Pituitary Adenoma in a dog

History: A 9.5 year old female, spayed, mixed breed dog with progressive paresis.

Gross Findings: Pituitary mass

Pituitary tumor in dog

Grossly the tumor appears hemorrhagic and more invasive than compressive but doesnt extend into very far into the thalamus.


Pituitary: The neoplastic cells are variable in size and shape but do occasionally form follicles with eosinophilic colloid (PAS positive). There were two main populations of cells visible by H&E. One type of cell had bright eosinophilic granules (ACTH positive). The other had pale eosinophilic cytoplasm and were only faintly ACTH positive. There were multifocal areas of hemorrhage and necrosis.

Histologically the tumor looks more compressive than invasive. The majority of tumor cells were ACTH negative, or only faintly positive, but there were areas that were strongly ACTH positve (see below)

The large pink area stained very positive for ACTH.


The adrenal cortices were 2x as large as the medulla, and there was one hyperplastic cortical nodule. We did not think these were significant changes. The tumor was mostly non-secreting chromophobe cells, but did have some nice ACTH producing cells.


About Brian

Anatomic Pathologist, VetPath Services, Stone Ridge, NY- musculoskeletal, oral/dental, and sinonasal diseases
This entry was posted in Necropsy Cases and tagged , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s