# Cannonball Metastases of the Lung: An Unusual Initial Manifestation of Endometrial Carcinoma

## TL;DR

A rare case of endometrial cancer presenting with unusual large lung metastases is reported, emphasizing the importance of recognizing this atypical symptom for timely treatment.

## Contribution

This case report highlights the rare initial manifestation of endometrial carcinoma as cannonball pulmonary metastases, expanding diagnostic awareness.

## Key findings

- Endometrial carcinoma presented with multiple large 'cannonball' lung metastases in a 60-year-old woman.
- Chemotherapy with carboplatin and paclitaxel led to significant regression of metastases and symptom improvement.
- Maintenance therapy with anastrozole achieved stable disease, demonstrating a treatment pathway for this rare presentation.

## Abstract

Endometrial carcinoma is the most common gynecologic malignancy in developed countries and is typically diagnosed at an early stage, with distant metastases uncommon at presentation. Pulmonary involvement occurs in less than 5% of cases and usually manifests as small nodules or interstitial disease; the appearance of multiple, large, round ‘cannonball’ metastases is exceptionally rare. We report the case of a 60‐year‐old woman who presented with cough and dyspnea. Imaging revealed numerous bilateral pulmonary ‘cannonball’ nodules, mediastinal lymphadenopathy, hepatic lesions, and an enlarged uterus. Endometrial biopsy confirmed endometrioid adenocarcinoma, staged as FIGO IV‐B. The patient underwent chemotherapy with carboplatin and paclitaxel, resulting in significant regression of pulmonary and hepatic metastases and symptomatic improvement, followed by maintenance therapy with anastrozole that achieved stable disease on surveillance. This case highlights the importance of recognising cannonball pulmonary metastases as a potential, albeit rare, initial presentation of endometrial carcinoma, thereby guiding timely diagnosis and treatment.

Cannonball pulmonary metastases, typically linked to renal cell carcinoma or choriocarcinoma, are rare in gynecologic cancers. Endometrial carcinoma seldom spreads to the lungs and usually presents as small nodules, making recognition of this atypical pattern crucial to avoid diagnostic delay.