Action tremor caused by olivary cavernoma in Klippel–Trénaunay syndrome mimicking asymmetric essential tremor

Abstract

A 52-year-old right-handed woman presented with a 24month history of a subacute and slowly progressive action tremor (5–6 Hz) of the upper limbs with dominance for her left side. Initially, the tremor syndrome was restricted to the left hand, but after a few months, the right side also demonstrated discrete affection. Other abnormal neurological signs like hypokinesia, rigidity, dystonia, or rest tremor were not observed. The patient reported that low doses of alcohol relieved the symptoms and a therapeutic trial with primidone (250 mg per day) significantly lessened the tremor. Her family history was unremarkable for vascular or neurological diseases, especially Klippel– Trenaunay syndrome (KTS), and she was born at term after an uncomplicated pregnancy. A cutaneous angiomatosis on the right hand and upper arm has been evident since birth. Furthermore, she presented with a varicosis on the back of her hand as well as hypotrophy of the right fingers and a discrete facial asymmetry. These clinical findings, however, were only distressing for cosmetic reasons, whereas the action tremor caused moderate functional problems for the left upper limb. The patient underwent a brain MRI examination, which revealed a 7.5 9 7.0-mm mass with a mixed signal core and a complete hypointense rim that affected the right inferior olive and also small portions of the left side (Fig. 1). There was no evidence of acute hemorrhage. In addition, detailed neuropsychological examination revealed regular cognitive findings. Motorevoked potentials, sensory-evoked potentials, cerebrospinal fluid analysis, and laboratory screening were normal. KTS is a rare sporadic congenital disease characterized by growth disturbances and capillary as well as venous malformations [1]. Clinical presentation is heterogeneous, though mainly unilaterally affecting the upper and/or lower limb. As only very few family cases of KTS are documented, a polygenic defect causing the disturbed angiogenesis has been postulated [2]. Nevertheless, the exact pathogenesis is still unclear and there is no firm chromosomal localization or linkage with a causative gene reported [1, 2]. Furthermore, it is only recently that Oduber and colleagues have proposed a common definition for the diagnosis of KTS by defining strict clinical criteria based on a detailed literature review. They suggest two major features characteristic to KTS: (1) congenital vascular malformation (including capillary, venous, arteriovenous, and lymphatic malformation), and (2) disturbed hyperor hypotrophic growth of the bone or soft tissue in the length or girth [1]. For the diagnosis of KTS at least capillary or venous malformation and growth disturbances must be obvious, which was fulfilled in our patient. In addition to the cutaneous involvement, visceral organs and the central nervous system can be affected by vascular anomalies [1, 3]. The most striking central nervous system findings are Electronic supplementary material The online version of this article (doi:10.1007/s00415-010-5675-4) contains supplementary material, which is available to authorized users.