[Multiple endocrine neoplasia presenting initially as acute pulmonary thromboembolism: a case report]

We reported a rare case in which acute pulmonary thromboembolism (APTE) was the initial clinical manifestation of multiple endocrine neoplasia type 1 (MEN1). A 44-year-old male presented with chest tightness and dyspnea, and was subsequently diagnosed with acute pulmonary embolism on computed tomography pulmonary angiography (CTPA). Medical history revealed a long-standing pituitary adenoma. During the etiologic evaluation, the patient was found to have a hypercalcemic crisis, hyperparathyroidism, and a pancreatic neuroendocrine tumor. Genetic testing confirmed a pathogenic MEN1 mutation (c.1664G>A), which established the diagnosis of MEN1. Along with regular anticoagulation therapy, the patient underwent multidisciplinary evaluation. Oral bromocriptine was continued for the pituitary adenoma, and parathyroidectomy was performed after correction of the hypercalcemic crisis. The pancreatic neuroendocrine tumor is being closely monitored, with elective surgery or somatostatin analogue therapy planned as appropriate to eliminate the underlying cause of pulmonary embolism. Through a brief literature review, we explored how MEN1 may contribute to a hypercoagulable state. The case highlighted the importance of endocrine and genetic screening in patients with unexplained pulmonary embolism.