[Clear cell sarcoma or gastrointestinal neuroectodermal tumor (GNET) of the tongue? Case report and review of the literature of an extremely rare tumor localization]. / Sarcome à cellules claires ou tumeur neuroectodermique gastro-intestinale de la langue ? Une observation avec revue de la littérature dans une localisation exceptionnelle.

Clear cells sarcomas (CCS) are exceptionally rare in the tongue, with, to our knowledge, only three previous reports in anglo-saxon literature. Through our case, we will discuss the differential diagnosis of clear cells tumors of the tongue and bring this tumour closer to the newly described entity of the gastrointestinal tract named "clear cells sarcoma-like gastrointestinal (SCCLGI)", recently renamed "gastrointestinal neuroectodermal tumour (GNET)". SCCLGI/GNET share morphological and molecular characteristics with SCC but had until then been observed only in the digestive tract. Our case could be a lingual localization of a SCCLGI/GNET. SCC and SCCLGI/GNET characteristic molecular profil involves EWSR1-ATF1 [t(12; 22) (q13; q12)] and EWSR1-CREB1 [t(2; 22) (q34; q12)] fusion genes, but it is not specific of these tumours.

Nonsurgical giant cell tumour of the tendon sheath or of the diffuse type: are MRI or 18F-FDG PET/CT able to provide an accurate prediction of long-term outcome?

PURPOSE: To investigate whether MRI (RECIST 1.1, WHO criteria and the volumetric approach) or (18)F-FDG PET/CT (PERCIST 1.0) are able to predict long-term outcome in nonsurgical patients with giant cell tumour of the tendon sheath or of the diffuse type (GCT-TS/DT). METHODS: Fifteen "nonsurgical" patients with a histological diagnosis of GCT-TS/DT were divided into two groups: symptomatic patients receiving targeted therapy and asymptomatic untreated patients. All 15 patients were evaluated by MRI of whom 10 were treated, and a subgroup of 7 patients were evaluated by PET/CT of whom 4 were treated. Early evolution was assessed according to MRI and PET/CT scans at baseline and during follow-up. Cohen's kappa coefficient was used to evaluate the degree of agreement between PERCIST 1.0, RECIST 1.1, WHO criteria, volumetric approaches and the reference standard (long-term outcome, delay 505 ± 457 days). The response rate in symptomatic patients with GCT-TS/DT receiving targeted therapy was also assessed in a larger population that included additional patients obtained from a review of the literature. RESULTS: The kappa coefficients for agreement between RECIST/WHO/volumetric criteria and outcome (15 patients) were respectively: 0.35 (p = 0.06), 0.26 (p = 0.17) and 0.26 (p = 0.17). In the PET/CT subgroup (7 patients), PERCIST was in perfect agreement with the late symptomatic evolution (kappa = 1, p < 0.05). In the treated symptomatic group including the additional patients from the literature the response rates to targeted therapies according to late symptomatic assessment, and PERCIST and RECIST criteria were: 65 % (22/34), 77 % (10/13) and 26 % (10/39). CONCLUSION: (18)F-FDG PET/CT with PERCIST is a promising approach to the prediction of the long-term outcome in GCT-TS/DT and may avoid unnecessary treatments, toxicity and costs. On MRI, WHO and volumetric approaches are not more effective than RECIST using the current thresholds.

Clear Cell Sarcoma of the Tongue on MRI and PET/CT.

F-FDG PET/CT and MRI were performed in a 44-year-old woman to characterize a mass of the anterior tongue. MR images showed a voluminous mass, well circumscribed and enhanced heterogeneously after gadolinium chelates injection. There was an intense uptake on PET/CT. Pathological examination and molecular analysis revealed the diagnosis of clear cell sarcoma of the tongue. We present a case of clear cell sarcoma of the tongue, which includes imaging features. It is an extremely rare tumor, with only 3 cases previously reported in the literature.

18F-fluorocholine PET/CT in patients with occult biochemical recurrence of prostate cancer: Detection rate, impact on management and adequacy of impact. A prospective multicentre study.

AIM: To prospectively evaluate the clinical impact and the diagnostic performance of FCH-PET/CT in patients with occult biochemical recurrence of prostate cancer (PCa). MATERIALS AND METHODS: Results of 179 patients (mean PSA = 7.5ng/mL) with negative/inconclusive results of pelvic-MRI and of bone-scintigraphy were analysed. To determine the impact of FCH-PET/CT on diagnostic thinking and on patient management, the referring physicians prospectively filled-in a 1st and 2nd questionnaire related to patient's planned management before and after FCH-PET/CT. Based on data from a 6-month follow-up after FCH-PET/CT, an independent assessor blinded to results of FCH-PET/CT determined the adequacy of management changes motivated by FCH-PET/CT. RESULTS: FCH-PET/CT localised foci evocative of recurrent PCa in 59% (105/179) of patients. Results of FCH-PET/CT motivated a change in scheduled patient management in 56% (100/179) of patients; which was considered as adequate in 89% (89/100) of patients. FCH-PET/CT also led to the detection of lung cancer in two patients. CONCLUSION: FCH PET/CT is a powerful tool to localise the sites of occult biochemical recurrence of PCa, leading to an adequate management change in half of patients.