Teaching Case

Painful swelling of the left finger of 4 weeks duration. No relevant medical history.

The patient complained of a painful swelling of the left finger of 4 weeks duration. He had no relevant medical history. Physical examination showed tenderness of the medial and distal phalanx. Flexion was limited to the proximal and distal interphalangeal joints. Enlarged lymph nodes were palpated in the left axillary region. Subsequently a radiograph and MRI of the left hand and a chest radiograph were performed. Microscopic examination of the lesion of the fifth finger and of an axillary lymph node showed numerous non-caseating granulomas with epitheloid cells and lymphocytes. Based on imaging findings and histological examination, the diagnosis of osseous sarcoidosis was established.

Sarcoidosis is a granulomatous disorder of unknown origin, characterized by non-caseating granulomas, affecting multiple organ systems especially in young people (age 20-40) with a predominance in female (3:1) and blacks (14:1). Major localizations are lungs (90% of cases), eyes (10-25% of cases) and skin (10-60% of cases). Other localizations include central or peripheral nervous system, heart, liver, spleen and muscles. Osseous manifestations occur in about 1 to 13% of cases. Small bones of the hand and feet are preferential locations. Lesion distribution is usually asymmetrical; the distal and middle phalanges and the metacarpals are preferentially involved. Bone lesions are usually asymptomatic. Soft tissue swelling, tenderness, stiffness, and deformity can accompany osseous lesions, which are generally associated with cutaneous and pulmonary involvement (80-90% of cases). The most characteristic are cortical and trabecular alterations with a reticular or lacelike appearance. Punched out lytic lesions are also commonly described. Occasionally, rapid bone destruction with a permeative pattern is reported. Periostitis is distinctly unusual. The joint spaces are relatively spared. A less typical manifestation is a generalized osteosclerosis of the spine, pelvis, skull and ribs. In 10-35% of cases acute or chronic polyarthritis is reported with symmetrical distribution affecting small and medium-sized joints. Radiographic findings may be refined by MRI. The diagnosis is substantiated by a combination of clinical, radiological and histological features with supporting laboratory data such as a positive reaction to Kveim antigen (60-80% of cases), elevated circulating levels of angiostensin – converting enzyme (80% of cases), anergy and elevated levels of serum gamma globulins. The differential diagnosis of bone lesions includes tuberculosis and other granulomatous infections, hemangiomatosis, xanthomatosis, skeletal metastases and fibrous dysplasia.