Tumor or not a tumor: Pitfalls and differential diagnosis in neuro-oncology

Available online 6 April 2023

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The majority of intracranial expansive lesions are tumors. However, a wide range of lesions can mimic neoplastic pathology. Differentiating pseudotumoral lesions from brain tumors is crucial to patient management. This article describes the most common intracranial pseudotumors, with a focus on the imaging features that serve as clues to detect pseudotumors.

Introduction

Intracranial expansile lesions primarily constitute neoplastic etiology. However, some of these lesions are pseudotumors. Identifying these pseudotumors, or raising suspicion of other alternative pathologies is essential for appropriate patient management. Apart from clinical and biological data, magnetic resonance imaging (MRI) with advanced sequences has a crucial role in identifying pseudotumors. A wide range of pathologies including cerebrovascular accident, abscess or demyelination can mimic a tumor [1], [2], [3], [4]. These pathologies, especially those that do not require invasive procedures, e.g., biopsy or surgery, must be identified as early as possible. The aim of this article is to describe the common intracranial pseudotumors and clues to detect them early in the course of the disease process.

Section snippetsTypical imaging findings of brain tumors

Intracranial tumors can be intra- or extra-parenchymal.

The scope of this paper is limited to include an exhaustive description of all intracranial tumors, however, specific imaging features for each pathology have been specified.

Intra-parenchymal tumors appear as an expansile infiltrative process involving white matter and gray matter for primary tumors like gliomas, or located at the gray/white matter junction with extensive disproportionate perilesional edema for secondary involvement. The

Infectious diseases

Infectious diseases are one of the main differential diagnoses of brain tumors, requiring rapid and appropriate therapeutic management. In oncology patients, any intracranial lesion should raise the suspicion of metastasis, but other possibilities have to be excluded. Indeed, the immunosuppression secondary to various chemotherapies favors bacterial, viral and fungal complications.

Conclusion

Intracranial expansive lesions of varying etiologies can mimic neoplasm. Clinical data should always be correlated with imaging features to formulate a better diagnostic hypothesis. Knowledge of specific radiological signs and the role of advanced imaging are vital to avoid erroneous diagnosis (Table 1).

Disclosure of interest

The authors declare that they have no competing interest.

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