Intracranial lipomas are congenital disorders resulting from abnormal differentiation of meningeal tissue during embryonic development. Most lipomas are small, usually pea-sized, and asymptomatic. They are often discovered incidentally on neuroimaging or only detected at autopsy, with incidence rates of 0.08% and 0.46%, respectively [
9]. It has been shown that the protomembrane contains primitive perivascular reticular endothelium, cells specialized in storing fat. These abnormalities in the primitive cells of the meninges may ultimately allow them to differentiate directionally into adipose tissue and form lipomas. Thus, meningeal lipomas are not true tumors but an aberrant developmental process [
9]. Intracranial lipomas are often accompanied by intracranial or extracranial malformations, with common comorbid malformations including hypoplasia of the corpus callosum, defect of septum pellucida, and craniosynostosis or agenesis. Interhemispheric lipomas interfere with the embryonic development of the brain, during which the corpus callosum is formed by the migration and attachment of nerve cells from midline structures, which may be the mechanism by which intracranial lipomas cause corpus callosum dysplasia. An intracranial lipoma may interfere with the normal cell migration and connections during these developmental processes, resulting in corpus callosum dysplasia. The patient in our case had a combination of corpus callosum dysplasia and an unclosed septum pellucidum [
10], consistent with the above theory.
The patient, in this case, was diagnosed with WD and had a concurrent intracranial lipoma.WD is caused by defects in the ATP7B gene, resulting in abnormal copper metabolism, tissue copper accumulation, and copper-induced oxidative damage [
11].Typical cranial MRI changes in WD usually present as symmetrical, high, or mixed signals on T2-weighted images, affecting mainly the putamen, pontine, midbrain, and thalamus [
12,
13]. Although previous studies have less frequently addressed corpus callosum abnormalities, a study by Trocello et al. demonstrated that some patients with Wilson’s disease also have abnormalities of the corpus callosum [
14]. The growth of intracranial lipomas may be associated with abnormal copper metabolism in WD. Abnormal copper metabolism affects lipid metabolism and triggers an inflammatory response. Abnormalities of lipid metabolism in a rat model of hepatic copper overload were demonstrated by Medici et al [
15]. First, liver damage in patients with WD affects lipid metabolic pathways, such as the sphingolipid and glycerophospholipid metabolic pathways, leading to elevated serum concentrations of several lipid molecules which may promote the growth of intracranial lipomas [
16,
17]. In addition, WD is accompanied by a certain degree of inflammatory response. Several studies have found that serum inflammatory factors such as interleukin-6(IL-6) and tumor necrosis factorα(TNF-α) are abnormally high in patients with WD. This phenomenon is attributed to the accumulation and abnormal metabolism of copper in the body, which leads to oxidative stress and cellular damage, triggering inflammatory responses and thus increasing the serum levels of various inflammatory factors [
18]. These inflammatory factors may promote adipocyte proliferation, inhibit adipocyte apoptosis, and promote fat synthesis, leading to the growth of intracranial lipomas [
19,
20]. Therefore, maintaining good liver function and keeping appropriate serum copper levels are essential to inhibit the growth of intracranial lipomas in patients [
21]
. In addition, Schaefer reported that the formation of subcutaneous lipomas in patients with WD may be associated with mutations in an adjacent region of the ATP7B gene [
22]. Unfortunately, the patient in this case did not undergo relevant genetic testing.
There are extremely limited reports on the coexistence of WD, corpus callosum dysplasia, and intracranial lipoma in this case. The patient’s small head circumference and wide eye spacing may be related to corpus callosum dysplasia, which does not require special treatment. In addition, the patient’s intracranial lipoma was small and clinically insignificant, so no specific treatment was required, and only regular imaging monitoring was required. Only when the intracranial lipoma enlarges and is accompanied by symptoms such as convulsions, mental retardation, pituitary-hypothalamic endocrine disorders, and visual disturbances does targeted treatment need to be considered [
23]. Currently, patients only need to be treated for WD to avoid copper’s high effects on the growth of intracranial lipomas [
24]. In addition, patients need to follow a low-fat diet [
25] because there is a correlation between significant lipoma growth and increased body fat content [
26].