The Groove Sign.

A 74-year-old patient initially presented with rapid onset of bilateral leg swelling, leukocytosis (monocytosis and eosinophilia), hand arthritis, elevated inflammatory markers, and 20% weight loss. Extensive workup, including a bone marrow biopsy, did not show evidence of malignancy. The patient was evaluated many months after initiation of symptoms and found to have deep hardening skin and multiple joint contractures. Pictures of his forearms are shown above. Cite this article as: Combarro AS, Guma J, Jimenez SA, Mendoza FA. The groove sign. Eur J Rheumatol. 2026, 13(2), 0079, doi: 10.5152/eurjrheum.2026.25079.