Introduction: Paragangliomas are neuroendocrine tumors arising from extra-adrenal chromaffin cells. Paragangliomas of the head and neck frequently originate from the paraganglionic system including the carotid bifurcation, middle ear and the ganglion nodosum of the vagus nerve. However, of paragangliomas of the head and neck, only 13% secrete hormones and majority are non-functional. Here, we describe a case of non-functional paraganglioma confused with parathyroid adenoma ultrasonographically.
Case: A 45-year-old female patient attending to our department with difficulty in swallowing was found to have a palpable mass lesion in the right lower cervical region. A neck ultrasound showed a hypo-echoic, solid lesion without increased vascularity (15×18×24 mm) adjacent to the capsule of the lower pole of the thyroid lobe. She was euthyroid and had normal calcium and parathyroid hormone levels. Its location adjacent to the thyroid capsule suggested a non-functional parathyroid lesion. Thus, a technetium sestamibi scanning did not demonstrate any activity uptake consistent with a parathyroid lesion. Also a neck exploration was performed for differential diagnosis. Encapsulated solid nodule was confirmed a benign paraganglioma by histopatologic examination. Hormonal profile revealed a serum menanephrine of 0.37 nmol/l (n: 0.080.51), serum normetanephrine of 1.24 nmol/l (n: 0.121.18), urinary menatephrine of 78.29 μg/day (n: 52341), and a urinary normetanephrine of 221.8 μg/day (n: 88444). Thus, a diagnosis of non-functional paraganglioma was established, and further radiological imaging did not reveal paragangliomas at other sites.
Conclusion: Herein, we reported a case of cervical non-functional paraganglioma located at the neck that can be confused with a parathyroid adenoma ultrasonographically. In normocalcaemic patients with normal parathyroid hormone levels, a diagnosis of cervical paraganglioma should also be considered due to its ultrasonographic similarity to parathyroid lesions.