Musculoskeletal and Skin Pathology for Medical II Students

Lab 1b Rheumatoid Nodule (03000-44940)

One of the extra-articular manifestations of rheumatoid arthritis is the rheumatoid nodule. These may occur in the subcutaneous layer of the skin (in 20% of patients with rheumatoid arthritis) and other organs, and are a reminder that rheumatoid arthritis (RA) is a systemic disease. The skin nodules are most often on the extensor surface of the arms. The association of pulmonary rheumatoid nodules and pneumoconiosis is termed Caplan's syndrome.

The histologic features of the rheumatoid nodule are irregular zones of fibrinoid necrosis surrounded by epithelioid cells (histiocytes) and chronic inflammatory cells. The epithelioid cells are frequently palisaded around the necrotic zone. Chronic inflammatory cells often collect around epithelioid cells.

Slides 3 & 4

Slide 3 A scanning view of the rheumatoid nodule with central fibrinoid necrosis surrounded by palisaded histiocytes.
Slide 4 The same lesion with a demonstration at higher power of the epithelioid cells with their long axes arranged radially around the zone of necrosis.

Digital Legends for Labs/Cases
Lab 1
1a | 1b | 1c | 1d | 1e | 1f | 1g
Gross & Radiographs
a | b | c | d | e | f | g | h 
Lab 2
2a | 2b | 2c | 2d | 2e | 2f

Home

Medical II

Updated January 15, 2008