Imaging features and clinical significance of atypical pleural plaques mimicking bone tumors: a retrospective case series

Our plain-English summary of Imaging features and clinical significance of atypical pleural plaques mimicking bone tumors: a retrospective case series, by Y.E. Sung, D.H. Han, K. Hyun, et al (Quantitative Imaging in Medicine and Surgery, 2023).

The study

• Authors: Y.E. Sung, D.H. Han, K. Hyun, J.Y. Jung, S. Chang
• Journal: Quantitative Imaging in Medicine and Surgery
• Published: 2023;13(12):8729-8738
• Read it: PubMed · Publisher · Free full text

Abstract

This study aimed to examine the imaging characteristics and clinical implications of atypical pleural lesions that mimic bone tumors and form along the inner margins of consecutive ribs. This retrospective analysis included 45 atypical pleural lesions arising from 13 patients who underwent chest computed tomography (CT) between April 2021 and March 2023. The clinical features, CT findings, and radiologic diagnoses prior to pathologic identification were examined. Pathological findings were reviewed in the surgically resected case. Subgroup analysis was performed based on the presence of concurrent typical pleural plaques. The mean age of the patients was 69.3±8.4 years with a predominance of males (76.9%). The lesions primarily exhibited unilateral involvement (84.6%), being most frequently located in the right mid-level posterior region. Calcification was present in 75.6% of cases, typically seen continuously along the ribs (82.4%). Adjacent rib changes were observed in 28.9% of cases. These lesions were frequently misdiagnosed as osteochondromas or bony spurs (55.6%) by thoracic radiologists. No significant growth was observed during follow-up (n=11, 47±41 months), and the pathological findings were consistent with pleural plaques. Patients with concurrent typical pleural plaques had more atypical pleural lesions without statistical significance (P=0.071) and showed a more even distribution (P=0.039). In conclusion, atypical pleural lesions resembling bone tumors along consecutive ribs represent a distinct subset of pleural plaques. Their unique distribution and morphology should be recognized by radiologists to avoid misinterpretation and unnecessary interventions.

2023 Quantitative Imaging in Medicine and Surgery. All rights reserved.

In plain English

This retrospective case series from Seoul St. Mary's Hospital in South Korea looked at unusual pleural lesions that form along the inner edges of consecutive ribs and can look like bone tumors on chest CT scans. The authors reviewed 45 such lesions in 13 patients (10 men; average age 69.3 years). Four patients (30.8%) had a recorded history of asbestos exposure. For the other nine, exposure was unconfirmed or not adequately assessed. Most lesions were on the right side (34 of 45), at the fourth to seventh ribs (37 of 45), and toward the back. Calcification appeared in 34 of 45 lesions. Before the condition was recognized, CT reports had called the lesions osteochondromas or bony spurs in 5 of 9 patients. Over an average of 47 months of follow-up in 11 patients, only one lesion grew noticeably, and it grew slowly. In the one patient who had surgery, the tissue matched pleural plaque, and the specimen showed no evidence of asbestos. The authors concluded these lesions are a distinct subset of pleural plaques. They suggested that both asbestos and other factors may contribute.

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: Retrospective case series (published as a brief report), with a subgroup comparison of patients with and without typical pleural plaques
• Who was studied: 45 atypical pleural lesions in 13 patients at Seoul St. Mary's Hospital, South Korea. Four cases were found earlier in routine practice. Nine patients (12 scans) were collected between April 2021 and March 2023 out of 17,433 chest CT scans. The CT scans reviewed dated from May 2012 to March 2023. Mean age was 69.3 years, and 10 of 13 patients were male.
• Exposure: Asbestos exposure history was taken from medical records. It was defined as work or residence near asbestos mines, factories, or transport sites, or work in asbestos-related jobs. It was recorded in 4 of 13 patients (30.8%); the other 9 had no confirmed exposure or were inadequately assessed. No fiber types are named.
• Main results:
  • Per patient: 11 of 13 patients (84.6%) had lesions on one side only.
  • Per lesion: 34 of 45 lesions (75.6%) were on the right side. Most were at the level of the fourth to seventh ribs (37 of 45, 82.2%) and in the back of the chest (42 of 45, 93.3%).
  • Calcification was present in 34 of 45 lesions (75.6%). Of these, 28 of 34 (82.4%) appeared continuous with the adjacent rib.
  • Changes in the adjacent rib (cortical thickening or widening) were seen in 13 of 45 lesions (28.9%).
  • Among the 9 patients with CT scans taken before the lesion type was identified, the initial diagnosis was osteochondroma or bony spur in 5 of 9 (55.6%) and post-inflammatory change in 1 of 9 (11.1%). No lesion was reported in 3 of 9 (33.3%).
  • Among the 11 patients with multiple CT scans (mean follow-up 47 months, range 4 to 118), only one lesion showed significant growth. It grew slowly over 6 years, with a volume doubling time of 1,116 days.
  • In the 6 patients who had PET/CT, 22 lesions were seen, and none showed significant FDG uptake.
  • In the one surgically resected case, microscopy showed 'basket weave' collagen fibrosis with focal calcification, consistent with typical pleural plaques. The specimen showed no evidence of asbestos.
  • Patients with concurrent typical pleural plaques (n=4) had more atypical lesions than those without (n=9): 5.0 versus 2.8 on average. The difference was not statistically significant (P=0.071).
  • Right-side dominance was seen in 88.9% of patients without concurrent typical plaques, compared with 25% of those with them (P=0.039).
  • Two patients without typical plaques had a known history of asbestos exposure but showed only atypical pleural lesions.
• The authors' conclusion: The authors concluded that these atypical pleural lesions are a distinct subset of pleural plaques, recognizable by their distribution and shape. They said radiologists should be aware of them to avoid misinterpretation and unnecessary work-up. They also suggested that both asbestos and other factors may contribute.
• Limitations the authors state:
  • The study was retrospective, had a small sample, and had limited pathological confirmation (only one lesion set was surgically examined).
  • The retrospective design limited investigation of smoking and asbestos exposure histories, possibly underestimating asbestos exposure.
  • The study did not establish a clear association between typical pleural plaques and the atypical lesions.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Statistical Significance.

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