We present a case of a 16-year-old boy who underwent 68 Ga-PSMA PET/CT for residual disease assessment of juvenile nasal angiofibroma. Positive uptake was noted in residual tumor on PET/CT imaging. However, there was no abnormal uptake in surrounding scar tissues as compared with contrast-enhanced magnetic resonance imaging. These findings were confirmed by biopsy from the scar tissue on posterior ethmoids. 68 Ga-PSMA PET/CT may be a potentially valuable tool especially in distinguishing recurrences from surgical site reparative tissue and in planning and delivering stereotactic radiotherapy.
Prostate-specific membrane antigen (PSMA) is expressed in the endothelial cells of tumor-associated neovasculature of various nonprostatic benign and malignant neoplasms including juvenile nasopharyngeal angiofibroma (JNA). Positive uptake on PET/CT imaging with 68Ga-labeled PSMA is noted in a patient with residual disease after initial surgery without any abnormal uptake in postoperative fibrosis, in contrast to contrast-enhanced MRI, which was confirmed by biopsy. 68Ga-PSMA PET/CT may be a useful tool clinically for identifying early biochemical recurrences and in specifically differentiating recurrences from surgical site reparative tissue.
Prostate-specific membrane antigen (PSMA) is expressed on the endothelial cells of tumor-associated neovasculature of various nonprostatic benign and malignant neoplasms. Positive uptake on PET/CT imaging with 68Ga-labeled PSMA is noted in a patient with juvenile nasal angiofibroma, and the same is noted to be absent following complete surgical excision. 68Ga-PSMA PET/CT may be a useful tool for juvenile nasal angiofibroma recurrence identification and in differentiating recurrence from surgical site reparative tissue.
The prostate-specific membrane antigen (PSMA) is highly expressed in prostatic cancer. However, PSMA expression is also noted in various benign and malignant nonprostatic neoplasms in the endothelial cells of tumor-associated neovasculature. We performed 68Ga-PSMA PET/CT in a 14-year-old boy with juvenile nasal angiofibroma (JNA) to explore its theranostic potential. The scan revealed high uptake in the lesion. Performance of PSMA PET/CT in JNA opens up new frontiers with respect to radiological staging, early recurrence identification, and perhaps even radioligand therapy of residual/recurrent JNAs in the future.
Purpose
Prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer cells and is exploited for imaging and treatment of patients with prostate cancer. Prostate-specific membrane antigen expression is also demonstrated in the tumor-associated neovasculature endothelium. Juvenile nasal angiofibroma (JNA), being a similar highly vascular tumor, may also demonstrate significant PSMA expression, which may be utilized for its imaging and treatment.
Methods
In this prospective study, 25 clinicoradiologically diagnosed primary JNA patients underwent PSMA PET/CT scan. The scan was performed after 45 to 60 minutes of intravenous injection of 2 to 3 mCi (74–111 MBq) of 68Ga-PSMA-HBED-CC on a dedicated PET/CT scanner. Low-dose CT scan was acquired from vertex to sternoclavicular joint (100 mA, 20 kVp, 3-mm slice thickness, 0.8 pitch). Images were reconstructed with iterative reconstruction technique (4 iterations, 24 subsets). The objective was to assess the intensity and pattern of PSMA uptake in primary JNA patients.
Results
All cases (n = 25) of primary JNA showed PSMA expression in the tumor (100%). The median PSMA SUVmax ratio of tumor to background was 4.57 (range, 2.08–7.27). Intracranial extension in 14 of 25 patients was prominently visualized because of absence of background uptake in the brain. Advanced stage tumors demonstrated greater uptake than early tumors (P = 0.011). A statistically nonsignificant trend was noted for decreasing uptake with increasing age after normalizing for stage (Spearman correlation coefficient r = −0.08).
Conclusions
Assessment of PSMA expression in JNA by PSMA PET/CT opens up a new window of opportunity with respect to its radiological staging, vascularity assessment, and molecular characterization. A potential role in identification of the difficult residual-recurrent disease is anticipated and perhaps also in radioligand therapy for residual/recurrent JNA.
Clinical Trials Registry of India (CTRI/2018/08/015479).
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