This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Cerebral Amyloid Angiopathy-Related Inflammation Mimicking Leptomeningeal Metastasis After Resected Lung Adenocarcinoma: A Case Report Highlighting Dynamic Diagnostic Reassessment
by
, , , and
Kodai Shigeyama
1, 
Yosuke Dotsu
1,*,
Shunsuke Yoshimura
2,
Takeshi Hiu
3,
Nozomi Ueki
4,
Ryo Futsuki
1,
Satoru Koga
1,
Noritaka Honda
1,
Kazumasa Akagi
1,5,
Midori Matsuo
1,6,
Hirokazu Taniguchi
1,5,7,
Shinnosuke Takemoto
1 and
Hiroshi Mukae
8 1
Department of Respiratory Medicine, Nagasaki University Hospital, 852-8501 Nagasaki, Japan
2
Department of Neurology and Strokology, Nagasaki University Hospital, 852-8501 Nagasaki, Japan
3
Department of Neurosurgery, Nagasaki University Graduate School of Biomedical Sciences, 852-8501 Nagasaki, Japan
4
Department of Tumor and Diagnostic Pathology Atomic Bomb Disease Institute, Nagasaki University, 852-8523 Nagasaki, Japan
5
Clinical Oncology Center, Nagasaki University Hospital, 852-8501 Nagasaki, Japan
6
Clinical Research Center, Nagasaki University Hospital, 852-8501 Nagasaki, Japan
7
Clinical Genomics Center, Nagasaki University Hospital, 852-8501 Nagasaki, Japan
8
Nagasaki Harbor Medical Center, 850-8555 Nagasaki, Japan
*
Author to whom correspondence should be addressed.
Curr. Oncol. 2026, 33(9), 562; https://doi.org/10.3390/curroncol33090562
Submission received: 3 August 2026
/
Revised: 9 September 2026
/
Accepted: 16 September 2026
/
Published: 16 September 2026
(This article belongs to the Special Issue Personalized Medicine and Multidisciplinary Approaches to Thoracic Malignancies)
Simple Summary
This report describes an older woman who had recently undergone surgery for early-stage lung cancer. A brain MRI performed after a fall showed abnormalities that initially looked like cancer spread to the lining of the brain. However, she had almost no neurological symptoms, no cancer cells were found in the cerebrospinal fluid, and a special MRI sequence later revealed many small brain bleeds. These findings suggested cerebral amyloid angiopathy-related inflammation, a rare inflammatory disease of small brain vessels. Because this condition and leptomeningeal metastasis require very different treatments, a brain biopsy was performed and confirmed the inflammatory disease. The patient remained stable and improved without steroid treatment. This case shows that brain MRI abnormalities in patients with cancer are not always metastases. Careful review of symptoms, cerebrospinal fluid results, appropriate MRI sequences, multidisciplinary discussion, and biopsy when needed can prevent an incorrect diagnosis, unnecessary cancer treatment, and serious treatment delays.
Abstract
Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare inflammatory subtype of cerebral amyloid angiopathy that may present with leptomeningeal enhancement on magnetic resonance imaging (MRI), thereby mimicking leptomeningeal metastasis (LM) in patients with cancer. We report the case of an 82-year-old woman with a recently resected lung adenocarcinoma who underwent brain MRI following a fall. MRI revealed bilateral asymmetric white matter hyperintensities and multifocal leptomeningeal enhancement, which initially suggested LM. However, preserved neurological function, negative cerebrospinal fluid cytology, and the subsequent identification of numerous cortical and subcortical microbleeds on targeted reassessment with susceptibility-weighted MRI prompted diagnostic reassessment. Brain biopsy demonstrated vascular amyloid deposition with perivascular inflammatory infiltrates, confirming CAA-ri. Because the patient remained neurologically stable, she was managed conservatively, and spontaneous radiological improvement was observed during follow-up. This case highlights the fact that leptomeningeal abnormalities in patients with lung cancer do not invariably represent leptomeningeal metastasis. When clinicoradiological findings are discordant, prompt reassessment using appropriately selected MRI sequences should be integrated with cerebrospinal fluid analysis and multidisciplinary evaluation, with pathological confirmation considered when clinically consequential alternative diagnoses cannot be excluded. This approach may help avoid inappropriate LM-directed therapy.
