ODP041 Hearing Loss Reveals Dopamine-secreting Metastatic Paraganglioma

Abstract

Abstract Background Paragangliomas are neuroendocrine tumors arising from chromaffin cells in extra-adrenal parasympathetic or sympathetic tissues. Frequently they produce catecholamines such as epinephrine and norepinephrine which cause adrenergic symptoms. Rarely, paragangliomas produce only dopamine. These tumors carry a worse prognosis than other types of paragangliomas, especially when associated with loss of SDH-B. Case A 41 year old African American female with developmental delay, allergic rhinitis, OSA, and obesity presented to a primary care clinic for evaluation of hearing loss and left ear pain. Patient was treated for acute otitis media but symptoms failed to resolve. She was referred to audiology where she was found to have a mixed conductive and sensorineural hearing loss on the left. Despite using hearing aids, a year later the patient presented to an ENT clinic with several weeks of worsening left aural fullness and decreased hearing. On otoscopy, a mass was visualized in the middle ear. CT scan identified a lytic lesion at the jugular foramen extending into the middle ear; MR of the inner auditory canal was concerning for a paraganglioma. PET CT revealed widely metastatic disease including FDG avid cervical and supraclavicular lymph nodes, pulmonary nodules, hepatic lesions, and sclerotic lesions in the vertebral column and right humerus. Biopsy of an hepatic lesion confirmed metastatic paraganglioma with loss of SDH-B. Labs were consistent with dopamine excess. A 24 hour urine dopamine was 1020 mcg/24 hour (normal 65-400) with plasma dopamine elevated at 191 pg/mL (normal <30). A 24 hour urine norepinephrine level was mildly elevated at 85 mcg/24 hours (normal 15-80) but plasma norepinephrine and epinephrine were both normal. The patient denied any history of palpitations, flushing, headaches, or chest pain. She was briefly started on doxazosin but this was later discontinued as metanephrines and normetanephrines were not significantly elevated. The tumor was not amenable for surgery. Ultimately after discussion with oncology, the patient opted to proceed with temozolomide and capecitabine chemotherapy. Discussion It is important to recognize differences in treating dopamine secreting paragangliomas compared with other catecholamine producing tumors. Preoperative alpha blockade is not routinely recommended as it may cause hypotension and postoperative cardiovascular collapse. While chemotherapy with Cyclophosphamide–dacarbazine–vincristine has historically been used for metastatic paragangliomas, temozolomide is now showing benefit in cases with SDH-B mutation. Sources cited: Foo, S. H., et al. "Dopamine-secreting phaeochromocytomas and paragangliomas: clinical features and management." Singapore Med J 51.5 (2010): e89-e93. Hadoux, J., Favier, J., Scoazec, J. -Y., et al (2014),SDHB mutations are associated with response to temozolomide in patients with metastatic pheochromocytoma or paraganglioma. Int. J. Cancer, 135: 2711-2720. https://doi.org/10.1002/ijc.28913. Presentation: No date and time listed