Abstract
INTRODUCTION: Paraganglioma is a malignant tumor that arises from the extra adrenal paraganglionic cells of the sympathetic or parasympathetic systems. Herein, we present a case of abdominal mass of unknown histology that underwent a very difficult surgical mass resection. Its final histologic diagnosis was non-functional paraganglioma that was presented as a huge intra-peritoneal mass. PRESENTATION OF CASE: The patient was a 55-year-old Iranian lady who referred to our center with a giant abdominal mass. Fine needle aspiration (FNA) biopsy showed undifferentiated carcinoma. After laparotomy for mass resection pathology evaluation revealed; malignant paraganglioma, non-metastatic type. Further post-operative patients evaluations showed that the tumor was sporadic in nature and the subsequent patient's natural history was uneventful. DISCUSSION: Pathologic evaluations have key roles in the exact diagnosis of abdominal masses with unidentified sources. For the paragangliomas, all of them should be regarded malignant until proved otherwise. However, combined use of biochemical markers, immunohistochemical techniques (IHC), and genetic analysis have key roles in the diagnosis and treatment of paragangliomas. Additionally, surgical removal is the proved curative way of paraganglioma treatment. CONCLUSION: Asymptomatic intra-peritoneal paraganglioma is very rare, especially its malignant variety. This case emphasizes that full pathologic investigation would reveal the exact nature of idiopathic abdominal masses, especially in the state of absence of typical clinical and para-clinical symptoms.