The Curbsiders Internal Medicine Podcast

Episode #513: Pituitary Incidentalomas

Release Date: February 2, 2026
Guest: Dr. Maria Fleischeriu, Professor of Medicine & Neurologic Surgery; Director of the Pituitary Center, Oregon Health and Science University
Co-hosts: Dr. Matthew Frank Watto, Dr. Paul Nelson Williams, Dr. Mobeen Ahmad

Overview

This episode explores the diagnosis, workup, and management of pituitary incidentalomas. Featuring internationally recognized pituitary expert Dr. Maria Fleischeriu, the hosts and guest delve deep into the crucial clinical pearls, nuances, and evolving understanding of these common but anxiety-inducing findings, guiding listeners on best practices and real-world approaches.

Key Topics & Discussion Points

1. Meet the Guest and Episode Purpose

• Introduction: Dr. Maria Fleischeriu shares her path from Transylvania to leading U.S. pituitary care, her love of travel, and advice on mentorship and curiosity in medicine.
• Key Quote (Maria): "Find something that you are passionate about—where curiosity meets clinical relevance... all the extra work is worth it." [08:11]

2. Definitions & Terminology

• Incidentaloma: Any pituitary region lesion found unexpectedly during imaging for unrelated reasons.

• Microadenoma: <10 mm in size.

• Macroadenoma: ≥10 mm (1 cm).

• Giant Adenoma: >4 cm.

• Functioning vs. Nonfunctioning:

  • Functioning: Clinical/laboratory evidence of pituitary hormone excess (e.g., prolactinoma, acromegaly, Cushing's).
  • Nonfunctioning: No evidence of hormone excess.

  "Microadenoma is less than 10 millimeter... 1 centimeter or more, that’s macro. And then over 4 centimeters, it’s called giant. All quite arbitrary but useful..." — Dr. Fleischeriu [12:04]

3. Case 1: Young Woman with Microadenoma (5mm)

Initial Hormonal Workup

Always check for:

• Prolactin (prolactinoma)
• IGF-1 (acromegaly)

“Now... we actually recommended... that everybody with a pituitary lesion should have at least a prolactin and IGF-1, which is the marker for growth hormone. Everybody.” — Dr. Fleischeriu [17:02]

Check for hormone deficiencies if concerning history or imaging

• AM cortisol and ACTH (adrenal insufficiency)
• TSH & Free T4 (central hypothyroidism—note: TSH may be normal in central causes)
• LH/FSH, estradiol/testosterone (hypogonadism)

“Just the TSH is not enough... If it’s the pituitary that’s not working, the TSH will be normal, but free T4 could be very low.” [19:09]

Cushing’s screening:

• Only if suggested by symptoms (e.g., uncontrolled hypertension, obesity, diabetes)
  • Data show false positives are common with indiscriminate testing.

  “If you have any clinical suspicion, that’s a different story. Otherwise, we’ll screen a lot of people for Cushing’s and get false positives.” [18:45]

Imaging & Follow-up

• MRI findings: Most microadenomas are benign and stable.
• Follow-up MRI usually in 2–3 years, but may be individualized.
• Explicitly reassure patients of the benign nature.

“The large, large majority of these lesions, either small or big, are benign. This is the first thing they want to hear.” [30:04]

4. Case 2: Young Man with Macroadenoma (~2.5cm, Cavernous Sinus Invasion)

• Initial steps:
  • Full pituitary hormonal workup before starting replacements, to capture true pituitary function.
  • Formal visual field testing—refer to neuro-ophthalmology for reliable assessment (“confrontation is not enough” [57:02]).
  • Neurosurgical evaluation—especially if compressing optic chiasm or demonstrating symptoms.
  • Prolactin with dilution for large tumors, to rule out lab artifact (“hook effect”).

“In a patient like this... the chance of having central hypogonadism is almost 100%. The chance of growth hormone deficiency, again, very high. Then the thyroid, then the last one is adrenal insufficiency.” [50:23]

• Imaging: Dedicated pituitary protocol MRI; can use initial brain MRI if already high quality.
• Immediate steroid replacement if signs of apoplexy/adrenal insufficiency.

5. Case 3: Empty Sella

• Definition: Sellar region appears “empty” due to CSF filling where gland is flattened; most often benign.
• Initial workup: Similar to other pituitary lesions:
  • Prolactin, IGF-1, AM cortisol, ACTH, Free T4/TSH, LH/FSH, estrogen/testosterone.
  • Consider Cushing’s screening if symptoms suggestive.
• Hyperprolactinemia: Common due to “stalk effect.” Treat only if symptomatic (e.g., menstrual disturbance).
• Follow-up:
  • Generally do not need repeat imaging unless symptoms progress.
  • Repeat labs if symptoms or every few years.

“Partial empty sella—sometimes I don’t even see them back. I tell them to have their internist check one more time and, if normal, no need to repeat unless there are symptoms.” [69:47]

Practical Clinical Pearls

• Order Specific Labs:
  • In central (secondary) hypothyroidism, order free T4 (not just TSH).
  • Always order prolactin and IGF-1 for any pituitary lesion.
  • For Cushing’s: screen only if you have true clinical suspicion; consider late-night salivary cortisol for best balance of sensitivity/specificity.
• Prolactin Levels:
  • Levels <200 in a large mass may be due to stalk effect, not a prolactinoma.
  • Antidepressants, antipsychotics, estrogen, and stress can affect prolactin.
• Patient Communication:
  • Reassure about benignity; explicitly state “not cancer.”
  • Still, discuss rare possibility of future growth (~10% of microadenomas may grow).
  • Tell patients what symptoms to watch for (visual changes, headaches, symptoms of hormone deficiency).
• Interdisciplinary Care:
  • Coordinate with neuro-ophthalmology, neurosurgery for macroadenomas and vision-threatened patients.
  • “We don’t make this decision alone—always multidisciplinary.” [58:48]
• Highly Individualized Follow-up:
  • Imaging intervals may extend to every 3–5 years for stable microadenomas.
  • Hormone retesting: repeat once if initially normal; more frequently if near optic chiasm, close follow-up needed, or developing symptoms.

Notable Quotes & Time Stamps

• Dr. Fleischeriu on terminology and prevalence:

  “In autopsy studies… up to 30% had something on the pituitary. Probably that’s too much, but 10% for sure, even on imaging.” [10:11]

• Hormonal Testing Nuance:

  “We like to check hormones for high and then way more hormones for low—you can have subtle adrenal insufficiency or central hypothyroidism even with small lesions.” [17:47]

• On Cushing’s Evaluation:

  “If you think about it, just test for it... but indiscriminate testing for Cushing’s mostly leads to false positives.” [26:30]

• On Patient Reassurance:

  “One of the biggest things I see, patients come in and no one told them it isn’t cancer. We have to up the communication.” [31:09]

Timestamps for Major Segments

• Advice & Guest Introduction: [04:08]
• Case 1 (Microadenoma): [08:49]
• Definitions & Hormonal Workup: [11:18]
• Symptoms & History-Taking: [24:38]
• Growth Risk & Follow-up: [28:28]
• Summary of Case 1/Clinical Recap: [31:57]
• Case 2 (Macroadenoma): [48:14]
• Management, Surgery Considerations: [49:22]
• Visual Field Testing Best Practices: [56:41]
• Case 3 (Empty Sella): [64:46]
• Hormonal Approach in Empty Sella: [65:48]
• Estrogen Effects on Lab Testing: [74:33]
• Final Teaching Points: [79:22]

Major Take-Home Points

(from Dr. Fleischeriu)

1. Pituitary gland is the “conductor” of many hormones. Pituitary disorders require rethinking standard lab interpretation—TSH alone is insufficient, always check free T4.
2. Workup must screen for both hormone excess and deficiency. Prolactin and IGF-1 for every lesion; screen for hypofunction too.
3. Most pituitary incidentalomas are benign. Provide clear, explicit reassurance to patients—but educate about symptoms of possible growth or dysfunction.
4. Management and follow-up are highly individualized, and care should be multidisciplinary where possible.
5. Pituitary incidentalomas are common—up to 10% on imaging in the general population.

Resources and References

• Pituitary Society: www.pituitarysociety.org — international pituitary expert consortium and consensus guidelines.
• Endocrine Society: www.endocrine.org — international society and guideline publisher.

For CME Credit: healthecurbsiders.vcuhealth.org

"The patients need to be listened to. Not just workup, but education is as important as testing—especially explaining that this is not cancer."
— Dr. Maria Fleischeriu [40:49]

Summary prepared for easy clinical reference and practical teaching; consult detailed guidelines as needed for specific management.