Neurologically asymptomatic cerebral oligometastatic prostate carcinoma metastasis identified on [Ga]Ga-THP-PSMA PET/CT

Abstract

Background Brain metastases from prostate cancer are rare and usually only occur in the context of widespread systemic disease. This is the first case report of a solitary brain oligometastasis, in a neurologically intact prostate cancer patient with no other systemic disease, detected using [68Ga]Ga-THP-PSMA PET/CT and only the second one using a PSMA-based radiopharmaceutical. Case presentation We report the case of a prostate cancer patient presenting 5 years after robot-assisted laparoscopic prostatectomy with biochemical recurrence, no neurological symptoms, and in the absence of metastatic lesions in the body on conventional imaging. A solitary cerebral metastasis was detected using [68Ga]Ga-THP-PSMA PET/CT, surgically resected, leading to a drop in serum PSA and a good recovery. Conclusion In this case, [68Ga]Ga-THP-PSMA PET/CT resulted in a major change in clinical management and avoided additional morbidity associated with delayed diagnosis and treatment. This report demonstrates the importance of considering the presence of metastatic disease outside the conventional locations of prostate cancer spread, as well as the importance of ensuring comprehensive [68Ga]Ga-PSMA PET/CT coverage from vertex to upper thighs.

What to Trust, PSA or [68Ga]Ga-PSMA-11: Learn from Experience

“…On contrast-enhanced MRI, intracranial metastases from prostate cancer appear as well-defined lesions, surrounded by edema with an enhancement pattern that varies from purely solid to ring-like and from mixed cystic to solid. 6 In our patient, MRI showed a mixed cystic intracranial non-hemorrhagic lesion ( Figure 2 ).…”

“…Indeed, literature shows that brain PCa metastases typically occur in patients suffering from advanced PCa with markedly elevated PSA values. 6 , 29 , 30 In our patient multimodal [ 68 Ga]Ga-PSMA-11 PET/CT together with brain MRI findings were suggestive of brain metastases, anticipating any neurological symptoms eventually impacting on the natural history of the disease. The subsequent surgical treatment determined a biochemical drop in PSA level.…”

“…A brain MRI, requested to characterize the suspected lesion confirmed the presence of a right temporal rounded cystic lesion (42x33x31 mm) which appeared hypointense in T1 and hyperintense in T2, with an inferior and lateral solid part (20 mm of maximum diameter) ( Figure 2C–F(i )). 6 , 15 , 16 The patient underwent an excisional biopsy of the brain lesion which documented a prostate adenocarcinoma metastasis with high expression of PSA, PAP, ERG e pan-CK ( Figure 2G–J ).

Figure 1 Timeline with main clinical events and patient’s PSA variation from January 2016 to June 2020.

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“…5 In some cases, patient do not complain any symptoms. 6 Commonly brain metastases occur in the frontal lobes (86% of patients). 5,7 Prostate-specific membrane antigen (PSMA) is a glycoprotein, a membrane-bound metallopeptidase, that is overexpressed in over 90% of PCa cells.…”

Incidental Detection of Asymptomatic Brain Metastases Due to Carcinoma Prostate in Ga-68 PSMA HBED-CC Positron Emission Tomography-Computed Tomography

“…[ 2 ] Asymptomatic brain metastases are relatively uncommon and have been reported in only very few instances. [ 3 4 ] Asymptomatic brain metastases with normal S. PSA levels are a rarity. [ 5 6 7 ]…”