Cavitary lung lesion suspicious for malignancy reveals Mycobacterium xenopi

Our plain-English summary of Cavitary lung lesion suspicious for malignancy reveals Mycobacterium xenopi, by S. Fogla, V.M. Pansare, L.G. Camero, et al (Respiratory Medicine Case Reports, 2018).

The study

• Authors: S. Fogla, V.M. Pansare, L.G. Camero, U. Syeda, N. Patil, A. Chaudhury
• Journal: Respiratory Medicine Case Reports
• Published: 2018;23:83-85
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

We report the case of a 68-year-old gentleman who presented with musculoskeletal chest pain which appeared suddenly when he bent over with his dog. The chest pain was localized to the left lower chest and increased with movement and deep breathing. The patient did not complain weight loss, night sweat, fever or chill. He complained of mild cough, with expectoration of whitish mucus. Imaging revealed cavitary chest lesion in the right upper lobe, which was initially suspected to be lung cancer. The patient had a 50-year-old history of smoking 2 packs per day. PET CT imaging did not reveal any specific activity. Needle biopsy and bronchoalveolar lavage, however, did not reveal any malignant cells. Rather, necrotic tissues were observed. A wedge resection of the lung mass was performed. No common organisms or fungi could be grown. However, acid fast bacilli were observed in clumps. The morphology hinted towards non-tuberculous mycobacterial organism(s). Molecular studies revealed infection with Mycobacterium xenopi. The patient was started on an anti-tuberculous regimen of INH, rifampicin, ethambutol and PZA, with pyridoxine. The patient is a Vietnam veteran and complained of exposure to dust from a bird's nest and asbestos exposure in childhood, but no specific exposure to tuberculosis. The patient had an uneventful recovery post-surgery. He complained of some nausea after initiation of the antituberculous medications, but his pain subsided with time. The patient had diabetes, though specific reasons of compromise of immune status could not be pinpointed as causative of his nontuberculous mycobacterial lung infection.

In plain English

This article is a case report about one 68-year-old man, a long-term smoker (2 packs per day for 50 years), who came to a clinic with pain in the left lower chest and upper abdomen. His history noted asbestos exposure in childhood, with no further detail, and exposure to "thick dust" from a large bird's nest. A CT scan showed a 6-cm mass at the top of the right lung with cystic areas in its center, and lung cancer was suspected. A needle biopsy showed necrosis, and bronchoscopy samples showed no malignancy. After surgery removed the mass, tissue examination found acid fast bacilli in clumps. Molecular testing detected Mycobacterium xenopi, a nontuberculous mycobacterium. He was started on anti-tuberculosis drugs and recovered uneventfully from surgery. The authors concluded that this type of infection should be considered in people with cavitary lung lesions, especially those with impaired immunity. They said the reasons for his infection remained unknown, though his diabetes may have contributed. The article did not describe the asbestos exposure further or discuss it as a cause.

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 (one patient)
• Who was studied: One 68-year-old man seen at an ambulatory clinic. He was a Vietnam veteran who had worked for a telephone company, and his history included diabetes mellitus and hypertension. No date or place of care is stated.
• Exposure: Asbestos exposure in childhood (no fiber type, source or amount given). Also noted: smoking of 2 packs per day for 50 years and exposure to "thick dust" from a large bird's nest. No specific exposure to tuberculosis was reported.
• Main results:
  • A chest CT showed a 6-cm mass in the right apex (top of the right lung) with cystic areas in its center.
  • A CT-guided needle biopsy of the mass showed necrosis, fibrosis and inflammation.
  • Bronchoscopy samples showed no malignancy, only necrotic material.
  • Examination of the surgically removed lung mass showed acid fast bacilli in clumps.
  • Molecular testing of the tissue detected Mycobacterium xenopi.
  • The patient recovered uneventfully from surgery. He was started on isoniazid, rifampicin, pyrazinamide and pyridoxine.
  • The patient recovered uneventfully from surgery.
• The authors' conclusion: The authors concluded that atypical (nontuberculous) mycobacterial infection should be kept in mind in patients with cavitary lung lesions, especially those with impaired immune status. They also stated that the patient's diabetes may have contributed to immunosuppression.
• Limitations the authors state:
  • The authors stated that the precise reasons why this patient acquired the infection remained unknown.

Topics

Medical terms in this study, explained in our Lexicon: Lung Cancer, Needle Biopsy, Bronchoalveolar Lavage (BAL), Asbestos Exposure.

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