case_images: PMC11770043_01
case_images: (A) Presents a cranial MRI image of the left side of the posterior internal auditory canal and temporal bone mastoid region, showing an irregular mixed signal with dimensions of approximately 28x21x27mm. The T1W1 signal is low and equal, and a high signal ring can be observed at the edge of the lesion, with a peripheral morphology that is not well-defined and foliated. (B, C) display T2W1 and FLAIR images, respectively, revealing an equal and slightly low signal at the center, along with multiple cystic high signals at the edge. (D) demonstrates obvious enhancement of the mass in the center, accompanied by an increase in signal in the left mastoid region, and the presence of a flowing void effect can be observed. (E) and (F) are not provided. After undergoing enhancement, there was a significant strengthening of the center of the mass. Additionally, there was an increase in the signal of the left mastoid, and the presence of a vascular void signal could be observed (E, F). Ear/mastoid/temporal bone CT scan revealed extensive worm-eaten bone destruction in the mastoid region of the temporal bone (G, H). Transverse common carotid artery angiography demonstrated abnormal visualization of the left posterior cranial fossa, with the left pharyngeal ascending artery supplying blood to the tumor and exhibiting a rich blood supply (G). Furthermore, left vertebral angiography indicated that there was no visualization of the left transverse sinus and the ethmoid sinus (H). The left vertebral imaging revealed a lack of visualization of the left transverse sinus and sigmoid sinus after one hour.
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case_images: T1W1 imaging demonstrated uniform and diminished signals, while the periphery of the lesion exhibited a high signal in the form of a ring, displaying an irregular lobular morphology ( Figure 1A ). T2-weighted imaging (T2W1) ( Figure 1B ) and fluid-attenuated inversion recovery (FLAIR) ( Figure 1C ) demonstrated a central region with uniform and slightly decreased signal intensity, while the periphery of the lesion exhibited a multicompartmental cystic high signal. Vascular flow void signal was observed in all images, as depicted in  Figure 1D . The surrounding brain tissue exhibited a slight decrease in density, as observed in  Figures 1E, F . Figure 1G ). Furthermore, imaging of the left vertebral artery indicated a lack of visualization of the left transverse sinus and sigmoid sinus ( Figure 1H ).
case_images: (A) Left and right ear air-conducted short acoustic auditory brainstem response (ABR) thresholds were measured at 60 dBnHL and 50 dBnHL, respectively, indicating the presence of moderate sensorineural hearing loss in both the left and right ears (B). Acoustic conductance exhibits a C-mode pattern in the left ear and an A-mode pattern in the right ear (C). Stapedial reflexes were not observed in the left ear, while a stapedial reflex was observed in the right ear (C). The left ear did not respond, while the right ear did respond.
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case_images: A-mode map in the right ear ( Figure 2B ). Additionally, the stapedius muscle reflex was not elicited in the left ear, while it was elicited in the right ear ( Figure 2C ).
case_images: (A): A substantial C-shaped incision was performed posterior to the left ear while the patient was positioned in the right lateral recumbent position. (B): The tumor exhibited a grayish-red hue, possessed a firm texture, and displayed a significant vascularization, necessitating intraoperative hemostasis with the use of gelatin sponges. (C): A panoramic view of the resected tumor reveals that the temporal floor dura and sigmoid sinus remained intact. The tumor cavity was situated in the deeper section of the rocky bone aponeurosis. This three-dimensional representation provides a comprehensive visualization of the surgical outcome. (D): Titanium plates were utilized for the purpose of repairing the bony defects of the mastoid processes, as well as serving as attachment points for the repositioning of the retrooccipital musculature.
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case_images: The procedure involved a large C-shaped incision made behind the left ear ( Figure 3A ), along with a distal lateral combined anterior approach to the sigmoid sinus. The tumor exhibited a highly abundant blood supply, characterized by surface hemorrhage, a grayish-red color, and a firm texture ( Figure 3B ). After sufficient exposure and total excision of the tumor, the temporal dura and sigmoid sinus were adequately visualized ( Figure 3C ), and the tumor cavity was packed with periumbilical fat to prevent any potential cerebrospinal fluid leakage. The utilization of a titanium plate was employed to address the mastoid bone defect, simultaneously serving as a reattachment site for the posterior occipital muscle group ( Figure 3D ).
case_images: (A, B). HE staining revealed that the tumor cells were organized in a papillary, glandular pattern within an enlarged lumen. The cells had round nuclei and abundant, eosinophilic, granular cytoplasm. (Original magnification: 400x) (C) Immunohistochemistry analysis revealed that tumor cells diffusely expressed SOX10.(Original magnification: 400x) (D) Immunohistochemistry showed diffuse expression of EMA by tumor cells, suggesting consideration of inner ear lymphocystoma. (Original magnification: 400x).
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case_images: The report showed epithelial tumors consistent with endolymphatic cystic tumors ( Figures 4A-D ). The tumor cells exhibited a papillary and glandular arrangement, characterized by rounded nuclei, abundant cytoplasm, and eosinophilic and granular features (Figs. The observed characteristics of the cells include mild anisotropy, as well as rare instances of nuclear schizophrenic images ( Figures 4A, B ). Immunohistochemical analysis revealed a diffuse positive reaction for epithelial membrane antigen EMA ( Figure 4C ), CK7, CK8-18, PAX-8, S0X10 ( Figure 4D ), PAX-2.
case_images: (A-D) MRI imaging reveals postoperative alterations in the left pontine cerebellar horn region, characterized by a diminished irregular sigh in comparison to the previous scan. The current extent of the mass measures approximately 26*17mm, accompanied by a thin layer of residual tumor. A new patchy short T1 signal (A) and long T2 signal (B, C) was observed in the surgical site, along with postoperative changes in the left mastoid and the presence of a fat filling the area. The enhancement scan of the operation area exhibited uneven enhancement, primarily characterized by marginal enhancement (D). (E, F) Postoperative CT scan revealed postoperative alterations in the left pontine cerebellar peduncle region, with persisting slightly hyperdense measuring approximately 27*17mm. Additionally, the left mastoid exhibited deformity, accompanied by the presence of fat measuring. (G): The patient exhibited symmetrical frontal striae and nasolabial folds bilaterally following the surgical procedure, with no evidence of asymmetrical mouth angle or facial paralysis. (H): The surgical wounds were closed in a cosmetically pleasing manner and exhibited satisfactory healing along the incision line.
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case_images: Postoperative evaluation of cranial MRI revealed the presence of a residual thin layer of tumor ( Figures 5A-D ). Figures 5E, F ). Facial auditory nerve and meridian injury were successfully prevented, and adjuvant gamma knife radiotherapy was administered to address the residual tumor layer. Furthermore, there was bilateral symmetry of the frontal lines and nasolabial folds, with no evidence of facial asymmetry or paralysis ( Figure 5G ). Additionally, there were no indications of cerebrospinal fluid leakage, and the wound along the incision site showed satisfactory healing ( Figure 5H ).
case_images: (A-F) MRI showed postoperative changes in the mastoid process of the left temporal bone, with irregular mixed-signal in the T1W1 (B), T2W1 (D), and FLAIR (E) areas, which were significantly reduced in extent compared with the previous ones, and the edges of the surgical area were little enhanced on the enhancement scans (C); no abnormal signal were seen in the adjacent soft tissues. The signal of the left mastoid process was increased and narrowed (F).
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case_images: Residual tumor at the nodal level in the left pontine cerebellar horn region, primarily presenting as a mixed lesion with a patent jugular venous area and irregular enhancement of the margins on contrast-enhanced scans. ( Figures 6A-F ).
case_images: MRI at 15 months postoperatively showed stabilization of the residual lesion and patency of the jugular vein.
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case_images: An MRI conducted 15 months post-surgery revealed no progression of the tumor, as illustrated in  Figure 7 .