Painful sixth cranial nerve palsy caused by a malignant trigeminal nerve sheath tumor

Spontaneous malignant transformation of trigeminal schwannoma: consideration of responsible gene alterations for tumorigenesis-a case report

Malignant peripheral nerve sheath tumors (MPNSTs) arising from the trigeminal nerves are extremely rare (only 45 cases, including the present case, have been published) and have been reported to develop de novo from the peripheral nerve sheath and are not transformed from a schwannoma or neurofibroma. Here, we report a case of MPNSTs of the trigeminal nerve caused by the malignant transformation of a trigeminal schwannoma, with a particular focus on genetic considerations. After undergoing a near-total resection of a histologically typical benign schwannoma, the patient presented with regrowth of the tumor 10 years after the primary excision. Histopathologic and immunochemical examinations confirmed the recurrent tumor to be an MPNST. Comprehensive genomic analyses (FoundationOne panel-based gene assay) showed that only the recurrent MPNST sample, not the initial diagnosis of schwannoma, harbored genetic mutations, including NF1-p.R2637* and TP53-p.Y234H, candidate gene mutations associated with malignant transformation. Moreover, the results of reverse transcription polymerase chain reaction showed that the fusion of SH3PXD2A and HTRA1, which has been reported as one of the responsible genetic aberrations of schwannoma, was detected in the recurrent tumor. Taken together, we could illustrate the accumulation process of gene abnormalities for developing MPNSTs from normal cells via schwannomas.

Malignant trigeminal nerve sheath tumor and anaplastic astrocytoma collision tumor with high proliferative activity and tumor suppressor p53 expression

Background. The synchronous development of two primary brain tumors of distinct cell of origin in close proximity or in contact with each other is extremely rare. We present the first case of collision tumor with two histological distinct tumors. Case Presentation. A 54-year-old woman presented with progressive atypical left facial pain and numbness for 8 months. MRI of the brain showed left middle cranial fossa heterogeneous mass extending into the infratemporal fossa. At surgery, a distinct but intermingled intra- and extradural tumor was demonstrated which was completely removed through left orbitozygomatic-temporal craniotomy. Histopathological examination showed that the tumor had two distinct components: malignant nerve sheath tumor of the trigeminal nerve and temporal lobe anaplastic astrocytoma. Proliferative activity and expressed tumor protein 53 (TP53) gene mutations were demonstrated in both tumors. Conclusions. We describe the first case of malignant trigeminal nerve sheath tumor (MTNST) and anaplastic astrocytoma in collision and discuss the possible hypothesis of this rare occurrence. We propose that MTNST, with TP53 mutation, have participated in the formation of anaplastic astrocytoma, or vice versa.

Malignant peripheral nerve sheath tumors of the trigeminal nerve: a systematic review of 36 cases

OBJECT

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare form of malignancy arising from the Schwann cells of peripheral nerves. MPNSTs of the trigeminal nerve are exceptionally rare, with only a handful of reports in the literature. These tumors are typically very aggressive, resulting in significant patient morbidity and a generally grim prognosis. Most current reports suggest that radical resection with radiation therapy offers the best benefit. In this study, the authors systematically reviewed the world English-language literature on MPNSTs of the trigeminal nerve to analyze the presentations, treatment options, and outcomes for patients with this disease.

METHODS

A literature search for MPNSTs of the trigeminal nerve confined to nonanimal, English-language articles was conducted utilizing the PubMed database, with additional cases chosen from the references of selected articles. Only cases of confirmed MPNSTs of the trigeminal nerve or its peripheral branches, based upon surgical, pathological, or radiological analysis, were included.

RESULTS

From the literature search, 29 articles discussing 35 cases of MPNSTs of the trigeminal nerve were chosen. With the addition of 1 case from their own institution, the authors analyzed 36 cases of trigeminal MPNSTs. The average age of onset was 44.6 years. These tumors were more commonly seen in male patients (77.1%). The gasserian ganglion was involved in 36.1% of the cases. Of the cases in which the nerve distribution was specified (n = 25), the mandibular branch was most commonly involved (72.0%), followed by the maxillary branch (60.0%) and the ophthalmic branch (32.0%), with 44.0% of patients exhibiting involvement of 2 or more branches. Altered facial sensation and facial pain were the 2 most commonly reported symptoms, found in 63.9% and 52.8% of patients, respectively. Mastication difficulty and diplopia were seen in 22.2% of patients, facial weakness was seen in 19.4%, and hearing loss was present in 16.7%. With regard to the primary treatment strategy, 80.6% underwent resection, 16.7% underwent radiation therapy, and 2.9% received chemotherapy alone. Patients treated with complete resection followed by postoperative radiation therapy had the most favorable outcomes, with no patients showing evidence of disease recurrence with a mean follow-up of 34.6 months. Patients treated with incomplete resection followed by postoperative radiation therapy had more favorable outcomes than patients treated with incomplete resection without radiation therapy or radiation therapy alone.

CONCLUSIONS

Trigeminal MPNSTs most commonly present as altered facial sensation or facial pain, although they exhibit a number of other clinical manifestations, including the involvement of other cranial nerves. While a variety of treatment options exist, due to their highly infiltrative nature, aggressive resection followed by radiation therapy appears to offer the greatest chance of recurrence-free survival.

Updates on the diagnosis and treatment of intracranial nerve malignant peripheral nerve sheath tumors

Background:

Malignant peripheral nerve sheath tumors (MPNSTs) are rare entities and MPNSTs of intracranial nerves are even more sporadic. MPNSTs present diagnosis and treatment challenges since there are no defined diagnosis criteria and no established therapeutic strategies.

Methods:

We reviewed literature for MPNST-related articles. We found 45 relevant studies in which 60 cases were described.

Results:

We identified 60 cases of intracranial nerve MPNSTs. The age ranged from 3 to 75 years old. Male to female ratio was 1.5:1. The most involved cranial nerves (CNs) were CN VIII (60%), CN V (27%), and CN VII (10%). Most of the MPNSTs reported (47%) arose sporadically, 40% arose from a schwannoma, 8% arose from a neurofibroma, and 6% arose from an unspecified nerve tumor. Twenty patients had a history of radiation exposure, four patients had neurofibromatosis type 1 (NF1), four patients had neurofibromatosis type 2 (NF2), and NF2 was suspected in two other patients. Twenty-two patients were treated with radiotherapy and presented a higher survival rate. Seventy-two percent of patients died of their disease while 28% of patients survived. One-year survival rate was 33%. Forty-five percent of tumors recurred and 19% of patients had metastases.

Conclusion:

MPNSTs involving CNs are very rare. Diagnosis is made in regards to the histological and pathological findings. Imaging may help orient the diagnosis. A preexisting knowledge of the clinical situation is more likely to lead to a correct diagnosis. The mainstay of treatment is radical surgical resection with adjuvant radiotherapy. Since these tumors are associated with a poor prognosis, a close follow-up is mandatory.