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A 62-year-old woman was referred for cough and lower abdominal pain. 18F-FDG PET/CT showed strong uptake not only in the left lung mass and hilar and mediastinal lymph nodes, but also a huge lower abdominal mass. All lesions were initially thought to be multiple metastases because bronchial biopsy of the lung mass showed poorly differentiated adenocarcinoma. However, the abdominal mass was found to be malignant peritoneal mesothelioma after surgical resection. It was difficult to diagnose this case correctly before resection because localized malignant peritoneal mesothelioma is rare.

Background The value of 18F-fluorodeoxyglucose positron emission tomography integrated with computed tomography (FDG-PET/CT) in diagnosis and monitoring of multiple myeloma (MM) has been demonstrated predominantly in younger patients who are eligible for autologous stem cell transplantation. However, a majority of the MM patients are known to be transplant ineligible because of advanced age, comorbidity and/or frailness. Therefore, to evaluate the diagnostic and prognostic value of FDG- PET/CT in such patients is expected to contribute the physicians to design the more adequate personalized therapies. Patients and Method We reviewed the medical records of previously untreated symptomatic MM patients who were diagnosed at Osaka Saiseikai Nakatsu Hospital between February 2008 and June 2013. In this retrospective study, transplant ineligible patients who received FDG-PET/CT examination prior to the initial treatment were evaluated. A total of 48 patients (17 males and 31 females, median age of 71 years (range 47-91) were evaluable. IgG, IgA, BJP and non-secretory types were 35 (73%), 10 (21%), 1 (2%), and 2 (4%), respectively. The ISS stage 1, 2 and 3 comprised 15 (31%), 17 (35%) and 16 (33%), respectively. Closely after the FDG-PET/CT, all patients underwent the treatment including novel agents (bortezomib or lenalidomide). The results from FDG-PET/CT were evaluated and categorized by a team of experienced radiologists into three groups just according to the criteria proposed by Zamangni et.al. (Blood 2011;118:5989-5995): focal lesion (FL), diffuse lesion (DL), and extramedullary disease (EMD). And standard uptake value maximum (SUV max) was recorded. Imaging valuables of FDG-PET/CT were analyzed for association with other baseline parameters including types of serum or urinary M protein, serum levels of albumin (Alb), beta-2-microglobulin (B2M), C-reactive protein (CRP), lactate dehydrogenase (LDH), and CD19, 20 and 56 expressions in CD138 positive plasma cells in bone marrow. Furthermore, valuable combination of these parameters in predicting a clinical outcome of the patients was screened. A Kruskal-Wallis or Mann-Whitney U test was used to compare imaging variables in relation to baseline parameters. Kaplan-Meier analysis was used to estimate overall survival (OS). Univariate and multivariate analyses of prognostic factors were carried out using logistic regression. Results Of the 48 patients, 17% of the patients had a negative PET/CT scan before the treatments, 24% had 1 to 3 FLs, 59% had either DL or more than 3 FLs, and 9% had EMD. The serum levels of CRP, LDH, B2M, and Alb were 1.9 mg/L, 174 IU/L, 3.8 mg/L, and 37 g/L, respectively. A median SUV max was 3.7 in the all patients. As shown in Table 1, a median serum B2M level was significantly higher in patients with >3 FLs and/or DLs compared with 1-3 FLs (p=.014). A median SUV max significantly higher in patients with >3 FLs and/or DLs or EMD (p=.001). In addition, SUV max was significantly higher in patient with CD56-low, compared with CD56-high myeloma cells (8.0 vs. 3.3 p=.017). In a median follow up period of 20 months (range 2-67), 45, 10 and 45% of the patients received the treatments with lenalidommide, bortezomib and both, respectively. Estimated median OS of the all patients was 40 months (range 33-48). The ISS staging at the baseline did not significantly affect the OS. On univariate analysis, low serum Alb (Alb <35g/L) and high SUV max (SUV max>3.7) were unfavorable prognostic factors (p=.042 and p=.062, respectively). On multivariate analysis, the results from FDG-PET/CT did not significantly correlated with the OS. Interestingly, however, the OS for patients satisfying with both low Alb and high SUV max was significantly shorter than those with the other patients. (median 19 month vs. 45 month p=.029) (Figure1). Conclusion This study demonstrated that FDG-PET/CT at baseline can exactly evaluate tumor spread and variability. Furthermore, FDG-PET/CT in combination with other parameter was expected to provide additional information on making treatment strategy in transplant-ineligible MM patients receiving novel agents. Disclosures: No relevant conflicts of interest to declare.

28% were treated with a cytarabine-based induction regimen. Overall, 61% of pts received EAR and 39% received G-CSF based mobilization. 52% of pts received BEC (carmustine, etoposide, cyclophosphamide) and 45% BEAM (carmustine, etoposide, cytarabine, melphalan) conditioning. 34% of pts received 2 weekly doses of rituximab consolidation, 12% received maintenance rituximab, 19% maintenance rituximab and bortezomib (on clinical study), and 35% received no post-transplant therapy. 5-year PFS for the entire population was 57%. According to MIPI score, the 5-year PFS was 28% for those with a high MIPI score (6.2), 63% for intermediate (5.7-6.2), and 73% for low MIPI scores (<5.7). On univariate analysis, male gender (HR 2.89, 95% CI 1.31-6.39) and a high MIPI score (HR 3.6; 95% CI 1.51-8.57) were associated with an inferior PFS. There was no significant association between age at transplant (<60 vs. 60), or the various induction, mobilization, conditioning, or maintenance therapy strategies and PFS. On multivariate analysis, a high MIPI score (HR 4.51; 95% CI 1.51-13.48) and male gender (HR 4.98; 95% CI 1.48-16.73) were associated with an inferior PFS. Conclusions: Our single-center experience demonstrates that induction chemotherapy and ASCT provides significantly longer PFS in pts with low and intermediate MIPI scores. Age was not an independent predictor of PFS, and age 60 should not preclude the use of ASCT in MCL. Our data suggests that novel treatment strategies should be explored in the subset of pts with high MIPI scores.