[561] Extra-Adrenal Pheochromocytoma/Paraganglioma – A Clinicopathological Study

David Molina, Samson W Fine, Hikmat A Al-Ahmadie, Ying-Bei Chen, Anuradha Gopalan, Victor E Reuter, Satish K Tickoo. Memorial Sloan-Kettering Cancer Center, New York, NY

Background: Criteria predicting malignant behavior in pheochromocytomas have been described. Extra-adrenal location (paragangliomas) is one of the features that predicts aggressiveness for pheochromocytoma. However, there are no established criteria for predicting clinical behavior in extra-adrenal paraganglioma. We studied a cohort of paragangliomas from different sites, to determine any pathologic features that may correlate with clinical outcome.
Design: 28 cases of extra-adrenal paraganglioma resected at our institution from 2000 to 2012 were retrieved from our surgical pathology files and form the basis of this study. Follow-up was obtained from the clinical records and outcomes were correlated with histopathological features of the tumors. Development of metastasis or local tumor recurrence was considered as “adverse outcome”.
Results: Among the 28 cases, 16 patients were female and 12 male, with a median age of 41 years [range: 20 to 75]; tumors ranged in size from 1.3 to 9 cm, with the retroperitoneum [n=7] and carotid body [n=6] being the two most common sites. Over a median clinical follow-up of 24 months [range: 1 to 156 months], 13 tumors developed metastasis/recurrences. Of these 13, one case that recurred had family history of paraganglioma and was excluded from final analysis. Among morphologic features, only microscopic tumor necrosis (p= 0.0237) and tumor cell spindling (p=0.0369) showed significant association with adverse outcomes. None of the other morphologic features [vascular invasion, capsular invasion, presence of large nests or diffuse growth (in >10% of tumor volume), high cellularity, cellular monotony, increased mitotic figures (>3/10 HPF) or profound nuclear pleomorphism/multinucleation] showed significant association with outcome.
Conclusions: Nearly half of extra-adrenal paragangliomas in this series showed aggressive clinical behavior. Like pheochromocytoma, tumor necrosis and spindling in paragangliomas are associated with adverse clinical outcome. Unlike pheochromocytoma however, other morphologic features do not seem to predict aggressive behavior.
Category: Endocrine

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 57, Wednesday Afternoon


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