Page 99 - GTM-3-3

Global Translational Medicine

CASE SERIES
Differential diagnosis between rheumatoid

nodules and fibrocaseous tubercles in the
lung: A case series

Miklós Bély * and Ágnes Apáthy 2
1
1 Department of Pathology, Hospital of the Order of the Brothers of St. John of God, Budapest, Hungary
2 Department of Rheumatology, St. Margaret Clinic, Budapest, Hungary

Abstract
The histological similarities between rheumatoid nodules and post-primary
fibrocaseous tubercles in the lung may present a significant challenge in differential
diagnosis. Differential diagnosis of fibrocaseous tubercles and rheumatoid nodules is
crucial in clinical practice, particularly due to the high risk of co-existing fibrocaseous
tuberculosis in rheumatoid arthritis. This condition increases the likelihood of military
dissemination and mortality, especially in elderly patients, with elderly women being
at the greatest risk. This case series aims to differentiate these two pathological
entities based on the clinical histories and histological analyses of surgical specimens
from two patients. The main histological marker for RhNod is the presence of vascular
remnants within the fibrinoid necrotic area, reflecting the vascular origin of RhNods.
Additional supporting evidence for the rheumatoid nature of the process includes
the presence of inflamed blood vessels elsewhere in the lung (such as non-specific,
fibrinoid necrotic, and/or granulomatous autoimmune vasculitis), as well as the
*Corresponding author: potential presence of co-existent interstitial pneumonitis, with or without pleuritis.
Miklós Bély In contrast, the necrotic tuberculous process is characterized by coalescent necrosis
(dr.bely.miklos@gmail.hu) that does not respect anatomical borders and lacks structural remnants of lung
Citation: Bély M, Apáthy Á. tissue, which is a hallmark of tuberculosis pathology.
Differential diagnosis between
rheumatoid nodules and fibrocaseous
tubercles in the lung: A case series. Keywords: Lung; Rheumatoid nodule; Fibrocaseous tubercle; Differential diagnosis
Global Transl Med. 2024:3(3):4104.
doi: 10.36922/gtm.4104
Received: July 1, 2024
Accepted: August 31, 2024
Published Online: September 20, 1. Background
2024
Until the end of the 20 century, all patients who died in hospitals in Hungary underwent
th
Copyright: © 2024 Author(s). autopsies. Between 1970 and 2000, a total of 11,537 patients died at the National Institute
This is an Open-Access article of Rheumatology, among whom 234 had rheumatoid arthritis (RA). In 28 of these
distributed under the terms of the
Creative Commons Attribution 234 autopsy cases (11.96%), RA was accompanied by post-primary tuberculosis (TB)
License, permitting distribution, localized in the lungs. Histological examination revealed that 16 of these 28 TB cases
and reproduction in any medium, (57.14%) were fibrous, anthracotic tuberculotic scars, while the remaining 12 cases
provided the original work is
properly cited. (42.86%) displayed fibrocaseous tubercles (fcTBs) (Miklós Bély & Ágnes Apáthy,
unpublished data, August 2024).
Publisher’s Note: AccScience
Publishing remains neutral with The histological similarities between RhNods and post-primary fcTBs of the lung may
regard to jurisdictional claims in 1
published maps and institutional present a significant challenge in differential diagnosis. This case series demonstrates
affiliations. the histological differences between these two pathological entities by discussing the

Volume 3 Issue 3 (2024) 1 doi: 10.36922/gtm.4104