pclps constitute almost half of all intracranial lipomas and corpus callosal anomalies are commonly present in cases with pclps . pclps may have calcification in the periphery and may continue into the lateral ventricles , which is a very rare presentation . although , pclp is often described as corpus callosal lipoma , it is most often pericallosal in location . a 58-year - old arab man presented to our hospital with a 12-month history of recurrent headache . radiological evaluation included computed tomography ( ct ) and magnetic resonance imaging ( mri ) scanning . the ct and mri images revealed a pclp cephalad to the entire antero - posterior extent of the corpus callosum ; continuing as bilaterally symmetrical lateral ventricular cplps [ figures 14 ] . the pclp continued through the choroidal fissure as bilaterally symmetrical lateral ventricular cplps [ figures 2 and 4 ] . peripheral calcifications were noted within the pclp [ figure 2 ] , and the corpus callosum was unremarkable [ figure 3 ] . discrete areas of fatty tissue were noted in the subarachnoid space along the anterior interhemispheric fissure [ figure 3 ] and also in the medial sulcus of the right frontal lobe [ figure 5 ] . incidentally , unusually thick dural calcifications and cavum septum pellucidum were also noted with bilateral supraventricular white matter ischemic lesions . sagittal unenhanced t1 weighted mri scans of a normal brain with superimposed black shading ( black arrows ) show morphological features that classify pclps into anterior [ figure 6a ] and posterior [ figure 6b ] groups and is compared to features seen in our case [ figure 6c ] . 58-year - old man with a 12-month history of recurrent headaches diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . axial unenhanced ct scan of the head shows midline pclp ( white arrows ) and left lateral ventricular cplp ( black arrow ) . 58-year - old man with a 12-month history of recurrent headaches diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . ( a and b ) axial unenhanced ct scans of the head show pclp with peripheral calcifications ( white arrows ) and pclp continuing as bilaterally symmetrical cplps ( black arrows ) . 58-year - old man with a 12-month history of recurrent headaches diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . sagittal unenhanced flair mri scan shows pclp ( white arrows ) and discrete areas of fatty tissue around the anterior interhemispheric fissure ( black arrow ) . also , evident is normal corpus callosum . 58-year - old man with a 12-month history of recurrent headaches diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . ( a and b ) coronal unenhanced t1 weighted mri scans show pclp ( black arrows ) continuing as bilaterally symmetrical lateral ventricular cplps ( white arrows ) . 58-year - old man with a 12-month history of recurrent headaches diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . axial unenhanced t1 weighted mri scan shows pclp ( white arrow ) and bilaterally symmetrical lateral ventricular cplps ( black arrows ) . also note discrete areas of fatty tissue in the medial sulcus of the right frontal lobe ( dashed arrow ) . 58-year - old gentleman complaining of recurrent headaches since twelve months diagnosed with pclp associated with bilaterally symmetrical lateral ventricular cplps without corpus callosal anomalies . ( a , b and c ) sagittal unenhanced t1 weighted mri scans of a normal brain with superimposed black shading ( black arrows ) show morphological classification of pclps ( a : anterior and b : posterior ) and c : appearance as in our case . pclps are classified into anterior [ figure 6a ] and posterior [ figure 6b ] groups indicating their location in relation to the corpus callosum . anterior ones are tubulonodular in shape , larger than 10 mm and are commonly associated with various intracranial malformations including those affecting the corpus callosum . posterior ones are elongated , thin , and smaller than 10 mm and are mostly located around the splenium . the incidence of the corpus callosal and other intracranial anomalies is significantly less in posterior lipomas . in our case , the pclp occupies anterior as well as posterior locations and its posterior part is thicker than the anterior part [ figure 6c ] . to the best of our knowledge pclps may occur with hypogenesis / agenesis of the corpus callosum in most of the cases ( 90% ) of anterior pclps and some of the cases ( 30% ) of posterior pclps . dysgenesis or persistence of the primitive meningeal tissue leads to the formation of the lipomas in the cranium . this process occurs during the first trimester of pregnancy , most likely between the eighth and the tenth weeks of intrauterine pregnancy . the primitive meningeal tissue is present along the inner parts of the pia , the arachnoid and the dura mater and is considered as a mesenchymal tissue originating from neural crest . it occupies the future cisterns in the developing brain of the embryo , and its subsequent resorption leads to the creation of the subarachnoid spaces . failure of this resorption and maldifferentiation of the primitive meningeal tissue leads to the development of the mesenchymal tissue including mature adipose tissue , calcifications , and mature bone tissue replacing its space . this mesenchyme may be located at various places in the cranium , which explains the presence of mature adipose tissue or lipomas and calcifications in multiple subarachnoid cisterns . the lipomas in the cranium can thus be considered as malformations and not true neoplasms . the normal structures in the subarachnoid space including nerves and vessels may traverse through these lipomas . the process of resorption of the primitive meningeal tissue and formation of the subarachnoid cisterns occurs in an orderly fashion , and preferential cisternal sites for development of lipomas in the cranium were described based on it . mature bone tissue is considered to be an osseous metaplasia occurring after the formation of calcifications , and occurrence of osseous tissue and lipomas in the cranium associated with corpus callosal agenesis is considered to be originating due to disturbances in development of the neural crest . the association of corpus callosal agenesis with pclp is common , because , maldevelopment of primitive meninx occurs before the interhemispheric commissural fissures develop . during the embryonic stage of the choroid plexus in lateral ventricles , there is an insinuation of a part of the interhemispheric cistern and the tela choroidea of the ependymal roof plate through the choroidal fissure with infolding of the primitive meninx . the developing choroid plexus is attached to the primitive meninx and thus the primitive meninx enters into the ventricle . pclp would use the same course to get into the lateral ventricles , even in cases with corpus callosal agenesis . these cases may present with various central nervous system related symptoms like headache , epileptic fits , limb weakness , and psychological or memory related problems . in our case also it was detected late at the age of 58 years because he had no significant neurological disabilities , possibly due to the absence of any central nervous system anomalies other than the pclp and cplps . our patient has an intracranial lipoma displaying fat density and peripheral calcifications on ct scans . it lies cephalad to the entire antero - posterior extent of the corpus callosum ( pclp ) . the pclp also extends into both lateral ventricles through the narrow neck of the choroid fissure to appear as cplps . management of pclp is mostly symptomatic , and prognosis depends on the presence of additional central nervous system abnormalities . surgery is not indicated in isolated pericallosal lipomas ; however , it is essential to exclude atypical intracranial lipomas which require surgery . the appearance of pclp in our case does not correspond to the descriptions of any of the existing morphological types ( anterior and posterior ) of classification of pclps ; it is rather a mixed variant , where pclp occupies both anterior and posterior locations around the corpus callosum . to our knowledge , this appearance has not been described in the published literature before . this rare presentation of intracranial lipomas may provide new insights to anatomists or embryologists to confirm or refute various theories related to the origin of intracranial lipomas . confirmed diagnosis of an isolated and typical pclp helps prevent any further costly investigations and interventions . also , it is necessary to diagnose rare and atypical pclps , which require surgical intervention . it is , therefore , essential for physicians and radiologists to know about this entity and its various atypical presentations .
lipomas constitute less than 5% of primary brain tumors . 
 pericallosal lipomas ( pclp ) constitute almost half of all intracranial lipomas . 
 corpus callosal anomalies commonly occur in cases with pclps . 
 although pclp is often described as corpus callosal lipoma , it is most often pericallosal in location . 
 pclps may have calcification in the periphery and may continue into lateral ventricles , which is a very rare presentation . 
 we observed a case of pclp with peripheral calcifications associated with pclp continuing as bilaterally symmetrical lateral ventricular choroid plexus lipomas ( cplp ) without any corpus callosal or other central nervous system anomalies , and as this is not been previously reported , we are presenting it . 
 the appearance of pclp in this case does not correspond to the descriptions of any of the existing morphological types ( anterior and posterior ) of classification of pclps ; it is rather mixed , where pclp occupies both anterior and posterior locations around the corpus callosum .