ODP052 Recurrent Pheochromocytoma Concerning For Surgical Seeding From Prior Partial Adrenalectomy

INTRODUCTION: Surgery for a sporadic pheochromocytoma does not always lead to long-term cure, even in patients with a benign tumor, with an estimated recurrence rate of 3% (1). We present a patient with a history of pheochromocytoma s/p partial adrenalectomy 10 years prior found to have recurrence not within the adrenal parenchyma, but in the prior resection bed and diaphragm, concerning for seeding of the surgical bed from prior surgery. CLINICAL CASE: A 56-year-old man with a history of pheochromocytoma s/p a laparoscopic left partial adrenalectomy 10 years prior, with no detected rupture of the capsule at time of surgery, presented with symptoms of palpitations and anxiety. The patient had previously tested negative for SDHB, SDHD, MEN2, and VHL. Repeat labs were concerning for recurrence: 24-hour urine normetanephrines 1192 μ g (156-729 μ g) and metanephrines 204 μ g (58-276 μ g), plasma normetanephrine 479.4 pg/mL (0. 0-136.8 pg/mL), metanephrines 38.2 pg/mL (0. 0-88. 0 pg/mL), and chromogranin A 129. 0 ng/mL (0. 0-101.8 ng/mL). MRI with contrast showed a mildly enhancing mass in the left adrenalectomy postsurgical bed with no changes noted in the liver, and an I-123 MIBG scan showed focal uptake in the left adrenal gland corresponding to the mass seen on MRI as well as heterogeneous uptake in the left hepatic lobe. A DOTATE PET scan done prior was negative. The patient underwent laparoscopic left adrenalectomy; the left adrenal gland was dissected and the patient was found to have multiple satellite lesions along the left diaphragm which were excised. On pathology, immunostains were positive for chromogranin and synaptophysin. Multiple nodules of pheochromocytoma/paraganglioma were seen involving the soft tissue of the diaphragm (<0.1-0.6 cm) and the periadrenal soft tissue and prior resection bed (<0.1-2.5 cm), with no tumor seen within the residual adrenal parenchyma. The tumor extended to the cauterized tissue edges and no lymphovascular invasion was seen. No necrosis, no increased mitotic activity, no atypical mitotic figures were noted, and Ki-67 proliferation index was <1%. Testing done six weeks postoperatively showed plasma normetanephrine 49.9 pg/mL, metanephrine <10 pg/mL, and chromogranin A 87.9 ng/mL. Repeat genetic testing was negative for SDHB, SDHD, VHL, and MEN2. One year postoperatively, the patient's blood pressures are well-controlled on a small dose of doxazosin, kept on as a prophylactic measure. CONCLUSION: This case demonstrates a rare presentation of recurrent pheochromocytoma found in the diaphragm, periadrenal tissue, and surgical bed from a prior partial adrenalectomy, concerning for recurrence in setting of surgical seeding from prior surgery. This case highlights the importance of perhaps considering a total adrenalectomy rather than partial when possible. Reference: (1) Holscher I, et al. Recurrence Rate of Sporadic Pheochromocytomas After Curative Adrenalectomy: A Systematic Review and Meta-analysis. J Clin Endocrinol Metab. 2021 Jan 23;106(2): 588-597. Presentation: No date and time listed