Hormonally Silent Multifocal Pheochromocytoma in the Setting of a Well-Differentiated Neuroendocrine Tumor of the Appendix: A Case Report.

Pheochromocytomas (PCCs) and paragangliomas (PGLs) represent tumors arising from chromaffin cells of the adrenal medulla and extra-adrenal sympathetic paraganglia, respectively. PCCs commonly produce one or more catecholamines (epinephrine, norepinephrine, and dopamine), but rarely are they biochemically silent. PGLs on the other hand, generally do not produce catecholamines. They have the highest heritability of all adrenal tumors and are known to be associated with genetic mutations. Patients with hereditary tumors typically present at a younger age and with multifocal disease when compared to sporadic disease. Specific genetic mutations have been well established with hereditary syndromes involving PCC/PGLs. Further research has aimed to identify other mutations and delineate specific phenotypes associated with these mutations. A 34-year-old woman presented for evaluation following a laparoscopic appendectomy that identified a 4-cm well-differentiated neuroendocrine tumor on final pathology. Further work-up included a repeat CT scan followed by a Dotatate PET CT scan which revealed a large (7.3 x 5.8 cm) periaortic mass related to the left adrenal gland. Functional adrenal work-up was negative and her Chromogranin A level was 679 ng/mL. She did report intermittent chest tightness and palpitations but was otherwise asymptomatic. The patient subsequently underwent an exploratory laparotomy with left adrenalectomy and adjacent tumor resection as well as completion of right hemicolectomy with ileocolonic anastomosis. Surgical pathology revealed two distinct masses consistent with multifocal PCC. No residual tumor was found in the colectomy specimen and 24 lymph nodes were negative. She had an uneventful recovery and genetic testing showed a variant of uncertain significance for the POLE and VHL genes. She has received genetic counseling and will be enrolled in an appropriate surveillance protocol.