Abstract Background Pituitary metastasis is a rare initial presentation of small cell carcinoma (SCLC) and accounts for less than 1% of symptomatic pituitary lesions. Pituitary metastasis secondary to lung cancer, is frequent but most commonly occurs in cases of known malignancy; only a minority present initially with pituitary symptoms or isolated pituitary involvement. Case Presentation A 75-year-old man with hypertension and atrial fibrillation was admitted after a fall following two months of progressive confusion, muscle weakness, visual hallucinations, headaches, and diplopia. He had a 30-pack-year smoking history but had quit 15 years prior. Physical examination revealed bilateral abducens nerve palsy and bitemporal hemianopia. Laboratory evaluation demonstrated selective anterior pituitary dysfunction: Free T4: 0.59 ng/dL, TSH: 0.29 µIU/mL, LH: 0.3 mIU/mL, Testosterone: 3 ng/dL and mild hyperprolactinemia (75.2 ng/mL). The hypothalamic-pituitary-adrenal axis appeared intact; serum sodium and urine osmolality were also normal. Chest CT showed a bronchial blockage with a collapsed right middle lobe, a 4mm nodule in the right lower lobe, a 5mm nodule in the left lower lobe, and a subcarinal lymph node of 1.3cm in size. CT Abdomen and Pelvis demonstrated multiple liver masses. MRI of the brain showed a 1.7 cm enhancing sellar mass, and diffuse thickening of the pituitary stalk. Endobronchial Ultrasound-guided Fine-Needle Aspiration (EBUS-FNA) of a mediastinal lymph node, along with a transbronchial biopsy of the right middle lobe done, confirmed an extensive-stage small cell lung cancer (SCLC). Immunohistochemical staining was positive for thyroid transcription factor-1 (TTF-1), synaptophysin, chromogranin A, and INSM1, with a Ki-67 proliferation index of more than 80%. Endoscopic endonasal transsphenoidal biopsy or mass resection was deferred due to systemic diagnosis. The patient’s ECOG performance status was 2; hormone replacement therapy was initiated, and platinum-etoposide with durvalumab was planned. Discussion Pituitary metastasis can be the first clinical sign of malignancy in nearly 25% of cases, with lung cancer being the predominant source 1,4. The posterior lobe is more commonly affected due to its direct arterial supply 2. Hormone replacement is started prior to systemic therapy 5. Neurosurgical decompression is reserved for severe or progressive vision loss 1. Extensive-stage SCLC is treated with systemic chemotherapy and immunotherapy 9, with radiotherapy for palliation 1,4. Conclusion Pituitary metastasis, though rare, can be the initial clinical presentation of small cell lung carcinoma, especially among elderly smokers. Early recognition and initiation of hormonal therapy and systemic therapy are critical for maximizing quality of life, and potentially prolonging survival. This abstract is funded by: None
Jereisat et al. (Fri,) studied this question.
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