A Rare Case of Corpus Callosum Lipoma with Corpus Callosum Dysgenesis and Subcutaneous Lipoma

DISCUSSION

Uncommon neoplasms seen within the brain include corpus callosum lipoma and pericallosal lipoma. Among tumors found within the brain, they constitute fewer than 1%.¹ The aberrant persistence of primitive meninges, which eventually transforms into adipocytes, is the root cause of many conditions.^2,3 Nevertheless, the exact cause of this lesion remains unknown. The Sylvian cistern, superior cerebellar cistern, suprasellar cistern, and quadrigeminal cistern are some other possible sites. Although headaches are uncommon, they can occur in rare cases among asymptomatic lesions.^1,5,6 Fewer case studies have described intracranial lipomas with extracranial subcutaneous extensions; for example, Mitilian et al.⁷ and Chen et al.⁸ have recorded three such cases.⁹

There are two main categories of intracranial lipomas, as described by Tart and Quisling¹⁰—curvilinear and tubulonodular. Smaller in size and arranged in a linear fashion, curvilinear lipomas tend to be placed further back in the body. Tubulonodular lipomas, on the contrary, are more commonly found anteriorly and have a spherical or cylindrical shape. Most cases of the tubulonodular type have a midline tract defect and an expansion of the subcutaneous tissue into the frontal region.¹¹

From a lack of direct connection⁶ to a fibrotic-lipomatous connection^12,13 and finally a direct connection through the cranium,¹¹ several communication patterns are noted between the intracranial and extracranial components of the lipoma. The dehiscence of the skull, together with the probable evagination of a small tuft of meninx primitiva, is the explanation put forth by Truwit and Barkovich³ for direct extension through the skull. Intracranial lipomas can spread to the subcutaneous tissue through a scalp defect.

Although most lipomas do not cause any noticeable symptoms, in rare cases they can be linked to neurological issues such as cerebral palsy, seizures, psychosomatic illnesses, and motor difficulties. The most prevalent symptoms are headaches and seizures. Obstructive hydrocephalus is a potential complication of seizures, which often begin before the age of 15.⁶ It is more common for women to experience these symptoms. These conditions are now more frequently detected starting at 26 weeks of gestation due to increased use of prenatal USG monitoring.^1,5 The CT scan, which shows calcifications most commonly in the tubulonodular form, is used to make the clinical diagnosis.^1,5 For accurate lesion characterization and size assessment, as well as for evaluating associated features and dysgenesis or agenesis of the corpus callosum, MRI is the examination of choice. All sequences demonstrate the lesion’s fatty intensity, with T1 and T2 sequences showing hyperintensity. It also shows suppression on fat saturation (fat SAT) sequences. If an electroencephalogram (EEG) is performed on a patient experiencing seizures, it may help identify the epileptic focus. Dermoid cysts and teratoma are among the possible alternative diagnoses. Unless hydrocephalus is present, surgical techniques are not advised for treating such anomalies.^5,14 The strong vascularity, adhesion, and infiltration of the capsule into neighboring tissues, coupled with the fact that these lesions typically do not expand, are reasons why surgical intervention is not recommended for them.^1,3,5,14 When dealing with individuals presenting with seizures, most literature reviews recommend anticonvulsant therapy for symptomatic relief. For patients experiencing developmental delays, recommendations include anti-migraine prophylaxis and interdisciplinary stimulation.