Normotensive incidentally discovered pheochromocytomas display specific biochemical, cellular, and molecular characteristics.

CONTEXT: A number of incidentally discovered pheochromocytomas are not associated with hypertension. The characteristics of normotensive incidentally discovered pheochromocytomas (NIPs) are poorly known. OBJECTIVE: The purpose of this work was to assess the clinical, hormonal, histological, and molecular features of NIPs. DESIGN: This was a retrospective cohort recruited from 2001 to 2011 in 2 tertiary care medical departments. PATIENTS AND METHODS: Clinical, biological, and radiological investigations performed in 96 consecutive patients with sporadic unilateral pheochromocytomas were examined; 47 patients had overt pheochromocytomas responsible for hypertension. Among the patients with incidental pheochromocytomas, 28 had hypertension and 21 were normotensive (NIPs). A total of 62 tumors were examined to determine the Pheochromocytoma of the Adrenal Gland Scale Score, and 29 were studied for the expression of 16 genes involved in chromaffin cell function. RESULTS: Tumor size and metaiodobenzylguanidine (MIBG) scintigraphy results were similar for hypertensive pheochromocytomas (HPs) and NIPs. Patients with NIPs displayed reduced summed levels of urinary catecholamines and metanephrines and, more specifically, reduced levels of adrenaline and metadrenaline compared with those of patients with HPs (P < .001). Urinary metanephrines had 98% diagnostic sensitivity in patients with HPs and only 75% in patients with NIPs (P < .01). Tumor diameter positively correlated with the total amount of urinary concentrations of metanephrines in patients with HPs (P < .001) but not in patients with NIPs. NIPs displayed global decreased chromaffin gene expression (reaching significance for 5 of them) and 2 corresponding proteins (phenylethanolamine N-methyltransferase and secretogranin II) and a significant increase in the cellularity, mitotic activity, and presence of atypical mitosis (P < .05). CONCLUSIONS: NIPs differ from pheochromocytomas responsible for hypertension and display features of altered chromaffin differentiation. These tumors may be misdiagnosed with the use of the usual biological diagnostic tools.

High-dose mitotane strategy in adrenocortical carcinoma: prospective analysis of plasma mitotane measurement during the first 3 months of follow-up.

BACKGROUND: The benefit-to-risk ratio of a high-dose strategy at the initiation of mitotane treatment of adrenocortical carcinoma (ACC) remains unknown. METHODS: To evaluate the performance of a high-dose strategy, defined as the highest tolerated dose administered within 2 weeks and maintenance therapy over 4 weeks, we conducted a single-center, prospective study with two main objectives: to evaluate the percentage of patients who achieve a plasma mitotane level above 14 mg/l and to evaluate the tolerance of mitotane within the first 3 months of treatment. Plasma mitotane levels were measured monthly using HPLC. RESULTS: Twenty-two patients with ACC were prospectively enrolled. The high-dose mitotane strategy (4 g/day or more in all patients, with a median of 6 g/day within 2 weeks) enabled to reach the therapeutic threshold of >14 mg/l at 1, 2, or 3 months in 6/22 patients (27%), 7/22 patients (32%), and 7/22 patients (32%) respectively. In total, a therapeutic plasma mitotane level was reached in 14 out of 22 patients (63.6%) during the first 3 months in ten patients, and after 3 months in four patients. Grade 3-4 neurological or hematological toxicities were observed in three patients (13.6%). CONCLUSION: Employing a high-dose strategy at the time of mitotane initiation enabled therapeutic plasma levels of mitotane to be reached within 1 month in 27% of the total group of patients. If this strategy is adopted, we suggest that mitotane dose is readjusted according to plasma mitotane levels at 1 or/and 2 months and patient tolerance.