Atypical Presentation and Neuroradiological Features of Giant Ecchordosis Physalyphora in a Seven-Year-Old Patient: A Case Report.

This study presented the rare case of a seven-year-old patient with atypical presentation and neuroradiological features of giant ecchordosis physaliphora. The patient underwent cross-sectional imaging due to persistent headache without neurological or visual symptoms. CT scan imaging of the head revealed a hypodense tumor in the prepontine cistern. This lesion caused smooth scalloping of the dorsal clivus without aggressive erosion or calcification, and an osseous stalk was also identified between the lesion and the dorsal wall of the clivus. Sagittal T1 weighted image (T1WI) MRI showed a bilobed, solid and cystic, well-defined lesion, measuring 3.5 cm in terms of craniocaudal diameter, found alongside the midline within the prepontine cistern. After the evaluation of radiological images, the patient was then subjected to endoscopic transnasal complete tumor excision. Histological examination revealed sheets and lobules of clear cells with cytoplasmic globules "physaliphorous cells", and myxoid stroma. There was nuclear pleomorphism associated with focal areas of necrosis. After full recovery and discharge, the patient was followed up for the first year with four-month interval brain MRI scans showing no evidence of residual tumors. On the 12 months follow-up scan, the MRI scan revealed a 1.5 x 0.7 cm recurrent mass in the retroclival right paramidline prepontine cistern, which was most notably seen on the diffusion-weighted images. Series of proton beam therapy with annual MRI scans demonstrated regression of the tumor, eventually allowing the patient to live free of neurological symptoms up to this day. Results suggest that the utilization of radiological imaging such as CT and MRI scans was successful in identifying the ecchordosis physaliphora and differentiating it from chordomas. It can also be inferred that atypical radiological and histopathological findings of ecchordosis physaliphora lesions might suggest that they are prone to recurrence, which is an atypical feature for such entities. Further studies are recommended to explore and better understand these uncommon observations in patients with ecchordosis physaliphora.