NEUROENDOCRINE TUMOURS ARE MOST FREQUENTLY LOCATED IN THE GASTROINTESTINAL ORGAN SYSTEM OR IN THE LUNGS, BUT THEY MAY OCCASIONALLY BE FOUND IN OTHER ORGANS.CASE: We describe a 56-year old woman suffering from a cardinoid syndrome caused by a large serotonin secreting pituitary tumour. She had for years suffered from episodes of palpitations, dyspnoea and flushing. Cardiac disease had been suspected, which delayed the diagnosis, until blood tests revealed elevated serotonin and chromogranin A in plasma. Somatostatin receptor (SSR) scintigraphy showed a single positive focus in the region of the pituitary gland and MRI a corresponding intra- and suprasellar heterogeneous mass. After pre-treatment with octreotide leading to symptomatic improvement, the patient underwent trans-cranial surgery with removal of the tumour. This led to clinical improvement and to a normalisation of SSR scintigraphy, as well as serotonin and chromogranin A levels.