Radiation-induced temporal lobe necrosis in a nasopharyngeal cancer patient after external beam radiotherapy: a case report and review of literature

Abstract

Background: Nasopharyngeal carcinoma is considered rare worldwide. The treatment of nasopharyngeal carcinoma primarily relies on radiotherapy, as the tumor cells in NPC exhibit radiosensitivity. However, excessive dosage can result in a delayed reaction that affects the healthy surrounding tissues, including the central nervous system, causing brain radionecrosis, a rare yet severe condition, which can develop approximately 6-12 months after radiation as a significant complication. The majority of studies on brain radionecrosis have been conducted in China, where nasopharyngeal carcinoma is most prevalent. However, to the best of our knowledge, this is the first reported case of brain radionecrosis following radiotherapy for nasopharyngeal carcinoma in our region, which was diagnosed using magnetic resonance spectroscopy.

Case presentation: This case report describes a 49-year-old Arab male who presented with memory loss, expressive aphasia, and delirium 5 months after undergoing radiotherapy with a total radiation dose of 66 Gray for nasopharyngeal carcinoma (NPC). Magnetic resonance imaging with magnetic resonance spectroscopy revealed the presence of focal lesions in the left temporal lobe with accompanying brain edema indicative of radionecrosis.

Conclusion: It is imperative to consider the possibility of brain radionecrosis in patients who have previously received radiation therapy for head and neck cancers, particularly nasopharyngeal carcinoma. Early detection of brain radionecrosis is essential, and diagnostic imaging should be performed regularly during follow-up using magnetic resonance imaging and magnetic resonance spectroscopy. The primary objective of treatment is to alleviate symptoms through medical and/or surgical interventions.

Keywords: Cerebral radiation necrosis; Nasopharyngeal carcinoma; Radionecrosis; Radiotherapy; Temporal lobe necrosis.

Fig. 1

A magnetic resonance imaging image of the brain showing four quarters: left upper quarter is a T2-weighted image, right upper quarter is a T1-weighted image with contrast, left lower quarter is diffusion-weighted magnetic resonance imaging, right lower quarter is susceptibility weighted imaging

Fig. 2

An image of press short-term effects spectrum showing a high lactate peak with normal choline, excluding high cellularity or cell destruction as seen in neoplastic lesions and suggesting necrosis due to hypoxia (high lactate levels on magnetic resonance spectroscopy)

Fig. 3

Axial T1-weighted magnetic resonance images (top left and center) showing the voxel placement (blue square) within the thalamic region of an 18-year-old male patient diagnosed with childhood absence epilepsy. The spectral curve analysis (bottom left and right) displays the metabolic profile. Key metabolites identified include N-acetylaspartate, choline, creatine, myo-inositol, lactate, glutamate + glutamine, and alanine. The table (bottom left, “Curve Analysis”) presents quantitative data for each metabolite, including its position, amplitude, height, area, and height/area ratio, measured from a voxel size of 12.0 × 12.0 × 12.0 mm. The spectral plot (bottom right) illustrates the characteristic peaks for these metabolites, providing insights into potential metabolic alterations in the thalamus. The image was acquired using syngo.MR

Fig. 4

A magnetic resonance imaging image of the brain showing four quarters: left upper quarter is T2-weighted Image, right upper quarter is T1-weighted images postcontrast, left lower quarter is diffusion-weighted magnetic resonance imaging, and right lower quarter is perfusion weighted imaging showing poor perfusion, which excludes brain metastasis