Histopathological and capillaroscopical features of the cuticles and bleeding clots in ring or middle fingers of systemic scleroderma patients

Sixty-three patients with systemic scleroderma (SSc) (Barnett I, 41; Barnett II, 17; Barnett III, 5), 14 with systemic lupus erythematosus (SLE), 9 with dermatomyositis (DM) and 10 healthy controls (HC) were subjected to histopathological examinations of the cuticles of ring or middle fingers. The sex ratios (male/female) in the patients with SSc, SLE, DM and HC were 7:56, 5:9, 5:4 and 5:5, and the ages were 22–74, 19–78, 45–70 and 13–78 years old, respectively. Biopsy samples were taken from the central portion of the cuticles, which showed the most severe change of elongation with or without bleeding clots of cuticle-proximal nailfolds (BC). Histopathologically, 61 (96.8%) cuticles of SSc patients consisted of the upper (U), middle (M) and lower (L) layers, which represent obliquely stacked, parabolic, and parallel stacked layers, respectively. The middle parabolic layer appeared to discharge homogenous eosinophilic globular deposits (ED). On the other hand, this typical three-layer-nail pattern was seen only in 9 (64.3%) of SLE, 3 (33.3%) of DM and none of HC, in total 12 (36.4%) of the non-SSc group, which included SLE, DM and HC. In SSc, there were statistical correlations ( R 2) between ED and BC, ED and cuticle-elongation, cuticle-layer and cuticle-elongation, ED and cuticle-layer, BC and cuticle-elongation. Capillaroscopically, bleeding clots located in the middle layer with ED of the cuticles in eight patients with SSc were transported rapidly within 1–2 weeks. The present histopathological findings show that longer cuticles with larger ED in the middle layer in SSc, and shorter cuticles with a much smaller number and size of ED in SLE and DM may be a useful marker in the differential diagnosis of SSc from other collagen diseases such as SLE and DM.