Male, 11 years old, with cough, potentially representing a tic. A T2 hyperintense, cystic-appearing lesion is evident arising from or protruding into the left medial thalamus. The lesion measures approximately 10 x 9 x 6 mm. Along the posterior margin of the lesion there is a 4 mm enhancing nodule which, although it resembles the pineal gland, is situated well above the typical location of the pineal. The native pineal gland is otherwise not discretely visualized, which could be technical. The lesion appears to indent the posterior aspect of the third ventricle. However, there is no associated mass effect on the cerebral aqueduct, and no evidence of ventricular obstruction.The cerebral hemispheres otherwise demonstrate normal morphology and signal characteristics. No evidence of significant edema or mass effect is seen. No diffusion restricting lesions are seen. No other pathologic parenchymal or extra-axial enhancement is observed. Ventricular size and morphology are within normal limits. No evidence of acute intracranial hemorrhage or any abnormal extra-axial fluid is seen. No susceptibility inducing lesions are detected.
A cyst-like lesion measuring up to 1 cm is demonstrated arising from or projecting into the medial surface of the left thalamus. An adjacent small enhancing nodule is favored to be related to the cyst as it is positioned above the typical location of the pineal gland.The differential diagnosis for this finding is broad and would include inflammatory lesions including atypical or parasitic infection. Cysticercosis would be a consideration in the context of the appropriate travel or exposure history. An early neoplastic process would be in the differential as well, particularly if the enhancing nodule is indeed associated with the cyst. A congenital lesion is considered somewhat less likely but not entirely excluded. For example, this could represent an atypical pineal cystic lesion with ectopic positioning of the pineal gland, or perhaps an ependymal cyst.On subsequent imaging, it is recommended to obtain high-resolution imaging centered on the midline, as would be provided in the dedicated pineal protocol. This would allow better characterization of the lesion and its relationship to the actual pineal gland.