Clinical, biochemical and imaging characteristics of Cushing's macroadenomas and their long-term treatment outcome.

Objective: Cushing's macroadenoma as a cause of Cushing's disease is less common than microadenoma. The data on nature and behaviour of Cushing's macroadenoma are limited to a few case series. We studied clinical, biochemical and imaging characteristics of macroadenoma and their long-term treatment outcomes.

Method: Retrospective analysis of 40 patients with macroadenoma managed at our centre from 1997 to 2013.

Results: Of 40 patients, there were 15 (37·5%) males and 25 (62·5%) females. Mean age at presentation was 26·7 ± 9·3 years. Visual field defects and/or cranial nerve palsies were found in 15 cases at presentation. Mean maximum tumour dimension was 20·83 ± 10·74 mm, and parasellar extension was seen in 25 (62·5%) patients. Plasma ACTH/maximum tumour dimension and 8 am serum cortisol/maximum tumour dimension decreased with increasing tumour size. Sixteen patients (40%) had remission (4: immediate, 12: delayed) after first transsphenoidal surgery (TSS). Larger tumour size and parasellar extension were predictors of failure to achieve remission. Four patients relapsed; noticeably all of them had delayed remission. Among the persistent and relapsed cases, second TSS was successful in two of eight patients, whereas 11 of 16 patients achieved remission after a mean duration of 12·14 ± 8·41 months postradiotherapy.

Conclusion: Younger age at presentation and larger tumour size compared with previous series were distinctive features of our series. Large tumour size and parasellar extension were negative predictors of surgical remission. Delayed remission was seen in significant proportion of patients, but one-third later relapsed. Radiotherapy was an effective second-line treatment modality.