Diagnostic value of 18F-FDG PET/CT in paediatric neuroblastoma: comparison with 131I-MIBG scintigraphy.

PURPOSE: The aim of the study was to evaluate the diagnostic value of fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in paediatric patients with neuroblastoma (NB) and compare the results with iodine-131 metaiodobenzylguanidine (131I-MIBG) scintigraphy. METHODS: Data on 40 paediatric patients (age, 5.5 ± 5.6 years; male, 32; female, eight) with histopathologically proven NB who underwent 18F-FDG PET/CT (staging, 21 patients; restaging/response monitoring, 19 patients) were retrospectively evaluated. I-MIBG scintigraphy data were available for 28/40 patients (median interval, 15 days; staging, 20 patients; restaging/response monitoring, eight patients). 131I-MIBG scintigraphy and 18F-FDG PET/CT images were evaluated by two nuclear medicine physicians in consensus and in separate sessions. Histopathology (n = 50 lesions) and/or clinical/imaging follow-up (n = 90 lesions) data were taken as the reference standard. RESULTS: Patient-wise sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of 18F-FDG PET/CT were 100, 50, 91.89, 100 and 92.50%, respectively. A total of 140 lesions (primary, 37; lymph node, 31; bone, 50; bone marrow, 15; and others, seven) were detected on PET/CT. In 28 patients undergoing both imaging studies, the sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of 18F-FDG PET/CT were 100, 60, 92, 100 and 92.80%, respectively, and those of 131I-MIBG were 95.65, 60, 91.67, 75 and 89.20%, respectively. In these 28 patients, PET/CT detected 107 lesions (primary, 25; lymph node, 22; bone/bone marrow, 56; and others, four) and 131I-MIBG scintigraphy detected 74 lesions (primary, 24; lymph node, five; and bone/bone marrow, 45). On a patient-based comparison there was no significant difference between 18F-FDG PET/CT and 131I-MIBG (P = 1.000), but 18F-FDG PET/CT was superior to 131I-MIBG on a lesion-based comparison (P < 0.0001). Although no difference was noted for primary lesions (P = 1.000), PET/CT was superior to 131I-MIBG scintigraphy for the detection of lymph nodal (P = 0.001) and bone/bone marrow lesions (P = 0.007). CONCLUSION: 18F-FDG PET/CT shows high accuracy in paediatric patients with NB and demonstrates more lesions as compared with 131I-MIBG scintigraphy.

Prospective evaluation of (68)Ga-DOTANOC PET-CT in differentiated thyroid cancer patients with raised thyroglobulin and negative (131)I-whole body scan: comparison with (18)F-FDG PET-CT.

PURPOSE: The purpose of the study was to evaluate the role of (68)Ga-DOTANOC PET-CT in differentiated thyroid cancer (DTC) patients with negative (131)I-whole body scan (WBS) along with serially increasing serum thyroglobulin (Tg), and compare the same with (18)F-FDG PET-CT. METHODS: Sixty two DTC patients with serially rising Tg levels and negative (131)I-WBS were prospectively enrolled. All patients underwent (68)Ga-DOTANOC PET-CT and (18)F-FDG PET-CT within an interval of two weeks. PET-CT analysis was done on a per-patient basis, location wise and lesion wise. All PET-CT lesions were divided into four categories-local, nodal, pulmonary and skeletal. Histopathology and/or serial serum Tg level, clinical and imaging follow up (minimum-1 year) were used as a reference standard. RESULTS: Ga-DOTANOC PET-CT demonstrated disease in 40/62 (65 %) patients and (18)F-FDG PET-CT in 45/62 (72 %) patients, with no significant difference on McNemar analysis (p = 0.226). Per-patient sensitivity and specificity of (68)Ga-DOTANOC PET-CT was 78.4 %, 100 %, and for (18)F-FDG PET-CT was 86.3 %, 90.9 %, respectively. Out of 186 lesions detected by both PET-CTs, 121/186 (65 %) lesions were seen on (68)Ga-DOTANOC PET-CT and 168/186 (90.3 %) lesions on (18)F-FDG PET-CT (p < 0.0001). There were 103/186 (55 %) lesions concordant on both. Excellent agreement was noted between (68)Ga-DOTANOC PET-CT and (18)F-FDG PET-CT for detection of local disease (ĸ = 0.92), while moderate agreement was noted for nodal and pulmonary disease (ĸ = 0.67). (68)Ga-DOTANOC PET-CT changed management in 21/62 (34 %) patients and (18)F-FDG PET-CT in 17/62 (27 %) patients. CONCLUSION: Ga-DOTANOC PET-CT is inferior to (18)F-FDG PET-CT on lesion based but not on patient based analysis for detection of recurrent/residual disease in DTC patients with negative WBS scan and elevated serum Tg levels. It can also help in selection of potential candidates for peptide receptor radionuclide therapy.

Isolated tuberculous splenic abscess in an immunocompetent individual.

Tuberculosis (TB) of the spleen is an extremely rare clinical entity particularly among immunocompetent persons. We report a case of isolated tuberculous abscess of spleen in a 13- years- old boy. No primary focus of infection was detected in lungs or any other organ. The patient was treated by splenectomy after a therapeutic failure with standard antituberculous medication.

Aggressive angiomyxoma of vulva and vagina: a series of three cases and review of literature.

BACKGROUND: Aggressive angiomyxoma is a rare locally aggressive mesenchymal tumor of unknown etiology usually affecting the vulva, perianal region, buttocks or pelvis of reproductive age women. MATERIAL: A series of three cases, one each of vaginal, vulval and labial angiomyxoma is being presented. The etiology, presentation, diagnosis and management of this rare genital tumor are outlined. CONCLUSION: Angiomyxoma of vulva and vagina refers to a rare disease; diagnosis is not at all clinical, thus, cases presenting as bartholin cyst, benign vulval lesions and vaginal wall cysts should have complete radiological work up before excision, as pre-diagnosis can change the treatment modality and prognosis of patient.