Cushing’s Disease Linked to Rare Pituicytoma in Case Report

Although rare, pituicytomas should still be considered as a possible cause of Cushing’s disease in patients experiencing the typical symptoms of the disease, a case report highlights.

The study, “Pituicytoma associated with Cushing’s disease: a case report and literature review,” was published in the Journal of Surgical Case Reports.

A pituicytoma is a brain tumor that is usually associated with the pituitary gland, the pea-size gland that sits at the base of the brain and is responsible for controlling the production of multiple hormones in the body.

Due to its close association with the pituitary gland, this type of tumor can also mimic the effects of a pituitary adenoma, another type of tumor that forms within the pituitary gland and is typically linked to Cushing’s disease, a disorder caused by the overproduction of the adrenocorticotropic hormone (ACTH).

Since its discovery in 1955, only 78 cases of pituicytoma have been reported in the literature.

Now, researchers in Saudi Arabia are reporting the case of a woman with Cushing’s disease associated with a pituicytoma.

The 47-year-old woman had a history of type 2 diabetes and high blood pressure, and complained of weight gain and muscle weakness upon arrival to the clinic. A physical examination revealed she had a large rounded face (moon face), along with fat accumulation in her neck and shoulders (buffalo hump) and on her abdomen (central obesity).

Lab tests also showed her cortisol levels were high at 489 nanomoles per liter (nmol/L), whereas the normal range is 138–690 nmol/L in the morning, and 0–276 nmol/L in the evening. Her ACTH levels were normal at 11.1 picomoles per liter (pmol/L), with the norm ranging between 1.3 and 16.7 pmol/L.

MRI brain scans found she had a small mass measuring 5 mm in diameter in the left side of her pituitary gland that resembled a microadenoma, a benign tumor of the pituitary gland that is normally less than 10 mm in diameter. She had surgery to remove the tumor, which was then sent for analysis.

Tissue analyses showed the tumor was composed of spindle cells — cells that are much longer than wider — that had oval nuclei, the cell compartment that stores a cell’s genetic information.

Additionally, investigators found the tumor cells contained thyroid transcription factor-1 (TTF-1) in their nuclei, a tumor marker normally found in pituicytomas. They also found some of the tumor cells were positive for other pituicytoma markers, including S100 and glial fibrillary acidic protein (GFAP).

According to investigators, these observations were crucial in reaching a final diagnosis.

“In our case, the tumor was so tiny [around] 0.5 cm that it could be missed … but being aware of this entity and having TTF-1 positivity helped us to reach to the definitive diagnosis,” they wrote.