# Co-occurrence of lung adenocarcinoma with rapidly progressive dementia and multiple cerebral microbleeds: a case report

## TL;DR

A 45-year-old woman with lung cancer developed rapid dementia and brain microbleeds, highlighting the complex connection between cancer and neurological decline.

## Contribution

This case report highlights a rare co-occurrence of lung adenocarcinoma, rapidly progressive dementia, and cerebral microbleeds.

## Key findings

- The patient exhibited rapid cognitive decline and brain microhemorrhages alongside lung adenocarcinoma.
- The apolipoprotein ε4 allele may be linked to brain lesions and microbleeds in this case.
- The tumor's role in causing brain lesions and microbleeds remains an area for further investigation.

## Abstract

Various neurological diseases can cause rapidly progressive dementia, which is a clinical syndrome characterized by a rapid decline in cognitive function over a short period, typically less than 1 or 2 years. It can be caused by various neurological diseases, including neurodegenerative, inflammatory, vascular, metabolic, and neoplastic central nervous system diseases. Rapidly progressive dementia is particularly associated with Creutzfeldt–Jakob disease, but other conditions such as immune-mediated encephalitis, rapidly progressive subtypes of Alzheimer’s disease, and various other mimics of prion diseases must also be considered. Multiple cerebral microbleeds are typical imaging features of cerebral small vessel diseases, but can also appear in other rare conditions.

We describe the case of a 45-year-old Asian female patient with lung adenocarcinoma who exhibited rapidly progressive dementia and multiple cerebral microbleeds. The patient was a 45-year-old woman who experienced rapid cognitive decline without obvious triggers, accompanied by disorganized speech, difficulty in expression, and short-term memory loss. Brain magnetic resonance imaging revealed widely distributed microhemorrhages, while computed tomography and pathological examination further confirmed the diagnosis of lung adenocarcinoma. The patient did not undergo a brain biopsy because of the rapid deterioration of her illness. Her condition deteriorated rapidly, leading to death in the fourth month.

Herein, we discuss the presence of the apolipoprotein ε4 allele risk gene and the role of the tumor in causing multiple nodular lesions in the patient’s brain, as well as multiple microbleeds. The role of the apolipoprotein ε4 allele risk gene in multiple nodular lesions of the brain and CMB requires further study, as it may be responsible for the rapid cognitive decline and imaging findings observed in patients. The role of the tumor in causing these brain lesions and cerebral microbleeds is also of interest as it may help to provide insight into the pathophysiological mechanisms of rapidly progressive dementia in the context of cancer. This case highlights the need for a comprehensive diagnosis, including magnetic resonance imaging, blood and cerebrospinal fluid analyses, and brain biopsy, to identify treatable causes of rapidly progressive dementia.

The online version contains supplementary material available at 10.1186/s13256-026-05846-x.