Electron microscopical morphometry of well-differentiated and undifferentiated ACTH secreting adenomas in Cushing's disease and Nelson's syndrome

Granulation Patterns of Functional Corticotroph Tumors Correlate with Tumor Size, Proliferative Activity, T2 Intensity-to-White Matter Ratio, and Postsurgical Early Biochemical Remission

Unlike somatotroph tumors, the data on correlates of tumor granulation patterns in functional TPIT lineage pituitary neuroendocrine tumors (corticotroph tumors) have been less uniformly documented in most clinical series. This study evaluated characteristics of 41 well-characterized functional corticotroph tumors consisting of 28 densely granulated corticotroph tumors (DGCTs) and 13 sparsely granulated corticotroph tumors (SGCTs) with respect to preoperative clinical and radiological findings, tumor proliferative activity (including mitotic count and Ki-67 labeling index), and postoperative early biochemical remission rates. The median (interquartile range (IQR)) tumor size was significantly larger in the SGCT group [16.00 (16.00) mm in SGCT vs 8.5 (9.75) mm in DGCT, p = 0.049]. T2-weighted signal intensity and T2 intensity (quantitative) did not yield statistical significance based on tumor granulation; however, the T2 intensity-to-white matter ratio was significantly higher in SGCTs (p = 0.049). The median (IQR) Ki-67 labeling index was 2.00% (IQR 1.00%) in the DGCT group and 4.00% (IQR 7.00%) in the SGCT group (p = 0.043). The mitotic count per 2 mm2 was higher in the SGCT group (p = 0.001). In the multivariate analysis, the sparse granulation pattern (SGCT) remained an independent predictor of a lower probability of early biochemical remission irrespective of the tumor size and proliferative activity (p = 0.012). The current study further supports the impact of tumor granulation pattern as a biologic variable and warrants the detailed histological subtyping of functional corticotroph tumors as indicated in the WHO classification of pituitary neuroendocrine tumors. More importantly, the assessment of the quantitative T2 intensity-to-white matter ratio may serve as a preoperative radiological harbinger of SGCTs.

Long-term treatment of Nelson's syndrome by octreotide: a case report

Medical management of Nelson's syndrome by drugs such as bromocriptine, sodium and magnesium valproate has provided disappointing or, at least, controversial results. We report here on the results of long-term (2 yr) treatment with the somatostatin analogue octreotide (300 micrograms daily sc) in one patient affected by Nelson's syndrome occurring after bilateral adrenalectomy for Cushing's syndrome. During treatment, skin hyperpigmentation and serum ACTH levels decreased dramatically and a slight (about 10%) reduction in tumor size, as assessed by computerized tomography, was also observed. These results suggest that octreotide may be useful for the medical management of Nelson's syndrome.