[A Case of Psoriatic Arthritis Confirmed by Re-examination of Skin Biopsy].

A 30-year-old woman had recognized general fatigue and joint pain 5 years before her first visit to our hospital. Keratinized skin lesions were also observed on her hand, elbows, and other interstitial sites at the same time. She was referred to our department for evaluation of her skin eruption because psoriatic arthritis was suspected. A physical examination revealed hyperkeratotic, brownish plaques on her hand, elbows, and knees. Although a skin biopsy taken from her right hand could not confirm a diagnosis, another biopsy taken from her right elbow revealed hyperkeratosis and parakeratosis with agranulosis epithelial hyperplasia, indicating a diagnosis of psoriasis. Taking an additional skin biopsy from a site other than the main one can be helpful for a diagnosis of psoriatic arthritis.