craniopharyngioma is an uncommon tumor of the nervous system ; it is well - known to recur even several years after surgery .
we are here with reporting a case of craniopharyngioma which recurred at a site removed from the original site 5 years after surgery and radiotherapy .
a 4-year - old girl was admitted for progressive deterioration of vision of 2 months duration . in addition
there was no history of endocrinopathy , fits or any symptom of raised intracranial pressure . on examination ,
visual acuity was questionable perception of light on the right side and counting fingers at 3 m distance on the left .
imaging revealed a solid and cystic craniopharyngioma in the sellar - suprasellar region [ figure 1a and b ] .
she underwent a right frontotemporal craniotomy and transsylvian exploration and almost total excision of the tumor .
postoperative mr showed a tiny residual tumor adherent to the pons [ figure 2a and b ] .
( a and b ) showing the preoperative images ( before first surgery ) ( a and b ) images after first surgery showing no residual tumour in the primary site but a small fragment adherent to the pons she was given a course of radiotherapy for this residue 54 gy in 30 fractions .
follow - up imaging at the end of 2 years did not reveal any residual tumor [ figure 3 ] .
two years after surgery and radiotherapy no recurrence imaging was being done periodically to check for recurrence .
the 5-year surveillance imaging showed a recurrence in the right sylvian fissure along the route taken during the first surgery .
there was no evidence of tumor in the sellar - suprasellar area [ figure 4a and b ] .
she underwent reexploration by the same route , and a tiny fragment densely adherent to the middle cerebral artery was left behind .
( a and b ) showing remote recurrence five years after first surgery and radiotherapy .
although craniopharyngiomas are benign tumors they are known to recur even after years and even after the administration of radiotherapy , recurrence rates ranging from 25% to 70% .
recurrences at a site removed from the original site are very rare < 25 cases have been reported .
these ectopic recurrences are not to be misinterpreted as ectopic primary occurrences since craniopharyngioma can occur anywhere along the obliterated rathke 's pouch
. these ectopic recurrences may occur along the surgical pathway or at a site , not along the surgical pathway .
the cells of the tumor may get implanted and may subsequently metamorphose into a fresh neoplasm .
these tumor cells may in turn give rise to the regrowth of the tumor . the usual time to recurrence is around 4 years . but why this has to be a peculiarity of craniopharyngiomas can not be explained . another way the tumor may get seeded at a distant site
the evidence for this is strong since tumor cells have been observed in the csf .
although most recurrences are along the surgical corridor an instance where the recurrence has occurred in the spine has been recorded .
when the transsphenoidal route is used , the csf spaces are not violated this may explain the absence of recurrences after transsphenoidal route .
it is not surprising to observe that the histologic examination of the primary and recurrent lesions are the same .
recurrences rates are said to be low after total surgical excision . but recurrences even decades after a quiescent period are well - known .
it can be assumed that radiotherapy would have  sterilized  the surgical corridor and ectopic recurrences will not occur .
but this was not the case in our patient , and in the few that have been reported .
total excision is not an assurance that recurrences at ectopic or primary site will not occur .
certain measures have been proposed to minimize these ectopic recurrences , protecting the operative field with patties to prevent seeding , emptying the cyst prior to removal of tumor , thorough irrigation of the field before dural closure .
probably , a higher mib-1 index and expression of p53 may predispose to these recurrences . but eternal vigilance and regular imaging are mandatory to detect recurrences . another point worthy of note
is why this phenomenon is not seen with respect to other benign tumors like meningiomas or even malignant tumors .
 the aim was to present a rare case of recurrent craniopharyngioma remote from the primary site of origin . 
 a young girl was operated for sellar region craniopharyngioma . for a small residual tumor 
 , she underwent radiotherapy . 
 follow - up imaging did not reveal any residual tumor or recurrence . 
 surveillance magnetic resonance imaging after 5 years revealed a recurrence in the right sylvian fissure . 
 this tumor was totally excised . 
 recurrence of craniopharyngioma is well - known , but recurrence at a site remote from the original site after radiotherapy is extremely rare . 
 one such case is being presented . 