Oktay Sari

The role of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiating between benign and malignant adrenal lesions.

ObjectivesThis retrospective study was designed to investigate the clinical role of whole-body positron emission tomography/computed tomography (PET/CT) by using 2-[18F]fluoro-2-deoxy-D-glucose (FDG), for the evaluation of adrenal lesions and to find the best index to distinguish benign from malignant lesions in various cancer patients. Materials and methodsA total of 81 patients (55 male and 26 female, age range: 31–81 years, mean: 61.5) who had confirmed primary malignancies (lung cancer in 47 patients, gastrointestinal malignancies in 13 patients, malignant melanoma in one patient, renal cell cancer in three patients, mesothelioma in two patients, breast carcinoma in nine patients, cervical cancer in one patient, ovarian cancer in two patients, pheochromocytoma in one patient, unknown primary in two patients) underwent PET/CT examinations for cancer screening, staging, restaging, and detection of suspected recurrence. Of the 81 patients, 104 adrenal lesions (34 benign and 70 malignant adrenal lesions) were shown by CT. On visual analysis of PET/CT imaging, adrenal uptake was based on a three-scale grading system. For final assessment standards of references for adrenal malignant lesions was based on biopsy (n=2), interval growth, or reduction after chemotherapy. An adrenal lesion, which remained unchanged on clinical and imaging follow-up of at least 7 months (mean follow-up time 19.31 months±6.46, range 7–30 months), was decided as a benign lesion. ResultsIn adrenal malignant lesions maximum standardized uptake value (SUVmax) (8.82±4.47) was higher than that of adrenal benign lesions (3.02±1.15, P<0.0001). In the differentiation of adrenal benign and malignant lesions, a CT threshold of 10 Hounsfield units corresponded to a sensitivity of 64.7%, specificity of 98.6%, and accuracy of 87.5%. An SUVmax cut-off value of 2.5 corresponded to a sensitivity of 100%, specificity of 38.2%, and accuracy of 80%. An SUVmax cut-off value of 4.2 corresponded to a sensitivity of 88.6%, specificity of 88.2%, and accuracy of 88.5%. The ratio of tumor SUVmax to liver SUVmean was 3.61±1.77 for adrenal malignant lesions whereas it was 1.20±0.38 for adrenal benign lesions (P<0.0001). T/L SUV ratio cut-off value of 1.8 corresponded to a sensitivity of 87%, specificity of 91%, and accuracy of 88.5%. T/L SUV ratio cut-off value of 1.68 corresponded to a sensitivity of 90%, specificity of 91.1%, and accuracy of 90.4%. Conclusion2-[18F]fluoro-2-deoxy-D-glucose-PET/CT improves the diagnostic accuracy in the differentiation of benign from malignant adrenal lesions in various cancer patients. Combined information obtained from PET/CT (SUVmax, T/L SUV ratio, visual analysis) and unenhanced CT (size, Hounsfield units measurement) is recommended for better differentiation.

The Role of FDG-PET/CT in Ovarian Cancer Patients with High Tumor Markers or Suspicious Lesion on Contrast-Enhanced CT in Evaluation of Recurrence and/or in Determination of Intraabdominal Metastases

OBJECTIVES This retrospective study was designed to investigate the role of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in determination of recurrence and/or intraabdominal metastasis in patients with ovarian cancer having increased tumor markers or suspicious lesion detected by a contrast-enhanced abdominal CT (ceCT). MATERIALS AND METHODS A total of 34 female patients who were treated for histopathologically proven ovarian cancer, underwent PET/CT examination for restaging and suspected recurrence. Patients with pathology report, tumor marker levels, ceCT and PET/CT performed within one month were included in the study. RESULTS A total of 34 patients were included in the study. 25 of 34 patients had high tumor marker (CA 125) level. The remaining 9 patients had suspected recurrence on ceCT imaging with normal tumor marker levels. Recurrence was confirmed by re-operation and biopsy (n=4), clinical and imaging follow-up (n=21) in 25 patients with elevated tumor markers. Recurrent disease was not shown in 5 of 25 patients on ceCT imaging and 1 of 25 patients on PET/CT imaging with high CA125 values. Both ceCT and PET/CT revealed recurrent disease in 19 of 25 patients. PET/CT showed more lesions in 11 of 19 patients. Sensitivity, specificity and accuracy of the PET/CT were 96.1%, 100% and 97%, respectively. CONCLUSION PET/CT is found as a beneficial method for detection of the recurrence, in patients with increased serum CA 125 level and negative CT findings or with normal CA 125 level and recurrence detected by CT which was performed due to clinical symptoms.

Askin's Tumor in an Adult: Case Report and Findings on 18F-FDG PET/CT

Primitive neuroectodermal tumor (PNET) of the chest wall or Askins tumor is a rare neoplasm of chest wall. It most often affects children and adolescents and is a very rare tumor in adults. In this case report, we present an Askins tumor occurred in a 73-year-old male. The patient was admitted with a history of 3-month lower back pain and cough. In computed tomography, there was a lesion with dimensions of 70 × 40 × 65 mm in the superior segment of the lower lobe of the left lung. Positron emission tomography/computed tomography with 18F-flourodeoxyglucose revealed a pleural-based tumor in the left lung with a maximum standardized uptake value of 4.36. No distant or lymph node metastases were present. The patient had gone through surgery, and wedge resection of the superior segment of left lobe and partial resection of the ipsilateral ribs were performed. Pathology report with immunocytochemistry was consistent with PNET and the patient received chemotherapy after that.

Differential diagnosis between secondary and tertiary hyperparathyroidism in a case of a giant-cell and brown tumor containing mass. Findings by 99m Tc-MDP, 18 F-FDG PET/CT and 99m Tc-MIBI scans

Brown tumor is one of the skeletal manifestations of hyperparathyroidism. It is a benign but locally aggressive bone lesion and its differential diagnosis with giant cell containing skeletal tumors or metastases may be complicated. We present a male patient with chronic renal failure who was initially misdiagnosed as having a giant-cell rich neoplasm of bone in his right thumb. Diffusely increased fluorine-18 fluorodeoxyglucose ((18)F-FDG) uptake in the axial and appendicular skeleton and multiple (18)F-FDG avid lytic lesions suggesting multiple metastases were observed on the (18)F-FDG positron emission tomography/computed tomography (PET/CT) scan. On the usual technetium-99m methylene diphosphonate ((99m)Tc-MDP) bone scan we noticed diffusely increased uptake in the skeleton and two focuses with very much increased uptake, which suggested a metabolic bone disease rather than a multiple metastatic giant cell tumor or bone metastases. Additional investigation documentated increased levels of parathyroid hormone. Parathyroid hyperplasia was finally diagnosed with (99m)Tc-methoxyisobutylisonitrile (MIBI) parathyroid scintigraphy. Fluorine-18-FDG avid lytic lesions were attributed to hyerparathyroidism associated brown tumors instead of multiple metastases. In conclusion, we present a patient with chronic renal insufficiency, who suffered from secondary and later from tertiary HPT with polyostotic brown tumors, which were best shown by the (18)F-FDG PET/CT than by the (99m)Tc-MDP or the (99m)Tc-MIBI scans.

The value of FDG-PET/CT in the post-treatment evaluation of endometrial carcinoma: A comparison of PET/CT findings with conventional imaging and CA 125 as a tumour marker

OBJECTIVES This retrospective study was designed to assess the value of positron emission tomography/computed tomography imaging (PET/CT) in the post-treatment evaluation of the patients with endometrial carcinoma and to compare PET/CT scan with conventional imaging (CI) including computed tomography (CT), ultrasonography (US) and magnetic resonance imaging (MRI) and CA 125 with both 20U/ml and 35U/ml cut-off values. MATERIALS AND METHODS A total of 31 patients who were treated for histopathologically proven endometrial adenocarcinoma, underwent PET/CT examination for restaging and suspected recurrence. Thirty five PET/CT studies were performed in 31 patients. Lesion status was determined on the basis of clinical follow-up including radiological imaging (follow-up CT scan) at least 6 months and response to therapy. RESULTS Of the 35 PET/CT studies, 13 (37%) studies were positive, whereas 22 (63%) of them were negative. On study-based analysis the overall sensitivity, specificity, accuracy for PET/CT imaging were 100%, 96% and 97%, respectively. The corresponding information for CI were 46%, 87% and 74%, for CA 125 (cut off=20U/ml) measurement were 45%, 88% and 74%, and for CA 125 (cut off=35U/ml) measurement were 27%, 100% and 78%, respectively. On lesion-based analysis, PET/CT revealed only one false positive case. In none of 21 patients with negative 22 PET/CT studies, no subsequent clinical or radiological recurrences were observed with a follow-up of at least 6 months. CONCLUSION FDG-PET/CT is found more useful modality than CI and CA 125 in the evaluation of post-treatment endometrial carcinoma patients, for suspected recurrence.

Undescended Testis in Inguinal Canal Detected Incidentally on Fluorodeoxyglucose PET/CT Imaging

The differential diagnosis at the inguinal region is very important for hypermetabolic foci because of the possibility of metastasis at this level in cancer patients ongoing PET imaging for detection of metastases. It is important to distinguish this activity from other possible malignant and benign conditions such as lymph node activity, testicular cancer, metastatic disease activity, inflammation and urine skin contamination artefact. A 66-year-old male patient with operated colon cancer and liver metastasis was referred for PET/CT examination for re-staging because of suspicious metastases. Findings of PET/CT imaging with undescended testis detected incidentally was presented.

Epitrochlear and axillary lymph node visualization on FDG-PET/CT imaging in a patient with rheumatoid arthritis.

An 38 year-old female with oral tongue cancer was referred for FDG-PET/CT scan for evaluating axillary lymph nodes and restaging malignancy. Bilateral uptake of axillary and epitrochlear lymph nodes were observed on PET/CT imaging. The uptake pattern was unexpected for the patient with this malignancy and she had a history of rheumatoid arthritis. Additionally, the wrists were included in the field of view and showed elevated FDG uptake. In this case report, we report benign axillary and epitrochlear tracer uptake on FDG-PET/CT scan in a patient with a history of rheumatoid arthritis.

Fluorodeoxyglucose positron emission tomography/computed tomography findings in a patient with cerebellar mutism after operation in posterior fossa

Cerebellar mutism is a transient period of speechlessness that evolves after posterior fossa surgery in children. Although direct cerebellar and brain stem injury and supratentorial dysfunction have been implicated in the mediation of mutism, the pathophysiological mechanisms involved in the evolution of this kind of mutism remain unclear. Magnetic resonance imaging revealed dentatothalamocortical tract injuries and single photon emission computed tomography showed cerebellar and cerebral hypoperfusion in patients with cerebellar mutism. However, findings with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in this group of patients have not been documented previously. In this clinical case, we report a patient who experienced cerebellar mutism after undergoing a posterior fossa surgery. Right cerebellar and left frontal lobe hypometabolism was shown using FDG PET/CT. The FDG metabolism of both the cerebellum and the frontal lobe returned to normal levels after the resolution of the mutism symptoms.

Fibrous dysplasia mimicking vertebral bone metastasis on 18F-FDG PET/computed tomography in a patient with tongue cancer.

A 50-year-old man presented to our hospital with complaints of back pain. He had been following with the diagnosis of tongue cancer for 2 years. The physical examination and laboratory findings were normal. Bone scintigraphy was done to rule out bone metastasis. Bone scintigraphy showed focally increased radiotracer uptake in the fifth thoracal vertebrae and right sixth rib, suspicious for metastasis. 18F-FDG PET-computed tomography was done for metastasis to other organs. On PET images, hypermetabolicfocuswasseenintheregionsdetectedonbonescintigraphy(Figs.1and2).Percutaneoustrucutbiopsywasperformed for the accurate diagnosis, and the diagnosis of fibrous dysplasia (FD) was made after a pathologic examination. Fibrous dysplasia is a benign and slowly progressive disorder in which normal bone is replaced by abnormal fibroosseous tissue [1]. The ribs, femur, tibia, calvarium, long bones, spine, and pelvis are the most frequently involved sites in FD [2]. Patients are often asymptomatic and the disease is detected incidentally on radiologic and scintigraphic examinations made for other reasons. Benign and malign bone conditions can show increased 18F-FDG uptake on PET-computed tomography, and increased FDG uptake may mimic bone metastasis of primary malignancy in cancer patients with FD [2,3]. Bone lesions should be carefully evaluated in patients with known malignancies, and FD should be given as a differential diagnosis.

Chronic myeloid leukemia detected on FDG PET/CT imaging in a patient with renal cell carcinoma

It is well known that hematopoietic cytokine stimulation can cause increased fluorodeoxyglucose (FDG) accumulation in bone marrow on PET/CT imaging, which simulates that seen in patients with bone marrow metastases. However, increased bone marrow FDG uptake can be caused by other etiologies. We report a patient with operated renal cell carcinoma had no history of hematopoietic cytokine stimulation. The FDG PET/CT images showed increased bone marrow FDG uptake, and the patient was diagnosed as chronic myeloid leukemia. This case revealed that increased FDG uptake on bone marrow may be related to neoplastic disease of the hematopoietic tissues.