LETTER TO THE EDITOR The journey of a floating fat: from suprasellar dermoid cyst to lateral ventricles S. Gasparini 1,2 & E. Ferlazzo 1,2 & U. Sabatini 1 & C. Sueri 2 & Umberto Aguglia 1,2 Received: 14 June 2017 /Accepted: 18 September 2017 # Springer-Verlag Italia S.r.l. 2017 A 68-year-old man had a history of hypertension and retinal detachment in the left eye, occurred 3 years be- fore that caused amaurosis. He presented with sudden nasal hemianopia in the right eye and tension-type head- ache mainly involving right frontal region, without head trauma. A CT-scan documented a hyperdense lesion in suprasellar cistern (Fig. 1a, b) with normal findings at intracranial angio-CT. Five days later, the hyperdense suprasellar lesion was no more visible at CT-scan, and MRI showed high-signal intensity foci within both lat- eral ventricles in T1, T2, and FLAIR sequences (Fig. 1c–f). Headache and visual symptoms gradually disap- peared within 1 week. These findings were in keeping with the migration of floating fat droplets from a rup- tured suprasellar dermoid cyst to lateral ventricles. Even though numerous reports of ruptured dermoid cysts ex- ist, the presence of an intact cyst and the following migration of its content after rupture are poorly docu- mented in literature. Dermoid cysts are intracranial tu- mors that may rarely appear hyperdense at CT-scan [1, 2], and fat droplets in the lateral ventricles are sugges- tive markers of their recent rupture [3]. Depending on the site, the rupture of the cyst may cause complications as, for example, acute hydrocephalus that should be ruled out particularly when the patient presents with new-onset headache. Traditional studies assert that cere- brospinal fluid (CSF) circulates from its production site in choroid plexuses, located in the inferior horn of the lateral ventricles, and flows via the foramina of Monro to third ventricle, aqueduct, and fourth ventricle towards central canal of spinal cord and subarachnoid spaces [4]. According to this model, the journey of fat droplets from suprasellar cistern would have occurred against CSF flow. Nevertheless, some recent studies [5–7] have applied advanced MRI techniques, particularly inversion pulse [5] and improved motion-sensitized driven-equilib- rium steady-state-free precession [6], to the study of CSF dynamics. Those studies have found that CSF mo- tion is complex and irregular in physiologic conditions, resulting from a combination of unidirectional flow, pul- satile back and forth movements, and constant fluid ex- change between CSF and interstitial spaces [7]. Thus, it is not surprising that fatty material, due to its relatively low specific weight, may be displaced in higher regions, like the frontal horns of lateral ventricles. * Umberto Aguglia u.aguglia@unicz.it 1 Department of Medical and Surgical Sciences, Magna Græcia University of Catanzaro, Viale Europa, Catanzaro, Italy 2 Regional Epilepsy Center, Great Metropolitan Hospital, Via Melacrino, 89100 Reggio Calabria, Italy Neurol Sci DOI 10.1007/s10072-017-3126-z