Introduction: Nelson’s syndrome (NS) is a rare clinical syndrome caused by an enlarging, aggressive corticotroph pituitary adenoma that can occur following bilateral adrenalectomy performed in the treatment of refractory Cushing’s disease (CD). Such tumours respond poorly to currently available therapeutic options, which include surgery, radiotherapy, pharmacotherapy, and chemotherapy. They are a challenging problem in neurosurgical practice. The aim of this work was to evaluate the early and long-term results of microsurgery in a single surgeon’s series of patients with NS.

Material and methods: During the period from January 2000 to December 2005, 10 patients with NS underwent surgery. The authors analysed surgical outcomes in the NS group of seven women and three men with the mean age of 47.99 years (range 39–66, SD ± 8.47 years). NS was diagnosed based on clinical signs and symptoms, especially hyperpigmentation of the skin, elevated serum ACTH levels, and pituitary tumour growth. Parasellar extension of the adenomas was assessed in both groups according to Knosp’s and Hardy-Wilson classifications. Pituitary function and radiographs were evaluated in the early postoperative period, 30 days after the operation, and during follow-up. Histological examination was based on the WHO (2004) criteria.

Results: According to the criteria for Nelson’s syndrome remission, five patients (50%) were cured. No perioperative mortality was reported. Three patients developed pituitary insufficiency and two patients developed diabetes insipidus. There was one case of postoperative cerebrospinal fluid leakage. One patient was diagnosed with pituitary carcinoma.

Conclusions: Transsphenoidal microsurgical removal of pituitary adenomas is a safe and effective treatment of Nelson’ syndrome. (Endokrynol Pol 2015; 66 (6): 504–513)