primary central nervous system ( cns ) lymphoma is a relatively uncommon malignancy , accounting for approximately 6% of all malignant cns neoplasms . they typically occur in middle - aged and older adults , although it can be seen more commonly in younger patients with human immunodeficiency virus ( hiv ) or transplant recipients . more than 90% of primary cns lymphomas are of the diffuse large b - cell variety .
most of these lesions appear hyperdense on a non - contrast enhanced computed tomography ( ct ) scan and tend to demonstrate restricted diffusion on magnetic resonance imaging ( mri ) , given their high cellularity .
this is the eighth reported case of cns lymphoma involving the pineal gland in the literature .
a 65-year - old male presented with a 2-week history of worsening headache and double vision .
initial non - contrast head ct demonstrated a homogeneous hyperdense mass in the pineal gland region with mild hydrocephalus , but no calcification or hemorrhage [ figure 1 ] .
contrast mri was performed , which demonstrated a homogeneously enhancing mass involving the pineal gland , with increased perfusion with corresponding low apparent diffusion coefficient values [ figure 2 ] .
the mass was hypointense on t1-weighted images and isointense to mildly hyperintense compared to brain parenchyma on t2-weighted images .
leptomeningeal enhancement was identified near the supraoptic recess and along the cerebellar velum [ figure 3 ] .
65-year - old male presented with headache and was later diagnosed with pineal gland lymphoma .
axial non - contrast ct of the head demonstrates a homogeneously hyperdense mass ( arrow ) in the pineal gland region .
65-year - old male presented with headache and was later diagnosed with pineal gland lymphoma .
( a ) axial t1 post - contrast mri image of the head demonstrates a homogeneously enhancing mass ( arrow ) in the region of the pineal gland .
( b ) axial mri diffusion - weighted imaging ( dwi ) sequence demonstrates increased signal ( arrow ) .
( c ) the corresponding axial apparent diffusion coefficient ( adc ) map demonstrates low adc values ( arrow ) .
65-year - old male presented with headache and was later diagnosed with pineal gland lymphoma .
( a ) axial t2 flair mr image demonstrates the pineal gland mass ( arrow ) as isointense to mildly hyperintense to brain parenchyma .
( c ) sagittal t1 post - contrast mr image again shows the enhancing pineal gland mass ( arrowhead ) as well as leptomeningeal enhancement near the supraoptic recess ( arrow ) and cerebellar velum .
the histopathology showed a hypercellular tumor with high nuclear / cytoplasmic ratio , but no pineocytomatous or homer wright rosettes or papillary architecture [ figure 4 ] .
tumor cells exhibited vimentin , cd45 , extensive cd20 , cd79a , and nuclear pax 5 reactivity . in situ hybridization showed kappa , but no lambda light chain hybridization .
there was focal granular synaptophysin , but no neuron specific enolase ( nse ) , glial fibrillary acidic protein ( gfap ) , beta tubulin , cam 5.2 , thyroid transcription factor ( ttf-1 ) , cd99 , pancytokeratin , myogenin , or neurofilament immunoreactivity .
65-year - old male presented with headache and was later diagnosed with pineal gland lymphoma .
( a ) hematoxylin and eosin staining at magnification ( 40 ) demonstrates malignant lymphoma with coarse chromatin , nucleoli ( arrow ) , and mitoses .
( b ) diaminobenzidene chromagen at magnification ( 40 ) demonstrates tumor cells ( arrow ) extensively exhibiting cd20 reactivity .
( c ) diaminobenzidene chromagen at magnification ( 40 ) demonstrates tumor cells ( arrow ) exhibiting extensive cd79a , but no neural , myogenic , or epithelial marker immunoreactivity . at the time of biopsy ,
staging chest , abdomen , and pelvis ct exams revealed no other areas of lymphomatous involvement .
the patient was discharged home in stable condition , but presented to the emergency department 1 week later with worsening hydrocephalus and headache . at this time
, the patient underwent ventriculoperitoneal shunt placement for management of his hydrocephalus and received one cycle of high - dose methotrexate .
however , he developed severe hypotension and acute kidney injury 2 months after his diagnosis and was re - admitted to the hospital , with repeat non - contrast head ct showing enlargement of the mass .
given his multiple medical comorbidities and evidence of disease progression , the patient and his family elected to pursue comfort care measures .
they can affect both immunocompetent and immunocompromised patients , although patients who are immunocompromised typically present at a younger age .
there is a predilection for the periventricular white matter and basal ganglia , and they can present as either solitary or multiple mass lesions .
on non - contrast ct , most masses are hyperdense , given the high cellularity , and surrounding edema is common .
contrast enhancement is typically homogeneous , but can have a more variable appearance in immunocompromised patients . on mri , although these lesions can appear hypointense to gray matter on t1-weighted imaging and hypointense to isointense on t2-weighted imaging , the hallmark is restricted diffusion due to the increased cellularity .
primary cns lymphoma has rarely been found to involve the pineal gland , with seven cases reported in the literature .
headache was one of the most common presenting symptoms in these patients , although symptoms include cranial nerve and cauda equina syndrome , focal neurologic deficits , fever , diplopia , altered mental status , and seizure .
the average age at diagnosis was 40 years , and only one female patient has been reported .
b - cell lymphoma has been the most common pathologic diagnosis , with cases including large b cell lymphoma , malignant b cell lymphoma , immunoblastic lymphoma , and anaplastic lymphoma kinase positive anaplastic large cell lymphoma ( alk-1 positive alcl ) .
there has been a single case of malignant t cell lymphoma and one case providing no additional detail to the diagnosis of lymphoma .
imaging features in these cases most commonly included hydrocephalus and relatively homogeneously enhancing lesions identified on mri .
the imaging findings in this particular case were typical of highly cellular tumor with leptomeningeal involvement , given the hyperdense mass on non - contrast ct and restricted diffusion with contrast enhancement on mri .
a histologic diagnosis is essential prior to beginning invasive treatment , as the imaging characteristics of pineal lymphoma are not necessarily pathognomonic .
other differential considerations for a tumor in the pineal region with these imaging characteristics include pineoblastoma , germ cell tumor , and metastatic disease .
pineoblastoma is a pediatric diagnosis with masses typically appearing more heterogeneous and with peripheral calcifications .
germ cell tumors are also typically diagnosed at a younger age and are associated with calcification . while metastatic disease may fit the imaging pattern and patient age seen in our case , a primary malignancy was not identified .
our patient was treated with high - dose methotrexate , which has been shown to increase survival in patients with primary cns lymphoma .
the addition of rituximab to this regimen has also been shown to improve remission rates and progression - free survival ; however , our patient decompensated and progressed prior to initiation of this therapy .
primary cns lymphoma is an uncommon primary cns malignancy , and rarely involves the pineal gland .
however , in the appropriate clinical context and with relevant imaging findings , lymphoma should be in the differential diagnosis of a pineal gland mass .
 a 65-year - old male presented to our institution with acute - onset headache . 
 imaging studies demonstrated a mass in the region of the pineal gland , with subsequent histopathology findings being consistent with large b cell lymphoma . 
 the patient was treated with methotrexate , but ultimately did not survive . primary central nervous system ( cns ) 
 lymphoma rarely involves the pineal gland , but should be considered in the differential diagnosis of pineal gland tumors in the appropriate clinical setting . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION
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