Metastatic Malignant Paraganglioma: A Case Report

Abstract

Abstract Objectives Paragangliomas are rare neuroendocrine tumors that arise from chromaffin cells with the ability to secrete catecholamines. The estimated combined prevalence is between 1:6,500 and 1:2,500. Paragangliomas can have a benign or a malignant course with incidence of malignant paraganglioma estimated to be 93/400 million. The majority of paragangliomas are sporadic but may be related to syndromes like multiple endocrine neoplasia type 2, von Hippel-Lindau disease, and neurofibromatosis type 1. Methods We present a unique case of a 25-year-old female who presented with a hepatic mass. Further workup showed an enhancing hypervascular mass along with lesions within the bilateral lungs, liver, spleen, and sclerotic osseous metastatic disease at cervical thoracic lumbar and sacral spine. A liver biopsy was performed, which was consistent with the diagnosis of a metastatic paraganglioma. Results The liver biopsy showed a tumor consisting of epithelioid and polygonal tumor cells with eosinophilic cytoplasm present in a vascularized fibrous stroma in a sinusoidal pattern. In certain areas, the tumor cells show marked pleomorphism with large cells with macronuclei and bizarre shapes. On immunohistochemistry (IHC), the tumor cells were strongly and diffusely positive for CD56 and vimentin and focally positive for synaptophysin and chromogranin. S100 highlighted sustentacular cells. Ki-67 was very low, staining less than 2%. In addition, the tumor cells showed loss of expression of SDHB by IHC. Conclusion Metastatic malignant nonsecretory paraganglioma is an extremely rare disease. The most unique pathological aspect of paragangliomas is that tissue acquired from different organ appears the same histologically and yet different in terms of prognosis. Metastatic hepatic paraganglioma in our patient offers interesting insights to appreciate the rare metastatic nature of paraganglioma to the liver. The elusive nature of the metastatic disease in paraganglioma poses a challenge to clinicians since the diagnosis of metastatic hepatic paraganglioma is usually clinically undiagnosed.