68Ga-DOTATOC PET/MR imaging and radiomic parameters in predicting histopathological prognostic factors in patients with pancreatic neuroendocrine well-differentiated tumours.

PURPOSE: To explore the role of fully hybrid 68Ga-DOTATOC PET/MR imaging and radiomic parameters in predicting histopathological prognostic factors in patients with pancreatic neuroendocrine tumours (PanNETs) undergoing surgery. METHODS: One hundred eighty-seven consecutive 68Ga-DOTATOC PET/MRI scans (March 2018-June 2020) performed for gastroenteropancreatic neuroendocrine tumour were retrospectively evaluated; 16/187 patients met the eligibility criteria (68Ga-DOTATOC PET/MRI for preoperative staging of PanNET and availability of histological data). PET/MR scans were qualitatively and quantitatively interpreted, and the following imaging parameters were derived: PET-derived SUVmax, SUVmean, somatostatin receptor density (SRD), total lesion somatostatin receptor density (TLSRD), and MRI-derived apparent diffusion coefficient (ADC), arterial and late enhancement, necrosis, cystic degeneration, and maximum diameter. Additionally, first-, second-, and higher-order radiomic parameters were extracted from both PET and MRI scans. Correlations with several PanNETs' histopathological prognostic factors were evaluated using Spearman's coefficient, while the area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to evaluate parameters' predictive performance. RESULTS: Primary tumour was detected in all 16 patients (15/16 by 68Ga-DOTATOC PET and 16/16 by MRI). SUVmax and SUVmean resulted good predictors of lymphnodal (LN) involvement (AUC of 0.850 and 0.783, respectively). Second-order radiomic parameters GrayLevelVariance and HighGrayLevelZoneEmphasis extracted from T2 MRI demonstrated significant correlations with LN involvement (adjusted p = 0.009), also showing good predictive performance (AUC = 0.992). CONCLUSION: This study demonstrates the role of the fully hybrid PET/MRI tool for the synergic function of imaging parameters extracted by the two modalities and highlights the potentiality of imaging and radiomic parameters in assessing histopathological features of PanNET aggressiveness.

Radiomics in pancreatic neuroendocrine tumors: methodological issues and clinical significance.

PURPOSE: To present the state-of-art of radiomics in the context of pancreatic neuroendocrine tumors (PanNETs), with a focus on the methodological and technical approaches used, to support the search of guidelines for optimal applications. Furthermore, an up-to-date overview of the current clinical applications of radiomics in the field of PanNETs is provided. METHODS: Original articles were searched on PubMed and Science Direct with specific keywords. Evaluations of the selected studies have been focused mainly on (i) the general radiomic workflow and the assessment of radiomic features robustness/reproducibility, as well as on the major clinical applications and investigations accomplished so far with radiomics in the field of PanNETs: (ii) grade prediction, (iii) differential diagnosis from other neoplasms, (iv) assessment of tumor behavior and aggressiveness, and (v) treatment response prediction. RESULTS: Thirty-one articles involving PanNETs radiomic-related objectives were selected. In regard to the grade differentiation task, yielded AUCs are currently in the range of 0.7-0.9. For differential diagnosis, the majority of studies are still focused on the preliminary identification of discriminative radiomic features. Limited information is known on the prediction of tumors aggressiveness and of treatment response. CONCLUSIONS: Radiomics is recently expanding in the setting of PanNETs. From the analysis of the published data, it is emerging how, prior to clinical application, further validations are necessary and methodological implementations require optimization. Nevertheless, this new discipline might have the potential in assisting the current urgent need of improving the management strategies in PanNETs patients.

Función pronóstica de los parámetros derivados de FDG PET en la estadificación preoperatoria del cáncer de endometrio / Prognostic role of FDG PET-derived parameters in preoperative staging of endometrial cancer

Objetivo: Investigar el papel pronóstico preoperatorio de la PET/TC con 18F-FDG en pacientes con carcinoma de endometrio (CE). Material y métodos: Se realizó PET/TC con 18F-FDG en 57 pacientes para el estudio preoperatorio del CE. Se evaluaron los valores de captación estandarizados máximos y medios (SUVmax, media), volumen tumoral metabólico (MTV) y glicólisis de lesión total (TLG) de tumores primarios, a diferentes umbrales de 40%, 50%, 60% (40-50-60), comparándose con las características anatomopatológicas. Se evaluó el rendimiento diagnóstico de los parámetros PET (categorizados por análisis ROC) en la discriminación de la enfermedad de bajo y mediano riesgo y el papel pronóstico en la supervivencia (supervivencia global-OS, supervivencia libre de enfermedad-SSE). Resultados: Los TLG40-50-60 categorizados fueron los únicos parámetros relacionados con FIGO estadio I versus II-III-IV (p = 0,0035 para todos). Los puntos de corte para la estratificación del riesgo fueron 83,69, 61,81 y 41,32, respectivamente (sensibilidad: 60%; especificidad, 71,43% para todos los parámetros. El estadio patológico 1 (pT1) del tumor primario se predijo con MTV60 y TLG40-50 (p = 0,0328, 0,0240 y 0,0147, respectivamente). Los umbrales óptimos fueron 7,795, 99,55 y 77,58, respectivamente (sensibilidad: 38,46%, 53,85% y 53,85%, respectivamente; especificidad: 88,64%, 79,55% y 81,82%, respectivamente). SUVmax y SUVmean40-50-60 fueron los únicos parámetros que discriminaron el subtipo endometrioide del no endometrioide. La sensibilidad fue del 64,86% y 62,16% para SUVmax y SUVmean50-60, y 62,16% para SUVmean40; la especificidad fue del 70% para todos los parámetros. La SG media (DE) fue del 79,77% (3,34%) y la SSE media fue del 77,89% (3,73%). El tipo de tumor fue la única variable significativamente asociada a la SG (p = 0,0486). TLG50 > 77,58 cm3 fue la única variable asociada a un mayor riesgo de recaída (p = 0,0472). Conclusión: TLG40-50-60 y MTV60 de EC primaria tienen valor pronóstico para discriminar FIGO y estadificación patológica. Estos resultados sugieren un posible papel de estos parámetros en la predicción de la agresividad de la CE, mejorando así la caracterización preoperatoria del cáncer de endometrio

Purpose: To investigate the preoperative prognostic role of 18F-FDG PET/CT in patients with endometrial carcinoma (EC). Methods: 18F-FDG PET/CT was performed in 57 patients for EC preoperative staging. Maximum and mean standardized uptake values (SUVmax, mean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary tumors, at different thresholds of 40%, 50%, 60% (40-50-60), were evaluated and compared with anatomopathological features. The diagnostic performance of PET-parameters (categorized by ROC analysis) in discriminating low-intermediate and high-risk disease and the prognostic role on survival (overall survival -OS; disease free survival - DFS) was evaluated. Results: The categorized TLG40-50-60 were the only parameters related to FIGO stage I versus II-III-IV (p = 0.0035 for all). The cut-off values for risk stratification were 83.69, 61.81 and 41.32, respectively (sensitivity: 60.00%; specificity; 71.43% for all parameters). Pathological stage 1 (pT1) of the primary tumor was predicted by MTV60 and TLG40-50 (p = 0.0328, 0.0240, 0.0147, respectively). The optimal thresholds were 7.795, 99.55 and 77.58, respectively (sensitivity: 38.46%, 53.85% and 53.85%, respectively; specificity: 88.64%, 79.55% and 81.82%, respectively). SUVmax and SUVmean40-50-60 were the only parameters discriminating endometrioid from non-endometrioid subtype. The corresponding sensitivity was 64.86% and 62.16% for SUVmax and SUVmean 50-60 and 62.16% for SUVmean40; specificity was 70.00% for all parameters. The mean (SD) OS was 79.77% (3.34%) and the mean DFS was 77.89% (3.73%). The tumor type was the only variable significantly associated with OS (p = 0.0486). TLG50 > 77.58 cm3 was the only variable associated with a higher risk of relapse (p = 0.0472). Conclusion: TLG40-50-60 and MTV60 of primary EC have prognostic value in discriminating FIGO and pathological staging. These results suggest a possible role of these parameters in predicting EC aggressiveness, thus improving the preoperative characterization of endometrial cancer

Prognostic role of FDG PET-derived parameters in preoperative staging of endometrial cancer. / Función pronóstica de los parámetros derivados de FDG PET en la estadificación preoperatoria del cáncer de endometrio.

PURPOSE: To investigate the preoperative prognostic role of 18F-FDG PET/CT in patients with endometrial carcinoma (EC). METHODS: 18F-FDG PET/CT was performed in 57 patients for EC preoperative staging. Maximum and mean standardized uptake values (SUVmax, mean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary tumors, at different thresholds of 40%, 50%, 60% (40-50-60), were evaluated and compared with anatomopathological features. The diagnostic performance of PET-parameters (categorized by ROC analysis) in discriminating low-intermediate and high-risk disease and the prognostic role on survival (overall survival -OS; disease free survival - DFS) was evaluated. RESULTS: The categorized TLG40-50-60 were the only parameters related to FIGO stage I versus II-III-IV (p = 0.0035 for all). The cut-off values for risk stratification were 83.69, 61.81 and 41.32, respectively (sensitivity: 60.00%; specificity; 71.43% for all parameters). Pathological stage 1 (pT1) of the primary tumor was predicted by MTV60 and TLG40-50 (p = 0.0328, 0.0240, 0.0147, respectively). The optimal thresholds were 7.795, 99.55 and 77.58, respectively (sensitivity: 38.46%, 53.85% and 53.85%, respectively; specificity: 88.64%, 79.55% and 81.82%, respectively). SUVmax and SUVmean40-50-60 were the only parameters discriminating endometrioid from non-endometrioid subtype. The corresponding sensitivity was 64.86% and 62.16% for SUVmax and SUVmean 50-60 and 62.16% for SUVmean40; specificity was 70.00% for all parameters. The mean (SD) OS was 79.77% (3.34%) and the mean DFS was 77.89% (3.73%). The tumor type was the only variable significantly associated with OS (p = 0.0486). TLG50 > 77.58 cm3 was the only variable associated with a higher risk of relapse (p = 0.0472). CONCLUSION: TLG40-50-60 and MTV60 of primary EC have prognostic value in discriminating FIGO and pathological staging. These results suggest a possible role of these parameters in predicting EC aggressiveness, thus improving the preoperative characterization of endometrial cancer.

FDG PET-derived parameters as prognostic tool in progressive malignant pleural mesothelioma treated patients.

PURPOSE: The value of FDG PET-derived parameters in predicting overall survival (OS), local relapse-free survival (LRFS) and distant relapse-free survival (DRFS) in treated patients with malignant pleural mesothelioma (MPM) was evaluated. METHODS: This retrospective evaluation included 55 MPM patients treated between March 2006 and February 2015 with FDG PET/CT-guided salvage helical tomotherapy (HTT) after previous surgery plus chemotherapy. Univariate Cox regression analysis was performed to assess the impact of the following FDG PET-derived parameters: biological target volume (BTV), mean and maximum standardized uptake values (SUVmean/max), metabolic tumour volume (MTV) and total lesion glycolysis (TLG), measured using different uptake thresholds (40%, 50% and 60%). Logistic regression was then performed to identify the best FDG PET-derived parameters for selecting patients with poorer survival. RESULTS: The median OS was 9.1 months (range 0.0 - 69.6 months) after the end of HTT; 54/55 patients were dead at the last follow-up. BTV and TLG40, TLG50 and TLG60 were the most significant predictors of OS (p < 0.005). The median OS was 4.8 months in patients with MTV60 >5 cm3 and TLG40 >334.4, compared with 13.8 months and 16.1 months in patients with smaller values, respectively. The median LRFS and DRFS were 6.2 months (range 1.2 - 39.4 months) and 6.5 months (0.0 - 66.4 months), respectively. TLG40, TLG50 and TLG60 were significantly correlated with LRFS (p < 0.015). Median DRFS was 6.4 months in patients with MTV40 >39.6 cm3 and 6.2 months in patients with TLG40 >334.4, compared with 17 months and 18.8 months in patients with smaller values. BTV, TLG40 and MTV40 were also found to be good predictors in patients with poor OS/LRFS/DRFS (median survival times less than the median values). CONCLUSION: FDG PET-derived parameters effectively discriminated patients with a poor prognosis and may be helpful in the selection of MPM patients for salvage HTT.

Evaluation of 18F-fluorothymidine positron emission tomography ([18F]FLT-PET/CT) methodology in assessing early response to chemotherapy in patients with gastro-oesophageal cancer.

BACKGROUND: 3'-Deoxy-3'-[18F]fluorothymidine ([18F]FLT) PET has limited utility in abdominal imaging due to high physiological hepatic uptake of a tracer. We evaluated [18F]FLT-PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (KSF) to improve tumour visualisation in patients with locally advanced and metastatic gastro-oesophageal cancer and as a marker of early response to chemotherapy. Dynamic [18F]FLT-PET/CT data were collected before and 3 weeks post first cycle of chemotherapy. Changes in tumour [18F]FLT-PET/CT variables were determined. Response was determined on contrast-enhanced CT after three cycles of therapy using RECIST 1.1. RESULTS: Ten patients were included. Following application of the KSF, visual distinction of all oesophageal and/or gastric tumours was observed in [18F]FLT-PET images. Among the nine patients available for response evaluation (RECIST 1.1), three patients had responded (partial response) and six patients were non-responders (stable disease). There was a significant association between Ki-67 and all baseline [18F]FLT-PET parameters. Area under the curve (AUC) from 0 to 1 min was associated with treatment response. CONCLUSIONS: The results of this study indicate that application of the KSF allowed accurate visualisation of both primary and metastatic lesions following imaging with the proliferation marker, [18F]FLT-PET/CT. However, [18F]FLT-PET uptake parameters did not correlate with response. Instead, we observe significant changes in tracer delivery following chemotherapy suggesting that further [18F]FLT-PET/CT studies in this tumour type should be undertaken with caution.

PET guidance in prostate cancer radiotherapy: Quantitative imaging to predict response and guide treatment.

Positron emission tomography (PET) allows a monitoring and recording of the spatial and temporal distribution of molecular/cellular processes for diagnostic and therapeutic applications. The aim of this review is to describe the current applications and to explore the role of PET in prostate cancer management, mainly in the radiation therapy (RT) scenario. The state-of-the art of PET for prostate cancer will be presented together with the impact of new specific PET tracers and technological developments aiming at obtaining better imaging quality, increased tumor detectability and more accurate volume delineation. An increased number of studies have been focusing on PET quantification methods as predictive biomarkers capable of guiding individualized treatment and improving patient outcome; the sophisticated advanced intensity modulated and imaged guided radiation therapy techniques (IMRT/IGRT) are capable of boosting more radioresistant tumor (sub)volumes. The use of advanced feature analyses of PET images is an approach that holds great promise with regard to several oncological diseases, but needs further validation in managing prostate diseases.

Imaging biomarkers in prostate cancer: role of PET/CT and MRI.

Prostate-specific antigen (PSA) is currently the most widely used biomarker of prostate cancer (PCa). PSA suggests the presence of primary tumour and disease relapse after treatment, but it is not able to provide a clear distinction between locoregional and distant disease. Molecular and functional imaging, that are able to provide a detailed and comprehensive overview of PCa extension, are more reliable tools for primary tumour detection and disease extension assessment both in staging and restaging. In the present review we evaluate the role of PET/CT and MRI in the diagnosis, staging and restaging of PCa, and the use of these imaging modalities in prognosis, treatment planning and response assessment. Innovative imaging strategies including new radiotracers and hybrid scanners such as PET/MRI are also discussed.

Epigenetic changes in gastroenteropancreatic neuroendocrine tumours.

An understanding of epigenetic drivers of tumorigenesis has developed rapidly during the last years. The identification of these changes including DNA methylation and histone modifications in gastroenteropancreatic neuroendocrine tumours (GEP-NETs) is a step forward in trying to define underlying biologic processes in this heterogeneous disease. The reversible nature of these changes represents a potential therapeutic target. We present an overview of the current knowledge of epigenetic alterations related to GEP-NETs, focusing on the influence and impact these changes have on pathogenesis and prognosis. The potential role of demethylating agents in the management of this patient population is discussed.

Predictive value of pre-therapy (18)F-FDG PET/CT for the outcome of (18)F-FDG PET-guided radiotherapy in patients with head and neck cancer.

PURPOSE: The aim of this study was to evaluate the predictive role of pre-therapy fluorodeoxyglucose (FDG) uptake parameters of primary tumour in head and neck cancer (HNC) patients undergoing intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) on FDG-positive volume-positron emission tomography (PET) gross tumour volume (PET-GTV). METHODS: This retrospective study included 19 patients (15 men and 4 women, mean age 59.2 years, range 23-81 years) diagnosed with HNC between 2005 and 2011. Of 19 patients, 15 (79 %) had stage III-IV. All patients underwent FDG PET/CT before treatment. Metabolic indexes of primary tumour, including metabolic tumour volume (MTV), maximum and mean standardized uptake value (SUVmax, SUVmean) and total lesion glycolysis (TLG) were considered. Partial volume effect correction (PVC) was performed for SUVmean and TLG estimation. Correlations between PET/CT parameters and 2-year disease-free survival (DFS), local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were assessed. Median patient follow-up was 19.2 months (range 4-24 months). RESULTS: MTV, TLG and PVC-TLG predicting patients' outcome with respect to all the considered local and distant disease control endpoints (LRFS, DMFS and DFS) were 32.4 cc, 469.8 g and 547.3 g, respectively. SUVmean and PVC-SUVmean cut-off values predictive of LRFS and DFS were 10.8 and 13.3, respectively. PVC was able to compensate errors up to 25 % in the primary HNC tumour uptake. Moreover, PVC enhanced the statistical significance of the results. CONCLUSION: FDG PET/CT uptake parameters are predictors of patients' outcome and can potentially identify patients with higher risk of treatment failure that could benefit from more aggressive approaches. Application of PVC is recommended for accurate measurement of PET parameters.

Sarcoidosis imitando metástasis de cáncer ginecológico: ¿un reto diagnóstico y terapéutico? / Sarcoidosis mimicking metastatic gynaecological malignancies: a diagnostic and therapeutic challenge?

Se han publicado casos clínicos que describen la asociación entre el cáncer y la sarcoidosis; por esta razón, la sarcoidosis siempre debe ser incluída en el diagnóstico diferencial cuando un paciente con cáncer presenta linfadenopatía. La tomografía de emisión de positrones (PET) con 2-[18F]-fluoro-2-desoxi- d -glucosa (FDG) combinada con la tomografía computarizada (TC) se utiliza ampliamente para la estadificación y la vigilancia del cáncer, ya que permite la localización de tejido maligno metabólicamente activo; los resultados de la PET/TC o TC en pacientes con sospecha de recurrencia de cáncer se pueden utilizar para guiar un tratamiento temprano y agresivo. Sin embargo, una adenopatía hipermetabólica benigna puede ser similar a una adenopatía maligna tanto en la TC como en la PET/TC por lo que es importante disponer de un diagnóstico histológico antes de iniciar una terapia antineoplásica basada en las imágenes. En este estudio se presentan cuatro pacientes con tumores ginecológicos malignos y sarcoidosis y se menciona la importancia clínica del diagnóstico diferencial entre recidiva tumoral y enfermedad granulomatosa(AU)

Several case reports describing the coexistence of sarcoidosis and malignancy have been published. Therefore, sarcoidosis should always be considered as a differential diagnosis when a cancer patient develops lymphadenopathy. Positron-emission tomography (PET) 2-[18F]-fluoro-2-deoxy- d -glucose (FDG) combined with computed tomography (CT) is widely used for cancer staging and surveillance because it permits localization of metabolically active malignant tissue. PET/CT or CT findings in patients with suspected cancer recurrence can be used to guide early and aggressive therapy. However, benign hypermetabolic lymphadenopathy can mimic malignant lymphadenopathy, both on a conventional CT scan and on PET/CT. Thus, it is important to obtain a histological diagnosis before initiating antineoplastic therapy based on imaging findings. Four cases of patients affected by gynaecological malignancies and coexisting sarcoidosis are reported in this study. Furthermore, the clinical relevance of making a differential diagnosis between gynaecological cancer recurrence and granulomatous disorder is given specific mention(AU)

Role of 18F-FDG PET in the management of gestational trophoblastic neoplasia.

PURPOSE: Gestational trophoblastic neoplasia (GTN) is a rare and aggressive tumour that is usually sensitive to chemotherapy. The usefulness of conventional imaging modalities in evaluating treatment response is limited, mainly due to the difficulty in differentiating between residual tumour tissue and necrosis. The aim of the present study was to evaluate the role of FDG PET or PET/CT in primary staging and in monitoring treatment efficacy. The effect of FDG PET and combined PET/CT on the management of patients with GTN was also evaluated comparing the differences between standard treatments based on conventional imaging and alternative treatments based on PET. METHODS: This retrospective study included 41 patients with GTN referred to San Raffaele Hospital between 2002 and 2010. All patients were studied by either PET or PET/CT in addition to conventional imaging. Of the 41 patients, 38 were evaluated for primary staging of GTN and 3 patients for chemotherapy resistance after first-line chemotherapy performed in other Institutions. To validate the PET data, PET and PET/CT findings were compared with those from conventional imaging, including transvaginal ultrasonography (TV-US) in those with uterine disease, CT and chest plain radiography in those with lung disease and whole-body CT in those with systemic metastases. Conventional imaging was considered positive for the presence of uterine disease and/or metastases when abnormal findings relating to GTN were reported. PET and PET/CT were considered concordant with conventional imaging when metabolic active disease was detected at the sites corresponding to the pathological findings on conventional imaging. In addition, in 12 of the 41 patients showing extrauterine disease, FDG PET/CT was repeated to monitor treatment efficacy, in 8 after normalization of beta human chorionic gonadotropin (ßHCG) and in 4 with ßHCG resistance. In some patients, PET or PET/CT findings led to an alternative nonconventional treatment, and this was considered a change in patient management for the study analysis. RESULTS: When compared to TV-US, chest radiography and CT for staging, PET showed a concordance in 91 %, 84 % and 81 % of patients, respectively. In 8 of the 41 patients with extrauterine disease during staging, PET/CT showed a complete response to therapy after ßHCG normalization. PET and PET/CT identified the sites of persistent disease in all seven high-risk patients with ßHCG resistance, of whom four underwent second-line chemotherapy, two surgical removal of resistant disease instead of additional chemotherapy, and one surgical removal of resistant disease and second-line chemotherapy with subsequent negative ßHCG. CONCLUSION: In staging, PET cannot replace conventional imaging and does not show any information in addition to that shown by conventional imaging. The additional value of PET/CT in GTN with respect to conventional imaging is found in patients with high-risk disease. PET can identify the sites of primary and/or metastatic disease in patients with persistent high levels of ßHCG after first-line chemotherapy and may be of additional value in patient management for guiding alternative treatment.

Sarcoidosis mimicking metastatic gynaecological malignancies: a diagnostic and therapeutic challenge?

Several case reports describing the coexistence of sarcoidosis and malignancy have been published. Therefore, sarcoidosis should always be considered as a differential diagnosis when a cancer patient develops lymphadenopathy. Positron-emission tomography (PET) 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) combined with computed tomography (CT) is widely used for cancer staging and surveillance because it permits localization of metabolically active malignant tissue. PET/CT or CT findings in patients with suspected cancer recurrence can be used to guide early and aggressive therapy. However, benign hypermetabolic lymphadenopathy can mimic malignant lymphadenopathy, both on a conventional CT scan and on PET/CT. Thus, it is important to obtain a histological diagnosis before initiating antineoplastic therapy based on imaging findings. Four cases of patients affected by gynaecological malignancies and coexisting sarcoidosis are reported in this study. Furthermore, the clinical relevance of making a differential diagnosis between gynaecological cancer recurrence and granulomatous disorder is given specific mention.

Lymph nodal metastases: diagnosis and treatment.

High risk prostate cancer patients have a significant risk to develop regional lymph node metastases, and this represent a major cause of biochemical failure. Although pelvic lymphadenectomy is the gold standard to assess the status of pelvic lymph nodes, a diagnostic imaging tool to non-invasively explore patients and to detect metastases, both in staging and in re-staging phase, would be of particular help in clinical management. In staging phase, while choline PET/CT specificity has been reported to be fairly high in lymph nodal detection, its sensitivity is not adequate due to its spatial resolution. Its role in the evaluation of patients with biochemical relapse or with suspected relapse has been successfully documented. In particular, choline PET/CT has great potential as a single step whole body diagnostic procedure to evaluate lymph nodal and bone metastatic involvement. Salvage lymph nodal dissection was recently listed as a possible experimental option for patients with nodal recurrent prostate cancer, even in the absence of solid prospective data. Radiation treatment for lymph-node recurrence is a therapeutic option evaluated in several studies, in particular by using stereotactic treatment or whole pelvic lymph-nodal irradiation plus a boost on choline PET/CT positive lymph nodes. In the present review an analysis of the specific role of choline PET/CT in guiding a specific treatment on lymph nodal site in prostate cancer patients is reported.

Unusual presentation of sarcoid-like reaction on bone marrow level associated with mediastinal lymphadenopathy on (18)F-FDG-PET/CT resembling an early recurrence of Hodgkin's Lymphoma.

(18)F-FDG-PET/CT is widely employed to evaluate lymphoma patients. False positive results are quite frequent, generally due to active phase of inflammation. We describe an unusual PET/CT presentation of a sarcoid-like reaction (SLR) in a patient monitored for Hodgkin Lymphoma characterized by an intense uptake in lymph nodes and multiple bone foci in a PET/CT study. The final diagnosis was obtained by biopsy. This study draws attention to the fact that multifocal bone marrow uptakes due to a sarcoideal reaction may be a possible cause of false positive results in (18)F-FDG-PET/CT studies in oncology patients.