CPA melanoma: diagnosis and management.
OBJECTIVE
Melanoma rarely invades the cerebellopontine angle (CPA) and can evade accurate diagnosis, which may alter management decisions. Diagnosis may be facilitated via careful history, magnetic resonance imaging (MRI) findings, and cerebrospinal fluid (CSF) analysis.


METHODS
Retrospective case review.


METHODS
Tertiary referral center.


METHODS
Thirteen internal auditory canal/CPA lesions in eight patients who presented with CPA syndrome and who had a pathological diagnosis consistent with malignant melanoma. There were four bilateral and four unilateral lesions. Six of eight patients had a history of melanoma. One was apparently primary CPA lesion, whereas all others were metastatic.


METHODS
T1- and T2-weighted precontrast and postcontrast gadolinium-enhanced MRI were obtained, including fat suppression and fluid-attenuated inversion recovery sequence images in two patients; lumbar puncture with CSF centrifugation and cytological analysis confirmed the diagnosis in two patients. Translabyrinthine craniotomy was performed for tumor extirpation in five patients.


METHODS
Symptoms at presentation, MRI findings, presence of malignant cells in CSF, tumor progression, intraoperative findings, response to treatment, time interval from initial diagnosis of melanoma elsewhere, and survival.


RESULTS
Seven of eight patients had history and/or MRI findings suggestive of malignancy in the internal auditory canal and/or CPA, and diagnosis was confirmed via CSF analysis in two patients. In one patient, diagnosis was made at surgery.


CONCLUSIONS
Internal auditory canal melanoma portends a grim prognosis, can occur up to 17 years after initial melanoma diagnosis/treatment, and can be detected with appropriate MRI sequences, especially enhanced fluid-attenuated inversion recovery images. In disseminated cases, diagnosis can be confirmed with lumbar puncture demonstrating malignant cells. Management includes tumor resection when melanoma seems to be solitary and malignant cells are not present in CSF. Intrathecal chemotherapy and radiation are recommended for dissemination, although the survival rate is still poor.
Brackmann
Derald E
DE
House Clinic, Los Angeles, California 90057, USA. dbrackmann@hei.org
Doherty
Joni K
JK
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002528:Cerebellar Neoplasms / Q000175:diagnosis* / Q000556:secondary / Q000628:therapy*; D002530:Cerebellopontine Angle; D003131:Combined Modality Therapy; D005158:Facial Paralysis / Q000209:etiology; D017809:Fatal Outcome; D005260:Female; D006312:Hearing Loss, Bilateral / Q000209:etiology; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008545:Melanoma / Q000175:diagnosis* / Q000556:secondary / Q000628:therapy*; D008875:Middle Aged; D019635:Neurosurgical Procedures; D012189:Retrospective Studies
D000970:Antineoplastic Agents