A 44-year-old lady with hypertension and type 2 diabetes of 10 years duration (BMI 47, HbA1c 9.1%) treated with metformin and exenatide presented with a few days history of feeling generally unwell, vomiting and confusion. Initial examination showed pulse 120 per min, BP 115/74 mmHg, normal temperature and multiple abdominal striae. Admission investigations showed Na 140, K 1.4, urea 3.9, creatinine 74, glucose 26, CRP 23 Hb 16.2, WBC 11.6. ABGS on room air showed pH 7.41, PCO2 3.5, PaO2 11.0. She was initially treated with intravenous KCl and received a total of 280 mmol in the first 48 h. On day 2 the potassium improved only to 2.4 but she developed evidence of sepsis (temp 39 ° C) and metabolic acidosis (pH 7.08). She was treated in ITU with IV antibiotics. Random cortisol came back at 2712 nmol/l with ACTH 50 pmol/l. Pituitary MRI was normal while CT of chest, abdomen and pelvis showed a bulky left adrenal gland and two focal liver lesions suggestive of metastasis but no primary tumour detected. A liver biopsy was eventually performed which showed a poorly differentiated large cell neuroendocrine carcinoma. The patient had a stormy hospital stay complicated by severe sepsis, DVT, C. Difficile diarrhea and acute renal failure needing haemofiltration. She died after 6 weeks stay in ITU. Metastatic neuroendocrine tumours causing ectopic Cushings syndrome are rare and as illustrated in this case these tumours can be very aggressive and have a very poor prognosis.