A 21-year-old man presented with 2 months history of weight gain, acne, hirsutism, lethargy, and muscle weakness. Examination revealed that he was cushingoid in appearance, had pustular acne and proximal myopathy. Initial 24 h urinary free cortisol was significantly raised at 5320 nmol/day (10147), with raised ACTH of 120 ng/l (<47). He failed to suppress his cortisol on the low dose dexamethasone suppression test (baseline 708 nmol/l and 48 h 706 nmol/l). Urinary and plasma 5-HIAA were normal. MRI pituitary showed no abnormality. He was started on metyrapone.
Thoracic CT scan revealed a 2 cm spiculated soft tissue nodule in right upper lobe and 1 cm well defined, round nodule in the left lower lobe. Further imaging (octreotide scan & PET-FDG scan) revealed the nodules to be consistent with functioning neuroendocrine tumours, with the right upper lobe nodule being markedly more FDG-avid than the left. The adrenal glands were bulky consistent with ACTH-driven adrenal hyperplasia.
The patient underwent a right upper lobectomy but histology revealed an unexpected finding- cryptococcal infection instead of a neuroendocrine tumour. He had never travelled abroad and was HIV negative. Post-operatively, his Cushings was still active and he was recommenced on metyrapone. He also received fluconazole for 6 months.
He then underwent inferior petrosal sinus sampling (IPSS) which did not indicate a pituitary source of ACTH. He subsequently had a left lower lobectomy. Histology and immunohistochemistry confirmed a carcinoid tumour. Post-operatively, his IMGST showed a peak cortisol of <50 nmol/l indicating cure.
Although there are a handful of cases describing opportunistic cryptococcal infection in pituitary Cushings disease, we believe that this is the first described case of opportunistic cryptococcal infection in a patient with Cushings syndrome due to bronchial carcinoid.