A 60 years old man was referred to the ENT department with a three week history of swelling in the left parotid gland region. Examination revealed a firm mass involving the left parotid gland. Fine needle aspiration cytology of the mass raised the suspicion of a malignancy. MRI scan of head and neck was consistent with metastatic involvement of the ipsilateral lymph glands. He underwent left radical neck dissection and left parotidectomy. Histology confirmed adenocarcinoma of the left parotid gland.
He represented three months later with one week history of acute confusional state, paranoid behaviour and hallucinations. Examination revealed bilateral leg edema. Initial investigations revealed hypokalaemic metabolic alkalosis (K+2.4 mmol/L and venous bicarbonate 34 mmol/L) suggesting hypercortisolism. This was supported by morning serum cortisol of 1575 nmol/L (range 171536 between 07001000), 24-hour urinary free cortisol 15374 nmol/d (<280) and ACTH levels 106 ng/L (normal<40 ng/L). Serum cortisol levels failed to suppress with low and high dose dexamethasone. Pituitary gland on MR scan and urinary 5HIAA estimation were normal. CT chest showed mediastinal and hilar lymphadenopathy and bilateral generalized enlargement of the adrenal glands. He is being treated with block and replace regimen and palliative chemotherapy which has resulted in clinical and biochemical improvement.
This presentation is consistent with ectopic ACTH secretion causing Cushings syndrome. The parotid gland tumour represents the most likely source. This has not been reported previously. Although the parotid gland tumour did not stain for ACTH, it is commonly reported that this is the case in high secreting tumours, and all the evidence suggests this as the source of this patients ectopic ACTH syndrome.