Diffuse-type giant cell tumor: clinicopathologic and immunohistochemical analysis of 50 cases with extraarticular disease

Clinical characteristics and treatment outcomes in six cases of malignant tenosynovial giant cell tumor: initial experience of molecularly targeted therapy

Background

Although tenosynovial giant cell tumor (TGCT) is classified as a benign tumor, it may undergo malignant transformation and metastasize in extremely rare occasions. High aberrant expression of CSF1 has been implicated in the development of TGCT and recent studies have shown promising activity of several CSF1R inhibitors against benign diffuse-type TGCT; however, little is known about their effects in malignant TGCT.

Case presentation

Information from six consenting patients (3 men, 3 women) with malignant TGCT presenting to Dana-Farber Cancer Institute for initial or subsequent consultation was collected. Median age at initial diagnosis of TGCT was 49.5 years (range 12–55), and median age at diagnosis of malignant TGCT was 50 years (range 34–55). Two patients developed malignant TGCT de novo, while four other cases showed metachronous malignant transformation. All tumors arose in the lower extremities (3 knee, 2 thigh, 1 hip). Five patients underwent surgery for the primary tumors, and four developed local recurrence. All six patients developed lung metastases, and four of five evaluable tumors developed inguinal and pelvic lymph node metastases. All six patients received systemic therapy. Five patients were treated with at least one tyrosine kinase inhibitor with inhibitory activity against CSF1R; however, only one patient showed clinical benefit (SD or PR). Five patients were treated with conventional cytotoxic agents. Doxorubicin-based treatment showed clinical benefit in all four evaluable patients, and gemcitabine/docetaxel showed clinical benefit in two patients. All six patients died of disease after a median of 21.5 months from diagnosis of malignant TGCT.

Conclusions

This study confirms that TGCT may transform into an aggressive malignant tumor. Lymph node and pulmonary metastases are common. Local recurrence rates are exceedingly high. Conventional cytotoxic chemotherapy showed clinical benefit, whereas tyrosine kinase inhibitors against CSF1R showed limited activity. Given its rarity, a prospective registry of malignant TGCT patients is needed to further understand the entity and to develop effective strategies for systemic treatment.

Tenosynovial Giant Cell Tumors in Children: A Similar Entity Compared With Adults

BACKGROUND

Tenosynovial giant cell tumor (TGCT) is a rare, benign, monoarticular entity. Many case-series in adults are described, whereas TGCT is only incidentally reported in children. Therefore, its incidence rate and natural history in children are unknown.

QUESTIONS/PURPOSES

(1) How many cases have been reported of this condition, and what were their characteristics? (2) What is the standardized pediatric incidence rate for TGCT? (3) Is there a clinical difference in TGCT between children and adults? (4) What is the risk of recurrence after open resection in children compared with adults?

METHODS

Data were derived from three sources: (1) a systematic review on TGCT in children, seeking sources published between 1990 and 2016, included 17 heterogeneous, small case-series; (2) the nationwide TGCT incidence study: the Dutch pediatric incidence rate was extracted from this nationwide study by including patients younger than 18 years of age. This registry-based study, in which eligible patients with TGCT were clinically verified, calculated Dutch incidence rates for localized and diffuse-type TGCT in a 5-year timeframe. Standardized pediatric incidence rates were obtained by using the direct method; (3) from our nationwide bone and soft tissue tumor data registry, a clinical data set was derived. Fifty-seven children with histologically proven TGCT of large joints, diagnosed and treated between 1995 and 2015, in all four tertiary sarcoma centers in The Netherlands, were included. These clinically collected data were compared with a retrospective database of 423 adults with TGCT. Chi-square test and independent t-test were used to compare children and adults for TGCT type, sex, localization, symptoms before diagnosis, first treatment, recurrent disease, followup status, duration of symptoms, and time to followup. The Kaplan-Meier method was used to evaluate recurrence-free survival at 2.5 years.

RESULTS

TGCT is seldom reported because only 76 pediatric patients (39 female), 29 localized, 38 diffuse, and nine unknown type, were identified from our systematic review. The standardized pediatric TGCT incidence rate of large joints was 2.42 and 1.09 per million person-years in localized and diffuse types, respectively. From our clinical data set, symptoms both in children and adults were swelling, pain, and limited ROM with a median time before diagnosis of 12 months (range, 1-72 months). With the numbers available, we did not observe differences in presentation between children and adults in terms of sex, symptoms before diagnosis, first treatment, recurrent disease, followup status, or median time to followup. The 2.5-year recurrence-free TGCT survival rate after open resection was not different with the numbers available between children and adults: 85% (95% confidence interval [CI], 67%-100%) versus 89% (95% CI, 83%-96%) in localized, respectively (p = 0.527) and 53% (95% CI, 35%-79%) versus 56% (95% CI, 49%-64%) in diffuse type, respectively (p = 0.691).

CONCLUSIONS

Although the incidence of pediatric TGCT is low, it should be considered in the differential diagnosis in children with chronic monoarticular joint effusions. Recurrent disease after surgical treatment of this orphan disease seems comparable between children and adults. With targeted therapies being developed, future research should define the most effective treatment strategies for this heterogeneous disease.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Giant Cell Poor Extra-Articular Diffuse-Type Tenosynovial Giant Cell Tumor With Extensive Desmin Expression: A Potential Diagnostic Pitfall With Cytogenetic Confirmation

Diffuse-type tenosynovial giant cell tumor can rarely present as an entirely extra-articular mass, which can be misdiagnosed as a sarcoma especially when giant cells are absent, dominated by large dendritic mononuclear cells, and desmin expression is extensive.

[CT imaging features of diffuse tenosynovial giant cell tumor of temporomandibular joint]

OBJECTIVE

This study aimed to investigate the characteristic features of CT images of diffuse tenosynovial giant cell tumor (D-TSGCT) from the temporomandibular joint (TMJ) to understand CT imaging diagnosis of the disease.

METHODS

CT images and clinical information from 10 patients with D-TSGCT of TMJ were recruited for retrospective analysis from March 2013 to March 2017 in Peking University Hospital of Stomatology. All cases were treated by surgery and confirmed by pathology.

RESULTS

CT scan demonstrated hyperdense soft-tissue masses and various kinds of calcification in all of the 10 subjects. Contrast-enhanced scan exhibited obvious enhancement in six patients. Bone destruction of the mandibular condyles and skull base was found in seven and six subjects, respectively.

CONCLUSIONS

CT appearance of D-TSGCT of the TMJ is characterized by hyperdense soft tissue with calcification, further enhancement in contrast-enhanced scan, and bone destruction in the mandibular condyles and skull base in some cases.

Extra-articular tenosynovial giant cell tumor of diffuse type in the temporal area with brain parenchymal invasion: a case report

Tenosynovial giant cell tumor of diffuse type is a locally aggressive neoplasm that most commonly arises in the lower extremities. Herein, we report for the first time a case of an extra-articular tenosynovial giant cell tumor of diffuse type in the temporal region with brain parenchymal invasion. Imaging studies revealed an intracranial expansile mass in the temporal bone without involvement of the temporomandibular joint. The unusual location of the tumor without involvement of the joint and the presence of brain parenchymal invasion made this case challenging to diagnose.

A rare case of localised pigmented villonodular synovitis in the knee of a 24-year-old female soccer player: diagnosis, management and summary of tenosynovial giant cell tumours

Localised pigmented villonodular synovitis (PVNS) of the knee is a rare diagnosis, with clinical signs and symptoms mimicking meniscal damage or other common knee injuries.We report the case of a 24-year-old female soccer player, seeking treatment after 7 months of persisting knee pain. Additionally, we present an overview of tenosynovial giant cell tumours.On examination, the patient was found to have tenderness in the medial joint space of the knee. MRI revealed a heterogeneous formation in the central part of the knee. The formation was completely enucleated arthroscopically, histological analyses confirmed the diagnosis of localised PVNS. The patient was subsequently free of symptoms with no signs of recurrence on MRI and had resumed soccer practice at the 1-year follow-up appointment.

Imaging features for diffuse-type tenosynovial giant cell tumor of the temporomandibular joint: A case report

RATIONALE

The tenosynovial giant cell tumor (TGCT) is a benign but locally aggressive tumor that arises from the synovial membrane of joints, tendon sheaths, and bursae. Although any joint can be affected, involvement of the temporomandibular joint (TMJ) was reported very rarely, and there is no relevant report on F-FDG PET/computerized tomography (CT).

PATIENT CONCERNS AND DIAGNOSES

We present here a rare case of diffuse-type of TGCT (D-TGCT) arising from the right TMJ in a 74-year-old woman. The patient was discovered a mass of the right temporal fossa during a head CT scan. However, she did not receive any treatment and was discharged from the hospital. She visited our institution again after 4 years with worsening headache and swelling of the right preauricular area. An enhanced CT demonstrated a 6.0 × 3.4 × 5.0 cm mass of mixed density involving the right TMJ, with evident enhancement and extensive erosion of adjacent bones. Magnetic resonance imaging (MRI) showed hypointensity in the solid part of the mass but high signal intensity in the cystic part or necrosis on T2-weighted images (T2WI). In F-FDG PET/CT images, the solid portion of the mass had increased FDG uptake with a SUVmax of 19.8. It was then diagnosed as D-TGCT by postoperative pathology.

LESSONS

The case report shows the imaging features of the TGCT, including CT, MRI, and F-FDG PET/CT, especially the typical hypointensity on T2WI. Careful preoperative examination and complete resection are the factors that lead to the optimal treatment of the TGCT.

Giant cell tumor of the tendon sheath: Magnetic resonance imaging findings in 38 patients

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 seath of the tendinous insertion in pes anserinus

A 56-year-old woman with a palpable lump in the medial surface of her left knee was referred for diagnostic workup with magnetic resonance imaging. The lesion was pathogically confirmed to be a giant cell tumor of the tendon seath. The MR features of the lesion are presented.

Giant cell tumor of soft tissues: A case report of extra-articular diffuse-type giant cell tumor of the quadriceps

INTRODUCTION

Giant cell tumors of soft tissue (GCTs) are a relatively rare entity. It is a distinct but uncommon group of neoplasms morphologically identical to osseous giant cell tumor. The diffuse type of extra-articular GCT arising within muscle is a rare benign soft tissue tumor with a wide spectrum of clinical presentation.

PRESENTATION OF CASE

This article reports a rare case of a 44-year-old woman with a mass arising from her right thigh. MRI showed only a few areas of low T2 signal in a mass that was hyper intense to muscle. Histopathology of this lesion located within the right quadriceps muscle revealed admixture of multinucleated giant cell with mononuclear cells. This patient was treated by surgical resection and followed up for recurrence.

DISCUSSION

Diffuse-type GCTs are commonly located in the periarticular soft tissues, but on rare occasions these lesions can be purely intramuscular or subcutaneous and can be challenging to diagnose. Characteristic findings include gradient echo secondary to hemosiderin deposition, and the low signal on T2.

CONCLUSION

Because extra-articular diffuse-type GCTs are rare, the differential diagnosis is challenging. The clinical outcomes of diffuse-type GCTs are unclear because of their rarity. Benign clinical course is expected if the lesion is excised adequately.

Extra-articular diffuse-type tenosynovial giant cell tumor with benign histological features resulting in fatal pulmonary metastases

Diffuse-type tenosynovial giant cell tumor (TS-GCT) is categorized as a locally aggressive but non-metastasizing neoplasm according to the WHO classification. Herein, we report an extremely rare case of a 41-year-old woman who developed multiple metastases from diffuse TS-GCT with benign histological features. The patient complained of a painful buttock mass and imaging studies revealed a soft tissue tumor of the buttock and multiple pulmonary nodules. The buttock tumor was excised and the final diagnosis was extra-articular diffuse-type TS-GCT. By video-assisted thoracic surgery, pulmonary nodules were pathologically identical to the primary tumor. Residual pulmonary nodules progressively grew, and she developed a muscle metastasis and a subcutis metastasis. She died of respiratory dysfunction due to multiple pulmonary metastases 1 year after primary surgery. Very few reports on histologically benign metastases from TS-GCT have been published, and the natural course of this rare condition remains unclarified. This rare case could provide important information for further clinical evaluation of this tumor.

Arthroscopic excision of giant cell tumor of the tendon sheath in the knee mimicking patellar tendinopathy: A case report

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.

Selected Lesions Featuring Giant Cells

Many neoplasms of the soft tissues feature giant cells, but this article covers entities in which giant cells are a striking feature. Specifically, we consider tenosynovial giant cell tumor (localized and diffuse types; giant cell tumor of tendon sheath, and pigmented villonodular tenosynovitis), reticulohistiocytoma, juvenile xanthogranuloma, giant cell fibroblastoma (a variant form of dermatofibrosarcoma protuberans), giant cell angiofibroma (which is essentially a giant cell-rich form of solitary fibrous tumor), and phosphaturic mesenchymal tumor.

Diffuse-type giant cell tumor of the tendon sheath in the temporal region incidentally diagnosed due to a temporal tumor: A report of two cases and review of the literature

Diffuse-type tenosynovial giant cell tumor (D-GCTS) is a rare benign lesion that not only frequently occurs in the fingers, but also along the tendon sheaths of the foot and ankle. The present study reports the cases of two middle-aged patients that were diagnosed with D-GCTS. The presentation of the D-GCTS lesions was extremely rare, as the tumors were located in the temporal fossa and threatened the skull base and external auditory canal. There were similarities and differences between the two patients in their clinical symptoms, disease progressions and invading sites. The patients' disease course occurred unnoticed with the absence of pain, was protracted and became infiltrative. However, the female patient was admitted to the hospital due to the occurrence of pain in the left temporal region, and the male patient presented at the doctor due to a painless left temporal mass and external auditory canal bleeding. Therefore, the operation area of the two patients was not the same. This type of illness should be considered in the differential diagnosis for masses occurring in the temporal region. Total tumor removal is the best treatment for D-GCTS, and the careful monitoring of recurrence can achieve a good clinical outcome subsequent to the surgical resection.

Metastasizing tenosynovial giant cell tumour, diffuse type/pigmented villonodular synovitis

Tenosynovial giant cell tumour, diffuse type, also known under a variety of other terms including diffuse pigmented villonodular synovitis, tends to be locally aggressive and not infrequently can show multiple recurrences. The differential diagnosis with the extremely rare and somewhat controversial malignant variant of tenosynovial giant cell tumour, diffuse type, is challenging due to overlapping radiologic features of these two entities. Malignant tenosynovial giant cell tumour is defined by the presence of overtly malignant sarcomatous areas. We describe a very unusual case of a 63-year-old man affected by tenosynovial giant cell tumour, diffuse type of the knee that, despite absence of morphologic evidence of sarcomatous transformation, developed inguinal lymph node metastases following multiple surgical procedures.

The effect of surgical synovectomy and radiotherapy on the rate of recurrence of pigmented villonodular synovitis of the knee

Pigmented villonodular synovitis (PVNS) is a rare proliferative process of the synovium which most commonly affects the knee and occurs in either a localised (LPVNS) or a diffuse form (DPVNS). The effect of different methods of surgical synovectomy and adjuvant radiotherapy on the rate of recurrence is unclear. We conducted a systematic review and identified 35 observational studies in English which reported the use of surgical synovectomy to treat PVNS of the knee.

A meta-analysis included 630 patients, 137 (21.8%) of whom had a recurrence after synovectomy. For patients with DPVNS, low-quality evidence found that the rate of recurrence was reduced by both open synovectomy (odds ration (OR) = 0.47; 95% CI 0.25 to 0.90; p = 0.024) and combined open and arthroscopic synovectomy (OR = 0.19, 95% CI = 0.06 to 0.58; p = 0.003) compared with arthroscopic surgery. Very low-quality evidence found that the rate of recurrence of DPVNS was reduced by peri-operative radiotherapy (OR = 0.31, 95% CI 0.14 to 0.70; p = 0.01). Very low-quality evidence suggested that the rate of recurrence of LPVNS was not related to the surgical approach.

This meta-analysis suggests that open synovectomy or synovectomy combined with peri-operative radiotherapy for DPVNS is associated with a reduced rate of recurrence. Large long-term prospective multicentre observational studies, with a focus on both rate of recurrence and function, are required to confirm these findings.

Cite this article: Bone Joint J 2015;97-B:550–7.

Nonsurgical giant cell tumour of the tendon sheath or of the diffuse type: are MRI or 18F-FDG PET/CT able to provide an accurate prediction of long-term outcome?

PURPOSE

To investigate whether MRI (RECIST 1.1, WHO criteria and the volumetric approach) or (18)F-FDG PET/CT (PERCIST 1.0) are able to predict long-term outcome in nonsurgical patients with giant cell tumour of the tendon sheath or of the diffuse type (GCT-TS/DT).

METHODS

Fifteen "nonsurgical" patients with a histological diagnosis of GCT-TS/DT were divided into two groups: symptomatic patients receiving targeted therapy and asymptomatic untreated patients. All 15 patients were evaluated by MRI of whom 10 were treated, and a subgroup of 7 patients were evaluated by PET/CT of whom 4 were treated. Early evolution was assessed according to MRI and PET/CT scans at baseline and during follow-up. Cohen's kappa coefficient was used to evaluate the degree of agreement between PERCIST 1.0, RECIST 1.1, WHO criteria, volumetric approaches and the reference standard (long-term outcome, delay 505 ± 457 days). The response rate in symptomatic patients with GCT-TS/DT receiving targeted therapy was also assessed in a larger population that included additional patients obtained from a review of the literature.

RESULTS

The kappa coefficients for agreement between RECIST/WHO/volumetric criteria and outcome (15 patients) were respectively: 0.35 (p = 0.06), 0.26 (p = 0.17) and 0.26 (p = 0.17). In the PET/CT subgroup (7 patients), PERCIST was in perfect agreement with the late symptomatic evolution (kappa = 1, p < 0.05). In the treated symptomatic group including the additional patients from the literature the response rates to targeted therapies according to late symptomatic assessment, and PERCIST and RECIST criteria were: 65 % (22/34), 77 % (10/13) and 26 % (10/39).

CONCLUSION

(18)F-FDG PET/CT with PERCIST is a promising approach to the prediction of the long-term outcome in GCT-TS/DT and may avoid unnecessary treatments, toxicity and costs. On MRI, WHO and volumetric approaches are not more effective than RECIST using the current thresholds.

Tenosynovial Giant Cell Tumor of Diffuse Type Mimicking Bony Metastasis Detected on F-18 FDG PET/CT

Tenosynovial giant cell tumor of diffuse type (TGCT-D) is a locally aggressive neoplasm that arises in the tendon sheath, bursa, or synovium. It typically involves the appendicular skeleton and rarely involves the axial skeleton. Because there are no specific findings of TGCT-D based on imaging studies or clinical symptoms, TGCT-D can be confused with other primary or metastatic bone tumors. We report findings of TGCT-D involving the T9 vertebra incidentally detected on F-18 FDG PET/CT in a patient with papillary thyroid cancer.

Intramuscular diffuse-type tenosynovial giant cell tumor of the deltoid muscle in a child

Tenosynovial giant cell tumors (GCTs) typically form in the joints or extra-articular soft tissues such as the tendon sheath, and are benign tumors that commonly occur in the hands or wrists in the third to fifth decades of life. However, the diffuse type of extra-articular GCT arising within muscle is a rare soft tissue tumor, especially in a pediatric patient. In this report, we describe the magnetic resonance imaging and sonographic findings of a rare case of intramuscular diffuse-type GCT in the deltoid muscle of a 9-year-old boy.

Multiple metastases from histologically benign intraarticular diffuse-type tenosynovial giant cell tumor: a case report

Diffuse-type tenosynovial giant cell tumor (D-TGCT) is a relatively rare mesenchymal tumor. It is a locally aggressive but virtually nonmetastasizing neoplasm and thus regarded as benign. Only a few D-TGCTs with benign histology have been reported to metastasize. We report an extremely rare case of benign D-TGCT in which multiple metastases developed 9 years after surgery for the primary tumor. The present case suggests that conventional D-TGCT has the potential to form distant metastases, albeit exceptionally rarely, and that this probable implantation phenomenon can be managed conservatively.

Novel CSF1-S100A10 fusion gene and CSF1 transcript identified by RNA sequencing in tenosynovial giant cell tumors

RNA-sequencing was performed on three tenosynovial giant cell tumors (TSGCT) in an attempt to elicit more information on the mechanisms of CSF1 expression in this tumor type. A novel CSF1-S100A10 fusion gene was found in a TSGCT that carried the translocation t(1;1)(q21;p11) as the sole karyotypic abnormality. In this fusion gene, the part of CSF1 coding for the CSF1 protein (exons 1-8 in sequences with accession nos. NM_000757 and NM_172212) is fused to the 3'-part of S100A10. Since the stop codon TAG of CSF1 is present in it, the CSF1-S100A10 fusion gene's predominant consequence seems to be the replacement of the 3'-untranslated region (UTR) of CSF1 (exon 9; nt 2092-4234 in sequence with accession no. NM_000757 or nt 2092-2772 in NM_172212) by the 3'-end of S100A10 (exon 3; nt 641-1055 in sequence with accession no. NM_002966). In the other two TSGCT, a novel CSF1 transcript was detected, the same in both tumors. Similar to the occurrence in the CSF1-S100A10 fusion gene, the novel CSF1 transcript 3'-UTR is replaced by a new exon located ~48 kb downstream of CSF1 and 11 kb upstream of AHCYL1. Although only 3 TSGCT were available for study, the finding in all of them of a novel CSF1-S100A10 fusion gene or CSF1 transcript indicates the existence of a common pathogenetic theme in this tumor type: the replacement of the 3'-UTR of CSF1 with other sequences.

Pigmented villonodular synovitis great toe

A young boy of 14 years. presented with swelling over dorsal aspect of right great toe, which was slightly tender, non fluctuant. It was excised under subarachnoid block. The mass was golden brown in colour encircling the extensor tendon (Extensor Hallucis Longus Tendon). Histopathology reported to be Pigmented Villonodular Synovitis.

Malignant giant cell tumor in the carpal tunnel: a case report and review of literature

Background Malignant tenosynovial giant cell tumors (GCTs) are extremely rare, and their etiology is unknown. However, this type of malignancy is associated with high metastasis and mortality rates. Therefore, the treatment of choice is wide excision. Case Description A 66-year-old man complained of tingling and loss of sensation in the left hand, caused by a tumor that compressed the median nerve. The tumor was excised. Histopathologic examination revealed a ganglion cyst. Two years later, the patient visited our clinic with recurrent and similar complaints of the left hand. This time, however, the lesion turned out to be a malignant tenosynovial GCT and was treated by amputation of the forearm. Literature Review Since 1979, only 37 malignant tenosynovial GCTs have been reported in literature. Follow-up of these patients showed that 11 patients died of the disease, 4 patients were still living with the disease, and 14 patients had no evidence of disease after treatment. The other seven patients were lost to follow-up, and one patient died of other causes. In these 37 patients, a high incidence of lymph node metastasis (41%) and a high mortality rate (30%) were seen. Clinical Relevance Although this malignant tenosynovial GCT is very rare, high mortality rates have been observed because of the high incidence of lymph node metastases. Therefore, more awareness has to be created, to recognize and treat this tumor timely.

Metastasizing "benign" cutaneous fibrous histiocytoma: a clinicopathologic analysis of 16 cases

Cutaneous fibrous histiocytoma (FH) is considered a benign tumor; however, certain types of FH have been shown to have a tendency for local recurrence, and there are rare reported cases of metastasis. In this study, 16 cases of morphologically benign FH with locoregional or distant metastasis were identified in consult files. Pathologic features of primary, recurrent, and metastatic tumors, as well as clinical outcome, were evaluated. Nine were male and 7 were female patients; mean age was 42 years (range, 3 to 68 y). Primary tumors arose on the leg in 5 patients, buttock in 1, trunk in 3, shoulder in 3, neck in 2, and finger in 1. The primary site in 1 case was unknown. Fifteen primary tumors available for review involved the dermis; 6 extended into the superficial subcutis. Tumor size ranged from 1 to 5 cm (median 3.2 cm). Histologically, primary tumors showed characteristic features of FH, being composed in most cases of a polymorphous population of bland spindle and histiocytoid cells in a mixed storiform and fascicular growth pattern with admixed foam cells, multinucleate cells, and inflammatory cells in varying proportions. Histologic variants included 11 cellular (2 with mixed atypical and cellular features), 2 aneurysmal, 1 atypical, and 1 epithelioid type. All tumors showed entrapment of hyalinized collagen bundles. Mitotic activity ranged from <1 to 13/10 HPF. Focal necrosis was seen in 1 primary tumor. Ten patients had local tumor recurrence; 4 patients had multiple local recurrences. Time to first recurrence ranged from 6 weeks to 13 years. The local recurrences of 1 tumor showed increased cytologic atypia, but recurrences were otherwise morphologically similar to primary tumors. Metastases occurred 0 to 180 months after diagnosis (median 17 mo) and involved the lungs (12 patients), lymph nodes (8), soft tissues (6), and liver (1). Five patients developed multiple satellite nodules in the region of the primary tumor. Metastases were morphologically similar to the primary tumors. So far, 6 patients died of disease, with a median time to death of 64 months (range, 10 to 168 mo). Four patients are alive with metastatic disease. Two patients are disease free at last follow-up, and 1 patient died of unrelated disease. Metastasis of morphologically benign cutaneous FH is an extremely rare but clinically aggressive event. Primary tumors tend to be large and cellular, but aggressive behavior cannot be predicted on morphologic grounds alone; however, early or frequent local recurrence may warrant closer clinical follow-up.

Bilateral cadaveric Achilles tendon graft in reconstruction after Achilles tendon tumor resection

The standard approach to reconstruction after resection of a diffuse-type tenosynovial giant cell tumor is a local patch with free flaps. However, in cases in which the Achilles tendon involvement is extensive, and the entire tendon must be removed, an autologous flap graft might not be adequate to allow a return to function. We report a case of a 52-year-old female patient who developed bilateral tumors of the Achilles tendon, with a 10-year duration. By the time, she sought medical help, both Achilles tendons required removal. We chose to use Achilles tendon allografts to replace the Achilles tendons. Postoperatively, the patient did well. The allograft shortened the recovery time, and the patient regained full ankle range of motion.

Tenosynovial Giant Cell Tumor: Case Report and Review

Tenosynovial giant cell tumors are a group of generally benign intra-articular and soft tissue tumors with common histologic features. They can be roughly divided into localized and diffuse types. Localized types include giant cell tumors of tendon sheath and localized pigmented villonodular synovitis, whereas diffuse types encompass conventional pigmented villonodular synovitis and diffuse-type giant cell tumor. Localized tumors are generally indolent, whereas diffuse tumors are locally aggressive. Recent developments indicate that tenosynovial giant cell tumors are clonal neoplastic tumors driven by overexpression of CSF1. Herein, I report a case of intra-articular, localized tenosynovial giant cell tumor (or localized pigmented villonodular synovitis) and review the classification, histopathology, and recent developments regarding its pathogenesis.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Low-dose external beam radiotherapy as a postoperative treatment for patients with diffuse pigmented villonodular synovitis of the knee: 4 recurrences in 23 patients followed for mean 9 years

BACKGROUND AND PURPOSE

Pigmented villonodular synovitis (PVNS) is a rare proliferative disorder involving synovial membranes, and patients with PVNS have a variable prognosis. We retrospectively analyzed clinical outcomes after synovectomy plus low-dose external beam radiotherapy for diffuse PVNS of the knee.

METHODS

We reviewed the medical records of 23 patients who underwent postoperative radiotherapy between 1998 and 2007. 19 patients had primary disease and 4 had recurrent disease with an average of 2.5 prior surgeries. After synovectomy (17 arthroscopic surgeries; 6 open), all 23 patients received 4-MV or 6-MV external beam radiotherapy with a median dose of 20 (12-34) Gy in 10 fractions.

RESULTS

At a median follow-up of 9 (0.8-12) years, 4 patients had recurrent disease, with a median disease-free interval of 5 years. Of these 4 patients, 3 received salvage synovectomy and regained local control. Univariate analysis showed that age, sex, history of trauma, and total dose of radiation were not predictive of local control. 22 patients reported excellent or good joint function, and 1 who refused salvage synovectomy had poor joint function. None of the patients experienced grade 3 or higher radiation-related toxicity or radiation-induced secondary malignancies.

INTERPRETATION

Postoperative external beam radiotherapy is an effective and acceptable modality to prevent local recurrence and preserve joint function in patients with diffuse PVNS of the knee. Low-dose (20 Gy) radiotherapy appears to be as effective as moderate-dose treatment (around 35 Gy).

Multicentric giant cell tumor: metachronous central and peripheral involvement

Giant cell tumors are rare in the head and neck region. The most frequently involved sites of giant cell lesions in the head and neck are the maxilla and mandible, whereas the sphenoid and temporal bones are rarely involved. This tumor is usually located in the long bones of limbs. Reparative granuloma and brown tumor of hyperparathyroidism must be included in the differential diagnosis. Here we report the clinical and radiologic findings of a multicentric giant cell tumor with skull base involvement in a female patient. This case report demonstrates the similar pathophysiology of peripheral and central giant cell tumors.

Giant cell tumor of the masticator space: case report and literature review

Giant cell tumors of the head and neck are rare. We describe the case of a 50-year-old man who presented with otalgia and eustachian tube dysfunction. After his symptoms persisted despite aggressive medical management, further investigation revealed the presence of a firmness in his left parotid tail. Computed tomography identified a heterogeneously enhancing mass in the left masticator space. The tumor was removed surgically, and it was diagnosed on histopathology as a giant cell tumor. The patient recovered uneventfully and was closely followed for signs of recurrence. To the best of our knowledge, ours is the first reported case of a giant cell tumor in the masticator space. We review the literature on giant cell tumors of the head and neck, with particular attention given to cases involving the temporomandibular joint.

Angiomatoid fibrous histiocytoma: unusual sites and unusual morphology

Angiomatoid fibrous histiocytoma is a soft tissue neoplasm of low malignant potential, typically occurring in the superficial soft tissues of the extremities in children and young adults. Occurrence outside somatic soft tissues is most uncommon. This report describes eight such cases, involving the lung (three cases), mediastinum (one case), vulva (two cases), retroperitoneum (one case) and ovary (one case), with the latter three locations being hitherto unreported sites of occurrence. Patients had a median age of 48 years, and presented with symptoms related to the mass lesion (five cases) or were incidentally found to harbor a tumor (three cases). Besides the typical histological features such as an outer shell of lymphoid tissue, multinodular aggregates of dendritic-like tumor cells, blood-filled spaces and abundant admixed plasma cells, unusual features were found focally in some cases, including clear cells, rhabdomyoblast-like cells, pulmonary edema-like pattern and tumor cell cords lying in a myxoid stroma. Immunoreactivity for the epithelial membrane antigen, desmin, smooth-muscle actin, CD68 and CD99 was found in 100, 63, 43, 100 and 100% of cases, respectively. Molecular studies provided support for the diagnosis in all seven tested cases-EWS gene translocation in six cases (partner gene being CREB1 in three and ATF1 in two in which information was available) and FUS gene translocation in one case. Comparison of the reported cases of extrasomatic angiomatoid fibrous histiocytoma with their somatic soft tissue counterparts showed a number of differences: higher mean age, slight male predominance (particularly for bone lesions), larger tumors, higher frequency of systemic symptoms, higher recurrence rate, myxoid change being more common and a much higher frequency of EWS/ATF1 gene fusion.

CUBITAL TUNNEL SYNDROME DUE TO GIANT CELL TUMOUR OF TENDON SHEATHS

Cubital tunnel syndrome is one of the most common entrapment neuropathies in adults. It is mainly caused by the depression of ulnar nerve from normal structures at the elbow area. Despite the fact that several pathgological entities can be potential mechanisms of the syndrome, the pathogenesis due to benign or malignant neoplasms is extremely rare. In the present report we describe the first case of cubital tunnel syndrome due to giant cell tumour of the tendon sheaths.

Giant cell tumor of soft tissue: Cytological diagnosis of a case

Giant cell tumors of soft tissue (GCT-STs) are rare neoplasms and are mainly seen in adults and in the elderly population, usually in the extremities. When evaluated along with clinical features, the cytological features are sufficient to distinguish GCT-STs from other more common tumors with giant cell morphology. We report here a case of a giant cell tumor of soft tissue diagnosed on the basis of fine needle aspiration cytology and confirmed after histopathology.

Treatment of tenosynovial giant cell tumor and pigmented villonodular synovitis

PURPOSE OF REVIEW

To review recent developments in the molecular pathogenesis of tenosynovial giant cell tumor (TGCT) or pigmented villonodular synovitis (PVNS) and its therapeutic implications.

RECENT FINDINGS

TGCT or PVNS is a benign clonal neoplastic proliferation arising from the synovium characterized by a minor population of intratumoral cells that harbor a recurrent translocation. These cells overexpress CSF1, resulting in recruitment of CSF1R-bearing macrophages that are polyclonal and make up the bulk of the tumor. Inhibition of CSF1R using small molecule inhibitors such as imatinib, nilotinib or sunitinib can result in clinical, radiological and functional improvement in the affected joint.

SUMMARY

Currently, surgery remains the treatment of choice for patients with TGCT/PVNS. Localized TGCT/PVNS is managed by marginal excision. Recurrences occur in 8-20% of patients and are easily managed by re-excision. Diffuse TGCT/PVNS tends to recur more often (33-50%) and has a much more aggressive clinical course. Patients are often symptomatic and require multiple surgical procedures during their lifetime. For patients with unresectable disease or multiple recurrences, systemic therapy using CSF1R inhibitors may help delay or avoid surgical procedures and improve functional outcomes.

Efficacy of imatinib mesylate for the treatment of locally advanced and/or metastatic tenosynovial giant cell tumor/pigmented villonodular synovitis

BACKGROUND

Pigmented villonodular synovitis (PVNS) (also known as diffuse-type giant cell tumor) and tenosynovial giant cell tumors (TGCT) are rare, usually benign neoplasms that affect the synovium and tendon sheaths in young adults. These tumors are driven by the overexpression of colony stimulating factor-1 (CSF1). CSF1 is expressed by a minority of tumor cells, which, in turn attract non-neoplastic inflammatory cells that express CSF1 receptor (CSF1R) through a paracrine effect.

METHODS

Imatinib mesylate (IM) blocks CSF1R, and previous case reports indicated that it also exerts antitumor activity in PVNS. The authors conducted a multi-institutional retrospective study to assess the activity of IM in patients with locally advanced/metastatic PVNS/TGCT.

RESULTS

Twenty-nine patients from 12 institutions in Europe, Australia, and the United States were included. There were 13 men, the median age was 41 years, and the most common site of disease was the knee (n = 17; 59%). Two patients had metastatic disease to the lung and/or bone. Five of 27 evaluable patients had Response Evaluation in Solid Tumor (RECIST) responses (overall response rate, 19%; 1 complete response and 4 partial responses), and 20 of 27 patients (74%) had stable disease. Symptomatic improvement was noted in 16 of 22 patients (73%) who were assessable for symptoms. Despite a high rate of symptomatic improvement and a favorable safety profile, 6 patients discontinued because of toxicity, and 4 patients decided to discontinue IM for no clear medical reason.

CONCLUSIONS

IM displayed interesting activity in patients with PVNS/TGCT, providing proof of concept for targeting CSF1R in this disease. The authors concluded that the benefits of alleviating morbidity in patients with localized PVNS/TGCT must be balanced against the potential toxicity of chronic drug therapy.

Tumors and diseases of the joint

A variety of different diseases affect the synovium, including infection, noninfectious immunologic inflammatory conditions, degenerative arthroses, crystal deposits, trauma, and tumors. Tumors of the synovium are relatively uncommon. Any mesenchymal tumor may arise in the synovium, but most recapitulate its normal counterpart including synoviocytes, blood vessels, fat, and fibrous tissue. These tumors can arise in any synovial lined structures both within joints and in extraarticular locations. Most synovial tumors are benign. Malignant tumors are rare but important to recognize because many are aggressive and must be treated appropriately. Among common nonneoplastic conditions that affect the synovium and surrounding structures are crystal deposits such as monosodium urate crystals, calcium pyrophosphate dihydrate crystals, and hydroxyapatite crystals. These crystal deposits may be asymptomatic or cause severe pain or chronic joint destruction. Their accurate identification is important to guide appropriate therapy.

Postsurgical paracicatricial cutaneous satellitosis of giant cell tumour of the tendon sheath, localized type

Tenosynovial giant cell tumour (localized type) is a tumour of tendon sheaths and interphalangeal joints, affecting the digits and arising from the synovium. It is characterized by a proliferation of mononuclear cells and osteoclast-like polykaryocytes. Its propagation to the skin is an exceptional event, which can take place either in localized form in the fingertips (localized type) or in the rare diffuse form called giant cell tumour of the tendon sheath (diffuse type). We report here a case of giant cell tumour with cutaneous satellites, which appeared close to and around the surgical scar following the excision of the primary lesion, in a 9-year-old boy. In the cutaneous satellites, a few signs of transformation could be observed, consisting of the lack of stroma and pronounced cellularity characterized by sheets of rounded synovial-like cells admixed with multinucleated giant cells and xanthoma cells. No relapse was observed 1 year after a plastic surgery procedure (complete replacement of the involved skin). Diffuse lesions usually represent a diagnostic problem in comparison with their localized counterparts. The malignant transformation of an originally typical tenosynovial giant cell tumour is a rare but well-documented event. Our case seems to represent a typical example because the pronounced cellularity might wrongly lead to a diagnosis of malignancy.

Pigmented villonodular synovitis of the temporomandibular joint: case report and review of the literature

Pigmented villonodular synovitis (PVNS) is an aggressive proliferative lesion that usually involves the synovial tissues of big joints. To date, there are ∼52 cases of PVNS affecting the temporomandibular joint reported in the English-language literature, about one-third of them exhibiting intracranial involvement. We herein describe an additional case of PVNS of the temporomandibular joint with skull base invasion affecting a 26-year-old male patient and discuss its clinicopathologic features considering previously published cases. Histopathology and imaging evaluation are important for the diagnosis of PVNS, which should be included in the differential diagnosis of preauricular aggressive swellings.

Pigmented villonodular synovitis of the distal tibiofibular joint: a case report

Pigmented villonodular synovitis (PVNS) is a proliferative disorder of the synovium. Monoarticular involvement is the more common process. This article presents a case of PVNS with rare location at the distal tibiofibular joint and discusses the current concepts of diagnosis and treatment of this disease.