Table 2: Comparison between RA and carcinomatous polyarthritis features [2-4,9].

Rheumatoid Arthritis Carcinomatous polyarthritis
Sub-acute onset Rapid onset
Female sex predominance Male sex predominance
Younger age Older age (except LORA)
Symmetrical involvement Asymmetrical involvement
Upper joints (hands and wrists) Lower joints
Seropositive for ACPAs Seronegative for ACPAs (may be positive for ANAs and RF)
Erosions on X-ray and deformities No erosions or deformities
No constitutional symptoms Constitutional systemic symptoms (fever, weight loss)
Responsive to standard therapy Refractory to corticosteroids