the most common site is legs and melanomas in men are most common on the back .
melanoma of the clivus is an extremely rare case presentation with only a few cases reported in the literature .
conventional imaging techniques like computed tomography ( ct ) and magnetic resonance imaging ( mri ) may be suboptimal in evaluating such tumor , and may lead to inaccurate staging . a multimodality whole body imaging technique , 2-deoxy-2-[18f ] fluoro - d - glucose positron emission tomography / ct ( 18f - fdg pet / ct )
is being increasingly used in oncology for staging of multiple malignancies to know the spread of the tumor in the body .
this rare case is important because it highlights the extensive disease that can be caused by a clival tumor and the role of noninvasive imaging , that is , 18f - fdg pet / ct in correct staging and hence , guiding further management of the disease .
a 55-year - old woman , presented to the hospital with chief complaints of headache , decreased vision in the left eye , and occasional episodes of vomiting since 3 months .
mri brain revealed altered signal intensity lesion with solid , hemorrhagic , and few cystic components in basiocciput , basisphenoid , clivus , sella , and right petrous apex ; displacing optic chiasma superiorly .
there was associated soft tissue component extending into cavernous sinus with partial encasement of cavernous segment of right internal carotid artery .
cemr study revealed a large moderately enhancing mass lesion involving the clivus with sellar - suprasellar extension with encasement of bilateral internal carotid arteries suggestive of plasmacytoma / chordoma or metastasis [ figure 1 ] .
she underwent endonasal transsphenoidal excision of clival tumor and the black colored , relatively avascular tumor was confirmed to be melanocytic melanoma of clivus on histopathological examination .
the patient was thoroughly examined to rule out any lesion on the skin and mucosa with other investigations including chest x - ray . a week after the surgery , this patient was referred to our department for a whole body 18f - fdg pet / ct scan for restaging .
whole body pet - ct scan was performed after intravenous ( iv ) administration of 10 mci of 18f - fdg .
pet and contrast - enhanced ct images were acquired and reconstructed to obtain transaxial , coronal , and sagittal views .
the study revealed residual hypermetabolic well - defined lobulated soft tissue lesion in the basisphenoid and sella turcica region extending into the extraaxial space of right middle cranial fossa causing destruction of the sella turcica , sphenoid sinus , dorsal sella , and clivus ; suggestive of residual disease .
also multiple metabolically active skeletal lesions were noted suggestive of skeletal metastasis [ figure 2 ] .
( a and b ) magnetic resonance images - t1 and t2 weighted axial sections of the brain ( preoperative ) showing altered signal intensity lesion with solid , hemorrhagic , and few cystic components in basiocciput , basisphenoid , clivus , sella , and right petrous apex ; displacing optic chiasma superiorly associated with soft tissue component extending into cavernous sinus with partial encasement of cavernous segment of right internal carotid artery ( a ) maximal intensity projection image of the patient from base of skull to mid - thigh showing focal areas of hypermetabolism throughout the body corresponding to multiple metastatic skeletal lesions .
physiological uptake noted in heart , liver , bowel , kidneys , and urinary bladder , ( b ) sagittal positron emission tomography and fused pet - computed tomography images reveal abnormal fluoro-2-deoxy - d - glucose uptake in spinal column corresponding to lytic lesions on ct , ( c ) metabolically active well - defined lobulated soft tissue lesion in basisphenoid and sella turcica region , extending into the extraaxial space of right middle cranial fossa and indenting the medial temporal lobe causing destruction of the sella turcica , sphenoid sinus , dorsal sella , and clivus , ( d ) hypermetabolic lytic intradiploic lesions noted in left anterior frontal , high frontal , and parietal region
eighty five percent of the patients diagnosed in early stages can be cured with surgery .
primary intracranial malignant melanoma is a rare entity with incidence estimated to be 0.005 cases per 100,000 population .
the age of the patients usually range from 15 - 71 years , with a peak incidence in the 5 decade .
symptoms at presentation include headache ; vomiting due to intracranial hypertension ; hydrocephalus ; focal neurological deficits due to compression of the brain , spinal cord , or cauda equina ; subarachnoid hemorrhage ; and seizures . to our knowledge ,
very few cases of primary melanoma of the clivus have been cited in the literature previously .
metastases involving this area have been previously described as a single case report or included in series with other skull base tumors . in 2009 ,
a literature review was performed by pallini et al . , which reveals that out of 46 patients who underwent surgery for clival bone tumor , seven proved to be metastatic , representing 0.18 and 0.42% , respectively of intracranial and skull base tumors which were treated in their institution in the study period between january 1995 and december 2007 .
the primary tumors associated were lung adenocarcinoma ( n = 2 ) , prostate carcinoma ( n = 2 ) , skin melanoma ( n = 1 ) , hepatocarcinoma ( n = 1 ) , and lung squamous cell carcinoma ( n = 1 ) . in 2010 , chaudhary et al . , presented a case of an atypical clival meningeal melanoma treated with a multidisciplinary staged transcrural and transsphenoidal endoscopic surgical approach .
no other metastases was evident for 2 years after initial symptoms and with no evidence of a cutaneous source , diagnosis of a primary meningeal lesion of the clivus was made .
bone metastases occur in a significant proportion of patients with metastatic melanoma . in such patients survival
, in 108 patients in 2008 , which revealed median survival following diagnosis of bone metastases in malignant melanoma to be 3.2 months ( range 0.3 - 47.4 months ) .
bone metastases most commonly occurred in patients with the primary melanoma originating on the back and lower limbs and spine was the commonest site of bone involvement , followed by ribs , pelvis , long bones , and skull .
fdg pet is a sensitive and specific technique for patients with melanoma but has limitations with small ( less than 1 cm ) , pulmonary , and brain metastases .
it is felt to be superior to ct alone in detecting abdominal , nodal , subcutaneous , and skin sites .
it is useful in assessing extent of disease in patients with surgically resectable disease by conventional methods as it may render them unresectable in a considerable population . in our patient ,
surgical removal of the tumor was done from an outside institution and was referred to us for further management .
pet - ct scan was performed for the patient in view of histological diagnosis of melanocytic melanoma .
also , no primary site could be localized after thorough general examination of the skin .
the findings on pet - ct scan suggest that the clival mass represents the primary site of malignancy .
this case adds to the literature on the occurrence of intracranial malignant melanoma in patients with extensive skeletal metastasis , and supports the finding that such tumors need to be followed carefully .
 malignant melanoma of the clivus is a rare entity , for which there is little evidence - based literature for guiding clinicians to understand the importance of disease staging via noninvasive imaging strategy . 
 this report highlights the case of a 55-year - old lady with histopathologically confirmed melanocytic melanoma of the clivus  postoperative status , with multiple skeletal metastasis , demonstrated on 2-deoxy-2-[18f ] fluoro - d - glucose positron emission tomography / computed tomography ( 18f - fdg pet / ct scan ) . the experience gained with this patient demonstrates the feasibility and usefulness of this noninvasive application in accurate staging and hence , correct decision making regarding further treatment . 
INTRODUCTION
CASE REPORT
DISCUSSION