A 38 years old female presented with increasing fatigue, weight gain, hyperpigmentation and increasing hairs since 9 months.

She had hypercortisolism.

MR brain showed a 12 mm sized adenoma on right side of anterior pituitary.

CT abdomen shows a large cystic pancreatic mass with specks of wall calcification.

PET (not shown) had shown a ‘Hot spot’ in duodenum.

Dexamethasone suppression test was inconclusive (suppressed with high dose, not suppressed with low dose).

She was hence taken up for inferior petrosal sinus(IPS) sampling.

Right ICA injection AP and Lateral views did not show filing of right IPS. In fact the cavernous sinus also is minimally seen.

Left ICA injection  AP and lateral views did show the left IPS.

Now there was a dilemma…

the adenoma was on the right side, and the right IPS was not seen….so what to do?

A vertebral artery injection was taken which did show both IPS. Sometimes the IPS drainage does get disconnected from the cerebral hemispheres and drains the posterior fossa via the petrosal vein.

A 5F catheter was navigated into the jugular vein and thence into the left IPS.

Venogram showed well the left IPS, left cavernous sinus. And as expected, a moderately forceful injection also filled the opposite cavernous sinus and with good reflux down the right IPS. What luck!

So we navigated another catheter (4F this time) into the right IPS and took samples as required.

three pairs of simultaneously drawn samples were sent to the laboratory along with a peripheral venous sample and a right femoral vein sample.

And as expected, ACTH values from right IPS were > 3 times of the left IPS.

The patient was sent for pituitary adenoma surgery.