What kind of mass in the pineal gland can lead to upward gaze limitations?

The mass in the pineal gland that can lead to upward gaze limitations is a pineal gland tumor. This type of tumor can cause a condition known as Parinaud's syndrome, which is characterized by various symptoms due to the compression of the midbrain structures, particularly the vertical gaze centers located around the cerebral aqueduct. When these areas are pressed upon, patients may experience difficulties in moving their eyes upwards, known as 'setting sun' sign, as well as other neurological symptoms.

Pineal gland tumors can manifest as either germ cell tumors (such as teratomas) or pineoblastomas, and can potentially obstruct the cerebrospinal fluid (CSF) pathways, leading to symptoms of increased intracranial pressure, further contributing to visual disturbances. In contrast, while other lesions such as a benign cyst, metastatic cancer, or arachnoid cyst might also occur in the region of the pineal gland, they do not typically present with the same degree of vertical gaze limitation as tumors do.