Aspirated Soybean Mimicking Endobronchial Tumour Removed With a Cryoprobe

Our plain-English summary of Aspirated Soybean Mimicking Endobronchial Tumour Removed With a Cryoprobe, by S. Matsumoto, Y. Takigawa, K. Sato, et al (Respirology Case Reports, 2025).

The study

• Authors: S. Matsumoto, Y. Takigawa, K. Sato, K. Honda, M. Otsuki, S. Ido, M. Goda, K. Shiraha, T. Ichikawa, S. Matsuoka, J. Nishimura, H. Watanabe, K. Kudo, K. Fujiwara, T. Shibayama
• Journal: Respirology Case Reports
• Published: 2025;13(10):e70366
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Adult airway foreign bodies are misdiagnosed as endobronchial tumours on imaging. A 77-year-old man with asbestosis presented with a worsening cough. Computed tomography (CT) showed a 12-mm low-attenuation right upper-lobe bronchial lesion with distal bronchiectasis and infiltrates. Magnetic resonance imaging (MRI) suggested a fat-containing tumour (lipoma or hamartoma). Flexible bronchoscopy revealed a yellowish polypoid mass; poor sedation tolerance necessitated rigid bronchoscopy under general anaesthesia. Using a 1.7-mm cryoprobe, the lesion was cryoactivated for 10 s and removed en bloc. It proved to be a foreign body resembling a legume and was later confirmed to be an aspirated soybean from 1 month earlier. The fat and water content of soybeans can yield MRI appearances similar to fatty tumours. Distinguishing tumours from foreign bodies by imaging or bronchoscopy alone is challenging. Cryoprobe extraction is effective for hydrated foreign bodies, and aspiration should be considered in the differential diagnosis of endobronchial tumours.

© 2025 The Author(s). Respirology Case Reports published by John Wiley & Sons Australia, Ltd on behalf of The Asian Pacific Society of Respirology.

In plain English

This was a case report about one patient at a hospital in Okayama, Japan: a 77-year-old man who had never smoked and who had a known history of asbestosis and chronic cough. The article gave no details of his asbestos exposure, and asbestosis was not the subject of the report. His cough worsened in late April 2025. A CT scan showed a 12-mm lesion in the right upper-lobe airway, and the radiologist read the MRI findings as suggesting a fat-containing tumour. A bronchoscopy (camera into the airway) showed a yellowish mass covered with mucus. He tolerated sedation poorly, so the lesion was removed under general anaesthesia using a 1.7-mm freezing probe (cryoprobe). The lesion split in half, and each half was frozen for 10 seconds and removed. It turned out to be a foreign body resembling a legume. On further questioning, he may have inhaled soybeans about a month earlier. The authors concluded that the soybean was safely and completely removed with the cryoprobe.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 77-year-old man who had never smoked, with a history of asbestosis and chronic cough, seen at the Department of Respiratory Medicine, NHO Okayama Medical Center, Okayama, Japan, after his cough worsened in late April 2025
• Exposure: The article did not describe any asbestos exposure (no fiber type, job or dose). Asbestosis was part of the patient's medical history. The event reported was inhalation (aspiration) of a soybean.
• Main results:
  • CT showed a 12-mm lesion with low attenuation in the right upper-lobe bronchus
  • The radiologist interpreted the MRI findings as suggesting a fat-containing tumour
  • Flexible bronchoscopy showed a yellowish, mucus-covered mass; the patient responded poorly to sedatives and coughed frequently
  • A 1.7-mm single-use cryoprobe was used to freeze the lesion for 10 seconds; the lesion split in half, and each half was frozen for 10 seconds and removed
  • The lesion was a foreign body resembling a legume; no remaining foreign material was seen
  • On further questioning, the patient may have aspirated a large quantity of soybeans about 1 month earlier
• The authors' conclusion: The authors concluded that the soybean, first thought to be a fat-containing airway tumour, was safely and completely removed under general anaesthesia using a cryoprobe.

Topics

Medical terms in this study, explained in our Lexicon: Bronchoscopy, Differential Diagnosis.

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