Endogenous hyperinsulinemic hypoglycemia: diagnostic strategies, predictive features of malignancy and long-term survival.

Diagnostic strategies, malignancy predictors and long-term survival were retrospectively evaluated in patients with hyperinsulinemic hypoglycemia (64 insulinomas). Lower median glycemia was 30 (range 20-53) mg/dl [1.6 (1.1-2.9) mmol/l] with concurrent insulin of 48 (13.2-217) microU/ml and 15 (2-46) microU/ml measured by radioimmunoassay (RIA) and immunofluorimetric assay (IFMA), respectively. All patients with insulinomas had a positive prolonged fast within 48 h. Sensitivity of localization methods was: ultrasonography (US) 23%, computed tomography (CT) 28%, magnetic resonance imaging (MRI) 65%, endoscopic US 75%, arteriography 38%, portal venous sampling 67%, selective arterial calcium stimulation 67%, intraoperative US 94% and palpation 92%. Nine patients (14%) had malignant insulinomas. Age at diagnosis (mean+/-SD, 53.8+/-19 vs 39.4+/-16.3 yr; p=0.03), insulin (1372+/-730 vs 785+/-659% (percentage of the method's diagnostic cut-off; 6 and 3 microU/ml for RIA and IFMA, respectively; p=0.007) and C-peptide levels (9.8+/-2.9 vs 3.9+/-2.8 ng/ml (3.2+/-0.9 vs 1.3+/-0.9 nmol/l; p=0.006), and tumor size (6.2+/-4.1 vs 1.5+/-0.6 cm; p=0.0002) were increased in malignant insulinomas. C-peptide level above 6.1 ng/ml (2.0 nmol/l) had a 100% sensitivity and 96% specificity, and tumor size above 2.6 cm yielded a sensitivity of 88% and specificity of 100% in predicting malignancy. Survival of patients with malignant insulinomas was significantly impaired (16 vs 100% at 5 yr; p=0.0000001). The diagnosis of insulinoma can be made within 48 h of fasting. The association between intraoperative US and palpation evidenced the tumor in 95% of the patients. C-peptide and tumor size were reliable malignancy predictors.

Adrenocortical carcinoma: clinical and laboratory observations.

BACKGROUND: The clinical features and natural history of adrenocortical carcinoma are highly dependent on the type of center reporting their experience. Observations from oncology services suggest a high incidence of nonfunctioning tumors, whereas reports from endocrine clinics emphasize excessive corticoid and androgen production in the majority of tumors. The incidence rate and natural history of childhood adrenal carcinoma generally has been under emphasized. METHODS: Over the past 17 years, the authors have evaluated and treated 47 patients with adrenocortical carcinoma referred to the University of Sao Paulo, 22 of whom were children. RESULTS: There is a bimodal age incidence of adrenal carcinoma, with the disease peaking in the first and fourth decades of life. Childhood adrenal carcinoma is characterized by a high rate of incidence of virilization, marked overproduction of androgens, and a less aggressive clinical course, and appears to be more amenable to surgical and other therapeutic modalities. By contrast, adrenocortical carcinoma occurring in adults presents more commonly as a mixed Cushing and virilizing syndrome, with overproduction of corticoids and androgens and a far more aggressive clinical course, leading to rapid death within months or years. Nonfunctioning adrenocortical carcinoma is less common; it generally occurs in older adults and exhibits a rapid downhill course. Modern day imaging methods have improved the diagnosis and staging of adrenal carcinoma greatly. In the authors' experience, the histologic criteria of Weiss appeared to predict tumor prognosis most accurately, whereas immunologic markers, cytoskeletal markers, DNA ploidy, cell phase markers, and oncogenic probes have yielded inconsistent results to date. Surgical removal of a localized tumor remains the best hope for long term survival. Medical therapy with mitotane and its successors in patients with Stage III or IV (MacFarlane system as modified by Sullivan et al.) disease appear to have added little to longevity or quality of life. CONCLUSIONS: When diagnosed in children, adrenal carcinoma is associated with virilism and a less aggressive natural history; however, when it occurs in adults, the disease presents more commonly as a mixed Cushing-virilizing syndrome and has a virulent course. The Weiss histologic criteria appear to correlate best with disease prognosis, but other histochemical, cell cycle, and genetic markers have not, to date, aided in disease management.