Giant frontal intraparenchymal schwannoma: unexpected diagnosis

Curious Case of Acoustic Schwannoma of Middle Cranial Fossa: A Case Report

Acoustic neuromas are the most common lesion in the cerebellopontine angle. The authors report a unique case of acoustic schwannoma, presenting in middle cranial fossa masquerading as meningioma in a 24-year-old man, presenting with headache and focal seizures. Contrast-enhanced MRI of the brain revealed a mass lesion of the right middle cranial fossa consistent with features of meningioma. Intraoperatively a well-defined tumor with attachment to anterior petrous bone was excised. In the immediate postoperative period, the patient developed right-sided hearing loss, which was proven to be retrochoclear hearing loss on brainstem evoked response audiometry. Histopathology findings were consistent with benign schwannoma. Acoustic schwannoma originating in an unusual location middle cranial fossa is a plausible explanation of such unusual occurrence. Such a case has never been reported in the literature.

Intraparenchymal Schwannoma: A Rare Entity

A 60-year-old woman noted headaches, transient visual obscurations and pulsatile tinnitus. She had Frisén grade 4 papilloedema. Brain magnetic resonance imaging showed a large subfrontal cystic mass with ring enhancement. Tumour pathology was in-keeping with an intraparenchymal schwannoma. This uniquely rare tumour is discussed.

Intraparenchymal schwannoma with calcification of the temporal lobe: Case report and literature review

RATIONALE

Intracranial schwannomas most frequently arise from the trigeminal nerve and the vestibular nerve. Schwannomas within the cerebral parenchyma are exceedingly rare. Additionally, calcification is an uncommon histopathological and radiological characteristic in schwannomas.

PATIENT CONCERNS

A 46-year-old man presented to us with sudden onset epileptic seizure and a 3-month history of intermittent headache. After admission, the physical and neurological examinations were all normal. Brain CT revealed an irregular, well-defined, hyperdense mass in the right temporal lobe. MRI showed a solid mass appearing iso- to hypointensity on T1-weighted imaging and heterogeneous intensity on T2-weighted imaging in the right temporal lobe; after Gd-DTPA administration, the lesion showed heterogeneous enhancement.

DIAGNOSIS

Histopathological examination revealed hyperchromatic nuclei and loose intercellular matrix with calcification. Immunohistochemical analysis demonstrated that the tumor was strongly positive for S100 protein but negative for GFAP and CK, which was consistent with a schwannoma.

INTERVENTIONS AND OUTCOMES

A surgical resection via the right temporal approach was performed. Intraoperatively, we noticed that the tumor was grayish yellow, capsuled, and located entirely within the temporal parenchyma. A gross total resection was achieved. The postoperative course was uneventful, and there was no epileptic seizure.

LESSONS

Intraparenchymal schwannoma with calcification is an uncommon histopathological and radiological characteristic in schwannomas. Intraparenchymal schwannoma with calcification is extremely rare. The early identification and appropriate surgical treatment should be highlighted.

Frontal lobe intracerebral schwannoma mimicking metastatic lesion in a patient with papillary thyroid carcinoma

Intracerebral schwannomas are quite rare. Due to their rarity and lack of pathognomonic imaging features, intracerebral schwannoma may be overlooked in the initial differential diagnosis of an intra-axial mass with heterogeneous ring enhancement, such as a high-grade glioma, metastasis or lymphoma. Here, we present a 21-year-old woman with prior diagnosis of papillary thyroid carcinoma and recent history of seizures who had a heterogeneously ring-enhancing left frontal lobe mass. Our presumptive diagnosis was a metastatic tumor since she had a history of thyroid cancer. Because of uncertainty in preoperative differential diagnosis, the decision was made to proceed with excisional biopsy of the tumor via craniotomy. She underwent uneventful gross total resection of the tumor that histopathology revealed as an intracerebral schwannoma.