The condition at the center of the case is otogenic sigmoid sinus thrombosis, an uncommon but feared intracranial complication of otomastoid infection, meaning infection of the middle ear and mastoid air cells. In this disease, infected material and inflammation extend from the temporal bone to the sigmoid sinus, one of the large venous channels that carry blood away from the brain, and a clot forms inside the vessel. The authors note that the older term lateral sinus thrombosis can be imprecise, because the lateral sinus encompasses both the transverse and sigmoid segments, and they argue that clinicians should describe the exact venous segments involved whenever possible. Contemporary literature, they add, generally supports combining medical and surgical treatment, while the extent of direct surgery on the sinus itself and the role of anticoagulation remain actively debated topics without randomized trial evidence to settle them.

The patient’s story began on 20 November 2024, when he was admitted to the neurosurgical service with no documented major comorbidities but with neuroimaging showing a left cerebellar abscess, obstructive hydrocephalus, and multiple intracranial venous sinus thromboses. The posterior fossa, the compartment housing the cerebellum and brainstem, is an unforgiving location for a growing abscess, because swelling there can compress the fourth ventricle and block the circulation of cerebrospinal fluid, driving pressure upward throughout the skull. Surgeons therefore moved on the day of admission, placing an external ventricular drain through a right frontal approach to divert cerebrospinal fluid and evacuating the cerebellar abscess through an occipital craniectomy. The referral documentation did not specify how long his symptoms had lasted or whether he had received antibiotics before arriving at the hospital, a gap that would later complicate the microbiological picture.

Once the immediate neurosurgical emergency was controlled, the patient was transferred intubated and mechanically ventilated to the ear, nose and throat service, whose task was to find and eradicate the source of the infection. High-resolution computed tomography of the temporal bone showed opacification of the left mastoid air cells and middle ear cavity, consistent with otomastoiditis and pointing to an otogenic origin for the intracranial disaster. Otomicroscopy revealed a polypoid lesion in the left external auditory canal, mainly in the anteroinferior quadrant, with bulging of the medial canal wall, while the visible portions of the tympanic membrane appeared intact. Formal audiometry was impossible in the acute setting because the patient was on a ventilator, and no quantitative hearing test from earlier evaluations was available to the team.

On 22 November 2024, surgeons performed a left canal-wall-down radical mastoidectomy, an operation that removes the infected bone and creates an open, drainable cavity. What they found inside was striking. The mastoid cavity was packed with chronically inflamed polypoid mucosa, the ossicular chain of the middle ear was partially eroded, the intratympanic segment of the facial nerve was dehiscent, meaning its bony covering was missing, and the plate of bone over the sigmoid sinus had been destroyed by disease. Through that dehiscent plate, the team could see an actual thrombus sitting inside the sigmoid sinus, a direct visual confirmation of the clot that imaging had suggested. Purulent secretion was collected for bacteriological analysis, tissue fragments went to histopathology, and hemostasis was secured before the cavity was packed with sterile gauze.

Here the case takes on its most instructive dimension: what the surgeons chose not to do. Despite directly visualizing the intrasigmoid thrombus, they did not incise the sinus, did not attempt thrombectomy, and did not ligate the internal jugular vein. Historically, management of otogenic sigmoid sinus thrombosis often included exactly those maneuvers, but contemporary practice tends to reserve direct sinus procedures for selected situations such as persistent septicemia, septic embolization, progressive thrombosis despite treatment, or failure of source control. The team weighed the extensive venous thrombosis, the very recent posterior fossa surgery, the substantial postoperative bleeding risk, and the absence of documented persistent septicemia, and concluded that otologic source control without opening the sinus was a reasonable, risk-balanced strategy. Histopathology showed severe suppurative polypoid otomastoiditis with destructive inflammatory changes; cholesteatoma, a keratin-producing destructive lesion that was clinically suspected, was not confirmed under the microscope.

The recovery was not linear. Early after mastoidectomy, otorrhea and vertigo improved, but on 6 December 2024 a follow-up cranial CT revealed recurrence or enlargement of the left cerebellar abscess, now measuring roughly 12 by 48 millimeters with surrounding edema and mass effect. The patient was transferred back to neurosurgery on 9 December but discharged himself the same day against medical advice, returning on 11 December, when repeat posterior fossa surgery was performed; the procedural record from 13 December documented drainage of the intracranial infection and posterior fossa decompression. The authors caution that the recurrence cannot be pinned on a single cause. Plausible contributors include advanced disease at presentation, a residual infected collection, impaired venous drainage, and the culture-negative microbiology that prevented therapy from being narrowed to a specific pathogen.

That microbiological silence is itself a central lesson of the report. Purulent mastoid secretion tested after 48 hours grew no pathogenic bacteria and no Candida species; cerebrospinal fluid obtained on 18 December was culture-negative with no organisms on Gram staining and no acid-fast bacilli on Ziehl-Neelsen staining; and otic and fungal cultures from 20 December were also negative. Blood cultures and cultures from the initial abscess drainage were unavailable in the reviewed records. With no isolate, susceptibility testing could not guide treatment, so the team relied on broad empirical coverage: piperacillin-tazobactam 4.5 grams every eight hours combined with amikacin 500 milligrams every twelve hours, reconstructible from the medication chart as approximately 18 treatment days of the former and 9 of the latter. Anticoagulation was similarly fragmented rather than protocolized, with unfractionated heparin listed around the second neurosurgical intervention, a single recorded enoxaparin syringe in intensive care, and additional heparin entries during the ENT admission lacking route, dose, frequency and duration. No anti-Xa monitoring, thrombophilia work-up or outpatient anticoagulation plan was documented.

By 17 December 2024, postoperative CT showed that the cerebellar abscess cavity had disappeared, with reduced edema and mass effect, yet the left internal jugular vein, sigmoid sinus and transverse sinus still failed to opacify with contrast, and no spontaneous recanalization was seen. The authors emphasize the distinction this reveals between clinical recovery and venous outcome: the patient improved even though his venous system had not. They note that MRI with magnetic resonance venography is generally preferred for characterizing thrombus and tracking venous follow-up, and they are careful not to claim that recanalization occurred. After intensive care from 13 to 15 December, during which he was weaned from sedation and successfully extubated, he returned to the ENT ward, where serohematic secretion interpreted as otoliquorrhea, a leak of fluid suggestive of cerebrospinal fluid, progressively diminished and remitted by discharge on 30 December 2024, afebrile and without documented neurological deficit.

The authors are candid about the limits of what this single case can prove. Retrospective documentation, the patient’s failure to attend the planned three-month outpatient reassessment, and missing blood-culture, audiological and venographic data all restrict conclusions about optimal antimicrobial duration, anticoagulation strategy and long-term outcome. Yet the report’s practical value survives those limitations. It demonstrates that otogenic sigmoid sinus thrombosis can present first as a neurological emergency, with posterior fossa abscess, hydrocephalus and widespread venous thrombosis overshadowing the ear disease that caused them; that staged neurosurgical and otologic source control remains the backbone of treatment; that conservative management of a thrombosed sinus can be defensible even when clot is visible at the operating table; and that favorable early outcomes are possible even when cultures stay negative and venous recanalization is not yet demonstrated, provided urgent source control, careful imaging surveillance and individualized, risk-balanced anticoagulant decisions are prioritized.

Subject of Research: Otogenic sigmoid sinus thrombosis complicated by cerebellar abscess and hydrocephalus

Article Title: Otogenic Sigmoid Sinus Thrombosis Complicated by Cerebellar Abscess and Hydrocephalus: A Case Report

Article References: Bizdu‐Branovici, A. M., Gherasie, L., Ionița, I. G., Zica, M. D., Rusescu, A., Hainaroșie, R., & Zainea, V. (2026). Otogenic Sigmoid Sinus Thrombosis Complicated by Cerebellar Abscess and Hydrocephalus: A Case Report. Clinical Case Reports, 14(10), Article e73589. https://doi.org/10.1002/ccr3.73589

Image Credits: AI Generated

DOI: 10.1002/ccr3.73589

Keywords: sigmoid sinus thrombosis, otogenic infection, cerebellar abscess, hydrocephalus, mastoidectomy, otomastoiditis, cerebral venous sinus thrombosis, anticoagulation, neurosurgery, ear infection, case report, posterior fossa

The research, led by Rong Zhang, Feng Chen, and Wenbin Li of Beijing Tiantan Hospital, Capital Medical University, together with colleagues at Tsinghua University and the Beijing Institute of Neurosurgery, set out to answer three linked questions. Could fresh surgical specimens from adult ependymoma patients be reliably converted into three-dimensional organoids? Would those organoids preserve the histological and molecular identity of the tumors from which they came? And would they retain the malignant capacity to seed new tumors when transplanted into animals? The answers, drawn from a cohort of twenty-two patients, are cautiously encouraging and candidly nuanced in equal measure.

Organoids are self-organizing, three-dimensional cell cultures that recapitulate key architectural and molecular features of the tissue or tumor from which they are derived. Unlike traditional two-dimensional cell lines, which often shed the very characteristics that make a tumor clinically distinctive, organoids preserve much of the original cellular complexity. For brain tumors, this matters enormously: ependymomas are defined by perivascular pseudorosettes, ependymal rosettes, and the expression of markers such as glial fibrillary acidic protein and epithelial membrane antigen, features that are notoriously difficult to maintain in conventional culture.

The team processed fresh tumor tissue from twenty-two adult patients, most of whom harbored tumors in the posterior fossa, the compartment at the back of the skull that houses the cerebellum and brainstem. The success rate was striking: organoids were established from twenty of the twenty-two specimens, a 90.9 percent efficiency that compares favorably with organoid platforms developed for more common brain tumors. Under the microscope, the organoids broadly retained the morphology of their parental tumors, and immunofluorescence staining confirmed the continued expression of major ependymoma-associated markers as well as neural and progenitor cell markers. Importantly, selected morphologic and immunophenotypic features remained detectable even during prolonged culture, with six organoid models maintained to at least passage forty still showing GFAP and EMA expression comparable to early passages.

To probe fidelity at the molecular level, the researchers performed RNA sequencing on three matched tumor-organoid pairs. The global expression profiles were highly similar, with Pearson correlation coefficients ranging from 0.84 to 0.88, indicating that the organoids had not drifted wholesale away from their tumors of origin. Yet the analysis also revealed something the authors describe as substantial culture-associated remodeling, a transcriptomic adaptation to life in a dish that anyone hoping to use these models for drug discovery will need to take seriously.

The remodeling followed recognizable patterns. Endothelial signatures and stromal scores derived from the ESTIMATE algorithm were reduced in all three organoid pairs, an expected consequence of removing tumor cells from their vascular and stromal surroundings. Other immune and stromal signatures, however, changed in a patient-specific manner, suggesting that each tumor responds to culture conditions in its own idiosyncratic way. Paired differential-expression and gene-set enrichment analyses further identified a consistent enrichment of ribosome and translation programs and oxidative phosphorylation in the organoids, accompanied by a reduction in cilia- and axoneme-associated programs. That last finding is particularly intriguing for ependymoma specialists, because cilia, the hair-like projections that define ependymal cells, have been linked to tumor aggressiveness in previous work, with decreased FOXJ1 expression and ciliogenesis programs reported in aggressive ependymoma and choroid plexus tumors.

Perhaps the most consequential experiment came next. Selected organoid models were transplanted into mice, both under the skin and directly into the brain. The organoid-derived cells demonstrated tumorigenic capacity in both settings, generating xenografts that confirmed the cultures had not lost their malignant identity. This in vivo validation matters because the field has seen cautionary tales: a 2023 study reported loss of tumorigenicity in a patient-derived orthotopic xenograft model of ependymoma, underscoring that not every culture system preserves the biological essence of the original tumor. The Beijing team’s organoids passed that test, at least for the selected models evaluated.

The platform arrives at a moment when the molecular classification of ependymoma has matured considerably. The 2021 WHO Classification of Tumors of the Central Nervous System and subsequent large-cohort studies have established that ependymomas are best understood as a family of molecularly defined subgroups, including posterior fossa groups A and B, spinal ependymomas, and entities not elsewhere classifiable, each with distinct demographics, genetics, and prognosis. DNA methylation profiling has become central to diagnosis in adults, and single-cell RNA sequencing studies in pediatric ependymoma have revealed cellular hierarchies and developmental trajectories within these tumors. Yet therapeutic progress has been slow; clinical trials of targeted agents such as dose-dense temozolomide combined with lapatinib have yielded limited advances, and the EANO guidelines still anchor treatment in surgery and radiotherapy. A renewable, patient-specific model system is precisely the kind of tool that could accelerate preclinical drug screening for a disease where trial enrollment is inherently constrained by rarity.

The authors are careful about what their platform does and does not show. The transcriptomic remodeling they document is not a flaw to be hidden but a boundary condition to be respected: organoids faithfully carry selected tumor-associated features while undergoing measurable transcriptional and microenvironment-associated adaptation to ex vivo culture. For experiments probing cell-autonomous tumor biology, such as intrinsic drug sensitivity or proliferation signaling, the models appear well suited. For questions that hinge on endothelial interactions, immune infiltration, or stromal crosstalk, researchers may need to complement organoids with co-culture systems, organotypic slices, or in vivo xenografts, an approach echoed in the broader glioblastoma organoid literature, where three-dimensional cultures have been shown to recapitulate hypoxic gradients and cancer stem cell heterogeneity while still requiring careful interpretation of microenvironmental signals.

Practical accessibility may prove to be the platform’s most viral quality. The RNA sequencing dataset has been deposited in the Gene Expression Omnibus under accession number GSE347879, and the established organoid models may be obtained from the corresponding authors upon reasonable request, subject to institutional approval and a material transfer agreement. The work was approved by the Institutional Review Board of Beijing Tiantan Hospital and conducted with written informed consent from all participants, with animal procedures approved by the Beijing Neurosurgical Institute. As living biobanks of pediatric high-grade glioma and ependymoma have already demonstrated, shared model systems can transform a rare tumor field almost overnight, converting isolated surgical specimens into cumulative, comparable experimental resources. For adult ependymoma, a tumor that has watched other neuro-oncology subfields sprint ahead, twenty patient-derived organoids that keep their shape, their markers, and their malignant spark may be the starting line the field has been waiting for.

Subject of Research: Patient-derived organoid models of adult posterior fossa ependymoma

Article Title: A patient-derived organoid platform for predominantly posterior fossa adult ependymoma: histopathologic preservation, culture-associated transcriptomic remodeling, and in vivo tumorigenicity

Article References: Zhang, R., Li, S., Sun, Y., Ma, S., Wang, C., Kang, Z., Yang, X., Zhang, B., Xu, N., Guo, A., Wu, Z., Chen, F., & Li, W. (2026). A patient-derived organoid platform for predominantly posterior fossa adult ependymoma: histopathologic preservation, culture-associated transcriptomic remodeling, and in vivo tumorigenicity. Journal of Neuro-Oncology, 179(3), Article 105. https://doi.org/10.1007/s11060-026-05814-x

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05814-x

Keywords: ependymoma, patient-derived organoids, brain tumor, posterior fossa, organoid culture, transcriptomics, xenograft, tumor modeling, neuro-oncology, RNA sequencing, tumor microenvironment, precision medicine

The story began two to three years before the young woman finally sought care. She experienced intermittent abdominal discomfort, recurrent vomiting, and mild to moderate headaches, symptoms that on their own could point in almost any direction in medicine. Then, over the final two to three months before presentation, her vision began to deteriorate in both eyes, progressively and relentlessly. Five days before she reached the outpatient department, she lost her sight entirely. By the time she was examined, she could perceive only fluctuating light in each eye. Her pupils remained equal and reactive to light, her mental functions were intact, and her limb strength was normal, but she showed subtle cerebellar signs on her left side, including an impaired finger-to-nose test and difficulty with rapid alternating movements.

Brain imaging explained much of what her examination could not. Computed tomography and magnetic resonance imaging revealed extensive, bilateral calcifications deposited in the basal ganglia, the thalami, and the dentate nuclei of the cerebellum, a distribution classic for Fahr-type intracranial calcification. Alongside these mineral deposits sat a well-defined cystic mass in the left cerebellum, with imaging features compatible with a pilocytic astrocytoma. Critically, the mass was compressing the fourth ventricle, the narrow channel through which cerebrospinal fluid drains from the brain’s interior, and the ventricles above it had dilated in response. The diagnosis was obstructive hydrocephalus, a build-up of fluid under pressure that, left untreated, is a neurosurgical emergency.

Fahr’s disease, more precisely termed primary familial brain calcification when no secondary cause can be identified, is a rare neurological disorder that most often affects young to middle-aged adults. The terminology matters: Fahr disease or PFBC refers to primary calcification without an identifiable underlying cause, while Fahr syndrome describes calcification arising secondary to another disorder, most commonly hypoparathyroidism or pseudohypoparathyroidism. In affected brains, abnormal deposits of calcium carbonate and calcium phosphate accumulate in the basal ganglia, thalamus, hippocampus, cerebral cortex, cerebellar white matter, and dentate nuclei. Clinically, these deposits are associated with movement disorders, psychiatric symptoms, cognitive impairment, and seizures. The pathogenesis is linked to disturbances in calcium metabolism and the neurovascular unit, and pathogenic variants in genes including SLC20A2, PDGFB, PDGFRB, XPR1, MYORG, and JAM2 have been implicated, several of which disrupt inorganic phosphate handling and the integrity of the blood-brain barrier.

Pilocytic astrocytoma is an entirely different entity. It is a World Health Organization Grade I glioma, a slow-growing and generally benign tumor that primarily strikes children and young adults, with a strong preference for the cerebellum. When completely resected, its prognosis is favorable. Its danger lies in location rather than biology: a cerebellar pilocytic astrocytoma can compress the fourth ventricle or the aqueduct of Sylvius, blocking cerebrospinal fluid outflow and driving intracranial pressure upward, producing exactly the progressive neurological decline this patient experienced. The coexistence of this tumor with Fahr-type calcification is extraordinarily rare, and it creates a diagnostic trap, because dense calcification can complicate radiological interpretation of posterior fossa lesions while the tumor-induced hydrocephalus demands urgent intervention.

Surgical treatment proceeded along standard lines for a posterior fossa mass with obstructive hydrocephalus. The neurosurgical team performed a suboccipital craniectomy and achieved gross total excision of the left cerebellar mass on operative assessment. When hydrocephalus persisted after the tumor was removed, the team placed a ventriculoperitoneal shunt, a catheter system that diverts excess cerebrospinal fluid from the ventricles to the abdominal cavity, a standard indication following posterior fossa tumor resection when fluid drainage fails to recover on its own. The postoperative course was uneventful. Headaches and vomiting gradually improved, and postoperative imaging showed expected surgical changes with the ventricular catheter correctly positioned. Vision, however, remained profoundly impaired.

Histopathology added an important layer of uncertainty. The resected tissue showed extensive hyalinization and regressive changes, with largely acellular material and no visible cellular areas, leading the pathologists to list pilocytic astrocytoma only as a possible differential diagnosis. This matters because regressive and degenerative features, including vascular hyalinization, calcification, and paucicellular fibrillary areas, are well recognized in pilocytic astrocytoma and can dominate the histological picture in long-standing lesions. Definitive confirmation would require the tumor’s characteristic bipolar piloid cells, Rosenthal fibers, and eosinophilic granular bodies, supported by GFAP immunohistochemistry and, where feasible, testing for the KIAA1549-BRAF fusion, which is present in approximately 90 percent of cerebellar pilocytic astrocytomas. Neither immunohistochemistry nor molecular testing was available in this case, so the tumor diagnosis remains presumptive.

The authors of the report are candid about the limits of what can be concluded. Serum calcium, phosphate, and parathyroid hormone levels were never obtained, so calcification secondary to a disorder of calcium metabolism could not be excluded biochemically, and the case cannot be firmly classified as primary familial brain calcification rather than Fahr syndrome. No family history was documented and no genetic testing was performed, leaving the calcification designation radiological rather than molecularly confirmed. Formal ophthalmologic assessment, including fundoscopy, grading of papilledema, and visual-field testing, was also unavailable, meaning the mechanism of visual loss must be inferred rather than directly demonstrated. Long-term follow-up is not yet established, and the team plans continued surveillance for visual recovery, tumor recurrence, and progression of the calcification.

The visual outcome deserves particular attention, because it carries the case’s most important clinical lesson. Posterior fossa masses rarely involve the visual pathway directly; bilateral visual failure most likely reflects raised intracranial pressure transmitted to the optic nerve heads, where sustained papilledema can produce axoplasmic stasis, ganglion cell axonal loss, and ultimately optic atrophy. Papilledema usually resolves after tumor resection or cerebrospinal fluid diversion, but deficits that are severe or long-standing at presentation may persist despite adequate treatment of the hydrocephalus, which accounts for the limited recovery observed here. Permanent visual loss is uncommon in posterior fossa tumors overall, reported in roughly 6 to 8 percent of children, and outcomes are generally most favorable for pilocytic astrocytoma, making the profound and largely irreversible deficit in this patient an atypical result. The authors argue it underscores the importance of early fundoscopic assessment and expedited cerebrospinal fluid diversion whenever visual symptoms accompany a posterior fossa mass.

How rare is this combination, really? A small number of comparable cases have been described. The first association was reported in 1984, when a patient’s scans showed Fahr-type calcification adjacent to a cystic astrocytoma. An autopsy study in 1993 identified a low-grade astrocytoma with extensive bilateral calcification and noted astrocytic proliferation near calcified deposits. In 2015, a 32-year-old woman was reported with bilateral calcification and an adjacent low-grade cystic astrocytoma, and the authors of that report observed a recurring pattern: relatively young patients with predominantly cerebellar tumors, where a cystic glioma arises next to a calcified dentate nucleus. In 2023, a coexistent meningioma broadened the reported tumor spectrum beyond astrocytoma. Current evidence suggests no established causal relationship between primary familial brain calcification and tumor development, and coexistence has generally been attributed to long-standing reactive astroglial proliferation around calcified deposits rather than a proven mechanism. Because the literature search underpinning this report was not systematic, the authors decline to assign a precise total to previously reported cases, and observations from a single patient cannot establish causation. What the case does establish is a diagnostic principle: when symptoms are progressive and disproportionate to any single diagnosis, clinicians should consider that more than one pathology may be at work, and they should match the certainty of their diagnostic language to the evidence actually available.

Subject of Research: Coexistence of Fahr-type intracranial calcification and a presumed cerebellar pilocytic astrocytoma with obstructive hydrocephalus

Article Title: Coexistence of Fahr‐Type Intracranial Calcification and a Presumed Cerebellar Pilocytic Astrocytoma With Obstructive Hydrocephalus: A Rare Case Report

Article References: Coexistence of Fahr‐Type Intracranial Calcification and a Presumed Cerebellar Pilocytic Astrocytoma With Obstructive Hydrocephalus: A Rare Case Report. (n.d.). https://doi.org/10.1002/ccr3.73552

Image Credits: AI Generated

DOI: 10.1002/ccr3.73552

Keywords: Fahr disease, primary familial brain calcification, pilocytic astrocytoma, obstructive hydrocephalus, cerebellar tumor, intracranial calcification, ventriculoperitoneal shunt, papilledema, posterior fossa, neurosurgery, SLC20A2, case report