Skeletal Sarcoidosis

Osseous sarcoidosis is an uncommon manifestation, reported in 3–13% of patients with sarcoidosis. Although older literature suggested that hands and feet are most commonly affected, axial bone involvement may be more common than previously reported, since earlier studies relied mostly on plain X-rays, which may be less sensitive for axial bone lesions. Newer imaging modalities such as MRI and PET/CT scanning have demonstrated a larger incidence of vertebral involvement. Bone lesions are commonly asymptomatic and patients who have bone involvement may have higher incidences of multi-organ involvement. Osseous sarcoidosis appears to be mainly osteolytic in nature, but the radiographic appearance may be indistinguishable from other osteolytic lesions and therefore a biopsy is usually required to confirm the diagnosis. The histological findings of sarcoidosis in the bone are the same as in other tissues of the body. No general consensus exists for the treatment of bone sarcoidosis but corticosteroids are the most commonly prescribed first-line drugs. Methotrexate is the most widely studied steroid-sparing agent for sarcoidosis and it has been reported useful for a variety of organ symptoms, but especially where there is bone involvement.

O07 Sarcoidosis: it's bone deep

Case report - Introduction This is a report of a Caucasian patient with sarcoidosis presenting as groin pain. Case report - Case description A 58-year-old Caucasian female from South Africa self-referred for physiotherapy following sudden onset right groin pain. Pelvic Xray was normal, but MRI pelvis showed lytic lesions in the acetabulum and proximal femur. The presence of night sweats suggested haematological malignancy leading to haematology referral. PET CT showed widespread metabolically active soft tissue lesions, lymph nodes and skeletal foci. Bone marrow trephine biopsy showed well-formed granulomata. An extensive infection screen was negative. A cervical lymph node biopsy and CT guided biopsy of pelvic and femoral lesions confirmed non-necrotising granulomas suggestive of sarcoidosis. Lung function tests were normal. Treatment with 30mg prednisolone for one month was poorly tolerated and steroids were rapidly weaned. She was unable to tolerate even low dose prednisolone. Severe pelvic pain and night sweats continue despite methotrexate, hydroxychloroquine and IV zoledronate (given for osteoporosis). Case report - Discussion This patient presented with groin pain, fatigue and night sweats, no demonstrable extra-osseous organ abnormality and normal plain radiography. Our diagnostic strategy was to first exclude malignancy and infection, particularly TB, but the unusual presentation created significant diagnostic uncertainty. Treatment is challenging due to intrusive side effects of steroids and hydroxychloroquine, and neutropenia induced by methotrexate. Osseous involvement is rare and has been reported in 1-15% of sarcoidosis patients. It is usually accompanied by skin lesions. There were no features on history or examination to suggest sarcoidosis and the diagnosis was based on bone biopsies. In a case series of 20 patients with osseous sarcoidosis, bone lesions were found on imaging during the initial presentation in 60% of cases. Ten patients were symptomatic, and all had multiple joint involvement. Axial involvement, primarily pelvis and lumbar spine was seen in 90% of cases. Lesions were detected on plain radiographs in 2 cases and were identified on MRI in 13 cases, PET-CT in 9 cases, CT in 4 cases and technetium-99m bone scintigraphy in 1 case. 55% of the cases required no treatment and 45% were treated most commonly with prednisolone, methotrexate, or hydroxychloroquine. Two cases required treatment with tumour necrosis factor inhibitors for refractory disease. Case report - Key learning points Osseous sarcoidosis can mimic many conditions including multiple myeloma and lymphoma, due to presentation with lytic lesions. Even pulmonary presentations can be atypical with predominant ground glass opacity or cavitating consolidation and parenchymal masses. Histopathological diagnosis is of critical importance, particularly in patients with atypical presentations. Assessment of organ involvement and disease extent is important in monitoring of treatment response. Plain radiographs tend to be normal in these cases and advanced imaging, including MRI, PET-CT, and CT, is often required. Symptomatic osseous disease may respond to steroids and conventional immunosuppression; a minority of refractory cases require TNF inhibition.

Resolution of Osseous Sarcoidosis with Methotrexate

Though a relatively uncommon manifestation of sarcoidosis, some clinicians are tasked with managing osseous involvement of disease, and the optimal treatment approach in this setting is not well established. Previous studies have shown variable efficacy for osseous sarcoidosis utilizing multiple agents alone or in combination, often using imaging follow-up in conjunction with clinical assessment to evaluate response to treatment. We present a case of widespread skeletal involvement of sarcoidosis without evidence of concurrent pulmonary disease demonstrating marked clinical improvement and near-complete resolution of imaging abnormalities on magnetic resonance imaging (MRI) following the use of methotrexate as the primary pharmacologic agent.