A giant cell tumor of the tendon sheath (GCTTS) is a benign tumor that can occur in the joint synovium, bursae, or tendon sheath. It generally emerges in the tendons/synovium of the bones of the hand. It has unique characteristics, as noted in histopathological, clinical, and published literature. GCTTS has been reported across different age groups, with higher incidence observed in middle-aged adults. We present an unusual occurrence of GCTTS arising from the foot in a 54-year-old female who visited our medical facility with a history of swelling in her right foot for one year. Ultrasonography suggested a well-defined 5 x 4 cm lesion deep to the flexor tendon with possible intertarsal extension, which was managed surgically. This article represents a detailed understanding of GCTTS, emphasizing its benign yet locally aggressive nature and the complexities involved in its diagnosis and management.

UNASSIGNED: Tenosynovial giant cell tumors (TSGCTs) are benign but aggressive lesions, and the treatment is resection. A low to intermediate signal intensity on both T1- and T2-weighted images of magnetic resonance imaging (MRI) is characteristic, which is similar to the signal intensity of muscle, and therefore can be challenging for lesion detection. T2-star (T2*)-weighted MR images reflect paramagnetic deoxyhemoglobin, methemoglobin, or hemosiderin.
UNASSIGNED: In 23 TSGCT patients (6 male and 17 females), the T2*MRI findings were analyzed. The tumor locations involved 10 large joints including nine knees and one ankle, 10 small joints including six fingers and four toes, as well as three wrists/hands.
UNASSIGNED: Ten diffuse and 13 localized tumors were predominantly located in the large joints and small joints, respectively. The T2*-weighted images indicated three signal patterns of low, iso and high signal intensity compared to muscle. Low-, iso- and high-signal intensities were seen in 22 (96 %), 23 (100 %) and 12 (52 %) of the locations, respectively. To distinguish TSGCTs from the surrounding tissue, the low intensity T2*-weighted images and low to intermediate intensity T1-weighted images when compared to muscle and fluid, respectively were useful for the large joints. Low to intermediate intensity on T1- or T2-weighted images was useful to distinguish TSGCTs from subcutaneous tissue in the small joints.
UNASSIGNED: MRI using T2*-, as well as T1- and T2-weighted images, may be useful to detect lesions and assess the extent of TSGCTs in a tissue-specific manner, which is important for surgical planning.

<b>Introduction:</b> Giant cell tumor of the tendon sheath is the most common benign proliferative lesion involving the upper limb, characterized by relatively high recurrence rate after surgery. <br><b>Aim:</b> The objective of the study was a retrospective analysis of outcomes of the operative treatment of these tumors, in a longterm (a mean of 4,2 year) follow-up. <br><b>Material and methods:</b> Preoperative examination was performed in 58 patients, 36 females (62%) and 22 males (38%), in a mean age of 41 years, and treatment outcomes were assessed in 47 persons (81% of the operated patients), at a mean of 4.2-year follow-up. The final assessment was performed in a form of phone interview. <br><b>Results:</b> The most common site of the tumors was the fingers - 42 cases (72%). In 31 patients (53%) the lesion had a well-defined capsule, and in 11 (19%) a satellite nodule was found around the main tumor. A total of 9 relapses (21%) occurred, all within the first 2 years following surgery. Two patients had a next episode of recurrence after the second operation. In 8 out of the 9 patients with a recurrence, the primary lesion did not have a well-defined capsule. In 38 patients who had no relapse, 31 were completely symptom-free, whereas 7 complained of mild pain of the scar and/or numbness of a part of the involved finger. <br><b>Conclusions:</b> The main factor that impacted the high rate of recurrence was incomplete tumor excision, which resulted from inadequately accurate surgery and the tumor morphology (having no well-defend capsule). The role of operating with the use of magnifying devices and keeping a greater surgical margin at resection of the non-capsulated lesions was emphasized, as it could translate into reducing the recurrence rate.

Tenosynovial giant cell tumor (TSGCT) represents a family of benign tumors that arise from the synovial tissue of a joint, tendon sheath, or bursa. It usually involves the joints of the extremities and rarely occurs in the head and neck region. Here, we describe a case of a 32-year-old man with a submucosal mass bulging in the posterior pharyngeal wall since one month. The lesion was removed and diagnosed with localized type of TSGCT based on histopathological investigations and clinical presentation. It is very rare that TSGCT occurs in the retropharynx, which reminds clinicians to consider this entity as a possible diagnosis.

This review examines the following aspects of tenosynovial giant cell tumors (TSGCTs): the use of multiple names, the complex relationship between tumor growth pattern and location, the high rate of postoperative recurrence, local invasiveness, use of nonsurgical therapy with molecularly targeted drugs, and best current treatments. This tumor has been referred to by various names, but is now most frequently referred to as TSGCT. TSGCT is classified as localized and diffuse, in accordance with its growth characteristics. Most TSGCTs of the fingers are localized. TSGCT is likely a neoplastic process arising from synovial lining cells, in which tumor cells express the colony stimulating factor 1 (CSF1) gene. The postoperative recurrence rate of TSGCT is approximately 15%. The intrinsic characteristics of recurrence are not clear, and complete resection of the lesion is still the treatment mainstay. Moreover, TSGCT commonly grows out of a pseudocapsule. Therefore, to perform complete resection of TSGCT, surgery must be performed cautiously after appropriate preparation, by using anesthesia, a tourniquet, surgical loupe, and surgical microscopy. After accurate preoperative diagnosis, meticulous planning by surgeons is necessary. The lesion should be resected along with approximately 1-mm of healthy tissue at the adhesion site. In addition, because satellite lesions might be present near the tumor, careful dissection and observation of the color of surrounding tissue are important. International clinical trials of CSF1 receptor inhibitors for TSGCT treatment are ongoing.

BACKGROUND: Tenosynovial giant cell tumor (TSGCT) originates from the synovial cells of the tendon sheath and is the most common soft tissue tumor of the foot and ankle. Due to the lack of clinical data about TSGCT in the foot and ankle, this study was performed with the aim of investigating the clinical characteristics, and surgical outcomes that might predict the likelihood of recurrence.
METHODS: Clinical data, obtained from the pathology records and the clinic files, along with the tumor subtype, local recurrence, and patient functional status among 26 cases of TSGCT were evaluated with the mean 73 months follow-up period.
RESULTS: There were 26 patients including 16 males and 10 females with a mean age of 40 years, who underwent surgery. There were 15 localised TSGCT and 11 diffuse TSGCT. The diffuse TSGCT was more likely to be in the hindfoot dorsum (54,5%, 6/11). The localised TSGCT was mostly located in the forefoot (80%, 12/15). The recurrence rate in the diffuse TSGCT was 27,3% (3/11). In the localised TSGCT, recurrence was seen in 6,6% of patients (1/15). The mean AOFAS score was 79.
CONCLUSIONS: Diffuse TSGCT is more likely to occur in the hindfoot and localised TSGCT is more common in the forefoot. Excision with clear margins is an effective treatment for TSGCT, with good oncological and clinical outcomes. But the orthopaedic surgeons should consider the equilibrium between surgical margins and the functional status of the patient.

Background: Emerging literature introduces radiation therapy for benign hand conditions. However, hand surgeons are wary recommending radiation therapy for nonmalignant conditions. In our practice, we have used radiation therapy for patients who present with infiltrative or recurrent giant cell tumor of the tendon sheath (GCTTS) since 1998. The purpose of this study is to examine the secondary effects of radiation to the hand through the critical lens of a hand surgeon. Methods: A case series of patients who received radiation therapy for GCTTS were reviewed. The Radiation Oncology/Toxicity Grading Late Radiation Morbidity Scoring Schema was used, and patients were questioned about symptoms and examined for physical findings involving their irradiated digits. Results: A total of 8 patients with GCTTS presented for follow-up. The average patient age was 59.1 years, and the average time since radiation therapy was 5.4 years. Patients had an average of 2.3 surgeries on the affected digit prior to receiving radiation therapy. The average Disabilities of the Arm, Shoulder, and Hand score was 8.1. The most common sign of radiation was nail changes. All patients complained of sensibility changes, although only 2 of the 8 patients had abnormal moving 2-point discrimination tests. There were no confirmed recurrences of GCTTS and no skin cancers. Conclusions: Patients who received radiation therapy to the hand report high levels of satisfaction with the therapy. Radiation therapy is tolerated well by these patients and has a low level of morbidity in our population.

Little is known about the burden of illness in patients with tenosynovial giant cell tumors (TGCT), which are rare, typically benign, lesions of the synovial tissue including giant cell tumor of the tendon sheath (GCT-TS) and pigmented villonodular synovitis (PVNS). The objective of this study was to describe health care resource use and costs for patients with GCT-TS and PVNS, which are rare and typically benign TGCT.
A retrospective cohort study design was used to analyze administrative claims for adult commercial and Medicare Advantage health plan enrollees with evidence of GCT-TS and PVNS from January 1, 2006 through March 31, 2015. Participants were continuously enrolled for 12 months before (pre-index period) and 12 months after (post-index period) the date of the first tenosynovial giant cell tumor (TGCT) claim (index date). Preindex and postindex measures were compared using the McNemar test and Wilcoxon signed-rank test. Results were stratified by TGCT type.
The study identified 4664 patients with TGCT, 284 with GCT-TS, and 4380 with PVNS. Mean age (GCT-TS group: 50 years; PVNS group: 51 years) and sex distributions (GCT-TS group: 60.2% female; PVNS group: 59.5% female) were similar for each group. Most patients with GCT-TS (78.2%) had at least one postindex surgery, compared with 38.7% of patients with PVNS. Mean total health care costs increased from $8943 in the preindex period to $14,880 in the postindex period (P < 0.001) for GCT-TS and from $13,221 in the preindex period to $17,728 in the postindex period (P < 0.001) for PVNS. Preindex to postindex ambulatory costs increased nearly 120% for patients with GCT-TS ($4340 to $9570, P < 0.001) and 50% for patients with PVNS ($6782 to $10,278, P < 0.001), and physical therapy use increased significantly during the same period (GCT-TS: 18% to 40%, P < 0.001; PVNS: 38% to 60%, P < 0.001).
Costs increased substantially 1 year after the first TGCT claim, with more than half the costs covering ambulatory care. These results suggest a high health care burden once TGCT is identified.

The present study aimed to investigate the value of magnetic resonance imaging (MRI) in the diagnosis of giant cell tumor of the tendon sheath (GCTTS), including localized (L-) and diffuse (D-) types. A total of 38 patients with GCTTS, including 31 with L-GCTTS and 7 with D-GCTTS, diagnosed by surgery and pathology, were retrospectively analyzed. All patients underwent MRI examination. Of the 31 patients with L-GCTTS, the tumors were located in the hand and wrist (18 patients), the ankle and foot (10 cases), the knee joint (2 cases) and the temporomandibular joint (1 case). All 31 lesions were either located in relation to a tendon or were partially/completely enveloping it and all were well marginated. With respect to the 7 D-GCTTS patients, the tumors were located in the ankle and foot (6 cases) or the hand and wrist (1 cases). All 7 lesions presented as an aggressive soft tissue mass infiltrating the tendon sheath and adipose tissue around the joint. The characteristic internal signal of GCTTS, including L-GCTTS and D-GCTTS, was demonstrated by MRI examination. MRI is currently the optimal modality for preoperative assessment of tumor size, extent and invasion of adjacent joint and tenosynovial space.

Giant cell tumor of the tendon sheath (GCTTS) predominantly occurs in the tendon sheaths of the hand, but rarely in those of the knee. The current study reports the case of a 36-year-old male patient presenting with anterior knee pain. The patient was ultimately diagnosed with GCTTS in the knee mimicking patellar tendinopathy. To the best of our knowledge, this is the first case of its kind. Magnetic resonance imaging revealed a well-defined oval intra-articular lesion located at the proximal segment of the infrapatellar fat pad. The lesion was completely excised under arthroscopy and pathological examination confirmed the diagnosis of GCTTS. There was no evidence of recurrence at the 2-year follow-up examination. The findings of the present study suggest that, despite its rarity, GCTTS should be considered in the differential diagnosis of patellar tendinopathy.