Résumé
Tailgut cysts are rare and uncommon congenital lesions of developmental origin arising from vestiges of the embryonic hindgut occurring in the retro-rectal space, frequent in middle-aged women. Tailgut cysts are part of the retro-rectal tumor group. These lesions are most often asymptomatic or pauci-symptomatic. Consequently, the diagnosis is frequently made by chance (incidentaloma) after a morphological examination such as an abdominal ultrasound or a CT scan. Magnetic resonance imaging (MRI) is the gold standard morphological exam to determine the structure of the lesion, its origin, its topography and, its extension to adjacent organs. Malignant transformation, especially adenocarcinomas and neuroendocrine tumors, is a rare complication. When possible, radical surgery is always the best option for tailgut cysts. However, there is, currently, no standardized therapy for neuroendocrine tumors arising in a tailgut cyst enhancing the need of a multidisciplinary approach to manage gastro-entero-pancreatic-neuroendocrine tumors. We present the case of a 31-year-old pregnant woman who developed a neuroendocrine tumor arising in a tailgut cyst, the first case reported during pregnancy to our knowledge.