Peripheral primitive neuroectodermal tumor of the cerebellopontine angle

High rate of bilaterality in internal auditory canal metastases

PURPOSE

Presentation of three cases of metastatic carcinoma to the internal auditory canal bilaterally, as well as a systematic review of the literature regarding the characteristics of these lesions.

MATERIALS AND METHODS

Using a MEDLINE Ovid search (1946-2015), we identified and reviewed 102 cases of metastatic carcinoma to the internal auditory canal. Metrics recorded include: patient age, sex, tumor type, laterality, past oncologic history, co-occurring metastatic sites, clinical findings, radiographic findings, therapy received, and outcome. Cases of unilateral versus bilateral IAC were compared.

RESULTS

Remarkably, 52.9% reported cases of internal auditory canal metastases have bilateral occurrence. The most common primary tumor sites for internal auditory canal metastases were lung (21.2%), skin (18.6%), and breast (16.7%), with lung and skin cancers having the highest rates of bilateral metastasis. Meningeal metastasis occurred at a much higher rate in bilateral cases (47.2%) versus unilateral cases (8.5%). Brain parenchymal metastasis also occurred at a higher rate in bilateral cases (38.2%) versus unilateral cases (19.2%). Outcomes for cases of internal auditory canal metastases are generally poor, with 56.3% of unilateral cases and 86.1% of bilateral cases reporting patient death within 5 years from diagnosis.

CONCLUSIONS

In cases of internal auditory canal metastasis, clinicians should carefully assess for not only contralateral disease but also additional metastatic disease of the central nervous system. Rapid-onset hearing loss, tinnitus, vertigo, or facial palsy should raise suspicion for internal auditory canal metastasis, particularly in patients with a known oncologic history.

First description of a primitive neuroectodermal tumor arising in the nose

We report the case of a 12-year-old girl, who consulted us with one-year history of an 8 mm nose lesion that was painless and firm upon palpation. The lesion was resected conservatively. Immunohistochemistry was in favor of a primitive neuroectodermal tumor (PNET)/Ewing's sarcoma lesion, excluding epithelial, lymphoid, and other tumors. After a second resection, our patient was referred to chemotherapy and has already undergone 9 cycles out of 14. The patient is to date with no evidence of persistent or recurrent disease. To our knowledge, this is the first description of a PNET arising in the nose.

Ewing's Sarcoma/Peripheral Primitive Neuroectodermal Tumor in the Cerebellopontine Angle : Diagnosis and Treatment

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an unusual malignancy with aggressive behavior. ES/PNET in the cerebellopontine angle (CPA) is extremely uncommon, and we report on a rare case here. A 31-year-old man presented with one month history of left facial palsy, hearing loss, swallowing difficulty, and hoarseness. Magnetic resonance images showed a large mass in the left CPA and a small one in the right cerebellar hemisphere. The patient underwent a surgery for the CPA mass lesion, and the pathology was compatible with ES/PNET. Radiation therapy and chemotherapy were administered. In contrast to the initial radiologic findings resembling vestibular schwannoma or meningioma, ES/PNET had several distinct clinical features. A patient with a CPA mass and presenting unusual clinical features should be suspected of having a rare malignancy.