Pseudo-tumor mimicking indwelling pleural catheter tract metastasis in mesothelioma

Our plain-English summary of Pseudo-tumor mimicking indwelling pleural catheter tract metastasis in mesothelioma, by R.L. Shrestha, B.A. Wood, Y.C. Lee (Journal of Bronchology & Interventional Pulmonology, 2014).

The study

• Authors: R.L. Shrestha, B.A. Wood, Y.C. Lee
• Journal: Journal of Bronchology & Interventional Pulmonology
• Published: 2014;21(4):350-2
• Type of article: Case report
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Patients with malignant mesothelioma are known to be at risk of developing needle tract metastasis from seeding of malignant cells at the pleural intervention site. Histologic confirmation of needle tract metastases is seldom sought. The diagnosis and management (often radiotherapy) are almost always based on clinical judgment of new subcutaneous lesions at prior pleural puncture sites in mesothelioma patients. We report 2 patients with mesothelioma who developed new subcutaneous nodules at their indwelling pleural catheter insertion site, mimicking tract metastases. Biopsies of both lesions revealed benign etiologies and both resolved without requiring irradiation. These cases remind clinicians that new subcutaneous lesions can be benign even when arising at pleural puncture sites of malignant pleural mesothelioma patients. Percutaneous biopsy can clarify the diagnosis in suitable cases.

In plain English

This case report described two patients with malignant pleural mesothelioma, treated in Perth, Australia, who developed new lumps under the skin where an indwelling pleural catheter (a long-term chest drain) had been inserted. Such lumps are often assumed to be cancer spread along the procedure tract and treated with radiotherapy without a biopsy. The first patient was a 74-year-old retired asbestos miner. The article gives no exposure history for the second, also aged 74. Both had a Staphylococcus aureus infection of the pleural fluid. In the first patient, a core biopsy of a firm, tender nodule showed inflamed tissue and no mesothelioma, and the nodule went away on its own within a month. In the second, needle aspiration of a 1 to 2 cm nodule released turbid fluid and showed inflammatory cells but no mesothelioma. After antibiotics, the lesion had not returned at 4 months. The authors concluded that such lumps can be benign and that sampling can help when in doubt. They noted that how often this happens is unknown.

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 (2 patients)
• Who was studied: Two 74-year-old men with malignant pleural mesothelioma and right pleural effusion, seen at Sir Charles Gairdner Hospital, Perth, Australia (author affiliation). Dates of care are not given.
• Exposure: Case 1 was a retired asbestos miner. No fiber type is named. No asbestos exposure history is given for case 2. The procedure studied was insertion of an indwelling pleural catheter (IPC).
• Main results:
  • Case 1: a core biopsy of the new nodule at the IPC insertion site showed no mesothelioma but inflamed granulation tissue. CT found no tract metastasis.
  • Case 1: the nodule resolved without treatment within a month and had not recurred after 7 months of follow-up.
  • Case 2: a 1 to 2 cm firm, nontender nodule deflated on fine-needle aspiration. Cytology showed acute inflammatory cells and no mesothelioma.
  • Case 2: pleural fluid drained from the IPC grew S. aureus. After antibiotics the lesion did not recur at 4 months of follow-up.
• The authors' conclusion: The authors concluded that benign inflammatory nodules can develop at pleural puncture sites in mesothelioma patients, mimicking tract metastases. They concluded that percutaneous sampling can be helpful when the diagnosis is in doubt.
• Limitations the authors state:
  • The authors stated that the incidence of these benign look-alike lesions is unknown.
  • The authors stated that it is unknown whether having an IPC or a pleural infection raises the risk of these lesions.
  • The authors noted that both nodules were small and that their benign nature might have become clear by simply watching them over time.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Indwelling Pleural Catheter, Tract Metastasis, Mesothelioma, Malignant Mesothelioma, Pleural Mesothelioma, Biopsy.

Related studies

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• Catheter tract metastasis associated with indwelling pleural catheters — R. Thomas, C.A. Budgeon, et al. (2014)
• Protocol of the Australasian Malignant Pleural Effusion-2 (AMPLE-2) trial: a multicentre randomised study of aggressive versus symptom-guided drainage via indwelling pleural catheters — M. Azzopardi, R. Thomas, et al. (2016)
• Histopathology of removed indwelling pleural catheters from patients with malignant pleural diseases — C.L. Tobin, R. Thomas, et al. (2016)
• Aggressive versus symptom-guided drainage of malignant pleural effusion via indwelling pleural catheters (AMPLE-2): an open-label randomised trial — S. Muruganandan, M. Azzopardi, et al. (2018)
• Intrapleural Fibrinolysis for the Treatment of Indwelling Pleural Catheter-Related Symptomatic Loculations: A Multicenter Observational Study — R. Thomas, F. Piccolo, et al. (2015)

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