[A retrospective study of 96 cases of adrenal metastases].

Objective: To analyze the clinical characteristics, etiological composition, imaging features, and prognosis of adrenal metastases. Methods: This study is a retrospective case series that included 96 patients with pathologically confirmed adrenal metastases who were treated at West China Hospital, Sichuan University, from 2007 to 2017. Clinical features such as sex, age, tumor size, biochemical tests, imaging characteristics, postoperative pathology, treatment methods, and prognosis were collected and analyzed. The prognosis of patients and its influencing factors were analyzed by Kaplan-Meier survival curve and single-factor Cox risk proportional model. Results: Among the 96 included patients, 64 were male and 32 were female, with a median age of 60 years. There were 89 cases of unilateral adrenal metastases, five cases of bilateral metastases, and two cases with unspecified laterality. The median diameter of the metastases was 3.5 cm×2.9 cm, with an average CT value of 31 HU. Thirty-four cases of adrenal hormones were evaluated, and no abnormality was found.The primary tumor sites were as follows: lung (n=36), kidney (n=19), liver (n=12), pancreas (n=7), rectum (n=3), stomach (n=2), and one case each of tumor in the esophagus, skin, thyroid, left maxillary muscle, breast, bladder, cervix, chest wall, and gastrointestinal tract. There were three cases with unknown primary tumors. The most common pathological type was lung adenocarcinoma (20.8%, 20/96), followed by hepatocellular carcinoma (9.4%, 9/96) and high-grade invasive urothelial carcinoma of the kidney (8.3%, 8/96). Thirty-nine cases were diagnosed concurrently with the primary tumor, while 37 cases were diagnosed after the primary tumor, with a median interval of 15 months (range: 2-144 months). There was no significant correlation between the death risk of adrenal metastatic tumor patients and gender, age, and the size of the metastatic tumor (all P>0.05). There were 4 patients with radiotherapy and chemotherapy alone, 19 patients with surgery alone, and 6 patients with combined radiotherapy and chemotherapy. The median overall survival was 1, 3, and 7 years, respectively. Conclusions: Adrenal metastases were mostly diagnosed at the same time as the primary tumor or within 15 months after the diagnosis of the primary tumor. Unilateral metastasis is common. The lungs are the most common primary lesion, followed by the kidney and liver. CT is the preferred method for the diagnosis of adrenal metastases, and the plain CT value is more than 30 HU. The overall prognosis of adrenal metastases is poor. The prognosis was better for patients who underwent surgery combined with radiotherapy and chemotherapy than those who received only surgery or radiotherapy and chemotherapy alone.

Long-term disease-free survival after MIBG therapy for metastatic pheochromocytoma.

Pheochromocytomas are rare tumours originating in chromaffin cells, representing 0.1%-1% of all secondary hypertension cases. The majority are benign and unilateral, characterised by the production of catecholamines and other neuropeptides. Mainly located in the adrenal gland, they are more frequent between the third and fifth decades of life. Iodine-131 metaiodobenzylguanidine (131I-MIBG), a radiopharmaceutical agent used for scintigraphic localisation of pheochromocytomas, has been employed to treat malignant pheochromocytomas since 1983 in a few specialised centres around the world. We reviewed our clinical experience in one such case of a young lady who presented with history of abdominal pain, headache and lower back pain. On evaluation, ultrasonography revealed a right adrenal mass and elevated urine vanillylmandelic acid levels. Following surgical resection and histopathological confirmation of pheochromocytoma, MIBG scintigraphy revealed osseous metastases and hence, she underwent 131I-MIBG therapy.

Uncommon adrenal rest tumors and massive adrenal enlargement in adult with congenital adrenal hyperplasia mimicking metastasis from pleomorphic sarcoma.

BACKGROUND: Congenital adrenal hyperplasia (CAH) encompassed a bunch of autosomal recessive disorders characterized by impaired cortisol levels due to an enzymatic deficiency in steroid synthesis. In adult male patients with CAH, a frequent complication related to poor disease control is the development of ectopic adrenocortical tissue in the testes, named testicular adrenal rest tumors (TART). Conversely, ovarian adrenal rest tumors (OART) in females are extremely rare and adrenal rests in sites other than gonads are so uncommon to have been described only few times in literature. CASE PRESENTATION: We report a case of a male patient with untreated CAH and oncologic history of pleomorphic sarcoma who presented with massive bilateral adrenal enlargement and adrenal rest tumors in peri-lumbar and peri-cecal sites, which mimicked metastasis from sarcoma. CONCLUSIONS: The development of massive adrenal enlargement and ectopic adrenal rest tumors in sites other than gonads, even if very uncommon, should be suspected in patients with CAH and prolonged periods of undertreatment.

Management of metastatic pheochromocytomas and paragangliomas: when and what.

Recently, the treatment landscape for metastatic pheochromocytomas and paragangliomas (MPPGL) has seen both progress and setbacks. We provide an up-to-date review of the multimodality management of MPPGL and discuss novel opportunities and current challenges in the treatment landscape. Given the unique clinical presentation of MPPGL, we discuss the management of hormone-related clinical sequelae and traditional modalities of therapy. Advances in the understanding of the molecular biology of these diverse tumors have enabled novel strategies such as augmenting DNA damage by targeted delivery of radionuclides such as 131I and 177Lu, abrogating tumor angiogenesis, hypoxia resistance, and DNA damage repair. Despite progress, we address the significant challenges still faced by patients and researchers engaged in efforts to improve outcomes in these rare cancers.

Adverse skeletal related events in patients with bone-metastatic pheochromocytoma/paraganglioma.

Metastatic pheochromocytomas and paragangliomas (PPGLs) are frequently associated with skeletal complications. Primary objective: to describe the frequency of adverse skeletal related events (SREs) in PPGL patients with bone metastases (BMs). Secondary objectives: to 1) identify predictive and prognostic factors for SREs and 2) obtain information on the effectiveness of bone resorption inhibitors in reducing SRE risk and improving outcomes in term of survival and SREs time onset. In this retrospective multicenter, multinational study, 294 PPGL patients were enrolled. SREs occurred in 90 patients (31 %). Fifty-five patients (19 %) had bone fractures, 47 (16 %) had spinal cord compression, and 11 (4 %) had hypercalcemia. Twenty-two patients (7 %) had more than one SRE. Sixty-four patients (22 %) underwent surgery, and 136 (46 %) underwent radiotherapy. SREs occurred a median of 4.4 months after diagnosis of BM (range, 0-246.6 months). Independent factors associated with reduced risk of SREs in multivariable analysis were I-131-MIBG radionuclide therapy (hazard ratio [HR], 0.536 [95 % CI, 0.309-0.932]; P = .027) and absence of liver metastases (HR, 0.638 [95 % CI, 0.410-0.992]; P = .046). The median overall survival duration was 5.3 year. In multivariable analysis, age younger than 48 years at PPGL diagnosis (HR, 0.558 [95 % CI, 0.3877-0.806]; P = .002), absence of liver metastases (HR, 0.618 [95 % CI, 0.396-0.965]; P = .034), treatment with bisphosphonates or denosumab (HR, 0.598 [95 % CI, 0.405-0.884]; P = .010), and MIBG radionuclide therapy (HR, 0.444 [95 % CI, 0.274-0.718]; P = .001) were associated with a reduced risk of death. SREs occur frequently and early in bone-metastatic PPGL patients but do not negatively impact survival. MIBG radionuclide therapy and treatment with bone resorption inhibitors are associated with favorable outcome.

Case report: A challenging case of severe Cushing's syndrome in the course of metastatic thymic neuroendocrine carcinoma with a synchronous adrenal tumor.

Ectopic ACTH syndrome (EAS) remains one of the most demanding diagnostic and therapeutic challenges for endocrinologists. Thymic neuroendocrine tumors account for 5%-10% of all EAS cases. We report a unique case of a 31-year-old woman with severe EAS caused by primary metastatic combined large-cell neuroendocrine carcinoma and atypical carcinoid of the thymus. The patient presented with severe hypercortisolemia, which was successfully controlled with continuous etomidate infusion. Complex imaging initially failed to detect thymic lesion; however, it revealed a large, inhomogeneous, metabolically active left adrenal mass infiltrating the diaphragm, suspected of primary disease origin. The patient underwent unilateral adrenalectomy, which resulted in hypercortisolemia resolve. The pathology report showed an adenoma with adrenal infarction and necrosis. The thymic tumor was eventually revealed a few weeks later on follow-up imaging studies. Due to local invasion and rapid progression, only partial resection of the thymic tumor was possible, and the patient was started on radio- and chemotherapy.

Safety and efficacy of thermal ablation of adrenal metastases secondary to lung cancer.

OBJECTIVES: Assess safety and efficacy of thermal ablation for adrenal metastases (AM) secondary to non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: This retrospective study included patients with NSCLC AM treated with thermal ablation between 2/2010-11/2021. Local tumor progression free survival (LTPFS) and overall survival (OS) were calculated using Kaplan-Meier method. Adverse events were graded using Common Terminology Criteria for Adverse Events v5. RESULTS: Seven patients (mean age ± SD, 63.9 ± 12.5 years; 6 males) with seven AM were treated in eight sessions. Retreatment was performed in one patient with residual disease. Five sessions were with microwave ablation and 3 with radiofrequency ablation. Mean tumor size was 20.1 ± 7.0 mm. Median number of ablation probes used was 1 (range, 1-5), with a median of 3 activations (range, 1-3), and average ablation time of 14.4 ± 15.0 minutes. Response based on RECIST v 1.1 or PERCIST criteria revealed stable disease in 1 tumor, progression of disease in 3 tumors (one was re-ablated), and partial response in 3 tumors. Median LTPFS was not reached (NR) [95 % CI: 1- NR]. Median OS was 47.97 months (95 % CI: 18.63- NR). Intraprocedural hypertension (blood pressure ≥180 mmHg) occurred during 5/8 (62.5 %) sessions and intraoperative tachycardia occurred during 2/8 (25 %) sessions. Complications within one month of ablation occurred in 3/8 (37.5 %) sessions: grade 2 pneumothorax, grade 1 hematuria, and grade 2 adrenal insufficiency. CONCLUSIONS: In this small series, thermal ablation for NSCLC AM resulted in prolonged local control and OS with no major complications.

Bilateral Adrenal Metastasis of Prostatic Adenocarcinoma on 68 Ga-PSMA PET/CT Imaging.

ABSTRACT: An 84-year-old man with prostate adenocarcinoma underwent 68 Ga-PSMA PET/CT due to PSA recurrence. Foci of 68 Ga-PSMA uptake were observed in bilateral adrenal glands. Adrenal MRI showed metastasis only in the left adrenal gland. Metastatic 68 Ga-PSMA uptake was also observed in the mediastinum and bone. Enzalutamide treatment was started. Follow-up 68 Ga-PSMA PET/CT scan showed regression in both adrenal gland metastases and other metastases.

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma.

OBJECTIVE: To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases. MATERIALS AND METHODS: Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported. RESULTS: Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03). CONCLUSIONS: [68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate. CLINICAL RELEVANCE STATEMENT: In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001). KEY POINTS: • Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Adrenal tumors in patients with neuroendocrine neoplasms.

PURPOSE: To study the prevalence of primary adrenal tumors and adrenal metastases in patients with neuroendocrine neoplasms (NENs) and describe these in detail. NENs can be further divided into neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC). METHODS: A review of medical files was conducted for all patients who underwent a 68Gallium-DOTATOC-PET/CT during 2010-2023 or adrenalectomy during 1999-2023 at the Karolinska University Hospital. RESULTS: In total, 68Gallium-DOTATOC-PET/CT was performed on 1750 individuals with NEN, among whom 12 (0.69%) had adrenal tumors. Of these, 9 (0.51%) were NEN metastases. Out of 1072 adrenalectomies, 4 (0.37%) showed evidence of NEN metastases. Thus, 16 patients with NEN exhibited adrenal tumors. The adrenal tumors were found on average 5 years after the NEN diagnosis and 19% of the adrenal tumors with simultaneous NEN were benign. Few had all adrenal hormones measured. None had an adrenal insufficiency nor an adrenal biopsy. Another synchronous metastasis was found in 69% at the time of the adrenal tumor discovery. During the median 2-year follow-up, 38% of the subjects had deceased (with the exclusion of individuals presenting supposedly benign adrenal tumors 31%) all due to tumor complications. A comparison between individuals identified through 68Gallium-DOTATOC-PET/CT and those who underwent adrenalectomy revealed a higher prevalence of NETs in the former group and NECs in the latter group. CONCLUSION: Adrenal primary tumors and adrenal metastases are infrequent occurrences in patients with NEN. Most cases involved the presence of NEN metastasis upon the initial discovery of adrenal tumors. The overall prognosis was found to be favorable.

Cutaneous, Subcutaneous, and Bilateral Adrenal Gland Metastases in Progressive Prostate Carcinoma: Theranostic Potential of 68 Ga-PSMA-11 PET/CT Imaging and 177 Lu-PSMA-617 Therapy.

ABSTRACT: Prostate carcinoma (PC) is the second most common malignant tumor in males globally. The metastatic spread of PC usually involves the pelvic and abdominal lymph nodes and the skeletal system. Cutaneous metastases are exceedingly uncommon and typically manifest themselves late in the disease course, considered as ominous sign with limited treatment options and a poor prognosis. We describe a patient wherein 68 Ga-PSMA-11 PET/CT detected multiple uncommon metastatic sites in the cutaneous region of the scrotum, penis, and thigh, as well as in the subcutaneous region of anterior abdominal wall, and in bilateral adrenal glands. These findings served as a theranostic tool for selecting 177 Lu-PSMA-617 treatment for these extremely rare metastatic sites.

Cabozantinib in patients with unresectable and progressive metastatic phaeochromocytoma or paraganglioma (the Natalie Trial): a single-arm, phase 2 trial.

BACKGROUND: Metastatic phaeochromocytomas and paragangliomas (MPPGs) are orphan diseases. Up to 50% of MPPGs are associated with germline pathogenic variants of the SDHB gene. These tumours and many non-familial MPPGs exhibit a phenotype that is characterised by abnormal angiogenesis. We aimed to assess the activity and safety of cabozantinib, an antiangiogenic multi-tyrosine kinase inhibitor, in patients with MPPGs. METHODS: The Natalie Trial is a single-arm, phase 2 clinical trial being conducted at The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients aged 18 years or older with histologically confirmed, progressive, and unresectable MPPGs, with an Eastern Cooperative Oncology Group performance status of 0-2, were treated with oral cabozantinib 60 mg/day. The primary endpoint was the investigator-assessed overall response rate per the Response Evaluation Criteria in Solid Tumours version 1.1 criteria. All outcomes were assessed in all evaluable participants who received any amount of study treatment. The trial is registered with ClinicalTrials.gov (NCT02302833) and is active but not recruiting. FINDINGS: From March 10, 2015, to May 11, 2021, 17 patients (13 male participants and four female participants) were enrolled. The median follow-up was 25 months (IQR 18-49). The overall response rate was 25·0% (95% CI 7·3-52·4; four of 16 patients). Seven grade 3 adverse events were reported in six patients, including single cases of hand-and-foot syndrome, hypertension, rectal fistula, QT prolongation, and asymptomatic hypomagnesaemia, and two cases of asymptomatic elevations of amylase and lipase. There were no grade 4 adverse events and no patient died on-study. INTERPRETATION: Cabozantinib shows promising activity in patients with MPPGs. FUNDING: Team NAT Foundation, Margaret Cazalot, and Clarence P Cazalot.

Diagnostic performance of photon-counting detector CT for differentiation between adrenal adenomas and metastases.

OBJECTIVES: Aim of this study was to assess the value of virtual non-contrast (VNC) reconstructions in differentiating between adrenal adenomas and metastases on a photon-counting detector CT (PCD-CT). MATERIAL AND METHODS: Patients with adrenal masses and contrast-enhanced CT scans in portal venous phase were included. Image reconstructions were performed, including conventional VNC (VNCConv) and PureCalcium VNC (VNCPC), as well as virtual monochromatic images (VMI, 40-90 keV) and iodine maps. We analyzed images using semi-automatic segmentation of adrenal lesions and extracted quantitative data. Logistic regression models, non-parametric tests, Bland-Altman plots, and a random forest classifier were used for statistical analyses. RESULTS: The final study cohort consisted of 90 patients (36 female, mean age 67.8 years [range 39-87]) with adrenal lesions (45 adenomas, 45 metastases). Compared to metastases, adrenal adenomas showed significantly lower CT-values in VNCConv and VNCPC (p = 0.007). Mean difference between VNC and true non-contrast (TNC) was 17.67 for VNCConv and 14.85 for VNCPC. Random forest classifier and logistic regression models both identified VNCConv and VNCPC as the best discriminators. When using 26 HU as the threshold in VNCConv reconstructions, adenomas could be discriminated from metastases with a sensitivity of 86.7% and a specificity of 75.6%. CONCLUSION: VNC algorithms overestimate CT values compared to TNC in the assessment of adrenal lesions. However, they allow a reliable discrimination between adrenal adenomas and metastases and could be used in clinical routine in near future with an increased threshold (e.g., 26 HU). Further (multi-center) studies with larger patient cohorts and standardized protocols are required. CLINICAL RELEVANCE STATEMENT: VNC reconstructions overestimate CT values compared to TNC. Using a different threshold (e.g., 26 HU compared to the established 10 HU), VNC has a high diagnostic accuracy for the discrimination between adrenal adenomas and metastases. KEY POINTS: • Virtual non-contrast reconstructions may be promising tools to differentiate adrenal lesions and might save further diagnostic tests. • The conventional and a new calcium-preserving virtual non-contrast algorithm tend to systematically overestimate CT-values compared to true non-contrast images. • Therefore, increasing the established threshold for true non-contrast images (e.g., 10HU) may help to differentiate between adrenal adenomas and metastases on contrast-enhanced CT.

Practical Considerations for the Treatment of an Adrenal Metastasis With Stereotactic Body Radiation Therapy.

The purpose of this paper is to summarize 3 methods for treating adrenal metastases with stereotactic body radiation therapy. This article is not meant to provide consensus guidelines but rather to present 4 practical examples of treatment techniques using different treatment platforms from 3 institutions.

Surgical resection of adrenal metastasis from colorectal cancers: a systematic review.

BACKGROUND: The decision for resection of adrenal metastasis from colorectal cancers remain controversial and there is no proposed standard treatment. The aim of the article is to review the available literature on outcomes and complications rates following adrenalectomy for adrenal metastasis from colorectal cancer. METHODS: Relevant papers were identified through electronic databases. Data was extracted independently by two authors on a Microsoft Excel spreadsheet up to June 2023. RESULTS: A total of 55 studies were included in the final analysis (145 cases). A large proportion of patients had an uneventful postoperative recovery following surgical adrenalectomy. The mean length of follow up ranged from 2 months to 9.5 years. A total of 33 (22.8%) patients were alive and well with no evidence of local or systemic recurrence; 2 (1.4%) patients had recurrence in the bed of adrenalectomy; 2 (1.4%) patients were alive with recurrence in the contralateral adrenal gland; 4 (2.8%) patients were alive with extra-adrenal metastasis, and 7 (4.8%) patients were alive and well with no comments regarding local and systemic recurrence. Post-operative mortality following adrenalectomy was uncommon: 1 patient died due to systemic sepsis following anastomotic leak. 17.2% of patients died due to disease progression. CONCLUSION: If complete resection can be achieved, surgical adrenalectomy in the surgically fit patient should be strongly considered, especially in patients with solitary adrenal metastasis which may translate into survival benefits and potential surgical cure.

Treatment of metastatic paraganglioma: experience of a single center.

PURPOSE: Data regarding treatment options and their efficacy for metastatic paragangliomas (mPPGL) is limited. This study aims to report a single center experience in treating mPPGL, comparing the efficacy and safety of various treatment approaches. METHODS: Retrospective analysis of patients with mPPGL treated at an Endocrinology Department of a cancer institute between January 2000 and October 2022. RESULTS: We analyzed 25 patients with mPPGL, 8 pheochromocytomas and 20 paragangliomas (12% multifocal), followed for a median of 9 [4; 14] years. Surgical approach, aimed at the primary tumor or at debulking of metastases, was the only treatment achieving complete response: 87% in primary tumor and 87.5% with debulking of metastases. These were long-lasting results with a duration of 69 (23.8; 136.8) months in primary tumor removal and 35.1 (15.3; 41) months in metastases debulking. As for other therapeutic approaches, such as radioactive isotopes, tyrosine kinase inhibitors, chemotherapy and external beam radiotherapy, the main outcome was stable disease, with few partial responses. At the last follow-up, 66% of the patients were alive, 15.4% were in remission and 84.6% had stable disease. Median overall survival was 14 years. The 5-year and 10-year survival rates from primary tumor diagnosis were 77.9% and 66.9% respectively, and from metastasis diagnosis were 67.4% and 55.6%, respectively. CONCLUSION: This is the only European single center analysis addressing outcomes of different therapies in mPGL. The results support surgery as a first-line treatment, being the only approach that may achieve complete response with satisfactory and long-lasting results.

Novel alternative tools for metastatic pheochromocytomas/paragangliomas prediction.

OBJECTIVE: The existing prediction models for metastasis in pheochromocytomas/paragangliomas (PPGLs) showed high heterogeneity in different centers. Therefore, this study aimed to establish new prediction models integrating multiple variables based on different algorithms. DESIGN AND METHODS: Data of patients with PPGLs undergoing surgical resection at the Peking Union Medical College Hospital from 2007 to 2022 were collected retrospectively. Patients were randomly divided into the training and testing sets in a ratio of 7:3. Subsequently, decision trees, random forest, and logistic models were constructed for metastasis prediction with the training set and Cox models for metastasis-free survival (MFS) prediction with the total population. Additionally, Ki-67 index and tumor size were transformed into categorical variables for adjusting models. The testing set was used to assess the discrimination and calibration of models and the optimal models were visualized as nomograms. Clinical characteristics and MFS were compared between patients with and without risk factors. RESULTS: A total of 198 patients with 59 cases of metastasis were included and classified into the training set (n = 138) and testing set (n = 60). Among all models, the logistic regression model showed the best discrimination for metastasis prediction with an AUC of 0.891 (95% CI, 0.793-0.990), integrating SDHB germline mutations [OR: 96.72 (95% CI, 16.61-940.79)], S-100 (-) [OR: 11.22 (95% CI, 3.04-58.51)], ATRX (-) [OR: 8.42 (95% CI, 2.73-29.24)] and Ki-67 ≥ 3% [OR: 7.98 (95% CI, 2.27-32.24)] evaluated through immunohistochemistry (IHC), and tumor size ≥ 5 cm [OR: 4.59 (95% CI, 1.34-19.13)]. The multivariate Cox model including the above risk factors also showed a high C-index of 0.860 (95% CI, 0.810-0.911) in predicting MFS after surgery. Furthermore, patients with the above risk factors showed a significantly poorer MFS (P ≤ 0.001). CONCLUSIONS: Models established in this study provided alternative and reliable tools for clinicians to predict PPGLs patients' metastasis and MFS. More importantly, this study revealed for the first time that IHC of ATRX could act as an independent predictor of metastasis in PPGLs.