Localized Nodular Tenosynovitis Originated near the Medial Plicae

The authors report a case of localized nodular tenosynovitis originating from the medial plicae of the knee that was grossly observable, palpable, and symptomatic. A 41-year-old male visited our hospital with a complaint of knee pain that began 4 years ago. He complained of intermittent catching and a mass that appeared in the medial side of the knee 18 months ago. On magnetic resonance imaging, the mass was found on the plicae area of the medial side of the knee, and thus excisional biopsy was performed under arthroscopy. Histological study showed characteristics of localized nodular tenosynovitis originating from the synovium of the knee. At the 1-year postoperative outpatient follow-up, no symptoms or signs of recurrence were found. Since the authors experienced excellent postoperative results of arthroscopically assisted resection of a grossly observable and palpable localized nodular tenosynovitis originating from the synovium of the knee plicae, we report the case with a review of the literature.

Chondroid tenosynovial giant cell tumor of the toe: A case report / 동물의과학연구지

Localized tenosynovial giant cell tumor (TGCT) usually occurs in the hand and foot regions. However, localized TGCT with extensive cartilaginous metaplasia is rare, especially in the tendon sheath of the toe. Here, we report a case of localized TGCT with cartilaginous metaplasia in a 57-year-old man. The tumor presented as a lobular mass measuring 2.2 cm in its greatest dimension and arose in the flexor digitorum tendon sheath of the right 2nd toe. Clinically, the mass was palpable 1 year ago and brought pain during walking. Microscopically, the mass was composed of focal conventional TGCT and cartilaginous components. The conventional TGCT areas consisted of mononuclear cells, multinucleated giant cells, and hemosiderin deposition. The chondroid areas were extensive and comprised more than 90% of the whole tumor. In this case, the mononuclear cells in the conventional TGCT areas showed focal immunohistochemical staining for podoplanin and S100 protein as well as diffuse staining for CD68, which is consistent with the staining pattern of conventional TGCT. The mononuclear cells in the chondroid areas were focal positive for podoplanin and diffuse positive for S100 protein. Chondroid metaplasia in diffuse TGCT has been reported in 10 cases involving the temporomandibular, elbow, and hip joints. However, there has been no report of a localized form of chondroid TGCT involving an extra-articular region.