Brain and lung connection in cancer metastasis

Unexpected Seizures? What Brain Metastasis and Lung Cancer Could Be Trying to Tell You

Theo Raines in Health & Wellness August 2025 • 4 min read.

"Decoding the link between brain metastasis, papillary adenocarcinoma, and seizure symptoms: a guide for early detection and understanding."

Brain metastases, the most common type of intracranial tumors in adults, are becoming increasingly prevalent. This rise is attributed to enhanced diagnostic capabilities, particularly magnetic resonance imaging (MRI) which detects smaller lesions, and more effective strategies for managing systemic diseases outside the brain.

While computed tomography (CT) is often the first imaging method used when assessing brain disorders, MRI stands out as the superior technique for diagnosing brain metastases. The use of contrast agents during MRI further improves the ability to identify these metastases, helping to distinguish them from other conditions affecting the central nervous system (CNS).

Key indicators that help differentiate brain metastasis from other diseases include the presence of multiple lesions, their location at the junction of white and gray matter, well-defined margins, and a significant amount of vasogenic edema relative to the lesion size. Modern MRI techniques offer detailed insights beyond mere location, providing information about the physiological and chemical composition of CNS tumors through spectroscopy, diffusion, and perfusion imaging.

Unveiling the Unexpected: Brain Metastasis as the First Sign of Lung Cancer

Brain and lung connection in cancer metastasis

In some instances, imaging results might not clearly distinguish between brain metastases and primary brain tumors, necessitating a biopsy to determine the primary site of the lesion. For patients undergoing brain biopsies without a known primary tumor, the lungs should be a key area of focus. Poorly differentiated lung carcinomas can lack specific characteristics, making immunohistochemistry essential for accurately classifying the type of lung cancer.

Consider the case of a 33-year-old woman, previously healthy, who experienced seizures and was subsequently diagnosed with brain metastasis resulting from papillary adenocarcinoma of the lung. This case underscores the importance of considering lung cancer, even when neurological symptoms appear first.

Initial Presentation: The patient presented with tonic-clonic seizures, with no prior history of such episodes.
Diagnostic Imaging: An MRI revealed multiple expansile cortical and subcortical masses in both brain hemispheres.
Diagnostic Journey: After initial nonspecific findings and the unavailability of advanced imaging techniques like perfusion studies or spectroscopy, a brain biopsy was performed.
Pathological Findings: Histopathology suggested metastasis from a papillary carcinoma, with the thyroid initially suspected as the primary site.
Immunohistochemistry: Further testing revealed the expression of TTF-1 and napsin-A markers, while thyroglobulin was negative, leading to the identification of the lung as the primary site of the papillary adenocarcinoma.

Following the diagnosis, the patient was referred for radiotherapy. However, after the third session, she developed erythematous papular lesions on her face and chest, leading to a suspicion of Stevens-Johnson syndrome and transfer to the intensive care unit. After 45 days, she was discharged with a plan for continued radiotherapy.

Key Takeaways: What This Means for Early Detection and Treatment

This case highlights the critical role of considering lung cancer in patients who present with seizures and are found to have brain metastasis, even in the absence of other typical cancer symptoms. It also emphasizes the importance of advanced imaging techniques like MRI and the definitive role of immunohistochemistry in identifying the primary site of the cancer. The synergy between early detection, accurate diagnosis, and appropriate treatment strategies is crucial for improving outcomes in these challenging cases.

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This article is based on research published under:

DOI-LINK: 10.1590/s0100-39842013000500008, Alternate LINK

Title: Brain Metastasis As Initial Presentation Of Papillary Adenocarcinoma Of The Lung: Case Report

Subject: Radiology, Nuclear Medicine and imaging

Journal: Radiologia Brasileira

Publisher: FapUNIFESP (SciELO)

Authors: Irving Gabriel Araújo Bispo, Diego Teixeira Nascimento, Karina Oliveira Ferreira, Ricardo Fakhouri, Atilano Salvador Godinho, Thiago De Oliveira Ferrão

Published: 2013-10-01

Everything You Need To Know

What is the primary advantage of using MRI over CT scans when diagnosing brain metastasis?

MRI is the superior technique for diagnosing brain metastases compared to CT scans because it offers higher resolution and better visualization of soft tissues. MRI is able to detect smaller lesions and provide more detailed images of the brain, which is critical for the early detection of brain metastasis. The use of contrast agents during MRI further enhances the ability to identify and characterize these metastases, which helps to differentiate them from other conditions affecting the central nervous system (CNS).

In the context of the case study, why was a biopsy performed, and what key findings led to the diagnosis of papillary adenocarcinoma of the lung?

A biopsy was performed because initial imaging results did not clearly distinguish between brain metastases and primary brain tumors. The biopsy was crucial to determine the primary site of the lesion. The pathological findings from the biopsy suggested metastasis from a papillary carcinoma. Immunohistochemistry revealed the expression of TTF-1 and napsin-A markers, while thyroglobulin was negative. These findings indicated the lung as the primary site of the papillary adenocarcinoma, specifically a papillary carcinoma.

How can the characteristics of brain metastases on MRI help in distinguishing them from other conditions?

Several key indicators on MRI can help differentiate brain metastasis from other diseases. These include the presence of multiple lesions, their location at the junction of white and gray matter, well-defined margins, and a significant amount of vasogenic edema relative to the lesion size. Modern MRI techniques also provide detailed insights into the physiological and chemical composition of CNS tumors through spectroscopy, diffusion, and perfusion imaging. These advanced imaging methods give more detailed information, therefore helping to refine diagnosis.

What is the significance of the case study involving the 33-year-old woman who experienced seizures and was later diagnosed with brain metastasis from papillary adenocarcinoma of the lung?

The case highlights the importance of considering lung cancer in patients who present with seizures and are found to have brain metastasis, even in the absence of other typical cancer symptoms. It emphasizes the critical role of early detection and accurate diagnosis in improving patient outcomes. The case underscores that seizures can be the initial presentation of brain metastasis, which is then linked to underlying papillary adenocarcinoma of the lung. This emphasizes the necessity of comprehensive diagnostic strategies when encountering neurological symptoms.

How does the diagnostic journey described in the case study exemplify the importance of advanced imaging and immunohistochemistry in the management of brain metastasis?

The diagnostic journey demonstrates the importance of advanced imaging, particularly MRI, in detecting and characterizing brain metastasis. When initial imaging is inconclusive, the case highlights the necessity for biopsy and immunohistochemistry. Immunohistochemistry is essential for identifying the primary site of the cancer, especially when the primary tumor is not immediately apparent. The expression of specific markers like TTF-1 and napsin-A, combined with negative thyroglobulin results, provided critical information that led to the correct diagnosis of papillary adenocarcinoma originating from the lung. This reinforces that a combination of advanced imaging and immunohistochemistry is crucial for accurate diagnosis and treatment planning.