Composite Pheochromocytoma-Ganglioneuroma of the Adrenal Gland: An Uncommon Entity with Distinctive Clinicopathologic Features.

Background: Adrenal composite pheochromocytoma-ganglioneuroma is uncommon. The aim of this study is to investigate the characteristics of patients with this tumor. Methods: Histologic features of 46 pheochromocytomas diagnosed over a 28-year period (1971-1998) were reviewed. The clinical records, pathologic features, and ploidy patterns of patients with composite pheochromocytoma-ganglioneuroma were studied. Cases reported in the literature were also reviewed and compared with typical pheochromocytomas. Results: Four patients (two men; two women) with composite pheochromocytoma-ganglioneuromas were found. The tumors comprised 8.7% of pheochromocytomas. The two male patients with composite tumors were younger than the two female patients (age = 32, 52 vs 73, 75, respectively). The radiologic, gross, and microscopic appearances of the tumors were heterogeneous. One patient had malignant tumor with distant metastases. Flow cytometric analysis showed that the pheochromocytoma component was aneuploid and the ganglioneuroma portion was diploid. A review of the literature showed 31 adrenal composite pheochromocytoma-ganglioneuromas. Composite tumors were seen in older patients and were bigger than typical pheochromocytomas. Conclusion: Composite pheochromocytoma-ganglioneuromas had distinctive clinicopathologic features. Life-long clinical and biochemical follow-up of these patients is essential in view of the non-diploid DNA pattern.