Christophe Chagnaud

Amplification of MDM2 is the molecular hallmark of atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and dedifferentiated liposarcoma (DDL). While fluorescence in situ hybridization (FISH) is widely used for diagnosis, the diagnostic and prognostic value of droplet digital PCR (ddPCR) remains poorly defined. We retrospectively analyzed 341 primary adipocytic tumors, including 85 liposarcomas (22 DDL), using ddPCR to quantify MDM2 copy number variation (CNV). Diagnostic performance was compared with FISH, and associations with clinicopathological variables and outcomes were evaluated using non-parametric tests, ROC analysis, survival analysis, and Firth’s penalized Cox models. Comparison with FISH confirmed the diagnostic utility of ddPCR for detecting MDM2 amplification, while quantitative CNV assessment provided additional prognostic information. CNV values were significantly higher in deep-seated and dedifferentiated tumors and were strongly associated with local recurrence. ROC analysis identified a threshold of 16.85 copies predicting both dedifferentiation and recurrence (AUC 0.982 and 0.942, respectively). Patients with CNV ≥ 16.85 copies had significantly shorter recurrence-free and overall survival. In multivariable analysis, high CNV remained an independent predictor of recurrence (HR 36.6, 95% CI 4.0–4914.2). These findings support ddPCR as a robust method for MDM2 assessment and suggest that quantitative MDM2 copy number may improve both diagnosis and risk stratification in liposarcoma.

The Mazabraud syndrome is a rare form of bone fibrous dysplasia associated with intramuscular myxomas. The McCune-Albright syndrome is characterized by the association of dysplasia fibrous bone to one or more extra-osseous manifestations, including café-au-lait skin spots and endocrine disturbances. Here, we report on a new case of a 52-year-old man with sacroiliac polyostotic bone fibrous dysplasia associated with intramuscular myxomas of the left buttock and thigh and a café-au-lait skin spot. Biopsy analysis of one muscular lesion on the left thigh analysis revealed a spindle cell tumor with myxoid stroma with GNAS gene mutation, confirming the diagnosis of intramuscular myxoma. Given the absence of radiological sign of malignancy at the bone level and a few pains relieved by simple analgesics, no specific treatment was applied. In March 2022, after 18 months of follow-up, the magnetic resonance imaging and the PET-CT scan showed a stable disease. To our knowledge, this case is the fourth one reporting association of Mazabraud syndrome and McCune-Albright syndrome in a man. The association of intramuscular tumors and bone tumors in the same anatomical region and without any continuity, especially in lower limbs, must evoke the diagnosis of Mazabraud syndrome.

BACKGROUND AND PURPOSE: Recurrent middle ear cholesteatomas are commonly preoperatively assessed using MR imaging (non-EPI-DWI) and CT. Both modalities are used with the aim of distinguishing scar tissue from cholesteatoma and determining the extent of bone erosions. Inflammation and scar tissue associated with the lesions might hamper a proper delineation of the corresponding extensions on CT images. Using surgical findings as the criterion standard, we assessed the recurrent middle ear cholesteatoma extent using either uncoregistered or fused CT–MR imaging datasets and determined the corresponding accuracy and repeatability. MATERIALS AND METHODS: Twenty consecutive patients with suspected recurrent middle ear cholesteatoma and preoperative CT–MR imaging datasets were prospectively included. A double-blind assessment and coregistration of the recurrent middle ear cholesteatoma extent and manual delineation of 18 presumed recurrent middle ear cholesteatomas were performed by 2 radiologists and compared with the criterion standard. “Reliability score” was defined to qualify radiologists9 confidence. For each volume, segmentation repeatability was assessed on the basis of intraclass correlation coefficient and overlap indices. RESULTS: For the whole set of patients, recurrent middle ear cholesteatoma was further supported by surgical results. Two lesions were excluded from the analysis, given that MR imaging did not show a restricted diffusion. Lesions were accurately localized using the fused datasets, whereas significantly fewer lesions (85%) were correctly localized using uncoregistered images. Reliability scores were larger for fused datasets. Segmentation repeatability showed an almost perfect intraclass correlation coefficient regarding volumes, while overlaps were significantly lower in uncoregistered (52%) compared with fused (60%, P < .001) datasets. CONCLUSIONS: The use of coregistered CT–MR images significantly improved the assessment of recurrent middle ear cholesteatoma with a greater accuracy and better reliability and repeatability.