Presentation
Increasing confusion and headaches. Gaze palsy. Initial management with-held.
Patient Data
A mass in the pineal region is demonstrated, measuring 19 x 13mm, which is primarily isodense to brain parenchyma, with a small amount of calcification. Hydrocephalus is present despite an EVD positioned within the right lateral ventricle.
There is no evidence of acute hemorrhage or infarction.
Centered within the pineal region is a T1 isointense, T2/FLAIR hyperintense mass measuring 18 x 20 x 16 mm in orthogonal planes. The mass contains a single focus of susceptibility artefact on the EPI sequence. There is no evidence of restricted diffusion to indicate high cellularity. The mass demonstrates fairly homogeneous enhancement except for several tiny foci of non enhancement. The lesion obstructs the aqueduct with resultant hydrocephalus of the third and lateral ventricles. FLAIR signal hyperintensity surrounding the lateral ventricles is consistent with transependymal CSF spread.The lesion appears separate from the tectal plate. There is potential extension into the posterior aspect of the third ventricle. A right ventricular drain is noted within the lateral ventricle. No further regions of abnormal intracranial enhancement is identified.
The patient went on to have a craniotomy and resection of the mass, although the patient had a known pulmonary mass.
Histology
MICROSCOPIC DESCRIPTION: Paraffin sections show fragments of a densely hypercellular tumor. This consists of papillary and glandular structures lined by a stratified arrangement of markedly pleomorphic cells with round and oval vesicular and hyperchromatic nuclei and a variable amount of pale cytoplasm. Several glandular spaces contain mucin. There are scattered mitotic figures. Necrotic debris is seen in the lumen of one gland.
Immunohistochemistry shows strong diffuse nuclear staining for TTF-1, strong cytoplasmic staining for carcinoembryonic antigen (CEA) and cytokeratins, AE1/AE3, CK7 and BerEp4 and strong membrane staining for epithelial membrane antigen (EMA). Occasional cells show strong reactivity for cytokeratin CK20. No staining for S-100 protein or synaptophysin is seen in tumor cells. The features are of metastatic moderately to poorly differentiated adenocarcinoma arising from lung.
FINAL DIAGNOSIS: Metastatic moderately to poorly differentiated adenocarcinoma arising from lung.
An 8 cm smooth mass is seen projecting over the right hilum (CT confirmed the mass to be posteriorly located within the lower lobe - not shown). There is pulmonary consolidation bilaterally in both lower lobes.
Case Discussion
Although rare, cerebral metastases can occur in the pineal gland, mimicking a primary pineal tumor.