Abstract Introduction Pituitary metastasis from a solid tumour is an extremely rare condition and is generally associated with a poor prognosis. Spontaneous regression is not typically expected, which further worsens the outlook. Here, we present a case of a patient with small-cell lung cancer (SCLC) who developed a pituitary mass. The marked regression of the lesion following chemotherapy strongly supported the likelihood of pituitary metastasis in this case. Clinical Case A 59-year-old female patient, diagnosed with SCLC one month ago, was receiving radiotherapy and she also had a chemotherapy plan. When visual impairment and ptosis developed, cranial MRI was performed. She was referred to our outpatient clinic due to pituitary lesion. On physical examination blood pressure was 130/70 mmHg and a heart rate was 92/min. She was mildly dyspneic, had no signs of endocrine hyperfunction, nor polyuria or polydipsia. Obesity was also noted. Her medical history included hypertension and ischemic heart disease. In laboratory examination; ParameterResultReference RangeNa⁺140 mmol/L135–145 mmol/LK⁺4.9 mmol/L3.5–5.0 mmol/LBasal Cortisol30.3 μg/dL6.2–19.4 μg/dLACTH164 ng/L7.2–63.3 ng/LIGF-1471 μg/L62–186 μg/LTSH1.52 mIU/L0.27–4.8 mIU/LfT41.26 ng/dL0.79–1.59 ng/dLFSH9.6 IU/L3.5–12.6 IU/LLH4.08 IU/L2.4–12.6 IU/LProlactin20.3 μg/L2.8–29.2 μg/L1 mg Dexamethasone Suppression Test (DST)15.7 μg/dL—4 mg Dexamethasone Suppression Test (DST)18 μg/dL—Liver and Renal FunctionsNormal— Pituitary MRI revealed a 17×15×12 mm suprasellar mass lesion compressing the optic chiasm (Figure 1A-B). PET-CT demonstrated intense FDG uptake in the pituitary region, as well as involvement in the right lung’s lower, middle, and upper lobes, the left adrenal gland, and multiple lesions in the skeletal system. The patient was evaluated by a multidisciplinary pituitary board, and no clinical signs of acromegaly or Cushing’s syndrome were identified. Due to the high surgical risk given her condition, chemotherapy was promptly planned. Cisplatin and etoposide chemotherapy protocol was started, and the patient's visual impairment subsided following treatment. At the 3-month follow-up her visual complaints and ptosis completely resolved, basal cortisol decreased to 20 μg/dL, ACTH to 60 ng/L, and IGF-1 normalized. Control pituitary MRI releaved significant regression of the lesion (Figure 1C-D). In the first year of chemotherapy, during the pulmonology and oncology follow-up, she was hospitalized because of confusion following radiotherapy for brain metastases. It was later reported that the patient had passed away. Conclusion The approach to pituitary metastases is generally palliative. On the other hand, if the primary tumor is expected to respond well to chemotherapy and surgery is considered high-risk, close monitoring may be considered to allow chemotherapy to be effective. Figure 1: A-B: Sagittal and coronal pituitary MRI images of the patient before chemotherapy. C-D: Sagittal and coronal pituitary MRI images of the patient 3 months after chemotherapy. Table 1:The patienteGFR: Estimated glomerular filtration rate, ACTH: Adrenocorticotropic hormone, IGF-1: Insulin-like growth factor 1, TSH: Thyroid stimulating hormone, fT4: Free thyroxine, FSH: Follicle-stimulating hormone, LH: Luteinizing hormone, E2: Estradiol, DST: Dexamethasone suppression test
Belten et al. (2026) studied this question.