Pathologic and MRI analysis in acute atypical inflammatory demyelinating lesions.

BACKGROUND: The diagnosis of atypical inflammatory demyelinating lesions can be difficult. Brain biopsy is often required to exclude neoplasms. Moreover, the relationship between these lesions and multiple sclerosis and NMOSD is not clear. OBJECTIVES: Our objectives were to describe radiological and pathological characteristics of patients with acute inflammatory demyelinating lesions. METHODS: We retrospectively identified patients with brain biopsy performed for diagnostic uncertainty revealing a demyelinating lesion. A complete clinical, biological, radiological and pathological analysis was performed. RESULTS: Twenty patients (15 with a single lesion) were included. MRI disclosed a wide range of lesions including infiltrative lesions (40%), ring-like lesion (15%) Baló-like lesion (15%) and acute haemorrhagic leukoencephalitis (20%). In spite of a marked heterogeneity, some findings were common: a peripheral B1000 hyperintense rim (70%), a slight oedema with mild mass effect (75%) and an open-rim peripheral enhancement (75%). Histopathology revealed that all cases featured macrophages distributed throughout, extensive demyelination, axonal preservation and absence of haemorrhagic changes. In the majority of cases, macrophages were the predominant inflammatory infiltrate and astrocytes were reactive and dystrophic. Aquaporin-4 staining was systematically preserved. After a mean follow-up of 5 years (1-12), 16/20 patients had a diagnosis of monophasic acute atypical inflammatory demyelinating lesion. One patient was diagnosed with MS and 3 with AQP4 negative NMOSD. DISCUSSION: Although imaging findings in patients with atypical inflammatory demyelinating lesions are heterogeneous, some common features such as peripheral DWI hyperintense rim with open-rim enhancement and absence of oedema argue in favour of a demyelinating lesion and should preclude a brain biopsy. In this context, AQP4 staining is systematically preserved and argues against an AQP4-positive NMOSD. Moreover, long-term follow-up is characterized by low recurrence rate.

Safety Considerations and Local Tumor Control Following Percutaneous Image-Guided Cryoablation of T1b Renal Tumors.

OBJECTIVE: To retrospectively assess the safety and oncological efficacy of percutaneous image-guided cryoablation (CA) of T1b (> 4 cm/< 7 cm) renal tumors. MATERIALS AND METHODS: Institutional electronic records were retrospectively reviewed to identify the patients who had undergone percutaneous CA of T1b renal tumors between 2008 and 2016. CA was proposed by a multidisciplinary tumor board for cases with poor renal function or a single kidney; unsuitable for surgical resection; or genetic syndromes predisposing to multiple hereditary renal tumors. Patients' demographics, procedural and follow-up data were accurately collected and analyzed. RESULTS: Twenty-seven consecutive patients (12 females, 15 males; mean age 72.3 ± 14.3 years) were included. Mean tumor diameter was 47.9 ± 6.3 mm. MRI guidance was used in 6/27 cases (22.2%) and CT guidance in the remaining 21/27 (77.8%) cases. Hydro- and/or carbo-dissections were necessary in 21/27 cases (77.8%). Complications graded ≥ II were reported in three (11.1%) patients. Technical success and technical efficacy were 100 and 87.5%, respectively. Local tumor control (LTC) evaluated at imaging follow-up ≥ 6 months was 82.6, 72.3 and 60.3% at 12-, 24- and 36-month follow-up, respectively. One patient passed away 3 months after CA due to the metastatic evolution of the primary kidney cancer. CONCLUSION: Percutaneous CA of T1b renal tumors is safe and satisfactory rates of LTC are expected at the early follow-ups. Further studies are needed to confirm the long-term efficacy of this procedure.