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Nerve tumors in the retroperitoneal space are a rarity. Radical surgery according to soft tissue tumors can lead to persistent pain and neurological deficits. This study aims to evaluate clinical outcomes of patients treated by a visceral- / neurosurgical approach. 33 patients with a retroperitoneal nerve tumor underwent surgery between 01/2002 and 12/2022 at our department. A visceral surgeon provided access to the retroperitoneal space, followed by micro-neurosurgical tumor preparation under neuromonitoring. Clinical examination and MRI were performed 12 weeks after surgery and further 3 months (WHO grade > 1) or 12 months (WHO grade 1). Further examinations were based on MRI findings and residual symptoms with median follow-up time of 24 months. One patient was treated for two distinct masses resulting in a total of 34 histological findings. Schwannomas (n = 15; 44.1%) and neurofibromas (n = 10; 29.4%) were the most common tumors. Long-term improvements were noted in radicular pain (15/18 patients; 83.3%), motor deficits (7/16 patients; 43.8%), abdominal discomfort and pain (5/7 patients; 71.4%). Recurrences were observed in 3/33 (9,1%) patients. This study represents the largest series of retroperitoneal BPNSTs treated with microsurgical techniques. Prospective multicenter studies are warranted to establish standardized treatment guidelines. [ABSTRACT FROM AUTHOR]

Simple Summary: This study analyzes 61 rare tumors and lesions mimicking peripheral nerve tumors using data from the German Peripheral Nerve Tumor Registry. These cases exhibit significant heterogeneity with various morphological features and biological potentials, including malignant peripheral nerve tumors, perineuriomas, and hybrid nerve sheath tumors. This study underscores the challenges in preoperatively differentiating these rare entities from benign tumors using clinical and radiological methods alone. It highlights the importance of a multidisciplinary approach involving radiologists, neurologists, neuropathologists, and neurosurgeons for accurate diagnosis and effective treatment. The supplementary material offers valuable insights to help clinicians recognize these rare tumors early, improving patient outcomes. The most common peripheral nerve tumors are of a benign nature and include schwannoma or neurofibroma. In rare cases, other tumors or non-tumorous lesions can mimic peripheral nerve tumors clinically or radiologically. Based on data from the multicentric German Peripheral Nerve Tumor Registry (PNTR), which encompasses current information on 315 surgically treated patients from three high-volume centers, we present 61 cases of rare tumors and lesions that mimic tumors associated with peripheral nerves. This cohort displays considerable heterogeneity, featuring a broad spectrum of morphological features and biological potentials. Histopathological diagnoses include various intrinsic peripheral nerve tumors such as malignant peripheral nerve tumors (MPNSTs) (n = 13), perineurioma (n = 17), and hybrid nerve sheath tumors (HPNSTs, comprising schwannoma/perineurioma and schwannoma/neurofibroma) (n = 14), as well as atypical neurofibromatous neoplasm with unknown biological potential (ANNUBP) (n = 1). Additionally, the cohort encompasses extrinsic tumorous lesions like lymphoma (n = 3), lymphangioma (n = 2), hemangioma (n = 2), solitary fibrous tumor (n = 2), metastatic disease (n = 1), and single cases of other rare tumor entities (n = 6). An overview of the underlying pathology, imaging features, and clinical presentation is provided, with a brief description of each entity. A definitive preoperative differentiation between benign peripheral nerve tumors and rare intrinsic and extrinsic tumors is often not possible. Clinical examination and subtle imaging clues can at least indicate the possibility of a rare entity. The basic requirement is close cooperation between radiologists, neurologists, neuropathologists, and neurosurgeons at a specialized center to develop a multidisciplinary concept and offer the patient the best therapeutic approaches. [ABSTRACT FROM AUTHOR]

Glioblastoma, the most common and lethal primary adult brain tumor, cannot be successfully removed surgically due to its highly invasive nature. Therapeutically, approaches must be aimed at a systemic brain disease and not merely at a tumor located within the brain, unless a successful containment strategy can be found. Reelin, an extracellular matrix glycoprotein, plays an important role in neuronal migration and serves here as a natural stop signal. Interestingly, the expression of reelin is negatively associated with tumor grade and, within glioblastoma, correlates with increased overall survival. To further elucidate a potential biological reason for these findings, we looked at the cellular behavior of glioblastoma cell lines grown on a pure fibronectin matrix or a matrix with reelin inserts. While reelin had no significant effects on cellular metabolism, proliferation, or resistance to chemotherapeutic agents, it did significantly affect the cells' interaction with fibronectin. Both matrix attachment and detachment were modulated by reelin, and thus, the invasion and motility of cells interacting with a reelin-containing matrix were altered. The data presented in this work strongly suggest that reelin might be a potential modulator of underlying molecular mechanisms that contribute to glioblastoma invasion. [ABSTRACT FROM AUTHOR]

Background Ventriculostomy (VST) is a frequent neurosurgical procedure. Freehand catheter placement represents the standard current practice. However, multiple attempts are often required. We present augmented reality (AR) headset guided VST with in-house developed head models. We conducted a proof of concept study in which we tested AR-guided as well as freehand VST. Repeated AR punctures were conducted to investigate if a learning curve can be derived. Methods Five custom-made 3D-printed head models, each holding an anatomically different ventricular system, were filled with agarose gel. Eleven surgeons placed two AR-guided as well as two freehand ventricular drains per head. A subgroup of four surgeons did a total of three series of AR-guided punctures each to test for a learning curve. A Microsoft HoloLens served as the hardware platform. The marker-based tracking did not require rigid head fixation. Catheter tip position was evaluated in computed tomography scans. Results Marker-tracking, image segmentation, and holographic display worked satisfactorily. In freehand VST, a success rate of 72.7% was achieved, which was higher than under AR guidance (68.2%, difference not statistically significant). Repeated AR-guided punctures increased the success rate from 65 to 95%. We assume a steep learning curve as repeated AR-guided punctures led to an increase in successful attempts. Overall user experience showed positive feedback. Conclusions We achieved promising results that encourage the continued development and technical improvement. However, several more developmental steps have to be taken before an application in humans can be considered. In the future, AR headset–based holograms have the potential to serve as a compact navigational help inside and outside the operating room. [ABSTRACT FROM AUTHOR]