Department of Orthopedic Surgery, University Medical Centre Ljubljana, Zaloška 9, 1000, Ljubljana, Slovenia.
Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia.
Virchows Arch. 2021 Jun;478(6):1117-1124. doi: 10.1007/s00428-020-02991-6. Epub 2021 Jan 6.
Intraarticular nodular fasciitis arising in the joint synovium is an uncommon lesion. Most cases have been reported in the knee and rarely in other joints. A USP6 gene fusion has so far been documented in only four cases of intraarticular nodular fasciitis, three were located in the knee and one in the proximal interphalangeal joint. In all three cases located in the knee, MYH9 was detected as a USP6 fusion partner. We analysed three cases of intraarticular nodular fasciitis for the presence of USP6 fusion by targeted RNA sequencing. Two cases were located in the hip (a 25-year-old female and 48-year-old male) and one in the shoulder (a 38-year-old male). We detected a MYH9-USP6 fusion in the two hip cases and a COL1A1-USP6 fusion in the shoulder case. Our findings provide additional evidence that intraarticular nodular fasciitis is a form of nodular fasciitis arising in the joint synovium, harbouring a USP6 fusion. Although a MYH9-USP6 fusion seems to predominate in intraarticular nodular fasciitis, other fusion partners of the USP6 gene may also be involved. Detection of a USP6 fusion by targeted RNA sequencing may assist in confirming the diagnosis in selected cases.
关节滑膜内结节性筋膜炎是一种不常见的病变。大多数病例发生在膝关节，很少发生在其他关节。迄今为止，仅在 4 例关节内结节性筋膜炎中记录到 USP6 基因融合，其中 3 例位于膝关节，1 例位于近指间关节。在所有 3 例位于膝关节的病例中，均检测到 MYH9 作为 USP6 融合伴侣。我们通过靶向 RNA 测序分析了 3 例关节内结节性筋膜炎是否存在 USP6 融合。2 例位于髋关节（1 例 25 岁女性，1 例 48 岁男性），1 例位于肩部（1 例 38 岁男性）。我们在 2 例髋关节病例中检测到 MYH9-USP6 融合，在肩部病例中检测到 COL1A1-USP6 融合。我们的发现提供了额外的证据表明，关节内结节性筋膜炎是一种起源于关节滑膜的结节性筋膜炎，存在 USP6 融合。虽然 MYH9-USP6 融合似乎在关节内结节性筋膜炎中占主导地位，但 USP6 基因的其他融合伴侣也可能参与其中。通过靶向 RNA 测序检测 USP6 融合可能有助于在选定病例中确认诊断。
