A 29-year-old lady presented with advanced nasopharyngeal carcinoma (NPC) that metastasized to lymph nodes, bilateral lungs and bones in December 2014. Her disease progressed despite chemotherapy including gemcitabine, platinum, 5-FU, capecitabine, taxane, cyclophosphamide. She received radiotherapy for progressive neck lymph nodes in March 2015 with good response. Her lung metastases further progressed to multiple cannon ball lesions, leading to significantly dyspnea requiring admission and 100% O2. Serum EBV DNA was 120000 copies/mL. Tissue biopsy for PD-L1 TPS was 100%. She was started on IV Pembrolizumab 2mg/kg every three weeks. Her symptoms markedly improved, allowing her to resume work as a life-guard. Her lung lesions resolved on CXR after four cycles, serum EBV DNA fell to 100 copies/mL. FDG PET-CT scan showed complete response after eight cycles.
She was on Pembrolizumab from September 2016 to April 2019 when later she presented to A&E for severe right lower quadrant pain. Computed tomography of abdomen showed terminal ileitis and multiple mesenteric lymph nodes. Colonoscopy was performed, and terminal ileum was biopsied, pathology showed multiple caseating granulomas with langerhan cells, consistent with tuberculous ileitis. Interferon gamma release assay was tested strong positive, indicating past MTB infection. She was started on anti-TB drug with Rifampicin, Ethambutol, Pyrazinamide, Isoniazid. The drug regimen was continued for four months. Pembrolizumab was withheld during that period. Her abdominal pain subsided after antibiotics. The terminal ileitis and mesenteric lymph nodes were resolved on CT scan. Colonoscopy was repeated whic showed no signs of further ileitis.
However, her blood tests showed progressive liver function derangement. Multi-disciplinary management team including microbiologist suggest liver derangement to be anti-TB drug related, with a plan for liver biopsy. Her anti-TB medication was adjusted and liver function gradually normalized. IV Pembrolizumab was re-introduced and continued to two years. FDG PET-CT showed no disease progression, and serum EBV DNA remained below 300 copies/mL.