but the decline continued while pembrolizumab was maintained. When kidney function deteriorated rapidly, doctors diagnosed pembrolizumab-related immune kidney injury on top of pemetrexed-associated nephrotoxicity. Pembrolizumab was stopped and she received steroid treatment for the kidney complication. From the cancer perspective, later follow-up showed no imaging findings or tumor-marker rise suggesting recurrence. She therefore remained under careful observation without antitumor drugs.