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Background and Purpose The rationale for performing a second brain biopsy after initial negativity is not well evaluated in the literature. This study was designed to 1) assess the efficacy of a second brain biopsy when the first biopsy was nondiagnostic, 2) identify possible factors associated with an increased diagnostic rate in the second biopsy, and 3) analyze additional morbidity induced by the second biopsy. Methods We performed a retrospective cohort study from 2009 to 2019, during which 1,919 patients underwent a brain biopsy, including 30 who were biopsied twice (1.6%). The specific histological diagnosis rate, diagnosis-associated factors, and complication rate were assessed for the 30 twice-biopsied patients. Results The second biopsy allowed a specific histological diagnosis in 86.7% of the patients who had initially undergone a nondiagnostic brain biopsy [odds ratio (OR)=7.5, 95% confidence interval (CI)=3.0-18.7, p<0.001]. The multivariate analysis showed that only prebiopsy corticosteroid administration (OR=2.6, 95% CI=1.1-6.0, p=0.01) was an important factor in predicting a nondiagnostic biopsy. None of the patients developed a symptomatic complication after the first biopsy, while two (6.0%) patients experienced a transient complication after the second biopsy (p=0.49). Conclusions Performing a second brain biopsy in patients who have an initial nondiagnostic biopsy is effective in most cases. We advocate that a second biopsy be systematically considered in the diagnosis algorithm of these patients after it has been verified that molecular testing cannot help to obtain a diagnosis. Corticosteroid administration can lead to nondiagnostic biopsies and should be avoided when possible during the prebiopsy period.

Background: Squamous cell carcinoma (SCC) is the most common form of nonmelanoma skin cancer after basal cell carcinoma. Simple excision can be the treatment at early stages of diagnosis. However, at late stages, treatment is more complex due to extension to the skull and the dura. In extremely rare cases, it can invade the brain making it a challenging situation for treatment. Case Description: We present the case of a 54-year-old man with a history of cutaneous SCC who presented an invasive left frontal recurrence with brain invasion 19 years after initial surgery. The patient underwent surgery which consisted in tumor removal and bone and skin reconstruction. Immediate and late outcomes were favorable. Conclusion: Multidisciplinary treatment for SCC diagnosed in advanced stages is the best way to obtain encouraging results. Although significant advancements have been made, further study is needed for cases with advanced disease.

HighlightsBrain metastases are rare forms of manifestations of gastro-intestinal stromal tumors.Brain metastases of gastro-intestinal stromal tumors are usually supra-tentorial. Infra-tentorial localizations are very rare.The treatment is based on surgery and radiotherapy. Chemotherapy has only limited interest.