Subcutaneous Granuloma Annulare Mimicking Rheumatoid Nodules: A Diagnostic Challenge.

Subcutaneous granuloma annulare (SGA) is a rare skin condition that has overlapping features with rheumatoid nodules due to similar clinical and histological features. A 42-year-old female with a history of celiac disease and a family history of rheumatoid arthritis developed progressively painful nodules on her right hand. She was initially thought to have rheumatoid arthritis, but her serological markers were negative, and an incisional biopsy revealed palisaded granulomas with central mucin and necrobiotic collagen that led to a diagnosis of SGA. Differentiating between these two conditions is important because rheumatoid nodules require immunosuppressive therapy due to systemic inflammation, while SGA is a self-limiting benign condition. This case highlights the need for a biopsy of atypical subcutaneous nodules and the importance of combining clinical, pathological, and interdisciplinary expertise to ensure accurate diagnosis and the best patient care.