[PET/CT imaging manifestations of different pathological subtypes of liposarcoma].

OBJECTIVE: To analyze PET/CT imaging manifestations of different pathological subtypes of liposarcoma. METHODS: The 18F-fluorodeoxyglucose(FDG) PET/CT features of 13 patients pathologically confirmed as liposarcoma were retrospectively reviewed. The metabolism degree and distribution of different subtypes of liposarcoma were compared. RESULTS: The well-differentiated liposarcoma showed fat density mass with septa and irregular strip with mild FDG uptake. The myxoid liposarcoma showed cystic or cystic solid mass, single or multiple with mild-moderate FDG uptake heterogeneously or homogeneously. The dedifferentiated liposarcoma showed mixed soft tissue mass with high FDG uptake heterogeneously, larger lesion with necrosis centrally. The mixed type contained well differentiated type and dedifferentiated type, and showed multiple lesion with combined imaging manifestations. There were local invasions in 12 cases, no lymph node matastasis, and the recurrence of dedifferentiated liposarcoma with lung metastasis in 1 case. The maximum standard values (SUVmax) of FNCCLE grade G1, G2 and G3 liposarcoma were 3.00, 5.67 and 10.33, respectively; there was significant difference between G1 and G3 groups, G2 and G3 groups (all P<0.05). CONCLUSIONS: PET/CT manifestations of liposarcoma of various pathological subtypes are different. Preoperative PET/CT examination can clarify the pathological types, scope of tumor invasion and metastasis of liposarcoma, which provides more information for clinical decision-making and is helpful for the preparation of surgical plan.

18F-FDG PET/CT in the Detection of Undifferentiated Carcinoma With Osteoclast-like Giant Cells of the Pancreas.

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas (UCOGCP) is a rare nonendocrine pancreatic tumor. We present a case of a very small UCOGCP. F-FDG PET/CT revealed a solid mass measuring 1.0 × 0.8 cm on CT images with an SUVmax of 5.0 in the body of the pancreas. CT revealed a solid mass with significant enhancement. The histopathologic and immunohistochemical studies confirmed the diagnosis. Our findings indicate F-FDG PET/CT is a useful imaging modality for UCOGCP diagnosis.

[Value of 18F-FDG PET-CT in detection of primary lesion and pelvic lymph node metastasis in FIGO stages â A2-â ¡A cervical cancer].

OBJECTIVE: To assess the value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography-CT (PET-CT) in detection of primary tumor and pelvic lymph node metastasis in International Federation of Gynecology and Obstetrics (FIGO) stages ⅠA2-ⅡA cervical cancer. METHODS: The clinical data of 91 patients with FIGO stagesⅠA2-ⅡA cervical cancer were retrospectively analyzed. The sensitivity of 18F-FDG PET-CT in detection of cervical cancer was calculated. The long diameter, short diameter and SUVmax were compared between metastatic lymph nodes (MLN) and non-metastatic lymph nodes (NMLN). The optimal cut-off values of different indexes were determined by receiver operating characteristic (ROC) curve and area under curve (AUC), and the sensitivity, specificity and accuracy were calculated. RESULTS: 18F-FDG PET-CT examinations were positive in 89 patients (89/91, 96.7%). The short diameters of NMLN and MLN were (6.50±2.31)mm and (4.21±1.49)mm(t=4.855, P<0.05); the SUVmax of NMLN and MLN were 4.56±3.34 and 1.92±1.41(t=31.685, P<0.05). ROC AUCs of the short diameter and SUVmax in diagnosis of metastatic lymph nodes were 0.802 and 0.861. Taken short diameter ≥ 5.05 mm and SUVmax ≥ 2.05 as cut-off values, the corresponding sensitivity, specificity and accuracy in diagnosis of metastatic lymph nodes were 85.0%, 93.0% and 86.8%, respectively. CONCLUSIONS: 18F-FDG PET-CT is sensitive to detect primary lesion and pelvic lymph node metastases in FIGO stages ⅠA2-Ⅱ A cervical cancer, and the highest diagnostic accuracy may be obtained by taking short diameter ≥ 5.05 mm and SUVmax ≥ 2.05 as the standard.