Case Of the Week (COW) 10 April 2016
Leptomeningeal carcinomatosis with bilateral IAC metastasis
Findings
Diffuse leptomeningeal enhancement with multiple nodular enhancing lesions noted along the leptomeninges predominant in the posterior fossa . Irregular thick linear enhancement noted within both internal auditory canals with leptomeningeal enhancement. Nodular enhancing mass noted in the bilateral cerebellomedulllary cisterns
Discussion
The vast majority of lesions of the cerebellopontine angle and IAC are benign tumors such as vestibular schwannoma and meningioma . Metastasis to IAC has rarely been reported and accounts for only 0.3% of CPA lesions. The most common origins of metastasis to the temporal bone are breast cancer, lung cancer, renal cancer, stomach cancer, and prostate cancer. Hematogenous dissemination, leptomeningeal carcinomatosis, and direct extension from the adjacent areas are considered as possible routes to temporal bone metastasis, and hematogenous spread accounts for most cases of brain metastasis.The presence of thick linear and extranodular contrast enhancement on MRI may favor metastasis . Clinical history of sudden/rapidly progressive sensorineural hearing loss must raise the possibility of IAC metastasis Facial nerve palsy was reported as the most common symptom of bilateral IAC metastasis.Hearing loss occurs in 71% of patients with bilateral IAC metastasis
Leptomeningeal carcinomatosis with bilateral IAC metastasis
Findings
Diffuse leptomeningeal enhancement with multiple nodular enhancing lesions noted along the leptomeninges predominant in the posterior fossa . Irregular thick linear enhancement noted within both internal auditory canals with leptomeningeal enhancement. Nodular enhancing mass noted in the bilateral cerebellomedulllary cisterns
Discussion
The vast majority of lesions of the cerebellopontine angle and IAC are benign tumors such as vestibular schwannoma and meningioma . Metastasis to IAC has rarely been reported and accounts for only 0.3% of CPA lesions. The most common origins of metastasis to the temporal bone are breast cancer, lung cancer, renal cancer, stomach cancer, and prostate cancer. Hematogenous dissemination, leptomeningeal carcinomatosis, and direct extension from the adjacent areas are considered as possible routes to temporal bone metastasis, and hematogenous spread accounts for most cases of brain metastasis.The presence of thick linear and extranodular contrast enhancement on MRI may favor metastasis . Clinical history of sudden/rapidly progressive sensorineural hearing loss must raise the possibility of IAC metastasis Facial nerve palsy was reported as the most common symptom of bilateral IAC metastasis.Hearing loss occurs in 71% of patients with bilateral IAC metastasis