An unusual case of localised tophaceous gout in the left index finger

The present article describes the biopsy-based (proximal interphalangeal joint II, HE staining) diagnosis of tophaceous gout. Eosinophilic/basophilic deposit surrounded by fibrohistiocytic cells and some giant cells of foreign type could be detected on light microscopy. No birefringent material could be observed. Differential diagnosis included caseating granulomatous infectious diseases, which are typically characterized by zonally organised granulomas with central necrosis, epitheloid cell reaction, as well as Touton-type giant cells.