Axial bone involvement in sarcoidosis has a good prognosis: Longitudinal study of a cohort of 48 patients

Abstract

Objectives

Axial bone involvement in sarcoidosis is observed in approximately 25 % of patients on positron emission tomography (PET). Many of these lesions are asymptomatic, and their long-term outcomes are not well defined. This study aims to evaluate the prognosis of axial bone lesions in histologically confirmed sarcoidosis.

Methods

We assessed initial and follow-up MRI and PET from 48 patients diagnosed with axial bone sarcoidosis (135 MRI and 132 PET), with a mean follow-up duration of 33 and 44 months, respectively. Baseline and longitudinal associations between imaging results and patient variables were evaluated.

Results

MRI revealed predominantly nodular marrow replacement lesions, while PET identified multifocal bone involvement, with no corresponding bone lesions detected on CT in 80.8 % of cases. Compared to baseline imaging, serial MRI and PET showed significant reduction or resolution of bone lesions over time (MRI: p < 0.01; PET: p < 0.001). This was more frequently observed on PET (68.3 % of patients) than on MRI (19.5). During follow-up, bone pain improved significantly (p = 0.01), which was associated with favorable changes in both PET and MRI findings (p = 0.02 and p = 0.04, respectively). Seven patients had bone relapse. No epiduritis or soft-tissue infiltration was observed.

Discussion

This longitudinal evaluation over a 3-year period, combining clinical, radiological, and biochemical data, shows that sarcoidosis axial bone lesions have a favorable prognosis. Significant improvement was observed on both MRI and PET. The improvement in bone pain was associated with favorable imaging changes.