title: Histopathology of tenosynovium in trigger fingers.
abstract: Stenosing flexor tenosynovitis, trigger finger, is a common clinical disorder causing painful locking or contracture of the involved digits, and most instances are idiopathic. This problem is generally caused by a size mismatch between the swollen flexor tendon and the thickened first annular pulley. Although hypertrophic pulleys have been histologically and ultrasonographically detected, little is known about the histopathology of the tenosynovium covering the tendons of trigger fingers. We identified chondrocytoid cells that produced hyaluronic acid in 23 (61%) fingers and hypocellular collagen matrix in 32 (84%) fingers around the tenosynovium among 38 specimens of tenosynovium from patients with trigger fingers. These chondrocytoid cells expressed the synovial B cell marker CD44, but not the chondrocyte marker S-100 protein. The incidence of these findings was much higher than that of conventional findings of synovitis, such as inflammatory infiltrate (37%), increased vascularity (37%), hyperplasia of synovial lining cells (21%), or fibrin exudation (5%). We discovered the following distinctive histopathological features of trigger finger: hyaluronic acid-producing chondrocytoid cells originated from fibroblastic synovial B cells, and a hypocellular collagen matrix surrounding the tenosynovium. Thus, an edematous extracellular matrix with active hyaluronic acid synthesis might increase pressure under the pulley and contribute to the progression of stenosis.
authors: Department of Pathology and Microbiology, Faculty of Medicine, Saga University, Saga, Japan.
authors: Kazuyoshi
authors: K
authors: Uchihashi
authors: Toshiyuki
authors: T
authors: Tsuruta
authors: Hiroko
authors: H
authors: Mine
authors: Shigehisa
authors: S
authors: Aoki
authors: Aki
authors: A
authors: Nishijima-Matsunobu
authors: Mihoko
authors: M
authors: Yamamoto
authors: Akio
authors: A
authors: Kuraoka
authors: Shuji
authors: S
authors: Toda
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009418:S100 Proteins / Q000378:metabolism; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology*; D013710:Tendons / Q000378:metabolism / Q000473:pathology*; D052582:Trigger Finger Disorder / Q000378:metabolism / Q000473:pathology*
chemical_list: D009418:S100 Proteins; D006820:Hyaluronic Acid
keywords: chondrocytoid cell; histopathology; hyaluronic acid; tenosynovium; trigger finger