ABSTRACT
Paraganglioma are tumors originating from paraganglial system and may be associated with parasympathetic [head, neck and anterior mediastinum tumors] or sympathetic [adrenal or extraadrenal or posterior mediastinal tumor] system. Majority of sympathetic paraganglioma and minority of parasympathetic tumor are functional and [131I or [132]I labeled MIBG [Meta Iodio Benzyl Guanidine] is a well established tool with good sensitivity and exceedingly high specificity. We are presenting a case report of a large extradrenal paraganglioma with extensive bony metastases and raised serum Chromogranin-A level. In this case [131]-MIBG was not only helpful in revealing the true burden of functional disease but also showed an overwhelming therapeutic response proven on post-therapy MIBG scan and normalization of serum Chromogranin-A level. This case report is followed by a mini-review about pathology, genetic mutation, diagnosis and treatment of focused on extraadrenal paragangliomas