Recent Advances in Genetics, Diagnosis, Localization, and Treatment of Pheochromocytoma

View larger version (34K): [in a new window]   Figure 1. The Knudson two-hit model.Diploid cells have two copies of each gene. A tumor suppressor gene, such as the von Hippel–Lindau gene, is consistent with the Knudson model. In the hereditary form of cancer, the patient inherits a mutation of one copy of the gene. In the tumor, such as a pheochromocytoma in a patient with von Hippel–Lindau disease, the second copy is inactivated by a mechanism such as mutation or deletion.

View larger version (14K): [in a new window]   Figure 2. Algorithm showing use of biochemical tests for diagnosis of pheochromocytoma.Values in parentheses indicate expected numbers of patients with and without pheochromocytoma at different steps during diagnosis, assuming a 2% incidence of the tumor in a population of 1000 patients undergoing testing for clinically suspected pheochromocytoma (that is, 20 patients with and 980 without pheochromocytoma). CT = computed tomography; MRI = magnetic resonance imaging. * For continuation of the algorithm, see Figure 4.

View larger version (28K): [in a new window]   Figure 3. 6-[ 18 F F]Fluorodopamine positron emission tomography before and after left adrenelectomy for a large pheochromocytoma.

View larger version (29K): [in a new window]   Figure 4. Imaging algorithm for patients whose results on biochemical tests are consistent with pheochromocytoma.CT = computed tomography; MIBG = metaiodobenzylguanidine; MRI = magnetic resonance imaging; PET = positron emission tomography.