Positive FDG-PET/CT of the pleura twenty years after talc pleurodesis: three cases of benign talcoma

Our plain-English summary of Positive FDG-PET/CT of the pleura twenty years after talc pleurodesis: three cases of benign talcoma, by T. Vandemoortele, S. Laroumagne, E. Roca, et al (Respiration; International Review of Thoracic Diseases, 2014).

The study

• Authors: T. Vandemoortele, S. Laroumagne, E. Roca, O. Bylicki, J.P. Dales, H. Dutau, P. Astoul
• Journal: Respiration; International Review of Thoracic Diseases
• Published: 2014;87(3):243-8
• Type of article: Case report
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The FDG-PET (fluorine-18 fluorodeoxyglucose positron emission tomography) scan is used with increasing frequency to investigate pleural abnormalities and to determine the possibility of neoplastic invasion. However, false-positive findings are not uncommon and talc pleurodesis has been reported to cause hypermetabolic pleural thickenings up to 5 years after the procedure. We report the cases of 3 patients (2 of whom had a history of asbestos exposure) requiring talc pleurodesis for recurrent pneumothoraces between 1988 and 1990, who were investigated in 2011 for pleural abnormalities. Avid pleural thickening on FDG-PET scan mimicking pleural cancer was found, but this was deemed secondary to the pleurodesis. Talc pleurodesis generates inflammation which promotes pleural adhesions. This inflammatory reaction could decrease with time, as in other inflammatory processes. Since talc is not metabolized by the body, the FDG-PET scan can remain positive, most likely because of a foreign-body granulomatous reaction, even 20 years later. It is important to be aware of this possibility and to question patients with pleural abnormalities about past procedures and mention such procedures to the colleagues who are responsible for interpreting metabolic imaging. Follow-up of hypermetabolic pleural lesions attributed to talc pleurodesis is important for the detection of new pleural lesions or neoplastic evolution.

© 2013 S. Karger AG, Basel.

In plain English

This article described three patients reported by doctors in Marseille, France. Each had been treated with talc pleurodesis, in which talc is placed into the lining of the chest, for repeated collapsed lungs (pneumothoraces) between 1988 and 1990. All three were investigated in 2011 for abnormalities of the pleura. Two of the three had a history of asbestos exposure: one as an electrician from 1984 to 1994, and one at a refinery since 1983. The article did not name fiber types. On FDG-PET scans, all three showed pleural thickening with high uptake, a pattern that can mimic pleural cancer. The peak values were 11, 8 and 9 g/ml. In the third patient, who had no asbestos exposure, a biopsy showed small granulomas around crystals that corresponded to talc particles. In the first patient, lymph node samples showed no cancer cells. Repeat scans after 6 months in one patient and 10 months in another showed no change in the pleural findings. The authors concluded that the reaction to talc can last more than 20 years, and that follow-up of such lesions is important to detect new pleural lesions.

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 series (three case reports)
• Who was studied: 3 patients aged 43, 46 and 45 who had talc pleurodesis for recurrent pneumothoraces between 1988 and 1990 and were investigated in 2011 for pleural abnormalities; authors based in Marseille, France
• Exposure: Prior thoracoscopic talc pleurodesis in all three (5 g of calibrated talc in patient 1; no details on amount or type of talc for patient 2). Asbestos exposure in two patients: an electrician from 1984 to 1994, and a worker described as an 'editor in a refinery' since 1983. Fiber type not specified. Patient 3 had no asbestos exposure.
• Main results:
  • Patient 1 (asbestos-exposed): FDG-PET showed multifocal hypermetabolism of right pleural thickening, mainly at the lung apex, with SUV max 11 g/ml. A repeat scan 6 months later was stable.
  • Patient 1: needle aspiration of mildly hypermetabolic hilar lymph nodes found normal lymphocytes, with no cancer cells, no granulomas and no talc particles.
  • Patient 2 (asbestos-exposed): FDG-PET showed multiple foci of hypermetabolism of the left pleura (SUV max 8 g/ml). A hypermetabolic nodule was also seen in the left fissure. No biopsy was performed.
  • Patient 3 (no asbestos exposure): bilateral pleural thickening (SUV max 9 g/ml). Biopsy of a calcified lesion showed microgranulomas with a foreign-body reaction around microcrystals corresponding to talc particles.
  • Patient 3: a repeat FDG-PET scan 10 months later showed no change in the pleural thickenings.
• The authors' conclusion: The authors concluded that talc pleurodesis induces a granulomatous reaction that can last more than 20 years and can cause high FDG uptake. They stated that clinicians should ask patients about past pleural procedures, and that follow-up of such lesions is important for detecting new pleural lesions.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening, Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Pleura, Talc Pleurodesis, Pleural Thickening, Asbestos Exposure, PET Scan, Pleurodesis, Inflammation, Talc.

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