Giant Posterior Fossa Tuberculoma Mimicking Atypical Teratoid/Rhabdoid Tumor in a Child: Illustrative Case

ABSTRACT

Intracranial tuberculomas are rare manifestations of extrapulmonary tuberculosis that can closely mimic malignant posterior fossa tumors in children, particularly in tuberculosis‐endemic regions. The radiological and clinical overlap with aggressive neoplasms such as atypical teratoid/rhabdoid tumor (AT/RT) poses a significant diagnostic challenge. A 5‐year‐old immunocompetent boy presented with progressive headache and irritability. Magnetic resonance imaging (MRI) of the brain revealed a large (45 × 38 mm) lesion in the cerebellar vermis and left hemisphere with mass effect on the fourth ventricle and brainstem, causing obstructive hydrocephalus. A ventriculoperitoneal (VPMP) shunt was placed for hydrocephalus management. Subsequently, left suboccipital craniectomy with tumor decompression was performed. Intraoperative crush biopsy was initially reported as atypical rhabdoid tumor. However, final histopathological examination revealed extensive granulomatous inflammation with epithelioid cell granuloma, Langhans‐type giant cells, and macrophages. Immunohistochemistry showed CD68 positivity (confirming macrophagic nature), EMA negativity (ruling out meningothelial tumor), and vimentin positivity in fibrotic tissue. Acid‐fast bacilli (AFB) staining was positive. The final impression was chronic granulomatous pathology consistent with tuberculosis. This case underscores the importance of maintaining a high index of suspicion for CNS tuberculoma in the differential diagnosis of posterior fossa space‐occupying lesions in children, particularly in endemic regions. Intraoperative crush biopsy may be misleading, and definitive histopathological examination with special stains is essential to avoid misdiagnosis and inappropriate treatment. Early confirmation of tuberculosis can dramatically alter management from aggressive oncological therapy to curative antitubercular treatment.

Key Clinical Message

Posterior fossa tuberculoma can closely mimic atypical teratoid/rhabdoid tumor both clinically and radiologically in the pediatric population. In TB‐endemic regions, a high index of suspicion for tuberculoma should be maintained in the differential diagnosis of posterior fossa space‐occupying lesions in children, regardless of the absence of systemic tuberculosis features.

1. Introduction

Tuberculosis (TB) remains one of the most significant infectious diseases worldwide, with the highest burden concentrated in developing nations. India accounts for approximately 27% of global TB cases, making it the country with the single largest share of the global TB burden [1]. While TB primarily affects the lungs, extrapulmonary manifestations occur in 5%–15% of cases, with central nervous system (CNS) involvement accounting for approximately 1% of all TB cases [2]. CNS tuberculosis carries significant morbidity and mortality and its varied presentations make early diagnosis challenging.

Intracranial tuberculomas are granulomatous mass lesions that develop through hematogenous dissemination of Mycobacterium tuberculosis to the brain parenchyma. They represent 5%–10% of intracranial space‐occupying lesions in developing countries and are more common in the pediatric age group, particularly children aged 6 months to 6 years [3, 4]. Cerebellar involvement is relatively more common in children than in adults. These lesions can present with symptoms of raised intracranial pressure, cerebellar dysfunction, and obstructive hydrocephalus, closely mimicking posterior fossa malignancies.

Atypical teratoid/rhabdoid tumor (AT/RT) is a highly aggressive embryonal CNS neoplasm predominantly affecting children under 3 years of age, accounting for 1%–3% of all pediatric CNS tumors [5]. AT/RT frequently arises in the posterior fossa and is characterized by loss of SMARCB1 (INI1) or SMARCA4 expression on immunohistochemistry. The clinical and radiological features of AT/RT can significantly overlap with those of posterior fossa tuberculomas, creating a diagnostic dilemma that has important therapeutic and prognostic implications.

We report an illustrative case of a 5‐year‐old boy from Kashmir, India, whose posterior fossa lesion was initially diagnosed as atypical rhabdoid tumor on intraoperative crush biopsy but was subsequently confirmed as tuberculoma on definitive histopathological examination with immunohistochemistry and special stains. This case highlights the critical importance of thorough pathological workup and the inclusion of infectious etiologies in the differential diagnosis of pediatric posterior fossa tumors, especially in TB‐endemic regions.

2. Case Description

2.1. Clinical Presentation

A 5‐year‐old boy presented to the Department of Neurosurgery at Sher‐i‐Kashmir Institute of Medical Sciences (SKIMS), Srinagar with chief complaints of progressive headache and increasing irritability over the preceding weeks. There was no prior history of tuberculosis contact, fever, weight loss, or night sweats. He had no significant comorbidities. On examination, his Glasgow Coma Scale (GCS) was E4V5M6 (15/15).

2.2. Investigations

Laboratory investigations revealed hemoglobin of 11 g/dL, total leukocyte count of 10,000/μL, and platelet count of 533,000/μL. Renal function, liver function, and coagulation parameters were within normal limits.

MRI of the brain demonstrated a T2/FLAIR hypointense lesion along the cerebellar vermis and left hemisphere measuring approximately 45 × 38 mm. The lesion was isointense on T1‐weighted images with a T2/FLAIR hyperintense rim. It exerted significant mass effect on the fourth ventricle, left middle cerebellar peduncle, and brainstem. There was no diffusion restriction on DWI and no blooming on GRE sequences. Surrounding vasogenic edema was present. Secondary obstructive hydrocephalus was noted with lateral ventricles measuring 40 mm at the trigone level, periventricular cerebrospinal fluid (CSF) ooze, and CSF loculation at the craniovertebral junction. The radiological differential diagnosis included medulloblastoma, atypical teratoid/rhabdoid tumor, and other posterior fossa malignancies (Figure 1).

FIGURE 1.

Showing different MRI sequences suggestive of posterior fossa malignant lesion.

2.3. Surgical Management

Given the obstructive hydrocephalus, a VPMP (ventriculoperitoneal) shunt was initially placed. Later, the patient underwent left suboccipital craniectomy with tumor decompression under general anesthesia.

A permanent VP shunt was preferred over a temporary external ventricular drain (EVD) to provide durable cerebrospinal fluid diversion given the size of the lesion and the anticipated need for prolonged management, and over endoscopic third ventriculostomy (ETV) because CSF loculation at the craniovertebral junction on imaging raised concern for a non‐communicating pattern of hydrocephalus that might not have been reliably managed by ETV alone at presentation. In retrospect, given that the underlying lesion proved to be a tuberculoma that resolved completely with antitubercular therapy, ETV or a temporizing EVD would have been reasonable alternatives that avoid permanent hardware and shunt‐related complications (infection, malfunction, over‐drainage), and this is acknowledged as a limitation of the surgical approach taken in this case.

Intraoperatively, the lesion was firm, non‐vascular and not amenable for aspiration with a cheesy, yellowish central core. The tumor arose from the vermis with adherence to the brainstem. It was non‐cusable and could not be adequately debulked using standard suction techniques. Intraoperative crush biopsy was sent, which was initially interpreted as atypical rhabdoid tumor.

2.4. Histopathological Examination

The final histopathology report provided a dramatically different diagnosis from the intraoperative crush biopsy. The gross specimen consisted of multiple gray‐white tissue pieces ranging from 0.5 × 0.3 cm to 1 × 1 cm.

Microscopic examination of multiple serial sections showed extensive necrotic tissue with epithelioid cell granuloma, Langhans‐type giant cells, and macrophages, with foci of dense acute inflammatory infiltrate. These findings were characteristic of granulomatous inflammation (Figure 2).

FIGURE 2.

Photomicrograph showing numerous Langerhan type giant cells, dense chronic inflammation along with epithelioid granulomas and extensive necrosis and AFB Staining positivity.

Immunohistochemistry (IHC) results were as follows (Table 1).

TABLE 1.

IHC markers with interpretation.

IHC marker	Result	Interpretation
CD68	Positive	Confirming macrophagic nature of cells
EMA	Negative	Ruling out meningothelial tumor
Vimentin	Positive	In fibrotic tissue

Special‐staining with Ziehl‐Neelsen technique for acid‐fast bacilli (AFB) was positive, confirming mycobacterial infection. The final pathological impression was chronic granulomatous pathology consistent with tuberculosis.

Based on the definitive diagnosis, the patient was put on antitubercular therapy. The patient received a 9‐month course of antitubercular therapy along with a short 3‐day course of postoperative corticosteroids to manage perilesional edema. Follow‐up MRI at 3 months showed significant reduction in lesion size, and repeat imaging at 9 months, at completion of ATT, demonstrated complete resolution with no residual lesion. The patient remained neurologically stable through follow‐up.

3. Discussion

This case illustrates a critical diagnostic pitfall in pediatric neurosurgery: a posterior fossa tuberculoma masquerading as an atypical teratoid/rhabdoid tumor. The initial intraoperative crush biopsy diagnosis of atypical rhabdoid tumor, subsequently overturned by definitive histopathology revealing tuberculoma, underscores several important clinical lessons.

The diagnostic challenge in this case arises from the considerable overlap in the clinical and radiological features of posterior fossa tuberculomas and malignant tumors such as AT/RT and medulloblastoma. Both entities present in young children with symptoms of raised intracranial pressure, cerebellar dysfunction, and obstructive hydrocephalus. On MRI, tuberculomas may appear as solid or ring‐enhancing lesions with surrounding edema and mass effect, closely resembling the heterogeneous enhancement patterns seen in AT/RT [5, 6]. In our patient, the T2/FLAIR hypointense lesion with a hyperintense rim, significant mass effect, and associated hydrocephalus was highly suggestive of a malignant posterior fossa tumor. The absence of diffusion restriction, which might have provided a clue against a highly cellular malignancy like AT/RT, did not sufficiently narrow the differential diagnosis.

The intraoperative macroscopic appearance of the lesion‐ firm, non‐vascular, with a cheesy yellowish core—could retrospectively be recognized as consistent with caseous necrosis typical of tuberculomas. However, the adherence to the brainstem and the non‐suckable, firm nature of the lesion contributed to the surgical impression of a malignant neoplasm. This phenomenon has been documented in previous reports where tuberculomas were only correctly identified after definitive histopathological examination [2, 3, 7].

The role of immunohistochemistry proved crucial in this case. CD68 positivity confirmed the macrophagic nature of the cellular infiltrate, pointing toward an inflammatory rather than neoplastic process. EMA negativity helped rule out meningothelial neoplasms. Importantly, in the differential with AT/RT, the loss of INI1 (SMARCB1) expression on immunohistochemistry is the hallmark of AT/RT diagnosis [5]. Although INI1 staining was not explicitly performed in this case, as it was not available at our institution, the overall IHC profile combined with the granulomatous histomorphology and positive AFB staining clearly established the diagnosis of tuberculoma. This highlights that a comprehensive IHC panel, including INI1 staining, should be considered when the crush biopsy suggests rhabdoid morphology in a setting where tuberculosis is endemic.

The AFB positivity on Ziehl‐Neelsen staining was the definitive confirmatory finding. In endemic regions, special stains for acid‐fast bacilli should be performed routinely on all posterior fossa lesions showing granulomatous features, even when intraoperative biopsy suggests malignancy [3, 8].

3.1. Public Health Implications and Tuberculosis Screening Considerations

This case also raises important public health considerations regarding tuberculosis screening in endemic settings. Although the patient resided in Kupwara district, a TB‐endemic area of Kashmir, tuberculosis was not considered in the preoperative differential diagnosis because of the absence of classical risk factors such as known TB contact, fever, weight loss, or night sweats. The child's Bacillus Calmette‐Guérin (BCG) vaccination status could not be definitively confirmed from available records; BCG, administered at birth under India's Universal Immunization Programme, confers only partial protection against disseminated and meningeal childhood tuberculosis and does not reliably prevent localized lesions such as intracranial tuberculoma. Our institution does not have a standardized protocol mandating universal preoperative tuberculosis screening (e.g., Mantoux/tuberculin skin testing, interferon‐gamma release assay, chest radiography) for children undergoing neurosurgical intervention for a presumed intracranial neoplasm; screening is currently performed selectively, guided by clinical suspicion, and this case illustrates how such selective strategies may miss CNS tuberculosis presenting atypically as an isolated mass lesion. Had tuberculosis been suspected or confirmed preoperatively, an initial trial of antitubercular therapy with close radiological monitoring could have been considered, although given the size of the lesion and its mass effect on the fourth ventricle and brainstem with obstructive hydrocephalus, some surgical intervention, whether a minimally invasive biopsy for diagnostic confirmation or CSF diversion for the hydrocephalus, would likely still have been required; earlier suspicion may nonetheless have permitted a more conservative surgical approach. We therefore recommend a lower threshold for preoperative tuberculosis workup, including chest imaging and Mantoux/IGRA testing, in children from TB‐endemic regions presenting with posterior fossa mass lesions, even in the absence of classical constitutional symptoms.

3.2. Comparison With Similar Published Cases

Several similar cases of posterior fossa tuberculomas mimicking malignant tumors in children have been reported in the literature (Table 2). A comparative summary is presented below:

TABLE 2.

Reported cases of posterior fossa tuberculomas in children, mimicking malignant tumor.

Study	Age/Sex	Location	Initial diagnosis	Surgery	AFB	Outcome
Present Case (2026)	5Y/M	Cerebellar vermis/left hemisphere	Atypical rhabdoid tumor (crush biopsy)	Craniectomy + decompression	Positive	Satisfactory; ATT initiated
Aniba et al. [3]	6Y/F	Left cerebellar hemisphere	Medulloblastoma	Surgical excision	Positive	Good; ATT
Koipapi et al. [4]	13Y/F	Left cerebellar hemisphere	Malignant posterior fossa tumor	VP shunt + craniotomy	Positive	Recovered; ATT
Escobedo‐Meléndez et al. [7]	12Y/F	Right posterior fossa	Primary brain tumor	VP shunt + resection	Positive	Died (respiratory complications)
Rasyid et al. [6]	4Y/M	Posterior fossa/cerebellum	Cerebellar abscess	Evacuation + VP shunt	N/A	Persistent hydrocephalus; VP shunt
Wulandari et al. [8]	6Y/F	Right occipital lobe/cerebral	Neoplasm (intraoperative)	Craniotomy + excision	Positive	ATT initiated

Note: Comparison of the present case with similar published cases of posterior fossa tuberculomas mimicking malignant tumors in children.

Aniba et al. [3] reported a 6‐year‐old girl who presented with a three‐month history of headache and gait disturbances. MRI showed a left cerebellar lesion initially suggestive of medulloblastoma. Surgical excision revealed a nodular, avascular lesion subsequently confirmed as tuberculoma on histopathological examination. Similarly, Koipapi et al. [4] described a 13‐year‐old immunocompetent girl from Tanzania who presented with headache, convulsions, blurry vision and gait disturbance. Brain imaging showed a left cerebellar lesion with obstructive hydrocephalus. She underwent VP shunting followed by suboccipital craniotomy and histology confirmed tuberculoma.

Escobedo‐Meléndez et al. [7] reported a 12‐year‐old Mexican girl with a large posterior fossa tuberculoma (61 × 69 × 62 mm) initially interpreted as a primary brain tumor. Despite surgical intervention and subsequent antitubercular therapy following molecular confirmation via Xpert MTB/RIF assay, the patient succumbed to respiratory complications, emphasizing the importance of early diagnosis. Rasyid et al. [6] documented a 4‐year‐old boy from Indonesia whose posterior fossa tuberculoma was initially suspected to be a cerebellar abscess. Following surgical evacuation, persistent communicating hydrocephalus developed, requiring VP shunt placement. Wulandari et al. [8] described a 6‐year‐old girl with a giant cerebral tuberculoma that resembled a neoplasm intraoperatively, with the diagnosis confirmed only after definitive histopathological examination.

The present case is unique in that the intraoperative crush biopsy specifically suggested atypical rhabdoid tumor, a diagnosis that would have significant therapeutic implications including multimodal aggressive oncological treatment with chemotherapy and radiation therapy. The correction to tuberculoma on definitive histopathology fundamentally altered the treatment approach to antitubercular chemotherapy, a potentially curative treatment. This emphasizes that intraoperative frozen section or crush biopsy findings must always be confirmed by definitive histopathology, particularly in TB‐endemic regions.

Several features distinguish tuberculomas from AT/RT that clinicians and pathologists should consider. AT/RT typically occurs in children under 3 years, whereas tuberculomas can occur at any age but are common in children aged 6 months to 6 years in endemic regions [5]. AT/RT characteristically shows loss of INI1 expression, which is absent in tuberculomas. The presence of caseous necrosis, epithelioid cell granulomas, Langhans‐type giant cells, and AFB positivity on special stains are pathognomonic of tuberculoma and are not features of AT/RT [2, 3]. Advanced molecular diagnostic techniques such as the Xpert MTB/RIF assay can rapidly confirm tuberculosis when histopathology is equivocal [7].

India, particularly the Jammu and Kashmir region, falls within a TB‐endemic zone where the incidence of both pulmonary and extrapulmonary tuberculosis remains high. The present case from Kupwara district highlights that even in the absence of pulmonary findings or known TB exposure, CNS tuberculoma must be considered in the differential diagnosis of posterior fossa mass lesions in children [1, 2].

4. Conclusions

This case demonstrates that posterior fossa tuberculoma can closely mimic atypical teratoid/rhabdoid tumor both clinically and radiologically in the pediatric population. The initial misdiagnosis on intraoperative crush biopsy underscores the limitations of frozen section analysis and the indispensable role of comprehensive histopathological examination with immunohistochemistry and special stains in reaching the correct diagnosis. In TB‐endemic regions such as India, a high index of suspicion for tuberculoma should be maintained in the differential diagnosis of posterior fossa space‐occupying lesions in children, regardless of the absence of systemic tuberculosis features. Early and accurate diagnosis is critical, as it can redirect management from aggressive and potentially toxic oncological therapy to curative antitubercular treatment, thereby substantially improving patient outcomes. These findings also underscore the value of a lower threshold for preoperative tuberculosis screening, including chest imaging and Mantoux/interferon‐gamma release assay testing, in children from TB‐endemic regions presenting with posterior fossa mass lesions, even when classical constitutional symptoms or a history of TB contact are absent.

Author Contributions

Aamir Hussain Hela: conceptualization, methodology, investigation, data curation, formal analysis, software, writing – original draft. Romana Makhdoomi: data curation, formal analysis, investigation, visualization, validation, methodology, writing – original draft. Nayil Khursheed: conceptualization, methodology, validation, visualization, supervision, writing – review and editing. Nazmin Ahmed: writing – review and editing, methodology, validation, supervision, visualization. Shazieya Akhter: data curation, investigation, formal analysis. Syed Sabina: data curation, investigation, formal analysis. Vishal Chavda: methodology, validation, visualization, supervision. Mohsin Fayaz: writing – review and editing, conceptualization, methodology, software, supervision, validation, visualization.

Funding

The authors have nothing to report.

Consent

Written informed consent from the patient was obtained for publication according to journal guidelines.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.