Transsphenoidal surgery in Cushing disease: The challenging microadenoma (Local experience)

Abstract

Background: Cushing disease is uncommon challenging disease. The adenomas are usually small in size in most case making the disease diagnosis and management is sometimes difficult. In some cases, the tumor cannot be identified on imaging studies and in many cases the adenoma is eccentric in location adding more difficulties to the trans-sphenoid approach for excision of such tricky tumors.
Object: to evaluate the challenge of diagnosis and trans-sphenoid surgery for ACTH pituitary microadenomas.
Methods: 21 patients with ACTH secreting adenomas were involved in this retrospective study. All cases were operated up on via trans-sphenoid approach during the period from January 2009 till October 2015. All of them were microadenomas. All patients had obvious Cushing manifestations. In all cases magnetic resonance (MR) imaging and CT paranasal sinuses were performed. In this study: cases with macroadenomas and recurrent cases after previous trans-sphenoid approach or gamma knife radiosurgery were excluded.
Results: Among the 21 patients; 14 were female and 7 weremale with age ranging from 21 to 44 years. The imaging study was positive for microadenoma in 18 patients while in 3 cases; no tumor was seen on the MRI imaging. All were operated via the trans-sphenoid approach (12 patients via the microscopic technique and other 9 patients via the endoscopic technique). The adenoma was successfully removed in 15 out of the 18 patients with evident adenoma on pre-operative MRI imaging while partial hypophysectomy were done in 5 cases without an evident adenoma on pre-operative MRI study or difficult adenoma identification. In one patient; the procedure was aborted because of sphenoid sinus abnormalities and the tumor was successfully removed via trans-cranial approach. Disease remission was achieved in 17 patients. In 4 patients; complete remission was not achieved and gamma knife radiosurgery was done after surgery. Disease progression occurred in two patients with initial remission and was treated gamma knife radiosurgery. 13 patients had an ACTH deficiency after surgery while other hormonal replacement therapy is needed in only 5 cases. CSF rhinorrhea occurred in 2 patients and was managed with transient lumbar drain without any subsequent morbidities. Transient diabetes insipidus occurred in 6 cases and was treated conservatively.
Conclusions: The transsphenoidal approach ACTH secreting pituitary microadenomas is considered safe and effective for achieving disease remission despite the challenge of diagnosis and intra-operative tumor identification.