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Dy, Benzon M.

https://orcid.org/0000-0001-6887-7974

Mayo Clinic

Mayo Clinic

Citations 15

C 11 Choline-PET/CT as a Localization Standard for Reoperative Primary Hyperparathyroidism
Hopmann, Peter , Foster, Trenton R. , Dy, Benzon M. , McKenzie, Travis, Wermers, Robert A. , Lyden, Melanie L. , Lund, Sarah , Foster, Trenton R , Lyden, Melanie, McKenzie, Travis J. , Johnson, Geoffrey B.

The American Surgeon™ | January 6, 2026 | Volume: 92 | Issue: 6 | Pages: 1806-1812

10.1177/00031348251413528 Get It

Introduction Previous studies have demonstrated that C 11 choline positron emission tomography/computed tomography (Choline-PET/CT) can localize abnormal parathyroid glands in the reoperative setting. This study assesses a large volume of patients with primary hyperparathyroidism (1HPT) who underwent Choline-PET/CT to confirm its utility in the setting of negative or equivocal conventional imaging. Methods All patients who underwent Choline-PET/CT for evaluation of 1HPT from July 2017 to July 2024 at a single institution were reviewed. Inclusion criteria were patients who underwent parathyroidectomy and had lab testing to assess for cure (defined as >50% drop from baseline PTH and into normal range, or resolution of hypercalcemia at follow-up). Sensitivity, positive predictive value (PPV), false negative rate (FNR), and accuracy were compared to conventional imaging (neck ultrasound, parathyroid scan, and parathyroid four-dimensional CT (4D-CT)). Subgroup analysis was conducted comparing sensitivity of modalities among index operations and separately in reoperations. Results 84 patients were included for analysis. 61 failed to localize on at least one conventional modality, and 15 failed to localize on all conventional studies. 67 patients (80%) achieved cure, of which 53 were reoperations. Choline-PET/CT outperformed conventional modalities across sensitivity, PPV, FNR, and accuracy. Choline-PET/CT also outperformed conventional modalities when comparing sensitivity in both subgroups. Conclusion C 11 choline-PET/CT is a valuable imaging modality in the reoperative setting and demonstrates utility for index operations. It provides localization when other modalities fail and allows for a high surgical cure rate. Further investigation into its utility as a primary imaging modality is warranted.
MON-755 C11 Choline-PET/CT Is A Localization Standard For Re-operative Parathyroidectomy In Primary Hyperparathyroidism
Hopmann, Peter , Foster, Trenton R. , Dy, Benzon M. , McKenzie, Travis J. , Wermers, Robert A. , Lyden, Melanie L. , Lund, Sarah , Johnson, Geoffrey B.

Journal of the Endocrine Society | October 23, 2025 | Volume: 9 | Issue: Supplement_1 | Pages: No page available

10.1210/jendso/bvaf149.497 Get It

Abstract Disclosure: P. Hopmann: None. S. Lund: None. T. Foster: None. B. Dy: None. T. McKenzie: None. G. Johnson: None. R.A. Wermers: None. M. Lyden: None. Background: Previous studies have demonstrated that C11 choline positron emission tomography/computed tomography (Choline-PET/CT) can localize abnormal parathyroid glands in the re-operative setting. This study assesses a large volume of patients with primary hyperparathyroidism (1HPT) who underwent Choline-PET/CT to confirm its utility in the setting of negative or equivocal conventional imaging. Methods: All patients who underwent Choline-PET/CT for evaluation of 1HPT from July 2017 to July 2024 at a single institution were reviewed. Inclusion criteria were patients who underwent parathyroidectomy and had lab testing to assess for cure (defined as >50% drop from baseline PTH and into normal range, or resolution of hypercalcemia at follow-up). Sensitivity, positive predictive value (PPV), false negative rate (FNR), and accuracy were compared to conventional imaging (neck ultrasound, parathyroid scan, and parathyroid four-dimensional CT (4D-CT)). Subgroup analysis was conducted comparing sensitivity of modalities among index operations, and separately in re-operations. Results: 176 patients were identified. 85 underwent parathyroidectomy, 1 patient was excluded due to lacking data to evaluate for cure. Of 91 patients who did not undergo parathyroidectomy, 45 were non-localizing on all imaging, and 46 had positive Choline-PET/CT findings but opted against surgery due to mild disease or prohibitive re-operative risk. Of the included 84 parathyroidectomy patients, 61 failed to localize on at least one conventional modality, and 15 failed to localize on all conventional studies. 67 patients (80%) achieved cure, of whom 53 were re-operations (range of 1-4 prior operations, average 1.5). Choline-PET/CT outperformed conventional modalities across sensitivity, PPV, FNR, and accuracy. Among index operations, Choline-PET/CT had significantly higher sensitivity than conventional modalities (100% vs 27% for ultrasound, 30% for parathyroid scan, 29% for 4D-CT; p values ≤0.01). This was also true in re-operations (95% for Choline-PET/CT vs 13% for ultrasound, 30% for parathyroid scan, 32% for 4D-CT; p values <0.01). Conclusion: C11 choline-PET/CT is a valuable imaging modality in the re-operative setting and demonstrates utility for index operations. It provides localization when other modalities fail and allows for a high surgical cure rate. Further investigation into its utility as a primary imaging modality is warranted. Presentation: Monday, July 14, 2025
Intraoperative Parathyroid Hormone Monitoring Is of Limited Usefulness in Guiding Autotransplantation in Reoperative or Subtotal Parathyroidectomy for Primary Hyperparathyroidism
Richards, Bradley A. , Dy, Benzon M. , Foster, Trenton R. , McKenzie, Travis J. , Lyden, Melanie L. , Vierkant, Robert A.

The American Surgeon™ | February 14, 2023 | Volume: 89 | Issue: 12 | Pages: 5421-5427

10.1177/00031348231156758 Get It

Introduction Patients with primary hyperparathyroidism (1HPT) undergoing reoperative or subtotal parathyroidectomy (PTX) may undergo autotransplantation (ATX) when the viability of remaining tissue is unknown. This study aims to identify whether intraoperative parathyroid hormone levels (IOPTH) can determine ATX candidacy. Methods Patients with 1HPT who underwent PTX with ATX at our institution were identified. IOPTH and PTH values within 24 h, 2-4 weeks, and >1 month postoperative were analyzed. Patients were classified as either a candidate for ATX (low PTH after 2-4 weeks) or not a candidate based on postoperative PTH (normal PTH after 2-4 weeks). Associations of ATX candidate status with demographic and clinical attributes were studied. Results 268 had a reoperative (49%) or subtotal PTX with ATX. 151 had data for PTH analysis, and 21 (14%) were identified as candidates for ATX. The mean % decline in IOPTH from baseline to 20 min post-excision was 51% in noncandidates vs 73% in candidates (P = .002). The mean change in IOPTH from baseline to final was 52% in noncandidates and 83% in candidates (P = .009). A decrease in IOPTH from baseline to 20 min post-excision of 23.4% or greater or a final PTH of 52 pg/mL or less would be an indication for ATX. Of the 21 who needed an ATX, it failed in 10. Conclusion Parathyroid ATX is frequently unnecessary, and the viability is less than expected. While candidates for ATX have a greater IOPTH % decline at all points during surgery and a lower final IOPTH, the clinical practicality of using IOPTH to determine ATX candidacy is limited.
Persistence and Recurrence of Hypercalcemia After Parathyroidectomy Over 5 Decades (1965–2010) in a Community-based Cohort
Mirande, Maxwell, Huang, Chieh-Ting, Kearns, Ann E. , Fyffe-Freil, Ria , Foster, Trenton R. , Thompson, Geoffrey B. , Lyden, Melanie L. , McKenzie, Travis J. , Wermers, Robert A. , Dy, Benzon M. , Szabo Yamashita, Thomas , Kearns, Ann, Foster, Trenton, Lyden, Melanie, Yamashita, Thomas Szabo , Huang, Chieh-Ting, Singh, Ravinder

Annals of Surgery | August 26, 2022 | Volume: 278 | Issue: 2 | Pages: e309-e313

10.1097/sla.0000000000005688 Get It

Background: There is limited long-term follow-up of patients undergoing parathyroidectomy. Recurrence is described as 4% to 10%. This study evaluated persistence and recurrence of hypercalcemia in primary hyperparathyroidism after parathyroidectomy. Methods: Single-institution retrospective (1965–2010) population-based cohort from Olmsted County (MN) of patients undergoing surgery for primary hyperparathyroidism. Patients’ demographic data, preoperative and postoperative laboratory values, clinical characteristics, surgical treatment, and follow-up were noted. Results: A total of 345 patients were identified, 75.7% female, and median age 58.4 years [interquartile range (IQR): 17.6]. In all, 68% of patients were asymptomatic and the most common symptoms were musculoskeletal complaints (28.4%) and nephrolithiasis (25.6%). Preoperative median serum calcium was 11 mg/dL (IQR: 10.8–11.4 mg/dL), and median parathyroid hormone was 90 pg/mL (IQR: 61–169 pg/dL). Bilateral cervical exploration was performed in 38% and single gland resection in 79% of cases. Median postoperative serum calcium was 9.2 mg/dL (IQR: 5.5–11.3). Nine percent of patients presented persistence of hypercalcemia, and recurrence was found in 14% of patients. Highest postoperative median serum calcium was 10 mg/dL (IQR: 6–12.4), and median number of postoperative calcium measurements was 10 (IQR: 0–102). Postoperative hypercalcemia was identified in 37% of patient. Fifty-three percent were attributed to secondary causes, most commonly medications, 22%. Three percent of patients required treatment for postoperative hypercalcemia. Median time to recurrence and death were 12.2 and 16.7 years, respectively. Conclusion: Recurrent hypercalcemia after successful parathyroidectomy is higher than previously reported. Most cases are transient and often associated to other factors with only the minority requiring treatment. Long-term follow-up of serum calcium should be considered in patients after successful parathyroidectomy.
Clinical course and imaging characteristics of benign adrenal cysts: a single-center study of 92 patients
Dogra, Prerna , Rivera, Michael , McKenzie, Travis J. , Foster, Trenton R. , Dy, Benzon M. , Lyden, Melanie L. , Bancos, Irina , Young, William F. , Bancos, Irina

European Journal of Endocrinology | July 5, 2022 | Volume: 187 | Issue: 3 | Pages: 429-437

10.1530/eje-22-0285 Get It

Objective Benign adrenal cysts are rare lesions of the adrenal glands. Limited data are available to guide management. We aimed to describe the presentation and outcomes of patients with benign adrenal cysts. Design Retrospective longitudinal cohort study. Methods Consecutive patients with histologically or radiologically confirmed adrenal cysts between 1995 and 2021 were identified. Pheochromocytomas and malignancy were excluded. Results Benign adrenal cysts were diagnosed in 92 patients (53, 57% women) at a median age of 45 years. Mode of discovery was incidental on imaging in 81 (88%), symptoms of mass effect in 9 (9.8%), and others in 2 (2.2%). Majority (89, 97%) of patients had unilateral cysts (45 right, 44 left) with a median size of 48 mm (range 4–200) at diagnosis. On imaging, most cysts were round/oval (85.4%), homogenous (83.2%) lesions with calcifications (64.0%) and no vascular enhancement (97.7%). During a median follow-up of 65 months (range 7–288), adrenal cysts demonstrated minimal enlargement (median size change 6 mm, median growth rate 2 mm/year). On hormonal evaluation, 10% (5/50 tested) had an abnormal overnight dexamethasone suppression test, and 9.5% (4/42 tested) had an abnormal case detection testing for primary aldosteronism. Patients treated with adrenalectomy (46, 50%) were younger (36.9 years vs 50.8 years, P = 0.0009) and had more rapidly enlarging cysts (median growth rate 5.5 mm/year vs 0.4 mm/year, P = 0.0002). Conclusion Benign adrenal cysts are usually incidentally discovered, non-functional, homogenous lesions without vascular enhancement that demonstrate minimal growth. Adrenalectomy should be reserved for patients with heterogeneous lesions, abnormal hormonal evaluation, or those with mass effect symptoms.
Clinical, imaging and biochemical presentation of cystic pheochromocytomas
Dogra, Prerna , Navin, Patrick J. , McKenzie, Travis J. , Foster, Trenton R. , Dy, Benzon M. , Lyden, Melanie L. , Foster, Trenton, Lyden, Melanie, Bancos, Irina , Navin, Patrick , Young, William F. , Bancos, Irina

Clinical Endocrinology | April 21, 2022 | Volume: 98 | Issue: 1 | Pages: 32-40

10.1111/cen.14743 Get It

Abstract Objective Cystic adrenal mass is a rare imaging presentation of pheochromocytoma. We aimed to describe the clinical, biochemical and imaging characteristics of patients with cystic pheochromocytoma. Design Single‐centre, retrospective study, 2000−2020. Patients Consecutive patients with cystic pheochromocytoma were identified from our institutional pathology and adrenal tumour database. Results Of the 638 patients with pheochromocytomas, 21 (3.2%) had cystic pheochromocytomas (median age: 57 years, 57% women). Most pheochromocytomas were discovered incidentally (57%) or due to symptoms of catecholamine excess (24%). The median tumour size was 6.4 cm. On imaging, cystic pheochromocytomas were round or oval (90%), heterogeneous lesions (86%) with a thick solid rim (median rim thickness 13.9 mm, unenhanced computed tomography (CT) attenuation 40 Hounsfield units (HU), venous‐phase CT attenuation 83 HU), and a median cystic component of 40% (unenhanced CT attenuation 17.6 HU, venous‐phase CT attenuation 20.4 HU), and rarely with calcifications (15%). All 20 patients with biochemical testing had functioning tumours (adrenergic in 80%, noradrenergic in 20%). Total urinary metanephrine excretion correlated with the volume of the solid component ( R 2 = .75, p < .0001) but not the cystic component ( R 2 = .04, p = .4386). All patients underwent adrenalectomy (48% laparoscopic, 52% open), and the median duration of hospital stay was 4 days. Conclusions Cystic pheochromocytomas are rare, large tumours with a phenotypic appearance that can masquerade as other adrenal cystic lesions. The degree of biochemical abnormality in cystic pheochromocytomas is associated with the volume of the solid component. All patients with adrenal cysts that have a solid component or an unenhanced attenuation >10 HU should undergo biochemical testing for pheochromocytoma.
Spindle Epithelial Tumor with Thymus-Like Differentiation: The First Case Report from Ecuador
Cordero-Garate, Juana, Rojas, Tatiana, Dominguez, Carla M , Godoy, Richard, Salazar-Vega, Jorge , Dy, Benzon M. , García, Cristhian, Rojas, Tatiana , Lincango-Naranjo, Eddy , Solís-Pazmiño, Paola

VideoEndocrinology™ | March 15, 2022 | Volume: 9 | Issue: 1 | Pages: No page available

10.1089/ve.2021.0032 Get It

SAGE-Journals-Accessible-Video-Player 10.1089/ve.2021.0032.M1 sj-vid-1-vde-10.1089_ve.2021.0032
Ultrasound-Guided Percutaneous Ethanol Ablation for Local Regional Recurrence of Medullary Thyroid Cancer
Yamashita, Thomas Szabo , Rogers, Richard T. , Foster, Trenton R. , Lyden, Melanie L. , McKenzie, Travis J. , Thompson, Geoffrey B. , Dy, Benzon M. , Yamashita, Thomas S, Szabo Yamashita, Thomas , Morris, John C.

The American Surgeon™ | August 31, 2021 | Volume: 87 | Issue: 9 | Pages: 1396-1399

10.1177/00031348211041563 Get It

Diagnostic Accuracy of Dehydroepiandrosterone Sulfate and Corticotropin in Autonomous Cortisol Secretion
Carafone, Lindsay , Zhang, Catherine D , Li, Dingfeng , Lazik, Natalia, Hamidi, Oksana , Thomas, Melinda, Dy, Benzon M. , Lyden, Melanie L. , Foster, Trenton R. , McKenzie, Travis J. , Bancos, Irina , Hurtado, Maria Daniela , Thomas, Melinda A, Bancos, Irina , Hamidi, Oksana , Hurtado, Maria D. , Young, William F.

Biomedicines | June 28, 2021 | Volume: 9 | Issue: 7 | Pages: 741

10.3390/biomedicines9070741 Get It

Autonomous cortisol secretion (ACS) affects up to 50% of patients with adrenal adenomas. Despite the limited evidence, clinical guidelines recommend measurement of serum concentrations of dehydroepiandrosterone-sulfate (DHEA-S) and corticotropin (ACTH) to aid in the diagnosis of ACS. Our objective was to determine the accuracy of serum concentrations of DHEA-S and ACTH in diagnosing ACS. We conducted a retrospective single center study of adults with adrenal adenoma evaluated between 2000−2020. Main outcome measure was diagnostic accuracy of DHEA-S and ACTH. ACS was defined as post-dexamethasone cortisol >1.8 mcg/dL. Of 468 patients, ACS was diagnosed in 256 (55%) patients with a median post-DST cortisol of 3.45 mcg/dL (range, 1.9–32.7). Patients with ACS demonstrated lower serum concentrations of DHEA-S (35 vs. 87.3 mcg/dL, p < 0.0001) and ACTH (8.3 vs. 16 pg/mL, p < 0.0001) compared to patients with non-functioning adrenal tumors (NFAT). Serum DHEA-S concentration <40 mcg/dL diagnosed ACS with 84% specificity and 81% PPV, while serum ACTH concentration <10 pg/mL diagnosed ACS with 75% specificity and 78% PPV. The combination of serum concentrations of DHEA-S <40 mcg/dL and ACTH <10 pg/mL diagnosed ACS with the highest accuracy with 92% specificity and 87% PPV. Serum concentrations of DHEA-S and ACTH provide additional value in diagnosing ACS.
Preoperative Imaging in Renal Transplant Patients with Tertiary Hyperparathyroidism
Berger, Megan , Pandian, T.K. , Lyden, Melanie L. , McKenzie, Travis J. , Dy, Benzon M. , Berger, Megan G, Drake, Matthew T.

World Journal of Surgery | March 27, 2021 | Volume: 45 | Issue: 8 | Pages: 2454-2462

10.1007/s00268-021-06098-0 Get It

AbstractBackgroundTertiary hyperparathyroidism following kidney transplantation is most commonly characterized by 4‐gland hyperplasia, but single and double adenomatous disease has been demonstrated in this population as well. It is unknown whether preoperative imaging can assist in identifying patients who may qualify for focused surgery for adenomatous disease.Materials and methodsWe performed a retrospective review of our patient database from 1998–2018 for patients with tertiary hyperparathyroidism following renal transplant. Patient charts were reviewed for patient demographics, laboratory values, preoperative imaging, operative findings, pathology, and complications.ResultsWe identified 113 patients with tertiary hyperparathyroidism following renal transplant who underwent parathyroidectomy. There were 51 females and 62 males with a mean age of 53.4 ± 13.4 years. Median preoperative calcium and PTH were 10.9 mg/dl (IQR 10.3–11.2) and 228 pg/ml (IQR 118–305). Preoperative ultrasound was performed in 60 patients. Of these, 11 (18%) were negative, 38 (63%) showed 1–2 adenomas, and 11 (18%) showed ≥ 3 adenomas. 99mTc‐sestamibi parathyroid scintigraphy was performed in 101/113 patients. Of these, 11 (11%) were negative, 62 (61%) showed 1–2 areas of discordant sestamibi uptake, and 28 (28%) showed ≥ 3 areas of discordant uptake. Ultimately, 19 (17%) patients had a single adenoma removed, 16 (14%) had 2 adenomas removed, and (69%) had multi‐gland disease. There were 26 ectopic glands found in 21 patients, 42.3% of which were identified on preoperative imaging. 94.1% of patients were eucalcemic at last follow‐up, mean (± SD) 5.8 ± 3.6 years. Adenomas that were visualized on ultrasound were larger on pathology than those non‐visualized (997 ± 120 mg (mean ± SE) vs. 388 ± 109 mg, p = 0.0003). This was also true for parathyroid scintigraphy (647 ± 41 mg vs. 355 ± 51 mg, p = 0.0001).ConclusionIn patients with tertiary hyperparathyroidism, preoperative imaging can aid in predicting which patients will have 1–2 gland disease. In patients with 1–2 gland disease on congruent ultrasound and nuclear medicine imaging studies, the accuracy increases to 59%. Preoperative imaging can help identify ectopic glands. Larger adenomas are more likely to be identified on both imaging modalities.