Physiological 68Ga-PSMA-11 Uptake in Dural Venous Sinuses.

ABSTRACT: We describe hitherto unreported physiological low-grade 68Ga-PSMA-11 uptake in dural sinuses of patients who underwent 68Ga-PSMA-11 PET/CT for evaluation of prostate carcinoma. A strong positive correlation was found between SUVmax of tracer uptake in dural sinuses and SUVmax of blood pool activity in superior vena cava. Low-grade 68Ga-PSMA-11 uptake seen in dural sinuses is physiological and is most likely result of venous blood pool activity. Such uptake should not be interpreted as pathological. Knowledge of such physiological uptake is essential for optimal interpretation of PSMA PET/CT images and differentiating physiological versus pathological uptake.

AuntMinnie Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Leads to Diagnosis of Immunoglobulin G4-Related Disease.

A 61-year-old male underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) for evaluation of fever and weight loss with clinical suspicion of occult malignancy or tuberculosis. The scan showed hypermetabolism in bilateral submandibular salivary glands, biliary radicles, pancreas, bilateral kidneys, prostate, and multiple lymph nodes. Based on the concomitant involvement of these sites, suspicion of immunoglobulin G4 (IgG4)-related disease was raised in PET-CT report. Further evaluation with serum IgG4 levels and histopathology of the submandibular salivary gland confirmed the diagnosis of IgG4-related disease. The ability of FDG PET-CT to evaluate the whole-body status of disease played a crucial role in this case.

Penile Metastasis from Renal Cell Carcinoma: Diagnosis and Posttreatment Response Seen on Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography.

We present fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) findings in an extremely rare case of penile metastasis from renal cell carcinoma. A 66-year-old male, a known case of renal cell carcinoma, underwent FDG PET-CT. The scan showed metabolically active cervical lymph nodes, lytic skeletal lesions, deposit in the left adrenal gland, and nodules in the bilateral lungs, indicating metastatic disease. In addition, a hypermetabolic lesion was seen in the corpus cavernosum of the shaft of the penis, suggestive of penile metastasis. Follow-up PET-CT after tyrosine kinase inhibitor therapy showed reduction in size and metabolic activity of all previously seen lesions including penile lesion, suggestive of favorable response to therapy.

The Great Mimicker-Tuberculosis Involving Prostate and Vertebrae Posing as Metastatic Prostate Carcinoma on FDG PET/CT.

A 65-year-old man underwent FDG PET/CT for evaluation of vertebral lesions, radiologically suspected to be metastases. The scan showed hypermetabolism in D8 to D9 vertebrae, retroperitoneal lymph nodes, and both the lobes of prostate. Transrectal ultrasound-guided biopsy of prostate was performed with suspicion of prostate malignancy. The biopsy revealed caseating granulomatous lesions in prostate suggestive of tuberculosis. Post antitubercular treatment patient showed excellent clinical response. Possibility of infective pathologies mimicking malignancy should be kept in mind while evaluating hypermetabolic foci seen on PET/CT. Although rare, tuberculosis of prostate needs consideration in differential diagnosis of FDG-avid foci seen in prostate.

68Ga-Prostate-Specific Membrane Antigen PET/CT Findings in Extra-axial Metastasis From Prostate Carcinoma.

A 67-year-old man with no previous history of malignancy presented with trigeminal neuralgia. MRI of the brain revealed extra-axial lesion along right trigeminal nerve suggestive of neuroma. On histopathology, the lesion was found to be metastasis from adenocarcinoma prostate. Patient underwent Ga-prostate-specific membrane antigen PET/CT for assessing the whole-body status of the disease, which revealed primary prostate lesion, metastatic bone lesions, and extra-axial lesion along the right trigeminal nerve. Extra-axial, intracranial metastasis from prostate carcinoma is an uncommon phenomenon. We describe Ga-prostate-specific membrane antigen PET/CT findings in an exceedingly rare case of extra-axial metastatic lesion from prostate carcinoma.

Coexistent Superscan and Lincoln Sign on Bone Scintigraphy.

A 70-year-old man underwent Tc-methylene diphosphonate scintigraphy for staging of adenocarcinoma prostate. Scintigraphy revealed diffuse increased tracer uptake in skeletal system along with faint renal visualization, a pattern compatible with metastatic superscan. The scintigraphy also revealed increased radiotracer uptake in the body of the mandible-Lincoln sign or black beard sign. Radiological imaging revealed sclerotic lesions throughout the skeleton including the mandible, confirming widespread skeletal metastases. Lincoln sign is previously described in monostotic Paget disease of the mandible and in contiguous spread of oral malignancy. We describe this pattern in distant metastatic involvement from carcinoma prostate with coexistent superscan pattern.

Incidental Warthin Tumor on Pertechnetate Scintigraphy.

A 30-year-old woman underwent Tc-pertechnetate scintigraphy for evaluation of thyrotoxicosis. The scintigraphy revealed hypervascular thyroid gland with markedly increased trapping function in both the lobes suggesting diagnosis of Graves disease. Incidentally, a hypervascular and pertechnetate avid focus was seen along the lateral margin of the right parotid gland. Pertechnetate avidity and site of uptake suggested possibility of Warthin tumor. Clinical examination and ultrasonography revealed a well-defined lesion in the superficial lobe of the right parotid gland favoring diagnosis of benign lesion. Postsurgery specimen confirmed diagnosis of Warthin tumor.

Acute pyelonephritis resulting in intense vascular blush during dynamic renal scintigraphy.

A thirty-year-old male underwent Tc-99m diethylenetriaminepentaacetic acid renal scintigraphy for evaluation of gross hydronephrosis of left kidney. The perfusion phase revealed an intense vascular blush in left renal fossa. The uptake phase of scintigraphy revealed the absence of tracer uptake in left kidney. Contrast-enhanced computed tomography (CECT) was performed for evaluating the cause of vascular blush. CECT demonstrated features suggestive of acute pyelonephritis (APN) involving lower pole of the hydronephrotic left kidney, corresponding to the site of vascular blush seen on renal scintigraphy. The postnephrectomy specimen confirmed the diagnosis of APN suggested on CECT.

Gutkha Addiction: Nicotine Dependence or a Conditioned Reflex?

BACKGROUND: A pre-packaged mixture of areca nut, tobacco, slaked lime, catechu, and flavoring agents is popularly known as Gutkha. Aim of study is to analyze the addiction biology of Gutkha chewing and to assess efficacy of a cessation program based on nicotine replacement therapy (NRT). MATERIALS AND METHODS: Patterns of addiction of 400 Gutkha chewers were analyzed with a questionnaire-based survey. Urine cotinine levels of 60 subjects undergoing NRT were periodically estimated using gas chromatography. RESULTS: Mean urine cotinine levels of relapse and relapse-free cases were 5800.38 µg/g of creatine and 5622.16 µg/g of creatine. The difference was not found to be statistically significant. A 83.3% of the subjects associated their chewing habit with day to day activities. Overall relapse rate was found to be 79%. The most common reported reason for relapse was unacceptable taste and form of nicotine chewing gums. CONCLUSION: Repetitive coexistence in time of an indifferent act and the act of chewing Gutkha where, the act of chewing is almost always preceded by the indifferent act sets in a conditioned reflex. Gutkha addiction can be considered as a form of conditioned reflex, rather than actual craving for nicotine.

FDG PET/CT findings in a case of nontuberculous abscess of adrenal gland.

Abscesses in the adrenal gland are extremely rare in adults with few cases reported in literature. We report FDG PET/CT findings in a unilateral adrenal abscess in a case of hepatocellular carcinoma. Though rare, this diagnosis should be kept in mind while evaluating cystic lesions of adrenal gland on PET/CT. Correlation with clinical picture and blood investigations is useful in such cases.

Lighting the tunnel: FDG PET/CT findings leading to incidental diagnosis of carpal tunnel syndrome.

Nonspecific accumulation of F FDG observed at sites of inflammation, during PET imaging of patients with cancer, is a known phenomenon, and PET/CT has evolved into a promising imaging technique to examine, diagnose, and manage inflammatory disorders. We describe nonspecific uptake of FDG in a patient with known malignancy, leading to incidental diagnosis of carpal tunnel syndrome.

Stromal myofibroblasts in nonmetastatic and metastatic oral squamous cell carcinoma: An immunohistochemical study.

BACKGROUND AND AIMS: Myofibroblasts are one of the important components of the tumor microenvironment which could possibly play an important role in tumor progression. The purpose of this study was to compare the presence of α-smooth muscle actin (α-SMA) and CD34 positive fibroblasts in nonmetastatic and metastatic oral squamous cell carcinoma and to evaluate their role in tumor metastasis. MATERIALS AND METHODS: Ten cases each of histologically proven metastatic and nonmetastatic oral squamous cell carcinoma formed the study group. The tissue sections were stained immunohistochemically for α-SMA and CD34. The stromal spindle cells positive for these markers in the study groups were counted and compared. RESULTS: α-SMA positive cases were more in the metastatic group and CD34 positive cases were found to be more in the nonmetastatic tumors. CONCLUSIONS: Though difference in the staining pattern was statistically nonsignificant, the inverse relationship between α-SMA and CD34 positive cells is indicative of dynamic nature and the influence of tumor stroma in tumor progression and metastasis.

Somatostatin receptor positron emission tomography/computed tomography (PET/CT) in the evaluation of opsoclonus-myoclonus ataxia syndrome.

Opsoclonus-myoclonus ataxia (OMA) syndrome is the most common paraneoplastic neurological syndrome of childhood, associated with occult neuroblastoma in 20%-50% of all cases. OMA is the initial presentation of neuroblastoma in 1%-3% of children. Conventional radiological imaging approaches include chest radiography and abdominal computed tomography (CT). Nuclear medicine techniques, in form of (123)I/(131)I-metaiodobenzylguanidine (MIBG) scintigraphy have been incorporated in various diagnostic algorithms for evaluation of OMA. We describe use of somatostatin receptor PET/CT with (68)Gallium- DOTA-DPhe(1), Tyr(3)-octreotate (DOTATATE) in diagnosis of neuroblastoma in two cases of OMA.

Stomach metastasis of breast carcinoma mimicking primary gastric neoplasm on fluorodeoxy glucose-positron emission tomography-computed tomography.

We present fluorodeoxy glucose positron emission tomography-computed tomography (FDG-PET/CT) findings in a case of breast carcinoma. The PET/CT findings in this case were suspicious of second primary neoplasm in the stomach. However, on endoscopic biopsy, the lesion was found to be stomach metastasis of breast carcinoma with estrogen receptor positivity. Stomach is a rare site of breast carcinoma metastasis. Our case suggests that it is difficult to distinguish a stomach metastasis of breast cancer from a primary gastric cancer on the basis of clinical and imaging features. However, this differential diagnosis must be kept in mind and it is important to make such distinction because of its implications on patient management.

Left is right and right is wrong: Fluorodeoxyglucose uptake in left hemi-diaphragm due to right phrenic nerve palsy.

A 36-year-old Indian man, a recently diagnosed case of the right lung carcinoma underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) for staging of the malignancy. PET/CT showed increased FDG uptake in the right lung mass, consistent with the known primary tumor. Right hemidiaphragm was found to be elevated on CT, suggesting right diaphragmatic paresis. The PET scan demonstrated asymmetric, intense FDG uptake in the left hemidiaphragm and accessory muscles of respiration, which was possibly due to compensatory increased workload related to contralateral right diaphragmatic paresis. The right diaphragmatic paresis was hypothesized to be caused by phrenic nerve palsy by right lung neoplasm.

Fluorodeoxyglucose positron emission tomography-computed tomography findings in a case of xanthogranulomatous pyelonephritis.

Xanthogranulomatous pyelonephritis (XGNP) is an uncommon condition characterized by chronic suppurative renal inflammation that leads to progressive parenchymal destruction. This condition can clinically present as recurrent urinary tract infections, flank pain, hematuria, and occasionally sepsis, and weight loss. This condition is usually associated with obstructing renal calculus. We present 18-fluorodeoxyglucose positron emission tomography-computed tomography (18-FDG PET/CT) findings in an elderly male suffering from pyrexia and weight loss and suspected urinary tract infection. PET/CT findings in this case lead to diagnosis of XGNP. This diagnosis should be kept in mind while evaluating similar symptoms and PET/CT scan findings.

Mortui vivos docent--the dead teach the living: 18-flurodeoxyglocose positron emission tomography-computed tomography findings in a case of intravascular B cell lymphoma.

Intravascular large B-cell lymphoma is a rare and aggressive variant of diffuse large B-cell non-Hodgkin's lymphoma. Its atypical presentation often delays the diagnosis and due to its aggressive behavior, the diagnosis is made post-mortem in half of the cases. We present FDG PET/CT findings in a case of IVLCL. In our case, the report of the patient's bone marrow biopsy after death of the patient revealed the presence of IVLCL. After availability of final diagnosis, we reviewed the literature and a better explanation of the FDG PET/CT findings could be obtained. We describe this case, to call for heightened awareness in physicians for the rare but possible diagnosis of IVCLL, particularly in an elderly patient who presents with fever of unknown origin and demonstrates similar FDG PET/CT findings. Considering the characteristic scan findings described in our patient and other cases in literature, FDG PET/CT can be used in suspected cases of IVLCL for early diagnosis of this rapidly fatal malignancy.