Epidermoid cyst with a metabolite pattern mimicking a brain abscess. A magnetic resonance spectroscopy study

Intrinsic epidermoid cyst of the brainstem in children-review and case report

PURPOSE

The study aimed to summarize all published cases of intrinsic brainstem epidermoid cysts in a timeline to highlight the specific characteristics and individualize the disease, in addition to discussing the best treatment used.

METHODS

The scientific literature on pediatric cases of intrinsic epidermoid cysts of the brainstem was analyzed. We present the case of a 1.5-year-old male with incidental presentation, who was treated with gross total resection. We summarize all previously published cases to individualize the disease.

RESULTS

We identified 21 patients, including 10 boys and 11 girls, with a mean age of 4.85 (1-15) years at the time of surgery. The most frequent symptoms were cranial nerve palsy (71.4%), pyramidal tract deficit (57.14%), and headache (52.38%). Among the affected cranial nerves, VII was the most frequently reported in 10 patients.

CONCLUSION

Brainstem epidermoid cysts are extremely rare pathologies with relevant age involvement in young children. The treatment objective should be the maximum resection of the lesion through a careful approach and with the appropriate tools for the functional preservation of the patient.

MR spectroscopy in pediatric neuroradiology

Magnetic resonance spectroscopy (MRS), being able to identify and measure some brain components (metabolites) in pathologic lesions and in normal-appearing tissue, offers a valuable additional diagnostic tool to assess several pediatric neurological diseases. In this review we will illustrate the basic principles and clinical applications of brain proton (H¹; hydrogen) MRS (H¹MRS), by now the only MRS method widely available in clinical practice. Performing H¹MRS in the brain is inherently less complicated than in other tissues (e.g., liver, muscle), in which spectra are heavily affected by magnetic field inhomogeneities, respiration artifacts, and dominating signals from the surrounding adipose tissues. H¹MRS in pediatric neuroradiology has some advantages over acquisitions in adults (lack of motion due to children sedation and lack of brain iron deposition allow optimal results), but it requires a deep knowledge of pediatric pathologies and familiarity with the developmental changes in spectral patterns, particularly occurring in the first two years of life. Examples from our database, obtained mainly from a 1.5 Tesla clinical scanner in a time span of 15 years, will demonstrate the efficacy of H¹MRS in the diagnosis of a wide range of selected pediatric pathologies, like brain tumors, infections, neonatal hypoxic-ischemic encephalopathy, metabolic and white matter disorders.

Magnetic Resonance Spectroscopy and its Clinical Applications: A Review

In vivo NMR spectroscopy is known as magnetic resonance spectroscopy (MRS). MRS has been applied as both a research and a clinical tool in order to detect visible or nonvisible abnormalities. The adaptability of MRS allows a technique that can probe a wide variety of metabolic uses across different tissues. Although MRS is mostly applied for brain tissue, it can be used for detection, localization, staging, tumour aggressiveness evaluation, and tumour response assessment of breast, prostate, hepatic, and other cancers. In this article, the medical applications of MRS in the brain, including tumours, neural and psychiatric disorder studies, breast, prostate, hepatic, gastrointestinal, and genitourinary investigations have been reviewed.

Multiparametric Imaging Analysis: Magnetic Resonance Spectroscopy

Magnetic resonance spectroscopy (MRS) is a magnetic resonance-based imaging modality that allows noninvasive sampling of metabolic changes in normal and abnormal brain parenchyma. MRS is particularly useful in the differentiation of developmental or non-neoplastic disorders from neoplastic processes. MRS is also useful during routine imaging follow-up after radiation treatment or during antiangiogenic treatment and for predicting outcomes and treatment response. The objective of this article is to provide a concise but thorough review of the basic physical principles, important applications of MRS in brain tumor imaging, and future directions.

Imaging Findings of an Epidermoid Cyst Undergoing Malignant Transformation

Malignant transformation of epidermoid cyst into squamous cell carcinoma (SCC) is rare. We report the case of a 39-year-old woman presenting with dizziness and cerebellar ataxia. MR scan revealed a mass in the left cerebropontine angle compressing the brainstem and the cerebellum, with two main components, a cystic and a solid one. The cystic component displayed imaging findings consistent with an epidermoid cyst. The solid component showed dense calcifications, low signal intensity on T1W, T2W and DW images and peripheral nodular enhancement. MR spectroscopy detected high lipid/lactate peaks and choline/creatine ratio. Imaging findings raised suspicion for malignant transformation, which was confirmed by histopathologic examination revealing an SCC. MR imaging with intravenous administration of gadolinium, DW images and MR spectroscopy can play a critical role in the diagnosis of malignant transformation of an epidermoid cyst.