SAT-309 A Case of Multifocal, Malignant Paraganglioma of the Head and Neck

Introduction Most head and neck paragangliomas (PGL) are benign with malignancy reported in less than 4% of the cases. Malignant PGL can be indolent or aggressive. The location of these tumors can make surgical resection difficult. We discuss the management of a case of malignant PGL with multifocal disease in the bilateral carotid bulbs, bilateral glomus vagale and right glomus jugulare. Clinical Case A 37 year old man underwent a CT scan of head and neck following a motor vehicle accident that showed a 5.5 cm x 2.5 cm mass at the left carotid bifurcation causing effacement of the jugular vein. MRI of neck revealed additional tumors in the left glomus vagale (1.7 cm), right glomus jugulare (1.6 cm), right glomus vagale (5 mm) and right carotid bulb (7 mm). The patient was asymptomatic and did not have catecholamine excess. Pre-operative embolization of the left glomus jugulare tumor was performed with 80% reduction in the tumor burden. Surgical resection of the left carotid bulb and vagal tumors was subsequently performed. Pathology showed malignant PGL with metastasis to 1 cervical lymph node. Genetic testing revealed succinate dehydrogenate complex, subunit D (SDHD) mutation. FDG PET-CT following surgery showed increased uptake only at the right jugular bulb area. He was evaluated by medical oncology who did not recommend chemotherapy. Radiation therapy (RT) was performed was performed as adjuvant therapy. Discussion SDHD mutations are transmitted in an autosomal dominant pattern and show a remarkable “parent of origin” inheritance, with disease manifestation occurring almost exclusively with paternally transmitted mutations. This has implications for genetic counselling of family members. Most cases of PGL in SDHD carriers are benign with malignancy found only in 3% of cases. SDHD mutation also predisposes to renal cell carcinoma and pituitary adenoma. Head and neck PGL are mostly non-secretory (95%), however, 3-methoxytyramine is a new marker that has been found to be elevated in one-third of head and neck PGL. Contrast MRI is preferred initial imaging. Functional imaging should be done to rule out metastasis. PET/CT is a sensitive modality to detect concurrent extra-cervical PGL. Surgical resection is preferred for carotid body tumors due to low risk of complications and higher risk of malignancy. RT is first line for vagal and jugular tumors in the absence of compressive symptoms and catecholamine excess. Conclusion While most head and neck PGL are benign, the presence of multifocal disease and malignancy complicates management of the same. Genetic evaluation must be pursued in all patients to predict risk of recurrent/metastatic disease. Complete surgical resection can be difficult due to the risk of cranial nerve palsies and hemorrhage and adjuvant RT should be considered. Five year mortality rate for malignant PGL is 37%, male sex and synchronous metastasis are associated with worse prognosis.