Clinical significance of incidental FDG uptake in the prostate gland detected by PET/CT.

The value of FDG-positron emission tomography/computed tomography (PET/CT) for detecting prostate cancer is unknown. We aimed to investigate the clinical value of incidental prostate FDG uptake on PET/CT scans. We reviewed 6128 male patients who underwent FDG-PET/CT scans and selected cases that reported hypermetabolic lesion in the prostate. The patients who have prior history of prostate carcinoma or prostate surgery were excluded from the study. We have analyzed the correlation between PET/CT findings and serum prostate-specific antigen (PSA) levels, imaging (USG), urological examinations and biopsy. Incidental 18F-FDG uptake of the prostate gland was observed in 79 patients (1.3%). While sixteen of them were excluded due to inadequate clinical data, the remaining 63 patients were included for further analysis. The patients were divided into two groups; 8 patients (12.7%) in the malignant group and 55 patients (87.3%) in the benign group. The SUVmax values were not significantly different between the two groups. In 6 (75%) patients with prostate cancer, FDG uptake was observed focally in the peripheral zone of the prostate glands. There was no significant correlation between the SUVmax and the PSA levels. Incidental 18F-FDG uptake in the prostate gland is a rare condition, but a substantial portion of it is associated with the cancer. Benign and malignant lesions of the prostate gland in FDG-PET/CT imaging could not be reliably distinguished. The peripheral focally FDG uptake of prostate glands should be further examined with the clinical and labaratory evaluations.

Regional reference values of thyroid gland volume in Turkish Adults.

INTRODUCTION: It is important to know the size of the thyroid gland, and its normal value may vary among different geographic regions. OBJECTIVE: In this study, we aimed to establish reference ranges for thyroid volume in euthyroid adults and to compare these results with the literature data. METHODS: Between June 2011 and June 2012,461 patients with normal laboratory results (serum TSH, anti-TG, anti-TPO antibodies and urine iodine level) that underwent thyroid gland ultrasound examination were retrospectively analyzed.Two hundred and 92 patients were females and 169 were males; the age range was 18-61 years with mean age 30.84±9.97 years. Length, breadth and thickness were measured, and the volume of each lobe was estimated using the ellipsoid formula. RESULTS: The overall mean thyroid volume in all patients who were examined was 12.98±2.53 mL. The mean thyroid volume in females and males was 12.09±2.05 mL and 14.53±2.55, respectively (p<0.05). The right thyroid lobe volume was greater than the left in all patients of both sexes. In addition, the study establishes a significant correlation between the thyroid volume and height, weight and body surface area of the subjects of both sexes (p<0.05). In the light of our findings we can provide reference values in order to evaluate patients who have thyroid hyperplasia or who are considered as normal. CONCLUSION: We consider that further studies are necessary to establish national references thyroid volume for each country.

Evaluation of conventional imaging techniques on preoperative localization in primary hyperparathyroidism.

We aimed to evaluate the diagnostic and preoperative localization capacity of 99mTc methoxyisobutylnitrile (MIBI) parathyroid scintigraphy and ultrasonography (USG) in enlarged parathyroid glands in the primary hyperparathyroidism (pHPT) as well as the relationship between the success rate of these techniques and biochemical values. In this study, we retrospectively evaluated 39 patients with clinical and biological evidence of pHPT who referred to the university hospital for MIBI parathyroid scintigraphy. Patients were examined with USG and double-phase MIBI parathyroid scintigraphy for the detection of enlarged parathyroid glands. Preoperative serum intact parathyroid hormone (iPTH) levels, calcium (Ca), phosphate and alkaline phosphatase measurements were obtained. A total of 45 parathyroid lesions in 39 patients were reviewed. Thirty-four patients had a single adenoma and 5 patients with multi-gland disease had 11 abnormal parathyroid glands including three adenomas, whereas the remaining 8 glands showed hyperplasia. The overall sensitivities of MIBI parathyroid scintigraphy, USG and combined techniques were 85.3%, 72.5% and 90.4%, respectively; the positive predictive values (PPV) were 89.7%, 85.2% and 92.6%, respectively. The most successful approach for detection of enlarged parathyroid glands in hyperparathyroidism is the concurrent application of USG and MIBI parathyroid scintigraphy modalities. The concomitancy of thyroid diseases decreases the sensitivity of both MIBI parathyroid scintigraphy and USG in enlarged parathyroid glands.

An Incidental Finding of Extraosseous Uptake in Technetium 99m Methylene Diphosphonate Bone Scintigraphy: Uterine Leiomyoma.

We present the case of a 58-year-old, postsurgical breast cancer patient who was examined for routine controls at the Oncology Department of Namik Kemal University, Tekirdag, Turkey. She was referred to the nuclear medicine department for possible metastatic spread to the skeleton; 740 MBq of methylene diphosphonate tecnetium 99m ([Tc-99m] MDP) was injected intravenously, and 3 hours later a whole-body bone scan was performed. The whole-body bone scan showed no abnormal uptake associated with bone metastases, but in the anterior projection images, an area of mildly increased technetium 99m methylene diphosphonate uptake was seen in the right pelvic region. This appearance did not seem related to bone structures. When a more detailed history of this region was obtained, we learned of the patient's uterine leiomyoma. As a result of ultrasound and magnetic resonance imaging findings, the mildly increased tracer uptake in the right pelvic area on bone scintigraphy was consistent with a calcified uterine myoma. We concluded that a soft tissue concentration of labeled phosphates should always be kept in mind when interpreting whole-body bone scans.

Mediastinal Ectopic Parathyroid Adenoma in a Patient Followed for Colon Cancer and Chronic Renal Failure: A Challenging Case.

Colorectal cancer is a significant cause of morbidity and mortality worldwide. The advances in early diagnosis and treatment have increasingly expanded the patient population surviving from colorectal cancer. Herein, we present a case of a patient with mediastinal ectopic parathyroid adenoma who has been followed up for postoperative colon cancer. The patient is a 59-year-old man with postoperative colon cancer and chronic renal failure in whom control positron emission tomography/computed tomography revealed multiple bone metastases. However, on methylene-diphosphonate bone scintigraphy, multiple involvement with increased uptake was associated with renal osteodystrophy/hyperparathyroidism; technetium-99m 2-methoxyisobutylisonitrile parathyroid scintigraphy was performed, which revealed mediastinal ectopic parathyroid adenoma. To the best of our knowledge, this is the first case report in the literature reporting the co-occurrence of colon cancer, chronic renal failure, and ectopic parathyroid adenoma.

Axillary lymph node metastasis of papillary thyroid carcinoma detected by FDG PET/CT in a thyroglobulin-positive patient with negative whole-body 131I scan.

Axillary metastasis is not a common finding in papillary carcinoma. 18F-FDG can detect foci of metastasis in patients with negative 131I scan. We report a case of a 64-year-old man who had undergone thyroidectomy and 131I ablation due to classic type of papillary carcinoma 14 years ago. Follow-up examination revealed high serum thyroglobulin and negative whole body 131I scan. 18F-FDG PET/CT showed focally increased uptake in right axillary as well as supraclavicular and bilateral cervical lymph nodes. Histopathological examination of the surgically removed lymph nodes confirmed the metastasis of papillary thyroid carcinoma.