SDHB-Associated Pheochromocytomas: What is Their Clinical Behavior?

INTRODUCTION: Germline pathogenic variants in succinate dehydrogenase subunit B (SDHB) cause paraganglioma/pheochromocytoma syndrome type 4 (PGL-4). SDHB-associated pheochromocytomas (PCC) are thought to be rare and little data exist about their clinical behavior. PATIENTS AND METHODS: Retrospective review of patients treated (1993-2023) at a tertiary cancer center for SDHB-associated PCC. Clinical and demographic variables were retrieved to characterize disease-free survival, disease progression, and overall survival. RESULTS: In total, 90 SDHB-carriers were identified, 18% had PCC (n = 16). Median age at diagnosis of was 40 (19-76) years, 50% (n = 8) of patients were male, 25% (n = 4) had distant metastasis (DM) at diagnosis, and 13% (n = 2) had synchronous PGL. No patients had bilateral disease, and 94% of patients underwent surgery as initial treatment with a curative intent in 75%. Overall, 64% of patients underwent open resection. Recurrence occurred in 77% of patients (n = 10), 75% in minimally invasive surgery (MIS) versus 77% open, p = 0.63. Bone was the most common site of DM (100%, n = 13). Metaidobenzyleguanidine (MIBG) imaging was performed in 69% of patients, 91% of which were positive. Median time from surgery until recurrence was 36 months (1-295 months). Radiation therapy was the most common adjuvant treatment (44%) followed by Iobenguane I-131 (31%) and systemic therapy (31%). Median follow-up time was 56 months (1-408 months). Overall, 33% of patients were alive, 19% of patients were disease-free, and 50% of the patients with DM had stable disease at last follow-up. CONCLUSIONS: Overall, 18% of germline SDHB mutation-carriers were diagnosed with PCC, all of which were unilateral. SDHB-associated PCC was associated with advanced and recalcitrant disease and was often MIBG positive. More studies are needed to better understand the clinical behavior of PCC in PGL-4.

Persistence and Recurrence of Hypercalcemia After Parathyroidectomy Over 5 Decades (1965-2010) in a Community-based Cohort.

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.

Unilateral Adrenalectomy for Primary Aldosteronism Due to Bilateral Adrenal Disease Can Result in Resolution of Hypokalemia and Amelioration of Hypertension.

BACKGROUND: Bilateral idiopathic hyperaldosteronism (IHA) is responsible for 60% of primary aldosteronism (PA) cases. Medical management is standard of care for IHA. Unilateral adrenalectomy (UA) with the intent of debulking total aldosterone production as a palliative measure remains controversial. METHODS: Single-center retrospective review (2010-2020) of patients undergoing UA with a diagnosis of PA due to IHA (lateralization index [LI] on adrenal venous sampling [AVS] < 4). Demographic, pre-operative, intra-operative, and post-operative variables were assessed. Hypertensive regimens were converted to the WHO Defined Daily Dose (DDD). RESULTS: Twenty-four patients were identified, 14, 58% male and mean age 52 ± 10 years. Preoperative hypokalemia was present in 22, 92% of patients. Median number of antihypertensives taken was 3 (interquartile range [IQR], 2-4) and median DDD was 4 (IQR, 3-5.3). Median lateralization index on AVS was 3.52 (range, 1.19-3.88). All operations were performed in minimally invasive fashion. There were no conversions to open procedure, ICU admissions, or post-operative complications. Median follow-up was 10.5 months (range, 1-145 months). Hypokalemia resolved in 17, 76% of patients at last follow-up. Post-operative median number of antihypertensives taken was 1 (IQR, 1-3) and median DDD was 2 (IQR, 0.5-2.75) from 4, P = 0.003. Three (%) patients required continuation of mineralocorticoid receptor antagonists post-operatively. Blood pressure control improved in 65% of patients. CONCLUSION: Unilateral adrenalectomy in the setting of bilateral hyperaldosteronism can improve blood pressure control and stabilize potassium levels in selected patients. Further prospective studies in larger cohorts will be necessary to further define the role of unilateral adrenalectomy in the setting of PA due to bilateral adrenal disease.

Bilateral Adrenalectomy: Differences between Cushing Disease and Ectopic ACTH-Producing Tumors.

BACKGROUND: Bilateral adrenalectomy (BA) is a curative treatment for hypercortisolism in patients with corticotropin (ACTH)-dependent Cushing syndrome. Indications include refractory Cushing's disease (CD) following failed pituitary surgery, and occult or unresectable ectopic ACTH-producing neoplasms (EA). METHODS: This was a single-center, retrospective review (1995-2017) of patients undergoing BA for CD or EA. Demographics, laboratory findings, and intraoperative and postoperative variables were analyzed. RESULTS: Of 137 patients, 83 (61%) had CD and 54 (39%) had EA; 87% of CD patients were female versus 46% of EA patients (p < 0.0001). Mean age at diagnosis was 40 ± 15 years for CD and 49 ± 18 years for EA (p = 0.004). Preoperative serum cortisol concentrations were higher in the EA cohort (63 ± 40 µg/dL) versus the CD cohort (33 ± 19 µg/dL) [p < 0.001], with no significant differences in serum ACTH. Time from diagnosis until adrenalectomy was 54 ± 69 months for CD versus 4 ± 13 for EA (p = 0.002). Most patients underwent minimally invasive surgery (MIS; 86% CD vs. 75% EA; p = 0.19). There was no difference between the rates of conversion to an open approach, intraoperative blood loss, or operative time between groups, and no difference between complications in CD versus EA (p = 1.0). Five-year survival was significantly shorter among the EA cohort (30% for EA vs. 80% for CD; p < 0.001). CONCLUSION: Patients with EA presented with higher serum cortisol levels compared with patients with CD. EA patients were more likely to require intraoperative transfusion and postoperative intensive care. BA in patients with CD and EA can be performed safely in an MIS fashion, with similar morbidity; however, survival at 5 years was significantly less in the EA cohort.

The Multi-Institutional Medullary Thyroid Cancer Collaborative Registry: Can a Rare Tumor Registry Accurately Represent the Real-World Patient Population?

Background: Large population-based registries, such as the Surveillance, Epidemiology and End Results (SEER) Registry, help in the study of rare tumors, including medullary thyroid cancer (MTC), but lack data to understand the natural history of the disease. The Medullary Thyroid Cancer Collaborative Registry (MTCCoRe) is an exhaustive multi-institutional collection of demographic, clinical, and pathological data. To determine the extent to which MTCCoRe represents the real-world MTC population, we compared the characteristics of patients enrolled in MTCCoRe with patients enrolled in population-based cancer registries. Methods: Comparison of demographic and clinical characteristics of MTC patients who were enrolled in MTCCoRe, Texas Cancer Registry (TCR), California Cancer Registry (CCR), and SEER between 1995 and 2018. Results: A total of 1416 patients were identified in MTCCoRe, 329 in TCR, 2105 in CCR, and 3820 in SEER. Percentages of patients 20-54 years in MTCCoRe were 58.0%, 50.2% in TCR, 47.2% in CCR, and 44.8% in SEER (p < 0.0001). About half of the patients were female (55.9% in MTCCoRe, 61.4% in TCR, 59% in CCR, and 57.5% in SEER (p = 0.3). Percentages of Hispanic and Black patients differed among cohorts (10.1% and 3.8% for MTCCoRe, 23.7% and 8.2% for TCR, 24.8% and 4.9% in CCR, and 15.9% and 8.2% for SEER, respectively; p < 0.001). MTCCoRe patients presented with more advanced T and N classifications than patients in the other registries (MTCCoRe, 28.6% T3-4 and 49.4% N1; TCR, 12.7% and 32.2%; CCR, 18.6% and 32.4%; and SEER, 24% and 37.8%; p < 0.0001). Prevalence of M1 disease was 10% in MTCCoRe, 11.9% in TCR, 14.1% in CCR, and 9.5% in SEER (p < 0.0001). In the MTCCoRe, 11.4% underwent systemic therapy (compared with 0.3% in TCR and 5.6% in CCR). Conclusions: The clinicodemographic profile of patients with MTC enrolled in a multi-institutional registry differs from those enrolled in population-based databases, with lower proportions of Hispanic and Black patients but additive data on treatment modalities. Moving forward, MTCCoRe and other registry and clinical trial enrollment efforts should intentionally include underrepresented groups via community engagement techniques, patient stakeholder involvement, and inclusion of languages other than English in study materials to yield more generalizable results and conclusions.

Is there a role for liquid biopsy in the surveillance of parathyroid carcinoma?

BACKGROUND: Parathyroid carcinoma is a rare malignancy with high recurrence rates. Liquid biopsy is a stratifying tool in disease recurrence/progression in other malignant processes. This study sought to assess the feasibility and application of liquid biopsy in parathyroid carcinoma and its impact on surveillance. METHODS: Retrospective review of a prospectively maintained database of adults treated for parathyroid carcinoma at a tertiary care center (2017-2023). Demographics, clinical characteristics, and laboratory variables were collected. Circulating cell-free deoxyribonucleic acid enrichment and circulating tumor cell enumeration were obtained from serial blood samples. RESULTS: A total of 25 patients were identified-64% were male patients, with a median age of 56 years (interquartile range 45-63). Fifty blood samples were collected postoperatively. At first, circulating tumor cell enumeration, 56% (14/25) of patients had no evidence of disease, and 32% (8/25) had distant metastasis. Median follow-up was 53 months (interquartile range 23-107). At the last follow-up, 40% (10/25) of patients were found to have distant metastasis. Serial circulating tumor cell enumeration was performed in 52% of patients, median highest circulating tumor cell was (interquartile range 1-22). Circulating cell-free deoxyribonucleic acid was assessed in 64% of patients (16/25). There was no difference in circulating tumor cells or circulating cell-free deoxyribonucleic acid between those with distant metastasis and those without distant metastasis. The most common mutation identified was TP53, present in 88% of circulating cell-free deoxyribonucleic acid samples with a mutation. Circulating cell-free deoxyribonucleic acid and parathyroid hormone levels were not found to have any association (r = -0.27, P = .39), but parathyroid hormone and circulating tumor cell had a linear relationship (r = 0.76, P < .001). CONCLUSION: Liquid biopsy appears to be a feasible tool in parathyroid carcinoma surveillance. The relationship between circulating cell-free deoxyribonucleic acid and parathyroid hormone levels remains unclear, and the association between circulating tumor cell enumeration and parathyroid hormone levels may be impactful. The finding that TP53 mutation is more prevalent in patients with distant metastasis may impact further management.

Pediatric primary hyperparathyroidism: Surgical pathology and long-term outcomes in sporadic and familial cases.

BACKGROUND: Primary Hyperparathyroidism (PHPT) is rare in pediatric patients. Data regarding surgical outcomes are scarce. METHODS: Single-center retrospective review (1994-2020) of patients ≤21 years undergoing surgery for PHPT. RESULTS: 66 patients were identified (61% female, 17 ± 3 years). 71% of patients were symptomatic at diagnosis. 32% of patients had known familial syndromes, most commonly MEN-1. 23% of patients without a known mutation had genetic testing, 22% positive. 56% of the total and 19% of the familial cohort underwent focused exploration. Single gland disease was found in 19% of familial vs 85% of sporadic cases, p < 0.00001. Persistence was 9%, all in the sporadic group, p = 0.11. Recurrence was 15%: 38% in the familial vs 2% in the sporadic groups, p=0.0004. Time to recurrence was 59 months (Q1-38, Q3-95), familial 61 vs 124 months sporadic, p=0.001. CONCLUSION: Pediatric PHPT is frequently sporadic, although 5% of apparent sporadic cases are secondary to syndromes. Familial cases have higher rates of recurrence, requiring closer follow-up.

Medullary thyroid cancer: What is the optimal management of the lateral neck in a node negative patient at index operation?

BACKGROUND: Medullary thyroid cancer is a neuroendocrine malignancy that can occur sporadically or as the result of genomic rearranged during transfection mutations. Medullary thyroid cancer has a higher rate of metastasis than well-differentiated thyroid cancer. Lateral neck dissection is often performed, and its prophylactic use is controversial. METHODS: Single-center, retrospective review (2000-2017) of patients undergoing primary surgical treatment for medullary thyroid cancer who had negative lateral neck imaging preoperatively. Demographics, genetic associations, clinical, and imaging findings were analyzed. Locoregional recurrence, overall recurrence, and overall survival were examined. RESULTS: A total of 110 patients were identified, of which 18 underwent prophylactic lateral neck dissection and 92 did not. Age, sex distribution, preoperative calcitonin levels, and follow-up were similar among groups. Overall recurrence was 20% for no prophylactic lateral neck dissection and 39% for prophylactic lateral neck dissection (P = .46). Most recurrences were locoregional recurrence, 7.6% for no prophylactic lateral neck dissection versus 22% for prophylactic lateral neck dissection (P = .08), half of it being to the lateral neck in both groups. A total of 7 patients from the no prophylactic lateral neck dissection group required treatment for recurrences versus 4 patients in prophylactic lateral neck dissection group (P = .57). Overall survival at 5 years was similar, 43% the no prophylactic lateral neck dissection group and 31% for prophylactic lateral neck dissection group (P = .52). CONCLUSION: Lateral neck dissection has no effect in decreasing locoregional or overall recurrences in medullary thyroid cancer and has no effect in overall survival when performed prophylactically at index surgical intervention.

Comparison Between Sporadic and Multiple Endocrine Neoplasia Type 1-Associated Insulinoma.

BACKGROUND: The differences between sporadic and multiple endocrine neoplasia type 1 (MEN-1)-associated insulinoma are not well described. Herein, we compared demographics, neoplasm characteristics, presentation, and survival in patients with sporadic vs MEN-1 insulinomas including benign and malignant disease. STUDY DESIGN: A retrospective study identified insulinoma patients. MEN-1 was defined based on genetic testing or clinically in patients with 2 or more primary MEN-1 tumor types. RESULTS: A total of 311 patients were identified: 84% benign and 16% malignant. The incidence of malignancy was similar (18% vs 16%, MEN-1 vs sporadic, p = 0.76). Within malignant patients, the median (interquartile range) age was 33 (25 ,44) years in MEN-1 vs 54 (41, 70) years in sporadic insulinoma (p = 0.04). There was no difference in sex or tumor size between MEN-1 and sporadic malignant insulinoma (p > 0.05). Of the 260 patients with benign insulinoma, 7% had MEN-1 syndrome. MEN-1 patients presented with insulinoma at a younger age: median (interquartile range) age was 38 (24, 49) years vs 52 (43, 65) years (p < 0.01). Resection of benign insulinoma was performed in 78% of the MEN-1 and 94% of the sporadic group (p = 0.03). Resected benign tumors were larger in the MEN-1 group: 2.0 (1.65, 2.45) cm vs 1.5 (1.2, 2.0) cm, respectively (p = 0.03). Concurrent insulinomas were more common in MEN-1 (17% vs 2%; p < 0.01). CONCLUSIONS: MEN-1 patients present with insulinoma at younger age and have larger benign pancreatic lesions at the time of resection compared with sporadic neoplasms. Younger patients and those with multifocal pancreatic neuroendocrine tumor in the setting of endogenous hyperinsulinism should be evaluated for MEN-1.

Differences in outcomes of bilateral adrenalectomy in patients with ectopic ACTH producing tumor of known and unknown origin.

BACKGROUND: Endogenous Cushing syndrome (CS) can be caused by ectopic corticotropin-producing tumors of known (EK) and unknown origin (EU). Bilateral adrenalectomy (BA) can be used as definite treatment of hypercortisolism in such cases. This study compared patients undergoing BA for CS secondary to EK vs EU. METHODS: Retrospective review (1995-2017) of patients undergoing BA due to EK or EU. We analyzed demographic characteristics, laboratory values, intraoperative variables, surgical outcomes, and survival. RESULTS: 48 patients (26 EU, 22 EK) were identified. Serum cortisol and ACTH concentrations were similar. 92% of BA for EU were performed minimally invasively vs 77% for EK, P = 0.22. Complications occurred in 19% of EU and 4.5% EK, P = 0.2. Mean survival was 4.3 years for EU and 4.0 years for EK without difference in all-cause mortality P = 0.63. CONCLUSION: BA cure rate was 100% for CS in EU and EK. Morbidity, long term and all-cause mortality differences were not statistically significant between EK and EU.

Occurrence and Natural History of Thyroid Cancer in Patients with Cowden Syndrome.

INTRODUCTION: Cowden syndrome patients are at an increased risk of developing differentiated thyroid carcinoma (DTC). There are limited studies of thyroid cancer biology within this population. We aimed to describe the frequency and progression of DTC in this population. METHOD: We reviewed all patients with clinically or genetically confirmed Cowden syndrome treated at our institution between 1979 and 2017. Presentation, operative details, pathology, and adjuvant treatment for all thyroid diseases were analyzed. RESULTS: Forty-seven patients were identified. Thirty-seven received a clinical diagnosis while 10 tested positive on genetic testing for the PTEN gene. Average follow-up time was 10 years. Twenty-three patients underwent a total thyroidectomy. Nine patients were diagnosed with thyroid cancer, with a mean age of 28.5 years, 4 cases of the follicular variant of papillary thyroid cancer (PTC), 4 of PTC, and 1 of cystic PTC. One patient required an interval lateral neck dissection but no patients developed distant metastasis. Fourteen patients underwent thyroidectomy, 12 due to follicular adenoma, Hürthle cell adenoma, or multinodular goiter, 1 due to Graves' disease, and 1 who elected to undergo a prophylactic thyroidectomy. No mortality was associated with thyroid cancer in these patients. CONCLUSION: Patients with Cowden syndrome are at a significantly increased risk of developing DTC and have a younger age of onset. In this study, 20% of the patients with Cowden syndrome were diagnosed with DTC, but distant metastasis and overall mortality were absent. Clinical features were similar to those of sporadic DTC, proving that, apart from screening, Cowden syndrome-related DTC can be treated in similar fashion.