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Intracranial aneurysms have an estimated prevalence of about 3%. A rare subgroup are aneurysms of the internal carotid artery that develop medially into the sellar region. Due to the risk of rupture with subsequent subarachnoid hemorrhage and of compression of surrounding structures, mechanical occlusion is advised. Hypopituitarism is not a rare disease and most often related to pituitary adenoma. Only 0.17% of cases with hypopituitarism are caused by unruptured intracranial aneurysms. Today, the predominant treatment of these aneurysms is endovascular coiling or application of flow diverting stents. We present the case of a 60-year-old female patient, who was treated with endovascular coiling for a right-sided, intracavernous, incidental internal carotid artery aneurysm. On postinterventional day 6, she was readmitted with contralateral third nerve palsy, mild hyponatremia und thyreotropic insufficiency. The symptoms recovered after anti-edematous treatment with corticosteroids; only an asymptomatic hyperprolactinemia persisted. To the best of our knowledge, this is the first case report of transient contralateral cranial nerve palsy combined with transient hypopituitarism after endovascular treatment of an internal carotid aneurysm. As treatment we propose corticosteroids, if necessary in combination with nonsteroidal anti-inflammatory drugs, in order to inhibit inflammatory reactions of the aneurysm wall compromising the nearby, partially compressed neural structures.

Intracranial aneurysms represent a potentially life-threatening condition and occur in 3–5% of the population. They are increasingly diagnosed due to the broad application of cranial magnetic resonance imaging and computed tomography in the context of headaches, vertigo, and other unspecific symptoms. For each affected individual, it is utterly important to estimate the rupture risk of the respective aneurysm. However, clinically applied decision tools, such as the PHASES score, remain insufficient. Therefore, a machine learning approach assessing the rupture risk of intracranial aneurysms is proposed in our study. For training and evaluation of the algorithm, data from a single neurovascular center was used, comprising 446 aneurysms (221 ruptured, 225 unruptured). The machine learning model was then compared with the PHASES score and proved superior in accuracy (0.7825), F1-score (0.7975), sensitivity (0.8643), specificity (0.7022), positive predictive value (0.7403), negative predictive value (0.8404), and area under the curve (0.8639). The frequency distributions of the predicted rupture probabilities and the PHASES score were analyzed. A symmetry can be observed between the rupture probabilities, with a symmetry axis at 0.5. A feature importance analysis reveals that the body mass index, consumption of anticoagulants, and harboring vessel are regarded as the most important features when assessing the rupture risk. On the other hand, the size of the aneurysm, which is weighted most in the PHASES score, is regarded as less important. Based on our findings we discuss the potential role of the model for clinical practice in geographically confined aneurysm patients.

Intracavernous aneurysms of the cranial base, though less frequent than intradural intracranial aneurysms, can pose considerable therapeutic problems. To date, little is known concerning their spontaneous development and eventual growth kinetics. We report the observation of two de novo aneurysms without prior therapeutic manipulation of the vessels. In our first case, the 33-year-old woman had suffered from an intracerebral hemorrhage at the age of 22. At this time, neurosurgical evacuation was performed, neither angiographically nor histologically was an underlying vascular malformation disclosed. During follow-up observation 11 years later, a cavernous aneurysm of the right internal carotid artery was detected, together with an arteriovenous malformation of the left pericallosal artery next to the former hemorrhage. In the second case, the 49-year-old woman had undergone magnetic resonance imaging (MRI) for headache, revealing two intracavernous aneurysms of the right internal carotid artery. During follow-up, 7 years later, angiography disclosed a de-novo aneurysm of the left internal carotid artery, and an enlargement of the more distal right-sided aneurysm. Most cases of de novo aneurysm formation are described intradurally and after manipulation of the harboring vessel. In the patients presented here, therapeutically induced hemodynamic changes or vessel wall manipulations are not involved, pointing to a cerebrovascular predilection, that-in combination with a set of risk factors-leads to the development of cavernous aneurysms.

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