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BackgroundSince disc sequestration that mimics a tumor is rare and sometimes presents with an atypical appearance upon magnetic resonance imaging (MRI), it is often confused with other more common epidural and intradural neoplasms, particularly neurinoma. Open surgery is necessary due to the difficult of achieving a definitive diagnosis using computed tomography, MRI, and gadolinium- enhanced MRI prior to operation. Herein, we describe the use of coronal MR images of 3D fast-field echo with water selective excitation in the diagnosis of disc sequestration mimicking a tumor.Case presentationTwo patients were admitted to our hospital with back pain, radiating pain, and hypoesthesia in the right lower limb. MRI revealed tumor-like masses in the lateral recess of L3 and posterior to the body of L4. The initial diagnosis indicated disc sequestration mimicking a tumor and neurinoma. The coronal MR images of 3D fast-field echo with water selective excitation showed a clear boundary between the tumor-like mass and the nerve root. Moreover, the mass was also completely separated from the dura. Therefore, neurinoma was excluded as a possible diagnosis prior to operation. Surgical excision to perform removal of the gross mass was performed in one patient. The histopathological diagnosis was consistent with the 3D fast-field echo with water-selective excitation MRI. Another patient was successfully treated by minimally invasive endoscopic surgery.ConclusionsDisc sequestration that mimics a tumor is difficult to diagnose preoperatively. As a non–invasive strategy, coronal MR images of 3D fast-field echo with water selective excitation is a helpful imaging tool for differentiating between diagnosis of disc sequestration that mimics a tumor and neurinoma prior to operation. If the disc fragment of mimicking tumor can be identified prior to operation, open surgery may not be necessary for all patients. Minimally invasive endoscopic surgery also is an alternative strategy.

Endocytosis is a cellular process mostly responsible for membrane receptor internalization. Cell membrane receptors bind to their ligands and form a complex which can be internalized. We previously proposed that F-BAR protein initiates membrane curvature and mediates endocytosis via their binding partners. However, F-BAR protein partners involved in membrane receptor endocytosis and the regulatory mechanism remain unknown. In this study, we established a group of database mining strategies to explore mechanisms underlying receptor-related endocytosis. We identified 34 endocytic membrane receptors and 10 regulating proteins for vesicle formation in clathrin-dependent endocytosis (CDE), a major process of membrane receptor internalization. We found that F-BAR protein FCHSD2 (Carom) may facilitate endocytosis via 9 endocytic partners. Carom is highly expressed, along with highly expressed endocytic membrane receptors and partners, in endothelial cells and macrophages. We established 3 models of Carom-receptor complex and their intracellular trafficking based on protein-protein interaction and subcellular localization. We conclude that Carom may mediate receptor endocytosis and transport endocytic receptors to the cytoplasm for receptor signaling and lysosome/proteasome degradation, or to the nucleus for RNA processing, gene transcription and DNA repair. HHS Public Access INTRODUCTIONEndocytosis is a cellular process by which molecules or substances are transported into the cell via cell membrane engulfment. Endocytosis is generally classified as phagocytosis and pinocytosis, which are distinguished by the size of the endocytic vesicles formed ( Figure 1A & B) (1). Phagocytosis implies to the ingestion of large and solid particle (diameter 0.5-10μm) such as pathogens. Pinocytosis refers to internalization of various liquid via small endocytic vesicles and can be divided into four subtypes: macropinocytosis, clathrindependent, caveolae-dependent, and clathrin/caveolae-independent endocytosis based on clatherin or caveolae involvement (2). Pathogens or ligands induce endocytosis by binding to the cell membrane via receptor-dependent or -independent mechanisms, and then form phagosome or endocytic vesicle (Figure 1B & C). Endocytic vesicle may be coated with clathrin, caveolae or regulated by flotillin, Rho GTPase activating protein 26 (GRAF1), ADP-Ribosylation factor 6 (Arf6) and Ras homology family membrane A (RhoA). During phagocytosis, solid particle containing-phagosomes fuse with lysosomes (marked by lysosomal associated membrane protein (LAMP1)) and subjected to lysosomal degradation. In the process of pinocytosis, internalized vesicles are transported to early endosome (marked by Ras associated protein (Rab5)), which delivers the cargoes to three locations: 1) late endosome (marked by Ras associated protein (Rab7)) then lysosome for degradation, 2) recycling endosome (marked by Rab11) for signal transduction or receptor recycling to cell membrane, and 3) nucleus to regulate transcription factor and ch...

Objective The complete view of the nerve root, including the extraforaminal zone, can be displayed by coronal magnetic resonance imaging (MRI) of three-dimensional (3D) fast-field echo with water-selective excitation (CMRI). However, its sensitivity, specificity, and reliability for the diagnosis of extraforaminal lumbar disc herniation are unclear. We compared the sensitivity, specificity, and reliability of conventional MRI, CMRI, and 3D MRI for the identification of extraforaminal lumbar disc herniation. Methods This study involved 140 patients (68 with extraforaminal lumbar disc herniation and 72 with paramedian disc herniation). Their mean age was 44.57 ± 14.59 years. Conventional MRI, CMRI, and 3D MRI of all patients were evaluated by five experts. The reliability, sensitivity, and specificity of the three imaging techniques for identification of extraforaminal lumbar disc herniation were compared using kappa statistics and the chi-squared test. Results CMRI showed higher agreement (0.843) than conventional MRI (0.671) and 3D MRI (0.771) for the identification of extraforaminal lumbar disc herniation. CMRI demonstrated higher sensitivity (95.6% vs. 91.2%) than conventional MRI (85.3% vs. 70.6%) and 3D MRI (92.6% vs. 86.7%) regardless of whether performed by junior or senior surgeons. Conclusions CMRI is helpful for identification of extraforaminal disc herniation by junior and senior orthopedic surgeons.