Intracranial neuroenteric cyst
Central nervous system neuroenteric cysts are congenital rare lesions that are more frequently seen involving the spine. Cases like this one, in a supratentorial location, are even rarer. On imaging, this case cannot be confidently distinguished from an arachnoid cyst, which is much more common.
The patient underwent further surgical resection of the frontal cystic lesion.
MACROSCOPIC DESCRIPTION: 1. "R frontal nodule of cyst": One tan core tissue, 9mm long. A1. 2. "R frontal cyst wall": A flap of thin translucent tissue, 10x3mm in area and <1mm thick. The cyst wall is smooth on both sides. No mass lesions identified. A1.
MICROSCOPIC DESCRIPTION: 1&2. The two specimens show similar features and are described together. Examined at multiple levels, the sections show cyst wall lined with pseudostratified ciliated columnar epithelium with fine intracytoplasmic brown pigment, mixed with goblet cells and cells with PASD positive granules. No complete epithelial excrescences are present. The underlying connective tissue also shows brown pigment. No pituitary tissue is identified. The cells show patchy positive staining for CDX2 and SOX10, and are negative for EMA and Transthyretin. In the context of the intra-axial site of the frontal lobe cyst the features are most in keeping with the neuro-enteric cyst. No atypical features are identified.
DIAGNOSIS: 1&2. Right frontal cyst wall biopsy: Benign developmental cyst in keeping with neuro-enteric cyst.