To analyze a rare triad of intracranial fetal pathologies and clinical study of the novel defined sequence pathogenesis based on prenatal and postmortem findings. Complex multidisciplinary clinical analysis and review of up-to-date literature. In an 18-gestational-week fetus the screening ultrasound scan resembled the semilobar type of holoprosencephaly and oral tumor. After the indicated termination of pregnancy, the histopathology results confirmed another pathologies - oral meningoencephalocele, teratoma of the sellar area and large arachnoidal cyst of the anterior cerebral fossa. The surprising final results were evaluated by specialists in prenatal diagnosis, histopathology, genetics, neurology, and radiology. We defined the final diagnosed triad oral meningoencephalocele - intracranial sellar teratoma- arachnoidal cyst as a novel sequence defect malformation. In the detailed sequence pathogenesis, the intracranial sellar teratoma created an aperture for meningoencephalocele in the cranial base and the arachnoidal cyst facilitated, by its growth and pressure, the protrusion of the brain tissues (Fig. 4, Ref. 10). Text in PDF www.elis.sk.