# Osseous Sarcoidosis: Three Typical Presentations of an Atypical Disease

## TL;DR

This paper presents three cases of osseous sarcoidosis, showing how bone involvement can appear years after initial diagnosis and often coexists with other organ disease.

## Contribution

Highlights the delayed and multi-organ nature of osseous sarcoidosis through detailed case studies.

## Key findings

- Osseous sarcoidosis can appear years after initial non-bone presentations.
- Subclinical bone lesions often coexist with symptomatic sites in sarcoidosis patients.
- Early detection of bone involvement may indicate more severe disease progression.

## Abstract

Sarcoidosis is a systemic inflammatory disease characterized by the formation of non-necrotizing granulomas in affected tissues. While it most commonly involves the lungs and intrathoracic lymph nodes, it can affect virtually any organ system. Osseous sarcoidosis is a less common manifestation, and its prevalence may be underrepresented, as many patients remain asymptomatic. When symptoms do occur, they may include bone pain, reduced exercise capacity, or localized swelling. The spine is the most frequently involved site. In this case series, we present three distinct patients with osseous sarcoidosis: Patient A was diagnosed with sarcoidosis at age 31, initially presenting with pulmonary and sinonasal involvement. Years later, he developed dactylitis in his right third digit. A hand X-ray revealed osseous sarcoidosis in multiple fingers, despite symptoms being limited to a single digit. He was treated with methotrexate and infliximab, with significant improvement. Patient B was diagnosed at age 40 with predominant neurological involvement. He later developed back pain, and imaging revealed lesions throughout the lumbar and sacral spine. A biopsy confirmed osseous sarcoidosis. Initial treatment included cyclophosphamide, and he is now maintained on azathioprine and adalimumab, which he tolerates well. Patient C was diagnosed at age 55. At 68, she developed neck and back pain. Imaging showed faint sclerotic lesions throughout the thoracic spine, raising concern for either metastatic disease or osseous sarcoidosis. Biopsy confirmed sarcoidosis. Despite treatment with infliximab, azathioprine, and low-dose prednisone, she continues to experience neck pain, which is managed with gabapentin. Sarcoidosis severity and clinical progression vary widely between individuals and can be unpredictable. Notably, all three patients in this series had initial presentations that did not involve bone, with osseous sarcoidosis being identified years after their initial diagnoses. At the time of osseous involvement, all had multi-organ disease. Interestingly, each case also revealed asymptomatic osseous lesions alongside symptomatic sites, suggesting that subclinical skeletal involvement may coexist even in patients presenting with localized symptoms. Early identification of osseous sarcoidosis may be valuable in recognizing patients at risk for more severe or multi-organ disease.