⁶⁸Ga-DOTATATE Uptake in Rare Metastatic/Inoperable Mediastinal Paraganglioma with Anomalous Coronary Supply

Abstract

Mediastinal paragangliomas (PGLs) are extremely rare neuroendocrine tumors. Clinical presentation varies and tumor resection can be challenging due to bleeding and risk of catecholamine surges in functional tumors. We report on a case 68 with a DOTATATE avid mediastinal mass which was histopathologically confirmed as a PGL that was fed by the coronary artery in whole-body positron emission tomography/computed tomography imaging using gallium-68-DOTATATE.

Ethics

Informed Consent: The written informed consent was obtained from the patient.

Figure 1.

A 52-year-old male patient with significantly elevated normetanephrine level presenting with headache and hypertension was referred for gallium-68 DOTATATE positron emission tomography/computed tomography (PET/CT) for further evaluation. The maximum intensity projection (A) and axial PET/CT (B and C) images revealed a high DOTATATE uptake in the mediastinal mass (black and white arrows; maximum [standard uptake values (SUV_max): 18.34] and lymph node at right level 2 (arrowhead; SUV_max: 56.56). A thoracotomy was performed to remove the mass, which was determined to be a paraganglioma by histopathology, but it was deemed inoperable because of proximity to major thoracic structures and fed by the coronary artery (D).

Figure 2.

Following embolization of the feeder branch using particles and four cycles of peptide receptor radionuclide therapy (PRRT) with lutetium-177 DOTATATE (¹⁷⁷Lu-DOTATATE) [whole-body scans after PRRT, (E) for first cycle and (F) for fourth cycle]. After 4 cycles of ¹⁷⁷Lu-DOTATATE, computed tomography (CT) (G) and single photon emission tomography/CT axial fusion (H) images of mediastinal mass. After treatment uptake of cervical lesion was decrease while mediastinal mass uptake was stable. Post-PRRT gallium-68 DOTATATE positron emission tomography/CT [⁶⁸Ga-DOTATATE PET/CT) maximum intensity projection (I) and axial fusion (J and K) images of mediastinal mass and cervical lymph node. ⁶⁸Ga-DOTATATE PET/CT imaging in March 2025, 9 months following to fourth cycle, showed partial decreased in tracer avidity with in cervical lymph node [maximum standard uptake values (SUV_max): decreased from 56.56 to 33.19; Krenning score of 4 to a score of 3]. Mediastinal mass was stable (SUV_max minimal decreased from 18.34 to 17.49; Krenning score of 3 to a score of 3). According to PERCIST criteria, the patient classified stable disease. The serum norepinephrine decreased from 432 to 282 nmol/L after 4 cycles. The patient’s symptoms were improved during follow-up. Mediastinal paragangliomas (PGLs) are extremely rare, accounting for approximately 1% to 2% of all PGLs. In patients with inoperable or metastatic PGL, symptomatic or progressive disease is usually treated with chemotherapy, radionuclide therapy, external radiotherapy or tyrosine kinase inhibitors. Functional mediastinal PGLs with anomalous coronary considered high-risk surgically. ¹⁷⁷Lu-DOTATATE therapy is safe modality for inoperable and metastatic mediastinal PGLs. ⁶⁸Ga-DOTA-coupled peptides can be used for imaging because PGLs, which are neuroendocrine tumors arising from pluripotent neural crest stem cells, express somatostatin receptors. Since neuroendocrine tumors overexpress somatostatin receptor like PGLs, 68Ga-DOTATATE PET/CT has a high specificity in detecting them. With the use of DOTATATE’s theranostic qualities, patients who may be suitable for PRRT can be chosen using ⁶⁸Ga-DOTATATE PET/CT (1, 2, 3, 4, 5, 6, 7). This report highlights the role of DOTA-coupled peptides in the diagnostic and therapeutic applications of a rare patient with a mediastinal PGL with an unusual coronary artery supply, which poses a high surgical risk.