Remote delayed recurrence of craniopharyngioma after radiotherapy.

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.

Introduction

Craniopharyngioma is an uncommon tumor of the nervous system; it is well-known to recur even several years after surgery. Radiotherapy may confer a benefit and mitigate the chance of recurrence. 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.

Case Report

A 4-year-old girl was admitted for progressive deterioration of vision of 2 months duration. In addition, the family noticed she was not very active. 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. Bilateral optic atrophy was present. Neurologic exam was unremarkable otherwise. 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. Postoperatively, she developed dyselectrolytemia. Histologic examination showed an adamatinomatous craniopharyngioma. Postoperative MR showed a tiny residual tumor adherent to the pons [Figure 2a and b].

Figure 1

(a and b) showing the preoperative images (before first surgery)

Figure 2

(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]. She had improved well and was attending school. Replacement hormonal therapy was being administered.

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. The tumor was solid and cystic in nature. There was no evidence of tumor in the sellar-suprasellar area [Figure 4a and b]. She did not exhibit any symptoms attributable to the recurrence. She underwent reexploration by the same route, and a tiny fragment densely adherent to the middle cerebral artery was left behind. Postoperative imaging has not shown any residual tumor. She continues to do well and is on replacement therapy.

Figure 4

(a and b) showing remote recurrence five years after first surgery and radiotherapy. The primary site is free of tumour

Discussion

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%.[12] Less than 20 cases have been reported.[2] Recurrence may occur even after a “total” excision of the tumor.[2] But almost all recurrences occur at the primary site. Recurrences at a site removed from the original site are very rare <25 cases have been reported.[13] The recurrence may occur even two decades after the primary has been treated.[4] Ectopic recurrences have been recorded in various sites.[5] These ectopic recurrences are not to be misinterpreted as ectopic primary occurrences since craniopharyngioma can occur anywhere along the obliterated Rathke's pouch.[67] 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.[4]

These ectopic recurrences may occur by three mechanisms. First, the tumor cells may get implanted along the corridor during dissection. These tumor cells may in turn give rise to the regrowth of the tumor. The usual time to recurrence is around 4 years.[23] But why this has to be a peculiarity of craniopharyngiomas cannot be explained. Another way the tumor may get seeded at a distant site is spread along the cerebrospinal fluid (CSF) pathways.[358] The evidence for this is strong since tumor cells have been observed in the CSF.[9] Tumor spread along the Virchow-Robin spaces have also been hypothesized.[12] Although most recurrences are along the surgical corridor an instance where the recurrence has occurred in the spine has been recorded.[8]

All recurrences along the surgical corridor have occurred after transcranial surgery.[110] When the transsphenoidal route is used, the CSF spaces are not violated this may explain the absence of recurrences after transsphenoidal route.[14] It is not surprising to observe that the histologic examination of the primary and recurrent lesions are the same.[1]

Recurrences rates are said to be low after total surgical excision. But recurrences even decades after a quiescent period are well-known. The role of radiotherapy in preventing or minimizing recurrences is still controversial. Recurrences after adjuvant therapy 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.[4] Only five cases of ectopic recurrence have been noted after postop radiotherapy.[10]

Total excision is not an assurance that recurrences at ectopic or primary site will not occur.[1] 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.[14] Probably, a higher MIB-1 index and expression of p53 may predispose to these recurrences.[10]

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.