Endocrine Abstracts

Background: Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal-dominant tumor syndrome associated with a wide tumor spectrum, in endocrine and nonendocrine tissues, key association being pituitary, parathyroid and enteropancreatic neuroendocrine tumors. Management of MEN1 is challenging because of its polymorphic, variable phenotypic expression.

Case report: Here, we present the case of a 68 year old patient diagnosed in 2004 with an 18 mm istmic pancreatic gastrinoma (gastrin=14239 pg/ml), on account of symptomatic, multiple duodenal ulcers. The diagnosis of MEN 1 is supported by the association with a prolactin secreting pituitary macroadenoma, well controled through time with low dose cabergoline; and hyperparathyroidism, which became apparent 10 years later through biological, ultrasound and osteodensitometric expression, but without TcMIBI scintigraphic confirmation so far. Upon surgical resection, the pathology report confirmed a chromogranin positive, moderately differentiated neuroendocrine carcinoma with a Ki67<1%. Within a year, the patient developed an infracentimetric within a year. A whole body scan with 111Indium-Octreoscan revealed uptake of the pancreatic lesion, so octreotide treatment was started in 2011, and serum chromogranin and gastrin levels normalized. Treatment was discontinued after a 99m Tc Tektrotide scan revelead a new pancreatic lesion and bilateral pulmonary secondary lesions. A follow-up CT scan reveals two infracentimetric pancreatic lesions; and a possible infracentimetric hepatic lesion. This, together with increasing gastrin, serotonin and cromogranin levels (650 ng/ml, 401 ug/dl and 509 mg/l, respectively), determined reinitiation of Octreotide treatment, which controlled tumor growth and neuroendocrine marker levels until 2023. In April 2023, the patient presents with altered condition and jaundice, and CT revelead cholelithiasis and a 3 cm pancreatic tumor which invaded the peripheral and common bile ducts; and liver metastases. Follow-up 99m Tc-Tektrotide scintigraphy revealed another liver metastasis and hyperfixation in the epigastrium. Therefore, peptide receptor radionuclide therapy (Lu-177-oxodoterotid) was employed, with two sessions so far, in parallel with octreotide between courses, with favorable evolution of tumors marker levels and tumor size.

Conclusion: MEN1-associated neuroendocrine tumors are indolent neoplasms, with a fluctuating evolution over time. A best-case scenario is when they express somatostatin receptors, which allows for treatment with somatostatin analogues, providing adequate tumor control for a long period of time. If they become inefficient, PRRT therapy can be employed alongside, which offers survival and quality of life benefits. All in all, managing these patients requires a multidisciplinary approach, including endocrinologists, surgeons, radiotherapists and oncologists, and management should be individualized on a case-by-case basis.