Magnetic resonance imaging of a transient splenial lesion of the

Radiography xxx (2015) 1e3

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Case report

Magnetic resonance imaging of a transient splenial lesion of the corpus callosum resolved within a week R. Conforti a, A.M. Porto b, R. Capasso b, *, M. Cirillo b, G. Fontanella b, A. Salzano c, M. Fabrazzo c, S. Cappabianca b degli Studi di Napoli, Dipartimento di Neuroradiologia, C/O C.T.O., Viale Colli Aminei 21, 80131 Napoli, Italy Seconda Universita Department of Internal Clinical and Experimental Medicine, Second University of Naples, Piazza Miraglia, Naples, Italy c degli Studi di Napoli, Dipartimento di Neuropsichiatria, Largo Madonna delle Grazie, Napoli, Italy Seconda Universita a

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a r t i c l e i n f o

a b s t r a c t

Article history: Received 5 February 2015 Received in revised form 1 March 2015 Accepted 5 March 2015 Available online xxx

The transient splenial lesion (TSL) of the corpus callosum (CC) is an uncommon radiologic finding incidentally detected on Magnetic Resonance Imaging (MRI). It was first observed in epileptic patients and ever since it has been described in varied neurologic conditions but its etiology is still little known. Slow disappearance of signal abnormalities in the CC mainly occurs after some weeks or months and then TSL carries a good prognosis making unnecessary invasive therapies and procedures. We report a case of an isolated TSL of CC in a patient suffering from psychotic and hormonal disorders, which spontaneously resolved within only one week. © 2015 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Keywords: Corpus callosum Antiepileptic drug Magnetic resonance imaging Splenium Transient lesions

Introduction

Case presentation

A focal and reversible lesion limited to the splenium of the corpus callosum (SCC), without other white matter lesions, is a rare radiologic finding incidentally detected on magnetic resonance (MR) imaging.1,2 Transient splenial lesion (TSL) of corpus callosum (CC) was first observed in epileptic patients and ever since it has been described in varied neurologic conditions.1,2 However, its etiology is still little known and although different hypotheses have been put forward to explain transient changes in the splenium, none of them has been well proven.2,3 We report a case of an isolated TSL of CC in a patient suffering from psychotic and hormonal disorders, which spontaneously resolved within a week.

A 32-year-old psychotic woman came to our observation to undergo MR investigation of the sellar region because of hyperprolactinemia (50.2 ng/ml). She complained of amenorrhea, galactorrhea, and weight gain; these symptoms were related to antipsychotic drugs given her for several months. The patient was suffering from psychotic syndrome for ten years, during that time she was treated with various antipsychotic drugs, alternating periods of psychological well-being with relapses. Her psychosis consisted of mystic-religious delirium and hallucinations. In the previous two years she was treated with carbamazepine (oxacarbazepina) 1200 mg/day, which was suspended 7 days before the examination. Brain MR was performed with an appropriate hypothalamusepituitary study before and after intravenous (i.v.) paramagnetic contrast medium (CM) administration. In all MR sequences the SCC presented an area of pathological signal intensity that was median, grossly round, 1.5 1.3 0.6 cm in size, with regular margins. It appeared hypointense on T1W images (Fig. 1a) while it was hyperintense on FLAIR images (Fig. 1b). Diffusion Weighted (DW) sequence showed restricted diffusivity (Fig. 1c) and after administration of i.v. CM the lesion had no enhancement (Fig. 1d). The examination revealed normal pituitary

Abbreviations: AED, anti epileptic drug; CC, corpus callosum; CM, contrast medium; DW, diffusion weighted; MR, magnetic resonance; MRI, magnetic resonance imaging; SCC, splenium of corpus callosum; TSL, transient splenial lesion. * Corresponding author. Tel.: þ39 081 566 52 00; fax: þ39 081 566 52 02. E-mail addresses: [email protected] (R. Conforti), annamaria.porto@ libero.it (A.M. Porto), [email protected] (R. Capasso), emmecirillo@ libero.it (M. Cirillo), [email protected] (G. Fontanella), antonio_ [email protected] (A. Salzano), [email protected] (M. Fabrazzo), [email protected] (S. Cappabianca).

http://dx.doi.org/10.1016/j.radi.2015.03.001 1078-8174/© 2015 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

Please cite this article in press as: Conforti R, et al., Magnetic resonance imaging of a transient splenial lesion of the corpus callosum resolved within a week, Radiography (2015), http://dx.doi.org/10.1016/j.radi.2015.03.001

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R. Conforti et al. / Radiography xxx (2015) 1e3

Figure 1. T1 axial (a) sequences show a hypointense area of CC which appears hyperintense on both FLAIR (b) and DW (c) sequences without enhancement after contrast medium administration (d); MR examination carried out one week later showed the disappearance of the pathological area on FLAIR sequence (e) and DW image (f).

gland. In order to monitor the evolution of the restricted diffusivity, MR study was performed one week later and showed the disappearance of the pathological SCC signal intensity (Fig. 1eef).

Discussion The transient involvement of the splenium has been widely described in association to many neurologic conditions rather than an isolated finding; however, after the intoxication by anti epileptic drug (AED) or its abrupt cessation a TSL of the SCC may also be found as an isolated finding.1e3 TSL of CC is probably a non-specific endpoint of several physiopathological mechanisms which lead to damage of this anatomic region. The most widespread opinion is that, whatever the cause, the SCC lesion is attributable to intramyelinic edema, due to the toxicity of AED.3 TSL of CC can appear in psychiatric patients after a suddenly reduction of carbamazepine therapy, as in our case report. It has been postulated that the sudden cessation of AED could lead to alteration of the arginineevasopressin (AVP) system, resulting into hydric imbalance determining a MRI signal alteration of the SCC.2 The real reason of the selective involvement of the SCC is not really known. It may be explained by the critical low blood supply to this part of the CC, which receives the terminal branches of posterior cerebral artery, whereas the remainder of the CC is vascularized by the more extensive carotid arterial vascular system.3,4 The recent literature describes two types of SCC lesions on MR Imaging: a) well-defined round or oval, circumscribed and median

signal alteration or b) less defined and more extended surface of signal alteration involving the entire splenium (Boomerang sign).2 In our patient the lesion of SCC was characterized by round morphology with limited extension (no more than 1.5e2 cm) and appeared hypointense on T1W and hyperintense in FLAIR sequences, showing a thin peripheral margin of healthy tissue, restricted diffusivity without enhancement after i.v. paramagnetic CM administration.2,5 These findings are theoretically consistent with reversible cytotoxic edema (intracellular) not affecting neurons, but glia and Schwann cells which can appear in psychiatric patients after a suddenly reduction of carbamazepine therapy.1,2 Slow disappearance of signal abnormalities in the SCC has been documented by various authors and mainly occurs after some weeks or months.2,5 Due to their reversibility, these TSL are a bening lesions and then unnecessary therapies and procedures should be avoided.2 The finding of a rapid disappearance of TLS has been rarely reported in the literature.5 In our case the disappearance of the alterated signal intensity of the SCC documented within a week after its discovery represents a distinguishing feature of the report. In summary, an isolated TSL of the SCC is a benign and spontaneously reversible lesion, therefore invasive diagnostic procedures and medical or surgical treatments may be avoided.

Conflict of interest statement The authors declare that there is no conflict of interests regarding the publication of this letter.


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