Differential diagnosis of<unk> s can be classified from localization, depth pathology, age of onset, persistence,<unk>  factor, concomitant joint disease, and bone erosions. Diagnosis is typically determined clinically by a rheumatologist.<unk>  arthritis associated<unk> s are typically subcutaneous and occur at extensor sites. The onset typically starts in adulthood and presents with<unk>  factors and bone erosions, and concomitant joint diseases. The pathology is characterized by central necrosis, palisading mononuclear cells, and perivascular lymphocytic infiltrations.<unk> sis is characterized by multiple subcutaneous nodules presenting with<unk>  factors but an absence of joint complaints. The nodules are typically small and concentrated on the extensor sites of the hands and feet, sometimes accompanied by bone erosions. The onset typically starts in adulthood with a pathology similar to<unk>  arthritis associated<unk> s. Benign<unk> s are often not associated with<unk>  factors or concomitant joint diseases. They are typically found on the feet, scalp, and pretibial regions. Frequently seen in children before the age of 18, the pathology is similar to that of<unk>  arthritis associated<unk> s. The nodules are non-tender and undergo rapid growth, but also resolve spontaneously. A similar presentation occurring more intracutaneously (superficial) is known as granuloma annulare. Rheumatic fever nodules are typically associated with acute rheumatic fever in children. They are not accompanied by<unk>  factors or bone erosions, but are associated with concomitant joint diseases. No larger than the size of peas, they are typically found at extensor sites and processus spinosi of the vertebrae. The pathology is characterized by central necrosis and little histiocytic/lymphocytic infiltration.
Rheumatoid nodule
Villonodular synovitis
Plasma cell granuloma
Eosinophilic granuloma
Fibrin ring granuloma
Palindromic rheumatism
Colloid nodule
Cold nodule