Cardiac paraganglioma, also known as extra-adrenal pheochromocytoma, is a rare neuroendocrine tumor arising from chromaffin cells. It constitutes less than 1% of all primary cardiac tumors. It typically locates in the atrioventricular (AV) groove, left atrial roof, and interatrial septum — regions where paraganglionic tissue is concentrated. 30-50% are functional, secreting catecholamines (predominantly norepinephrine) causing paroxysmal symptoms such as hypertension, palpitations, sweating, and headache. On MR, it is recognized by the classic 'salt-and-pepper' T2 pattern (flow voids + hemorrhagic/necrotic areas), intense hypervascular enhancement, and MIBG/DOPA PET positivity. 10% are malignant and can metastasize; 10% are bilateral/multifocal; 10% are hereditary/syndromic (SDH mutations, MEN2, VHL, NF1).
Age Range
20-60
Peak Age
40
Gender
Equal
Prevalence
Rare
Cardiac paragangliomas arise from chromaffin cells in paraganglionic structures of the autonomic nervous system. Paraganglionic tissue around the heart and great vessels is concentrated particularly in the AV groove, left atrial roof, pulmonary artery root, and aorticopulmonary window — hence the tumor favors these locations. Chromaffin cells have the capacity to synthesize and store catecholamines (norepinephrine > epinephrine); in functional tumors, these catecholamines are released paroxismally causing sympathetic overactivation. The hypervascular character of the tumor originates from its rich capillary network, manifesting as intense enhancement on imaging. The 'salt-and-pepper' pattern on T2 reflects the coexistence of high-velocity flow areas (flow void = 'pepper') and slow flow/stasis/hemorrhage/necrosis areas (hyperintense = 'salt') within the tumor. Succinate dehydrogenase (SDH) subunit mutations (SDHA, SDHB, SDHC, SDHD) disrupt the mitochondrial electron transport chain and activate pseudohypoxic pathways contributing to tumor development.
The 'salt-and-pepper' pattern seen in paraganglioma on T2-weighted MR sequences is a direct reflection of the tumor's heterogeneous vascular and stromal structure. 'Salt' components (hyperintense foci) represent areas of slow flow, stasis, hemorrhage, and necrosis, while 'pepper' components (signal voids/flow voids) represent feeding vessels carrying high-velocity arterial flow and intratumoral vascular channels. This pattern is the pathognomonic imaging finding of the paraganglioma/pheochromocytoma family and is seen in all adrenal, retroperitoneal, head-neck, and cardiac paragangliomas. In small (<2 cm) tumors, the pepper (flow void) component may be less prominent.
On T2-weighted sequences, the classic 'salt-and-pepper' pattern is seen in paraganglioma. 'Salt' component: T2 hyperintense foci due to slow flow, stasis, hemorrhage, and necrosis areas. 'Pepper' component: signal voids (flow voids) due to high-velocity arterial flow areas within the tumor. This pattern is the pathognomonic finding seen in paragangliomas at all locations (adrenal, retroperitoneal, head-neck, cardiac). In large tumors, hemorrhage and necrosis areas are more prominent and the 'salt' component predominates.
Report Sentence
Salt-and-pepper pattern (flow voids and hyperintense foci) in the mass located in the AV groove on T2-weighted sequences, consistent with paraganglioma.
On dynamic contrast-enhanced MR, paraganglioma shows intense, rapid enhancement in the early arterial phase — hypervascular character. Enhancement pattern can be homogeneous or heterogeneous; in large tumors, areas of central necrosis show no enhancement. Contrast washout may be observed in late phases — signal decrease in venous/delayed phase following pronounced arterial phase enhancement. This hypervascular pattern reflects the rich arterial vascularity of paraganglioma and is important for preoperative embolization planning. Vascular relationship with surrounding great vessels — encasement without typically invading — should be assessed.
Report Sentence
Intense arterial phase enhancement with late phase washout in the mass on dynamic contrast-enhanced imaging, consistent with hypervascular tumor.
On I-123 or I-131 MIBG (metaiodobenzylguanidine) scintigraphy, cardiac paraganglioma shows positive uptake. MIBG, as a norepinephrine analogue, is specifically taken up by chromaffin cells. Uptake intensity correlates with functional activity — more intense uptake in functional tumors. SPECT/CT fusion improves anatomical localization. Sensitivity is 80-90%, specificity >95%. It is also valuable for screening metastatic disease and multifocal paraganglioma. In MIBG-negative cases, 68Ga-DOTATATE PET/CT or 18F-DOPA PET can be used as alternatives — particularly in SDHB mutation cases, MIBG sensitivity decreases.
Report Sentence
Intense positive uptake in the cardiac mass on I-123 MIBG scintigraphy, consistent with neuroendocrine tumor (paraganglioma/pheochromocytoma).
On contrast-enhanced CT, paraganglioma appears as an intensely enhancing, well-defined or lobulated mass in the AV groove or left atrial roof. It shows intense homogeneous or heterogeneous enhancement in the arterial phase — density may be comparable to surrounding vascular structures (aorta, pulmonary artery). In large tumors, areas of central necrosis and hemorrhage show no enhancement. The tumor's proximity to coronary arteries and great vessels — encasement or displacement — is critically important preoperatively. ECG-gated CT minimizes motion artifacts. Calcification is rarely seen.
Report Sentence
Intensely enhancing, well-defined mass in the AV groove on contrast-enhanced CT, consistent with paraganglioma.
On T1-weighted sequences, paraganglioma shows isointense to slightly hyperintense homogeneous or heterogeneous signal relative to myocardium. Focal T1 hyperintensity may be seen in hemorrhagic areas due to methemoglobin accumulation. Flow void areas appear as low signal on T1 as well. In large tumors, necrotic areas show low T1 signal. Heterogeneous T1 pattern reflects the complex internal structure of paraganglioma — solid tumor tissue, vascular spaces, hemorrhage, necrosis.
Report Sentence
Heterogeneous signal isointense to myocardium with focal hyperintense foci (hemorrhage?) in the mass on T1-weighted sequences.
On 68Ga-DOTATATE PET/CT, paraganglioma shows intense uptake — due to somatostatin receptor type 2 (SSTR2) expression. In MIBG-negative cases and particularly in SDHB mutation patients, 68Ga-DOTATATE PET shows higher sensitivity (95-100% vs MIBG 80-90%). Provides whole-body assessment for metastatic disease screening. May also be positive on FDG PET but specificity is low. 18F-DOPA PET shows high sensitivity in hereditary cases. Functional imaging is superior to anatomical imaging for detecting multifocal/metastatic disease.
Report Sentence
Intense somatostatin receptor uptake in the cardiac mass on 68Ga-DOTATATE PET/CT, consistent with neuroendocrine tumor (paraganglioma).
Criteria
Catecholamine (norepinephrine/epinephrine/dopamine) secreting; elevated plasma/urine metanephrines; paroxysmal hypertension/tachycardia/sweating symptoms; MIBG positive
Distinct Features
Constitutes 30-50% of cases. Risk of catecholamine crisis during anesthesia and surgery — preoperative alpha+beta blockade mandatory. Biopsy contraindicated (provocation risk). MIBG uptake is usually more intense. Norepinephrine dominance (versus epinephrine dominance in adrenal pheochromocytoma). Symptom paroxysms can be triggered by tumor manipulation, anesthesia, exercise, or spontaneously.
Criteria
Non-secreting or subclinical catecholamine levels; normal plasma/urine metanephrines; symptoms from mass effect (arrhythmia, obstruction, effusion) or asymptomatic
Distinct Features
Constitutes 50-70% of cases. Low catecholamine crisis risk but preoperative biochemical verification is mandatory. Imaging features do not differ from functional type — salt-and-pepper, hypervascularity. MIBG uptake may be lower than functional type. Diagnosis is usually made during cardiac mass workup.
Criteria
Presence of distant metastasis (bone, lung, liver, lymph nodes) or local invasion; malignancy cannot be determined histologically — malignancy is defined by presence of metastasis; SDHB mutation high risk
Distinct Features
Constitutes approximately 10% of cases. SDHB mutation increases malignancy risk to 30-70%. Bone metastases are the most common metastatic site. 68Ga-DOTATATE PET/CT is superior to MIBG for metastatic disease screening. Prognosis worsens significantly in malignant disease — 5-year survival 40-60%. I-131 MIBG therapy or peptide receptor radionuclide therapy (PRRT, 177Lu-DOTATATE) can be applied in metastatic disease.
Distinguishing Feature
Hemangioma shows homogeneous T2 hyperintensity ('light bulb'), progressive fill-in enhancement pattern, and no MIBG uptake. Paraganglioma shows salt-and-pepper T2 pattern, rapid hypervascular enhancement, and MIBG positivity. Hemangioma can be found at any cardiac location while paraganglioma favors the AV groove and left atrial roof.
Distinguishing Feature
Angiosarcoma is dominant in right atrium (80%), irregularly bordered, invasive, causing pericardial effusion. May be hyperintense on T1 due to hemorrhage but does not show salt-and-pepper pattern. MIBG uptake is negative. Angiosarcoma shows rapid growth, metastasis, and poor prognosis while paraganglioma usually grows slowly. Paraganglioma is distinguished by AV groove location and catecholamine symptoms.
Distinguishing Feature
Cardiac metastasis occurs in the setting of known primary malignancy, with pericardial involvement and effusion, as multiple lesions. High FDG PET uptake but MIBG/DOTATATE negative. Does not show salt-and-pepper pattern. Paraganglioma is usually solitary, AV groove located, and MIBG/DOTATATE positive. Clinical history (known cancer vs. paroxysmal hypertension) is critical for differentiation.
Urgency
highManagement
surgicalBiopsy
Not NeededFollow-up
Cerrahi sonrası yıllık biyokimyasal tarama (plazma metanefrinler) + görüntüleme (MR veya DOTATATE PET). SDH mutasyonu varsa ömür boyu takip. Genetik danışmanlık önerilir.Cardiac paraganglioma is a rare tumor requiring surgical resection. Biopsy is contraindicated in functional tumors — due to catecholamine crisis risk. Diagnosis is made with a combination of MR (salt-and-pepper + hypervascularity), MIBG/DOTATATE PET, and biochemical tests (plasma metanephrines). Preoperative preparation is critical: in functional tumors, at least 2 weeks of alpha-blocker (phenoxybenzamine/doxazosin) followed by beta-blocker is started. Due to AV groove location, coronary artery relationship should be assessed with preoperative CT angiography. Surgical resection is curative but technically challenging due to the tumor's proximity to great vessels and coronary arteries — requires cardiopulmonary bypass. Genetic testing (SDH mutations) and lifelong follow-up is recommended for all patients due to 10% malignancy risk. Patients with SDHB mutations have higher metastasis risk.
Cardiac paraganglioma is rare but clinically significant. Functional tumors can cause catecholamine crises; preoperative alpha-blocker therapy is mandatory — biopsy is contraindicated as it may trigger catecholamine discharge. SDH gene mutation screening (SDHB, SDHD) is important for hereditary paraganglioma-pheochromocytoma syndrome. Surgical resection is the mainstay of treatment but is technically challenging due to posterior AV groove location and close relationship with great vessels. Malignant transformation may occur in approximately 10% of cases; long-term follow-up is required.