Purpose of the Report Prostate-specific membrane antigen (PSMA) is a type II membrane glycoprotein, which is not only overexpressed in prostate cancers but also in variety of solid tumors including glioblastoma multiforme. The aim of the present study was to demonstrate PSMA expression in gliomas using 68Ga-PSMA-HBED-CC(PSMA 11) PET/CT. Patients and Methods Ten patients with initially MRI suspected and eventually histopathologically proven gliomas [8 males (age range 30–73 yr; mean age 51.8 yr); 2 females aged 39 and 55 years] were subjected preoperatively to regional brain PET scan with 68Ga-PSMA-11 and 18F-FDG PET/CT. Final histopathology of brain lesions, their MIB-1 proliferation index (MIB-1 PI) were compared with PSMA and FDG PET findings. Results FDG PET/CT showed distinct FDG uptake in high-grade gliomas, whereas low-grade gliomas were non-FDG-avid amidst physiological tracer uptake. In vivo PSMA expression was seen in all patients with glioma. Of these, the 7 patients of glioblastoma harboring 8 lesions showed significantly higher PSMA expression than those with low-grade gliomas, average SUVmax being 16.93 and 2.93, respectively. Similarly, average tumor-to-background ratios (13.95 and 3.42, respectively) and MIB-1 PI (17.31 and 3.3, respectively) were substantially more in high-grade versus low-grade gliomas. Conclusions The results of this pilot study show that 68Ga-HBED-CC-PSMA PET/CT can be used to characterize the PSMA expression in gliomas, high-grade ones demonstrating higher SUVmax, MIB-1 PI tumor-to-background ratio than the low-grade ones. With these results as basis, certain patients may benefit from potential PSMA-targeted radionuclide therapy.

Ga-PSMA-HBED-CC PET/CT is a potentially useful imaging modality in patients of mDTC with most (70%) of PSMA expressing metastasis being localized to the bones. PSMA PET/CT could be useful for identifying patients with limited therapeutic options (eg, TENIS) who might benefit from PSMA-targeted radionuclide therapy.

The management of gastrointestinal stromal tumors (GISTs) has been revolutionized in recent years by two major developments: the introduction of imatinib mesylate as a targeted therapeutic agent and the dramatic change in the tumor metabolic activity following successful therapy making in fluorodeoxyglucose (FDG)-PET as the modality of choice for monitoring therapeutic response. In the present communication, we have explored the current role of PET/computed tomography (CT) imaging in GIST on the basis of a brief overview of the published studies and our experience on the subject gained in a large tertiary care setting. There is now convincing evidence that serial PET study is more sensitive and reliable for determining treatment response to imatinib mesylate in patients of GIST, when compared with only conventional CT monitoring. This modality also appears to be of potential value in initial disease evaluation including prediction of malignant potential in recently diagnosed GIST and in selection of optimal dose of imatinib for therapy. The findings of detection of disease recurrence on discontinuing imatinib and acquired resistance to imatinib provide insight into the issue of therapeutic endpoint definition. On the basis of the experience gained in recent times, the future potential of this powerful modality in this setting is hypothesized.

We report a rare case of adrenal and renal metastases from papillary thyroid carcinoma (PTC). A 30-year-old man underwent total thyroidectomy with left neck dissection for cytology proven nodal metastases from PTC. This was followed by high-dose radioiodine therapy with a dose of 265 mCi (9.805 GBq). Thereafter, patient was lost to follow-up. He presented 2 decades later with low backache radiating to both the lower limbs. Magnetic resonance imaging examination of spine detected left SI joint, dorsal and lumbar vertebral metastases. A whole-body radioiodine scan showed extensive iodine avid foci in thyroid bed, mediastinum, bilateral lungs, liver, bones, and in bilateral lumbar regions. An abdominal single photon emission computed tomography-computed tomography (CT) revealed the lumbar lesions to be within bilateral adrenal glands. Contrast-enhanced CT of abdomen revealed lesions in bilateral adrenals and renal regions suggestive of metastases. A CT-guided biopsy of left adrenal focus confirmed metastasis from the carcinoma of thyroid. A high degree of suspicion with further radiologic and cytologic correlation clinched the diagnosis of both adrenal and renal metastases from PTC, which has been rarely reported. Fortunately, radioiodine concentration in adrenal metastases made them amenable to high-dose radioiodine therapy. Therefore, 225 mCi (8.325 GBq) of radioiodine was administered to this patient. This case is a strong reminder of the fact that regular and long-term follow-up is imperative in the management of thyroid cancer patients.