intracranial dermoid cysts and colloid cysts are rare congenital lesions generally occurring along the midline .
dermoid cysts are known to be ectodermal in origin while debate still exists about the embryological origin of colloid cysts . here
, we report a 22-year - old young male with suprasellar dermoid cyst associated with a colloid cyst of the third ventricle and discuss the possibility of their unified embryological derivation . to best of our knowledge ,
a 22-year - old male patient presented with on and off frontal headaches and occasional blurring of vision for 1 year .
clinical examination was normal with visual acuity of 6/6 in both eyes without evidence of any field defects on perimetry .
magnetic resonance imaging ( mri ) revealed mainly cystic lesion in the suprasellar region with small solid component anteriorly which was hyperintense on t1-weighted sequences without any contrast enhancement .
a colloid cyst of 1.2  1.5 cm was seen at the foramen of monro , mainly occupying third ventricle with evidence of mild hydrocephalus [ figure 1a ] .
an old bifrontal craniotomy was re - explored and complete excision of suprasellar dermoid cyst was achieved through bilateral subfrontal approach along with transcortical transventricular excision of colloid cyst in the same setting .
intraoperatively , suprasellar cyst was containing a whitish fluid with fat globules with small solid vascularized fatty nodule .
post - operative scans showed complete excision of both the lesions [ figure 1b ] .
sagittal sections of contrast - enhanced magnetic resonance images of brain showing cystic lesion in the suprasellar area with small solid part anteriorly .
post - operative scans ( 48 hrs ) scans showed complete excision of dermoid and colloid cyst with decreased mass effect on the optic chiasm ( b ) photomicrographs showing stratified squamous epithelium with underlying sebaceous glands ( a ) .
colloid cyst wall comprising fibrocollagenous wall and is lined by columnar epithelium ( c ) with high - power view of lining epithelium ( d ) .
( a , b : hande 100 ; c , d : h and e 200 )
intracranial dermoid cysts generally occur along the midline and are derived from the trapped somatic ectoderm during embryological development during third to fifth week of gestation .
these cysts are generally associated with dermal sinus tracts and other neural tube closure defects ; however , dermal sinus tract may be absent in suprasellar and cerebello - pontine angle dermoids .
these lesions mainly presents with headache , local sings of mass effect , or neural compression .
colloid cysts of the third ventricle are also rare benign midline lesions presenting during early adulthood .
colloid cyst generally become symptomatic in early adulthood and mainly presents with headache and hydrocephalus .
although controversy exists about timing of surgery of asymptomatic colloid cysts , symptomatic ones are excised surgically at the earliest . with advent of endoscopy , complete or partial resection of colloid cyst
congenital origin of these cysts is accepted universally ; however , cell of origin is highly debated .
initial reports suggested their neuroepithelial origin as the derivatives of paraphysis or ventricular ependyma and these were further supported later by other studies .
however , mackenzie in 1991 suggested the endodermal derivation of these cysts on the basis of ultrastructural features which was supported by other authors . until recently endodermal derivation of these cysts enjoyed the favor when nagaraju et al .
, in 2010 reignited the debate by claiming colloid cysts as paraphysis remnants in human .
colloid cysts are associated with various developmental malformations like corpus callosal agenesis , anterior cranial fossa encephalocels , cavum veli interpositi , and multiple neuroepithelial cysts and aqueductal stenosis .
these malformations represent a spectrum of neural tube closure defects and associated anomalies . although isolated sporadic form of colloid cyst is most common occurrence , these associations suggest disordered embryogenesis as a possible mechanism in their formation .
cheng et al . , in 1999 reported a case of nasal dermoid sinus cyst associated with colloid cyst of third ventricle and proposed a fascinating theory of  anterior neuropore corridor defects  to explain the spectrum of these associated rare midline lesions . according to this theory , defective closure of situs neuroporicus promotes the neuroepithelium adjacent to commissural plate derivatives to form a vacuolated paraphysis growing slowly as colloid cyst of the third ventricle .
similar derivation from paraphysial remnants was also reported by nagaraju et al . , in 2010 supporting cheng 's hypothesis .
although lack of substantial evidence remained main drawback of this theory , disordered embryogenesis appears to be the most plausible explanation in our case rather than mere coincidence .
suprasellar dermoid cyst associated with colloid cyst of the third ventricle is a rare presentation .
this association appears more than coincidence and can be partially explained by anterior neuropore corridor defect theory .
 intracranial dermoid cyst and colloid cysts of the third ventricle are rare benign congenital lesions of early adulthood . 
 both lesions are thought to be congenital in origin however association is rare . 
 only one case of this association has been reported . 
 we report a 22-year - old male with suprasellar dermoid cyst and colloid cyst of the third ventricle presenting simultaneously . 
 embryogenesis of this association has been discussed . 
Introduction
Case Report
Discussion
Conclusions