Isolated Testicular Metastasis from Prostate Cancer Detected on Ga-68 PSMA PET/CT Scan.

Although prostate cancer can metastasize to any part of the body, isolated testicular metastasis is very rare and only few cases have been reported so far. Here we present a case of 65-year-old male patient, known case of prostate adenocarcinoma, referred for 68Ga-PSMA PET/CT scan, post radiotherapy, and androgen deprivation therapy, for rising serum PSA levels. He was found to have an isolated testicular metastasis on the scan. This report highlights the importance of 68Ga-PSMA PET-CT scan in detecting these unusual and rare sites of metastasis from prostate cancer.

Prostate-Specific Membrane Antigen-Avid Meningioma Detected in 68Ga-Prostate-Specific Membrane Antigen PET/CT.

A 64-year-old man with recently diagnosed prostate adenocarcinoma with a total prostate-specific antigen level of 3.32 ng/mL and Gleason score 4 (3 + 4) was referred for Ga-prostate-specific membrane antigen PET/CT scan for pretreatment staging. Prostate-specific membrane antigen-avid lesion was noted in the right lobe of the prostate gland, corresponding to the known primary lesion. Note was made of another prostate-specific membrane antigen-avid lesion in the right parietal lobe of brain, likely meningioma. MRI scan performed later confirmed the brain lesion to be meningioma.

Metabolic imaging patterns in posterior cortical atrophy and Lewy body dementia.

PURPOSE: To study the imaging patterns of Posterior cortical atrophy (PCA) and Dementia with Lewy bodies (DLB) on fluoro-deoxyglucose positron emission tomography computed tomography ([F]FDG PET/CT), identify areas of overlap and differences and to develop a prediction model to assist in diagnosis using univariate and multivariate analysis. METHODS: A retrospective analysis of 72 patients clinically suspected of having posterior dementia was done. All patients underwent [FF]FDG PET/CT of the brain and dopamine transporter imaging with [[Tc]TRODAT-1 SPECT scan on separate days. The patients were divided into PCA with normal TRODAT uptake (n=34) and DLB with abnormal TRODAT uptake (n=38). The FDG PET/CT uptake patterns were recorded and areas of significant hypometabolism by z score analysis were considered as abnormal. Receiver operator characteristics (ROC) curve analysis was used to determine cutoff z scores and binary logistic regression analysis was used to determine the Odds ratio of being in the predicted groups. RESULTS: Significantly hypometabolism was found in parieto-temporo-occipital association cortices and cingulate cortices in PCA patients. DLB patients showed significantly reduced uptake in the visual cortex. No significant difference was found between z score of occipital association cortex which showed hypometabolism in both groups. The cut-off z-score values derived from the ROC curve analysis were as follows- parietal association (cut-off-3, sensitivity-65.6%, specificity - 68.7%), temporal association (cut-off-2, sensitivity-78%, specificity-75%) and posterior cingulate (cut-off-0.5, sensitivity-93.7%, specificity-40.6%), their respective Odds ratio (with 95% confidence interval) for being in the PCA group as derived from univariate logistic regression were 3.66 (1.30-10.32), 10.71 (3.36-34.13) and 7.85 (1.57-39.17). The cut-off z score of primary visual cortex as derived from ROC curve was zero with sensitivity of 87.5%, specificity of 71.9%, and the Odds ratio for being the in the DLB group was 24.7 with 95% confidence interval of 5.99-101.85. CONCLUSION: [F]FDG PET may be useful as a non-invasive diagnostic modality in differentiating the two posterior cortical dementias, despite significant overlap. Primary visual cortical hypometabolism can serve as an independent diagnostic marker for DLB, even in the absence of TRODAT imaging.

Correlation of 99mTc-TRODAT-1 SPECT Imaging Findings and Clinical Staging of Parkinson Disease.

PURPOSE: The aims of this study were to evaluate Tc-TRODAT-1 SPECT imaging patterns and to assess their correlation with disease severity in clinically diagnosed patients of Parkinson disease (PD). METHODS: The study included 241 patients with clinically diagnosed idiopathic Parkinson disease who underwent Tc-TRODAT-1 SPECT/CT scan. Binding ratios were calculated for each striatum, caudate, and putamen individually, by drawing region of interest. Occipital cortex region of interest was taken for background correction. Correlation of binding ratio with increasing clinical stage was derived, as described by modified Hoehn and Yahr scale. RESULTS: Median binding ratio was least in the contralateral putamen for all stages of modified Hoehn and Yahr. A statistically significant negative correlation was found between increasing disease severity and binding ratio in all subregions of striatum. Patients were clinically categorized into postural instability and gait disorder group and tremor-dominant PD group. No significant asymmetry was found between the left and right striatum in patients belonging to postural instability and gait disorder group and in those with bilateral tremors without lateralization. CONCLUSIONS: Tc-TRODAT-1 SPECT is useful in early detection and in assessing disease severity of PD. A significant asymmetry with the contralateral side being affected more than the ipsilateral side can be attributed to tremor-dominant patients. The binding ratio of the ipsilateral striatum may serve useful as a marker of remaining functional dopaminergic neuronal reserve in the striatum.

Incidental Detection of Skeletal Metastases on 99mTc-DTPA Renography.

We present the case of a 53-year-old man with left hydroureteronephrosis who underwent Tc-DTPA renography for functional assessment of bilateral kidneys. Tc-DTPA renography of the patient showed diffusely increased extrarenal Tc-DTPA uptake in the visualized lumbosacral vertebrae and in the pelvic bones, on the blood flow and functional phase of the renography, which was suggestive of disseminated skeletal disease. Subsequent MRI lumbosacral spine and F-FDG PET/CT revealed extensive skeletal metastases corresponding to the increased extrarenal Tc-DTPA uptake in the lumbosacral vertebrae and the pelvic bones from primary left lung mitotic lesion.

Ga-68 DOTANOC PET/CT imaging in detection of primary site in patients with metastatic neuroendocrine tumours of unknown origin and its impact on clinical decision making: experience from a tertiary care centre in India.

BACKGROUND: Neuroendocrine tumours (NETs) are rare, heterogeneous group of tumours which usually originate from small, occult primary sites and are characterized by over-expression of somatostatin receptors (SSTRs). Positron emission tomography/computed tomography (PET/CT) using Ga-68-labeled-somatostatin-analogues have shown superiority over other modalities for imaging of NETs. The objective of the study was to retrospectively evaluate the efficacy of Ga-68 DOTANOC PET/CT imaging in detecting the primary site in patients with metastatic NETs of unknown origin and its impact on clinical decision making in such patients. METHODS: Between December 2011 and September 2014, a total of 263 patients underwent Ga-68 DOTANOC PET/CT study in our department for various indications. Out of them, 68 patients (45 males, 23 females; mean age, 54.9±10.7 years; range, 31-78 years) with histopathologically proven metastatic NETs and unknown primary site (CUP-NET) on conventional imaging, who underwent Ga-68 DOTANOC PET/CT scan as part of their clinical work-up were included for analyses. Histopathology (wherever available) and/or follow-up imaging were taken as reference standard. Quantitative estimation of SSTR expression in the form of maximal standardized uptake value (SUVmax) of detected primary and metastatic sites was calculated. Follow-up data of individual patients was collected through careful survey of hospital medical records and telephonic interviews. RESULTS: Maximum patients presented to our department with hepatic metastasis (50 out of 68 patients) and grade I NETs (>50%). Ga-68 DOTANOC PET/CT scan identified primary sites in 40 out of these 68 patients i.e., in approximately 59% patients. Identified primary sites were: small intestine [19], rectum [8], pancreas [7], stomach [4], lung [1] and one each in rare sites in kidney and prostate. In one patient, 2 primary sites were identified (one each in stomach and duodenum). Mean SUVmax of the detected primary sites was 25.1±18.0 (median: 16.25; range, 2.1-150). Significant positive correlation was found between SUVmax of detected primary site and SUVmax of the histopathologically proven sites of metastasis (r=0.662; P<0.0001). Based on the findings of the Ga-68 DOTANOC PET/CT scan, 3 out of 40 patients underwent definitive treatment for their primary tumour (1 gastric, 1 ileal and 1 prostatic tumour). One patient was being planned for resection of primary rectal lesion at the time of data-collection. Thirty-six out of 68 patients were started on long-acting somatostatin analogues or chemotherapy or targeted therapy. Two patients underwent multiple cycles of peptide receptor radionuclide therapy (PRRNT) using (90)Y and (177)Lu labeled somatostatin analogues. CONCLUSIONS: Our findings indicate that Ga-68 DOTANOC PET/CT is a promising imaging modality in patients with metastatic NETs of unknown origin for detection of the primary site and in guiding their therapeutic management.

Primary malignant melanoma of the esophagus.

Primary malignant melanoma most commonly originates from the skin; other less common extra cutaneous sites include squamous mucous membranes, uvea, retina, leptomeninges, genitourinary tract, digestive tract, biliary tract, and upper respiratory tract. Primary melanoma of the gastrointestinal tract is exceedingly rare. We are reporting a histo-pathologically proven rare case of primary malignant melanoma of the esophagus and its findings on fluorodeoxyglucose positron emission tomography and computed tomography.

Merkel cell carcinoma--a rare cause of non-healing skin ulcer: a case report.

Merkel cell carcinoma (MCC) is a rare tumour of skin which needs to be differentiated from other small cell tumours like small-cell carcinoma of lung, melanoma, and lymphoma. Definitive diagnosis is made by immunohistochemistry and staining positively with cytokeratin. There is very little data regarding treatment of metastatic MCC and many questions remain unanswered. MCC is a chemosensitive tumour and many different chemotherapeutic regimens have been used alone or in combination with radiotherapy to treat metastatic MCC. Although complete and partial responses are achieved, they are mostly short lived and tumour usually recurs. Here a case is reported who had partial remission with chemotherapy (etoposide and cisplatin) and radiation therapy in a patient with metastatic MCC.