tumors of the clivus are very rare ; chordomas are the most common type of tumors in this region , representing only 0.1 - 0.2% of all intracranial tumors9 ) .
common sources of bone metastases are breast , prostate , kidney , and thyroid tumors .
kistler and pribram8 ) reported 11 cases with metastatic disease in the sella turcica originating from prostate , breast , lung , thyroid , or lymphosarcoma malignancies .
metastasis from gastric adenocarcinoma is extremely rare and could be explained by a rapid progression of the gastric adenocarcinoma . with regard to sites of intracranial metastasis ,
a literature review revealed only two case reports5,6 ) of clival metastasis from stomach cancer . to the best of our knowledge ,
this is the second published english case report of skull base metastasis originating from a gastric adenocarcinoma . in this study , we report the case of a 42-year - old female patient with an adenocarcinoma of the stomach that metastasized to the clivus .
a 42-year - old female patient was admitted to our hospital with 1-month history of headaches , nausea , and vomiting . in the previous month , she had lost 2 kg of weight .
laboratory examination detected abnormally elevated levels of the alpha feto - protein ( 1665 ng / ml ) , carcinoembryonic antigen ( 1493 ng / ml ) , and carbohydrate antigen 19 - 9 ( 695 u / ml ) .
a computed tomography ( ct ) scan of the brain showed a bulging bony mass , which had destroyed the clivus and affected the sphenoid and cavernous sinuses ( fig .
1 ) . magnetic resonance imaging ( mri ) scan showed an abnormal mass in the upper portion of the clivus , extending to the cavernous sinus and invasion into both carotid arteries .
the mass showed cystic change and heterogeneous patterns of enhancement after intravenous injection of gadolinium ( fig .
a mass ( approximate diameter , 2.7 1.62.0 cm ) was detected in the sellar region .
the mass involved the sphenoid sinus , cavernous sinus , both internal carotid arteries , and the optic chiasm , but had destroyed the clivus and sphenoid corpus .
an abdominal ct scan suggested gastric cancer with liver and multiple lymph node ( ln ) metastases .
a fiber endoscopic study of the stomach confirmed advanced cancer with poor differentiation at the cardia ( fig .
lumbar puncture yielded a watery - clear fluid but the cerebrospinal pressure was not increased and subsequent cytological examination of the fluid revealed no malignant cells .
a chest ct scan showed left supraclavicular lymphadenopathy , indicative of metastasis . for diagnostic purposes ,
histopathological findings of this biopsy were similar to those obtained from the tumor of the stomach ( fig .
the immunohistochemical analysis of the stomach specimen revealed negative results for mucin 5ac , mucin 6 , and mucin 2 on a mucin stain and a positive result for the cd10 protein , which was similar to the results obtained for intestinal - type adenocarcinoma and for clivus metastasis .
after three cycles of chemotherapy [ folfox : folinic acid ( leucovorin ) , fluorouracil ( 5-fu ) , and oxaliplatin ( eloxatin ) ] , the patient 's condition deteriorated rapidly ; liver and ln metastasis progressed , and she developed tumor thrombosis at the splenoportal and superior mesenteric veins and cancer peritonei .
the clivus is a single midline structure of bone comprising a part of the skull base and is formed from the sphenoid rostrally and the occiput caudally . both benign or malignant primary tumors as well as secondary metastatic tumors may occur at the clivus .
some lesions that specifically involve the clivus are chordomas , chondrosarcomas , or lymphomas3,11 ) .
a chordoma is a rare , slow - growing tumor that originates from remnants of the primitive notochord along the craniospinal axis , particularly at either end .
cranial chordomas constitute less than 1% of all intracranial neoplasms , and patients can present with headaches and diplopia11 ) .
metastasis to the clivus is very rare , and only few cases have previously been reported4 ) .
hematogenesis is the most common route of metastasis , and most clival metastatic lesions arise from prostate , thyroid , or breast cancers13 ) .
this is in contrast to chordomas , where surgical decompression commonly results in improvements in eye movement1 ) .
ct evaluation is required to assess the degree of bone involvement or destruction and to detect patterns of calcifications within the lesion .
mri scans provide excellent 3-dimensional analysis of the posterior fossa , especially the brainstem , sella turcica , cavernous sinuses , and middle cranial fossa .
ct is better than mri to observe calcifications and the precise involvement of skull base osteolysis , especially those at the skull base foramina2 ) .
three - dimensional gradient - echo t1-weighted sequences are helpful because they allow the tumor to be visible in 3 planes within a short time and allow a good signal analysis of the tumor2 ) .
skull base chordomas are well delineated at the outset because they displace adjacent structures ; however , more advanced tumors become invasive and have a pseudomalignant appearance with bone erosion and soft tissue invasion , mimicking malignant clival tumors including metastasis2 ) .
one feature that may help distinguish metastases from chordoma - like tumors is hypo - intensity on t2-weighted mri images ; this would be possible because of the higher cellular density and lower cytoplasm to nuclear ratio in metastases12 ) .
most chordomas exhibit a high - intensity signal on t2-weighted images , which is nonspecific . fluid and gelatinous mucoid substances associated with recent and old hemorrhage and necrotic areas are found within the tumor ; in some patients , calcification and sequestered bone fragments are found as well .
the variety of these components may explain the signal heterogeneity observed on an mri scan .
incomplete delineation of the tumor and microscopic distal extension of tumor cells may explain the frequency of recurrences2 ) . on imaging , other primary tumors of the clivus show findings similar to those of metastases of the skull .
lymphoma and plasmacytoma of the clivus , for example , may show a similar mri signal on t2-weighted images7 ) .
another useful diagnostic indication on an mri scan that may help distinguish chordomas from metastases is the heterogeneity with a honeycomb appearance shown by chordomas in lobulated areas , corresponding to low - intensity t1-signal areas within the tumor after contrast infusion .
the pattern of contrast enhancement can be related to the pathologic features of the chordoma , which is organized in lobules with mucinous and gelatinous contents2 ) . in patients without a history of cancer , metastasis to the clivus occurring as the first indication of a primary neoplasm is difficult to identify . in addition , delayed clivus metastases are difficult to detect13 ) .
pallini et al.12 ) reported metastasis to the clivus from a cutaneous melanoma 8 years after the primary tumor was detected , and altman et al.1 ) described a single metastasis to the clivus that presented 12 years after treatment of a follicular thyroid carcinoma .
our patient showed symptoms of cranial nerve palsy as the first sign of metastasis , prior to the diagnosis of the primary stomach malignancy .
the overall prognosis of patients with clival metastases is very poor , with a median overall survival of about 2.5 years .
cranial nerve palsies are associated with a poorer prognosis , with an average survival of only 5 months10 ) .
clival metastasis of gastric adenocarcinoma is extremely rare , but should be considered in the differential diagnosis of bony lesions of the clivus .
 tumors of the clivus and metastases to the clivus are very rare . 
 metastasis involving the clivus has previously been described in only two case reports . in skull metastasis , 
 the breast and prostate are the most common primary foci , while metastasis from gastric carcinoma is extremely rare . 
 a review of the english literature revealed only one published case of clivus metastases from gastric adenocarcinoma . 
 there is no literature thoroughly explaining the differential diagnosis between chordoma and metastasis . 
 here we report a rare case of metastasis to the clivus from a gastric adenocarcinoma in a 42-year - old female patient with sudden blurry vision , presenting as bilateral cranial nerve vi palsy . 