Elsevier

Clinical Radiology

Volume 68, Issue 8, August 2013, Pages e453-e459
Clinical Radiology

Natural history of cerebral dot-like cavernomas

https://doi.org/10.1016/j.crad.2013.02.010Get rights and content

Aim

To elucidate the natural history of dot-like or “black spot” cavernomas.

Materials and methods

Data of 18 children with black spot cavernomas were analysed retrospectively.

Results

Eleven boys and seven girls presented 187 black spot cavernomas during a mean observation period of 5.5 years. Mean and median age at diagnosis of the 187 cavernomas was 9.6 years. There were 70 de novo black spot cavernomas. Boys presented significantly more cavernomas than girls. There were three KRIT1 mutation carriers and four PDCD10 mutation carriers. Children with a PDCD10 mutation presented significantly more lesions than those children with a KRIT1 mutation (mean number of lesions per patient: 23.3 versus 3.3, respectively). There were 10 radiological haemorrhagic events caused by 10 black spot lesions. Two of these events were symptomatic. The haemorrhage rate of black spot cavernomas was 0.7% per lesion-year.

Conclusions

A mean bleeding rate of 0.7% per lesion-year is lower than the overall haemorrhage rates provided in the literature. Nonetheless, black spot cavernomas are not purely benign lesions. Furthermore, genetic mutations may play a role in the natural history of black spot cavernomas.

Introduction

Cerebral cavernous malformations (CCM), also known as cavernomas, are vascular malformations affecting the central nervous system and have a prevalence of 0.3–0.6% and an annual incidence between one and 5.6 new patients per 1,000,000.1, 2, 3 The existence of multiple lesions has been shown in up to 27% of cases.4

Although the imaging appearance of cavernomas may vary, magnetic resonance imaging (MRI) has been proven to be both a highly specific and sensitive tool in the diagnosis of CCM. In summary, the imaging appearances correspond mostly to the pathophysiological hallmark of CCM, which is recurrent thrombosis and haemorrhage.5

Among other manifestations, such as mulberry-like lesions, small T2*-hypointense dots ≤1 mm corresponding to small cavernomas are a typical form of CCM. These small cavernomas are defined as type IV lesions by Zabramski et al.6 and occur in the context of multiple cavernomas (Table 1).6 They correspond to susceptibility artefacts in T2*-weighted gradient-echo (T2*-GRE) sequences caused by haemosiderin depositions in small cavernomas that are not or barely visible in spin-echo (SE) sequences.6

Whereas there are numerous publications dealing with cavernomas,7, 8, 9, 10, 11, 12, 13, 14, 15 little is known about the nature of these dot-like or so-called “black spot” cavernomas and their clinical impact. Thus, the aim of the present study was to analyse the natural history of these cavernomas.

Section snippets

Materials and methods

Data from the medical files of the Department of Paediatric Neurosurgery of Hôpital Necker Enfants Malades, Paris were assessed between 1 January 1993 and 31 December 2009 to provide results concerning epidemiological aspects, imaging features and clinical considerations. Charts and MRI studies of these patients were analysed retrospectively. Among 70 patients with clear radiological and/or pathological criteria of a cerebral cavernoma, 18 patients (26%) had additional black spot lesions in the

Results

Eighteen children presented 187 black spot cavernomas additionally to other cavernomas during a mean observation period of 5.5 years per child (range: 18 days to 13.1 years). The mean number of black spot lesions was 10.4 ranging from 1 to 24.

Bigger dominant cavernomas initially lead to symptoms (seizures, signs of raised intracranial pressure, or focal neurological deficits) in 16 children, but none of the 187 black spot cavernomas could be related to any given symptoms during the observation

Discussion

Genetic analyses and MRI examinations have fundamentally changed our understanding of the nature of intracranial cavernomas. The discovery of de novo lesions, the link to genetic mutations, and a considerable haemorrhage rate underline the clinical need to better understand the natural history of cavernomas.

A limitation of this work is the diagnostic uncertainty concerning T2*-black spots. Establishing a definite diagnosis of black spot lesions in T2*W- images always poses a dilemma, especially

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