Cerebral aneurysms in a patient with osteogenesis imperfecta and exon 28 polymorphism of COL1A2.

We read with interest the article by Megdiche-Bazarbacha et al, in which the authors report a case of a giant intrasphenoidal Rathke cleft cyst (RCC). In our recent review of RCCs, we mentioned a comparable case reported by Meyer et al in the AJNR of such a giant RCC centered on the sphenoid bone, mimicking a chordoma. A search of PubMed with the keywords “Rathke cyst sphenoid” revealed at least another very similar case recently published in the Journal of Neurosurgery. The MR signal intensity characteristics of all these lesions were identical, with T1 and T2 signal intensities slightly greater than that of CSF. It is well known that the signal intensities of RCCs are variable and directly depend on their biochemical content, with most of the reported RCCs demonstrating T2 high signal intensity. It is, however, crucial to point out for practicing radiologists that a homogeneous T2 hypointense signal intensity within a nonenhancing midline sellar cyst is highly suggestive of a RCC. Figure 1 illustrates this feature and also demonstrates how T2-weighted images are more sensitive than T1-weighted images in depicting small cysts located between the anterior and the posterior pituitary lobes. Finally, the postoperative RCC recurrence rate of only 5% of Megdiche-Bazarbacha et al seems quite low. Although considered as benign lesions, RCCs commonly recur, with reported rates as high as 33%. Independent of the neurosurgeons skill, this recurrence is due to the fact that the most common and safest surgical technique consists of draining the contents of the cyst with only a partial excision or fenestration of the paper-thin wall cyst, leaving in place the source of the secretions that may re-accumulate.