A Case of an Immature PIT1-Lineage Pituitary Neuroendocrine Tumor of the Nasopharynx.

Pituitary neuroendocrine tumors (PitNETs) located in the nasopharynx are a rare occurrence. This case report highlights a case of a 64-year-old female diagnosed with a PitNET incidentally found in her nasopharynx. The tumor was initially seen on MRI, excised, and analyzed with immunohistochemistry, ultimately confirming an immature pituitary-specific positive transcription factor 1 (PIT1)-positive-lineage pituitary neuroendocrine tumor. The tumor contained thyrotropes, somatotrophs, and lactotrophs expressing thyroid stimulating hormone, growth hormone, and prolactin, respectively. These tumors have the potential to exhibit aggressive behavior and can disrupt the surrounding tissue. Furthermore, they can be clinically silent or, conversely, secrete multiple hormones, causing hyperthyroidism, hyperprolactinemia, and acromegaly. For these reasons, they are deemed high risk. Treatment includes surgical excision with or without anti-hormone medications prior to surgery. Medications such as somatostatin analogs are used to decrease tumor size and reduce excessive hormone excretion.