PO:27:106 | Role of histology in interstitial lung involvement of rheumatic diseases in real life scenario

Francesca Cozzini^1|2, Francesco Falco¹, Lucia Spaggiari^1|3, Alberto Cavazza¹, Adele Del Giudice^1|2, Lucia Dardani¹, Fabio Brandolino¹, Emanuele Cocchiara¹, Ilaria Chiapparoli¹, Luca Magnani⁴, Gianluigi Bajocchi¹, Carlo Salvarani^1|2, Andreina Manfredi^1|2 | ¹IRCCS Arcispedale Santa Maria Nuova Reggio Emilia, Italy; ²Università degli Studi di Modena e Reggio Emilia Modena, Italy; ³AUSL area NORD Montecchio-Guastalla, Italy; ⁴UOC di Medicina Interna ad Indirizzo Reumatologico, Azienda USL Bologna, Ospedale Maggiore Bologna, Italy

Introduction. Interstitial lung diseases (ILD) are a heterogeneous group of pulmonary disorders with different features and causes. Careful diagnosis, definition and etiology, when available, is crucial for determining the appropriate treatment. While clinical history, radiological patterns, and laboratory tests are highly valuable for this purpose, some cases remain without a clear diagnosis. In these challenging scenarios, a lung biopsy can be very helpful, provide essential information regarding the disease's severity, histological patterns and etiology. Our study aimed to investigate the advantages of biopsy in real life scenario of multidisciplinary discussion by analyzing retrospectively a small group of patients followed at our hospital. Material and

Methods. Patients with autoimmune rheumatic diseases (ARDs)- ILD who underwent lung biopsy in the last ten years were identified by mean of clinical records. The indication for biopsy and the histological findings were analyzed. Moreover, histological patterns with the radiological patterns classifications derived from the concomitant HRCT were compared. Finally, we analyzed how histological findings weighted in final decision of multidisciplinary team.

Results. Data from18 patients were available. The mean age at ILD onset was 58.1 ± 13 years, and in 88.9% of cases, ILD was the first clinical manifestation. The primary indication for biopsy was to differentiate among infection, neoplasia, and other pathologies causing ILD. In Table 1 details about the radiological and histological ILD patterns are reported. HRCT data was unavailable for one patient. We observed a certain concordance in detecting fibrosis between radiological and histological methods, with the exception of one case. Notably, biopsies more frequently identified the presence of organizing pneumonia, a significant indicator of inflammation, sometimes useful to support diagnosis of an ILD associated to autoimmune diseases. The final diagnoses among our patients were: Rheumatoid Arthritis (27.8%), Sjögren's Syndrome (22.2%), Interstitial Pneumonia with Autoimmune Features (22.2%) anti-synthetase syndrome (16.7%). Additionally, one patient was diagnosed with sarcoidosis, another with IgG4-related disease and one patient received a diagnosis of both carcinoma and ILD from the biopsy.

Conclusions. The ATS/ERS/ JRS/ALAT guidelines recommend HRCT and multidisciplinary discussion for diagnosing patients ARD-ILD, reserving biopsy for only the most complicated cases. In line with these guidelines, we proposed biopsy for only a few patients. For three of them, histology led directly to a diagnosis, while for the remaining cases, it helped clarify the diagnosis and guide appropriate therapy. Ultimately, the decision to perform a lung biopsy remains a key point requiring discussion within a multidisciplinary team. Further studies with larger patient cohorts will be needed to explore a possible correlation between radiological and histological patterns.