Rosai-Dorfman disease presenting as a pituitary tumour

A 45-year-old woman had pyrexia, headaches, collapse and hyponatraemia. Int racerebral abscess, bacterial meningitis and subarachnoid haemorrhage were excluded. She was given intravenous antibiotics and gradually recovered, On e month later she was readmitted with diplopia, headache and vomiting. Seru m sodium was low (107 mmol/l) and a diagnosis of inappropriate ADH secretio n was made. MRI scan showed a suprasellar tumour arising from the posterior pituitary gland. A skin rash gradually faded, Serum cortisol, prolactin, g onadotrophins and thyroid hormone levels were low, A pituitary tumour was r emoved trans-sphenoidally, she had external pituitary radiotherapy, and rep lacement hydrocortisone and thyroxine, She was well for 12 months when she developed progressive weakness and numbness of both legs. Examination sugge sted spinal cord compression at the level of T2 where MRI scanning showed a n intradural enhancing mass, This spinal tumour was removed and her neurolo gical symptoms disappeared. Nine months after this she developed facial pai n and nasal obstruction. CT scan showed tumour growth into the sphenoid sin us and nasal cavities, A right Cauldwell-Luc operation was done and residua l tumour in the nasal passages was treated by fractionated external radioth erapy and Prednisolone, Histological examination of the specimens from pitu itary, spinal mass, and nasal sinuses showed Rosai-Dorfman disease, a rare entity characterized by histiocytic proliferation, emperipolesis (lymphopha gocytosis) and lymphadenopathy, Aged 48 she developed cranial diabetes insi pidus, Although Rosai-Dorfman syndrome is rare, it is being reported with i ncreasing frequency, and should be borne in mind as a possible cause of a p ituitary tumour.