Endobronchial Metastasis with Extension to the Left Atrium from Adenocarcinoma of Gastric 3 Years after Total Gastrectomy

Summary

Endobronchial metastases extending to the heart from gastric cancer are rare. This case report describes a 69-year-old man who presented to a tertiary care hospital in Shahrekord, Iran, in 2022 with a history of cough and haemoptysis. He had previously undergone total gastrectomy and adjuvant chemotherapy for gastric adenocarcinoma three years earlier. Imaging and pathological evaluation confirmed endobronchial metastasis with extension to the left atrium. The patient responded well to chemoradiotherapy, maintaining a good quality of life.

1. Introduction

Metastasis is a leading cause of mortality in patients with malignant tumours.¹ Distinguishing between metastasis and primary bronchogenic carcinoma can be challenging based on radiological and clinical findings alone. Immunohistochemistry plays a crucial role in confirming the diagnosis of endobronchial metastasis (EBM) following treatment for gastric adenocarcinoma. EBM is associated with a poor prognosis; however, a multidisciplinary approach can improve long-term survival. We report a case of gastric adenocarcinoma with metachronous endobronchial metastasis, which invaded the pulmonary vein and extended into the left atrium. This case highlights the importance of early diagnosis using bronchoscopy and echocardiography in patients presenting with respiratory symptoms after treatment for gastric adenocarcinoma.

2. Case report

A 69-year-old male patient presented to a tertiary care hospital in Shahrekord, Iran, in 2022 with a 3-week history of cough and haemoptysis. He had undergone total gastrectomy 3 years earlier for poorly differentiated gastric adenocarcinoma (stage IIB: T3, N1, M0), followed by adjuvant chemotherapy with 5-fluorouracil, leucovorin, oxaliplatin, and docetaxel.

Physical examination was unremarkable. Blood tests revealed leukocytosis with neutrophilia. Echocardiography showed a large, lobulated mass involving the left atrium and extending into the middle and inferior pulmonary veins, suggestive of metastasis [Figure 1A]. Chest computed tomography (CT) revealed reticular lymphangitic carcinomatosis, along with a soft tissue mass with irregular borders measuring 49 × 76 mm, involving the right main bronchus and right pulmonary vein, extending into the left atrium [Figure 2A]. Moderate pleural effusion was noted on the right side.

Fig. 1.

Echocardiography (A) showing a large mass in the left atrium (arrows) and (B) after treatment showed resolution of the left atrial mass.

Fig. 2.

Axial chest computed tomography scan obtained at the pulmonary window of the lower region of the thorax (A) showing an ill-defined mass measuring 49 × 76 mm, encasing the right main bronchus and the right pulmonary vein and extends to the left atrium and (B) showing a mass measuring 16 × 31 mm, encasing the right main bronchus after treatment.

Fibreoptic bronchoscopy identified an infiltrative lesion in the right middle [Figure 3A] and lower bronchi [Figure 3B] with partial obstruction. Biopsy confirmed poorly differentiated adenocarcinoma, consistent with metastatic disease [Fig. 4]. Immunohistochemical staining showed that the tumour cells were negative for thyroid transcription factor-1 (TTF-1) and HER-2, while positive for caudal-type homeobox 2 (CDX2), cytokeratin 7 (CK7), and cytokeratin 20 (CK20), confirming metastasis from gastric adenocarcinoma.

Fig. 3.

Bronchoscopy showed an infiltrative lesion in the right middle (A) and lower bronchus (B).

Fig. 4.

The biopsy specimen showed histologically identical to the gastric poorly differentiated adenocarcinoma in favour of metastasis (Haematoxylin and Eosin staining, magnification at ×100).

A multidisciplinary team recommended surgical resection of the endobronchial metastasis, followed by a combination of radiation therapy and chemotherapy. However, the patient declined surgery. He was started on weekly 24-hour infusions of cisplatin (75; mg/m²/day) and 5-fluorouracil (800; mg/m²/day) for six cycles. Concurrent radiation therapy was administered to the chest, delivering a total dose of 50.4 Gy at 1.8 Gy per fraction.

Follow-up echocardiography after six months showed resolution of the left atrial mass [Figure 1B]. Post-treatment chest CT demonstrated a reduction in tumour size to 16 × 31 mm [Figure 2B]. At 12 months post-treatment, the patient remains asymptomatic and in good general health, despite the presence of residual tumour.

3. Discussion

Endobronchial metastases (EBM) with extension to the heart from primary gastric malignancies is extremely rare. The likelihood of gastric cancer spreading to the heart via the endobronchus is much lower than its metastasis to other organs. Non-cardiac malignancies can reach the heart through haematogenous spread, direct extension, or, in rare cases, via the pulmonary veins. Tumours invading the left atrium may occupy a significant portion of the atrial cavity, leading to mitral valve dysfunction and an increased risk of thromboembolic events. Echocardiography plays a crucial role in diagnosing and monitoring tumour progression or regression within the heart.

Endobronchial masses originate from various sources, with approximately 1.1% being metastatic.² The most common primary cancers leading to EBM are those of the colon, breast, and kidney.³ Symptoms of EBM with cardiac extension include cough, haemoptysis, arrhythmia, and heart failure. The interval between the diagnosis of the primary tumour and the onset of EBM typically ranges from nine months to five years.⁴ In this case, recurrence occurred three years after surgical resection and adjuvant treatment of the primary gastric carcinoma. Biopsy is essential to differentiate EBM from primary bronchogenic carcinoma.

The prognosis of EBM is poor, with a median survival of 19 months after diagnosis.⁵ Survival depends on the biological behaviour of the primary tumour, the presence of metastases in other organs, and hilar lymph node involvement. Distinguishing bronchogenic carcinoma from metastasis originating from extrathoracic malignancies is challenging but critical for treatment planning. Previous reports indicate that the right bronchial tree is more frequently affected than the left, although the reason for this remains unclear.⁶ Additionally, EBM from extrapulmonary malignancies is more common in women, with an incidence of 66.7%.⁶

As there are no standardised treatment protocols for EBM, accurate diagnosis is essential. Treatment strategies depend on factors such as tumour resectability, patient performance status, primary tumour control, and the presence of distant metastases. This case report underscores three key points: (1) the rare occurrence of gastric adenocarcinoma metastasising to the endobronchus and extending to the left atrium; (2) the metastatic behaviour of gastric adenocarcinoma; and (3) CDX2 positivity as a marker associated with a relatively better prognosis.⁷

4. Conclusion

An intracardiac mass can indicate a metastatic lesion, and it is crucial to consider the possibility of endobronchial metastasis when a lung mass is detected in a patient with a history of gastric cancer. Diagnosis is confirmed through biopsy, morphological evaluation, and immunohistochemistry. Involvement of the bronchus with extension to the heart in gastric cancer is generally associated with a poor prognosis, and many surgeons regard such tumours as inoperable. Treatment should be tailored by a multidisciplinary team, considering factors such as the pathology of the primary tumour, the anatomical location of the metastasis, the presence of other metastases, and the patient's overall health. A chemoradiation regimen for EBM following treatment for gastric adenocarcinoma can yield a positive response, helping to preserve quality of life.

Ethics Statement

Written informed consent was obtained from the patient for the publication of this case report and accompanying images.

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Authors' Contribution

BS drafted the manuscript and MHM revised it. Both authors approved the final version of the manuscript.