Endocrine Abstracts

Pituitary carcinomas are rare and represent a challenge in clinical practice. Most secondary tumour localizations are intracranial and spinal, followed by liver, cervical lymph node, bone and, rarely, lung. PC frequently exhibit resistance to most usual therapies and the mean survival time is usually <4 years once metastases have been identified. Ectopic ACTH Syndrome is, in up to 50% cases, caused by lung tumours including carcinoids or Small Cell Lung Carcinomas (SCLC). SCLC can secrete ACTH in 1-6% cases. Pituitary metastasis are rare and mainly derived from breast and lung cancers. We report a case of 75 years old men with past history of hypertension, that entered the emergency room with pulmonar tromboembolism (PTE). Two days after he suffered apoplexy of a a previously unknown pituitary macroadenoma. He had elevated ACTH, urinary free cortisol, late serum night cortisol and normal abdominopelvic TC (beyond PTE lesions). He had no cushingoid features. Lab values and adenoma volume improved, but 9 months later he suddenly developed symptoms of hypercortisolism with worsening lab and imaging. He underwent transphenoidal surgery with partial removal. Immunohistochemistry revelead: ACTH adenoma with bone invasion, Ki 40%. He was reoperated and submitted to CyberKnife/SRS for residual left intracavernous adenoma in 3 months. He was clinicaly stable for 8 months, although without remission, under Metirapone therapy. Due to adenoma regrowth, a third surgery with a macroscopically extended removal was performed. Two days after he had basal cortisol 132 mg/dl and severe de novo hypokalemia. 18F-FDG PET-TC showed a suspicious lung nodule and hepatic metastasis. He maintained Metirapone and initiated Ketoconazole. The hepatic biopsy revealed neoplastic cells, Ki 90%, CK CAM5.2, Sinaptofisin, CD56 and Cromogranin A positive; CK7 and CK5/6 negative. It was assumed a probable origin in SCLC. The pulmonary biopsy revealed necrotic tissue. Pituitary histology was reviewed: Sinaptofisin positive, TTF1, napsina A and P40 negative. The results excludes pulmonary origin. Pulmonary oncology group classified the pulmonary lesion as SCLC, T3N0M1c-IVB and patient began chemotherapy with inicial clinical and pulmonar nodule improvement. Subsequent complications as pancitopenia, large haematomas, severe hypokaliemia, SARS CoV 2 infection and Klebsiella sepsis led to chemotherapy interruption and lastly patient’s death. A post morten hepatic biopsy immunohistochemistry review showed TTF1 and ACTH negative. The authors conclude this is a rare case of an ACTH secreting Pituitary Carcinoma with fulminant metastatic lung and hepatic disease and highlight for the challenges and difficulties in diagnosing and treating those patients.