Unusual Cystic and Papillary Appearance of Brain Metastasis from Papillary Lung Adenocarcinoma on MRI. Radiologic-Pathologic Correlations in Two Similar Cases

Patrick Mailleux,Anne-Sophie Marchand,Marie Mailleux

doi:10.4236/alc.2020.92002

Abstract

We report two cases of brain metastasis from a lung adenocarcinoma. Magnetic Resonance Imaging (MRI) appearance was closely correlated with the macroscopic and microscopic findings that showed multiples nodules of a well-differentiated papillary adenocarcinoma with secreting tubules, surrounded by mucoid fluid.

Highlights

License (CC BY 4.0).Brain metastases are more frequent than primary brain tumors
In the cases reported, the close correlation between the Magnetic Resonance Imaging (MRI) images and the histologic appearance lets us suggest that the MRI pattern could help the diagnosis and narrow the differential diagnosis to papillary secreting adenocarcinoma
Both patients had brain metastases of a lung adenocarcinoma, the brain lesions having a very similar aspect on MRI imaging: a large cystic component, a thin enhancing capsule or pseudo-capsule, and their non-cystic part was made of multiple enhancing small vegetations or papillae with some nodularity. Those nodules did not enhance homogeneously (Figure 3 and Figure 5) but sometimes had non enhancing central areas. This peculiar MRI pattern on T1-weighted images post-injection can be closely correlated with the histologic observations of the papillary type of the adenocarcinoma, where irregular papillae branch from large to progressively smaller papillae

Summary

Introduction

It usually gives no hint about the origin of the primary tumor. On MRI, the mass was 39 mm-large, surrounded by edema beyond a 1.4 mm-thick regular peripheral wall, enhancing homogeneously. Inside the mass were a large peripheral fluid area and multiple nodules. Those nodules had 5 to 7 mm of outer diameter and demonstrated intense peripheral contrast enhancement similar to the capsule. Histology (Figure 4) revealed a metastasis of a large-cell mucosecreting adenocarcinoma of a papillary type, consisting of mucus surrounding small tumoral proliferations, consisting of peripheral papillary tumoral structures with a hierarchical branching pattern: irregular papillae branch from large to progressively smaller papillae and terminating in detached tufts of epithelial cells.

Case 2

Discussion

Conclusion