Neuroendocrinology and Pituitary

SAT-110 - Pituitary Metastasis of EGFR-mutant Lung Adenocarcinoma Responsive to Targeted Therapy

Saturday, June 13, 2026

9:30 AM - 4:30 PM CT

Late-Breaking Poster Presenter(s)

SK

Sahana Karkera, MBBS, MD

Resident
MedStar Health-Georgetown University/Washington Hospital Center
Washington, District of Columbia, United States

Co-Author(s)

SK

Sahana Karkera, MBBS, MD

Resident
MedStar Health-Georgetown University/Washington Hospital Center
Washington, District of Columbia, United States
VM

Vivek Moorthy, MD

Clinical Fellow
National Institute of Health
Rockville, United States
KM

Kajol Manglani, MD

Fellow
MedStar Health-Georgetown University/Washington Hospital Center
Washington, District of Columbia, United States

Senior Author/Primary Investigator(s)

SS

Susmeeta T. Sharma, MBBS, MHSc

Associate Professor
Georgetown Univeristy/MedStar Washington Hospital Center
Washington DC, District of Columbia, United States

Co-Author(s)

SS

Susmeeta T. Sharma, MBBS, MHSc

Associate Professor
Georgetown Univeristy/MedStar Washington Hospital Center
Washington DC, District of Columbia, United States

Background: Pituitary metastases represent ~0.4% of intracranial metastases; lung and breast cancer are the most common primary site. Radiological overlap with pituitary adenomas and a low symptomatic rate render early diagnosis challenging.

CLINICAL

Case: A 46-year-old woman with infertility and prior IVF presented with progressive headache, bitemporal visual field deficits, and floaters in the left eye. Review of systems was positive for amenorrhea for the past six months and a 40 lb weight loss. Ophthalmology evaluation in ED revealed a left choriorteinal lesion concerning for metastases. MRI brain demonstrated a 30×22×24 mm sellar-suprasellar mass splaying the optic chiasma, with overall features favoring a pituitary macroadenoma; frontal calvarial metastasis was also seen. CT chest, abdomen & pelvis revealed 4 cm lung mass, with biopsy showing adenocarcinoma carrying an EGFR mutation on molecular testing. Laboratory evaluation showed central hypothyroidism (TSH 0.149 mIU/L, fT4 0.56 ng/dL), central hypogonadism (FSH 1.3, LH < 0.3 mIU/mL), and mild hyperprolactinemia (40.1 ng/mL) due to stalk effect. Given the procedural risk, pituitary mass biopsy was deferred to assess response to treatment with platinum-based chemotherapy and Osimertinib, a third generation EGFR tyrosine kinase inhibitor. A dramatic response with marked sellar regression and optic chiasm decompression was seen on MRI, supporting the diagnosis of pituitary metastasis over a concurrent non-functioning pituitary adenoma. Lung mass, calvarial metastases and subcutaneous nodules on the chest wall also regressed. Ophthalmology confirmed choroidal metastasis regression averting surgery entirely.

Conclusion: The adenoma-like appearance on MRI highlights the need for a high index of suspicion for atypical presentations of pituitary metastases. Only 7% of pituitary metastases are reported to be symptomatic, with a higher affinity for posterior pituitary involvement and therefore AVP deficiency compared to other pituitary pathologies, which was not seen in our patient. In the setting of a primary malignancy carrying specific targetable mutations, a conservative approach with close monitoring of the pituitary lesion on targeted therapy must be weighed against transsphenoidal resection. The lack of data for treatment response, risk of panhypopituitarism with either approach, surgical risk, patient characteristics and preference must be considered in the decision-making process.

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