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

Malignant pigmented villonodular synovitis of the temporomandibular joint with lung metastasis: a case report and review of the literature

Malignant pigmented villonodular synovitis (PVNS) is an extremely rare lesion. Approximately 30 cases of malignant PVNS have been reported to date and of these, only 1 case involved the temporomandibular joint. Owing to the rarity of well-documented cases and the heterogeneous histologic features of this group of tumors, there has been some confusion regarding its diagnosis. The heterogeneous features of the sarcomatous areas contain fibrosarcomatous, myxosarcomatous, malignant fibrous histiocytomalike or giant cell tumorlike patterns. However, despite the absence of frank sarcomatous change in the histopathogy of PVNS, there have been 3 reported cases of metastatic lesions in the lung or lymph nodes. Here we present an additional case of clinically malignant PVNS with pulmonary metastasis after recurrence. A 29-year-old man presented in our hospital with a recurrent swelling and pain in the right preauricular area, where benign tumor had been previously resected. MRI demonstrated a large mass with a low signal intensity that seemed to demonstrate a ferromagnetic effect. Surgical resection of the lesion was performed and the diagnosis of PVNS with focal atypical cells was made. Unfortunately, at 30 months post surgery, a thoracic CT found a metastatic nodule in the left lower lobe of the lung.

Malignant pigmented villonodular synovitis in the knee - report of a case with rapid clinical progression

Malignant pigmented villonodular synovitis (PVNS) (or malignant giant cell tumor of tendon sheath (GCTTS) is an extremely rare condition defined as a malignant lesion occurring with concomitant or previously documented PVNS at the same site. To date, only less than 20 cases have been reported in English literatures. We report a case of malignant PVNS in the knee in a 56-year-old woman with unpredictable rapid progression. This case raised a caution that when atypical components in specimens of recurrent benign PVNS are detected, even if low-grade or tiny, both pathologists and surgeons should consider the risk of malignant PVNS, which could display aggressive clinical progression.

[Benign soft tissue tumors in orthopedics]

For the most part soft tissue tumors are benign. However, the clinical presentation, including radiological aspects, is not always clear. Therefore, a biopsy is necessary in some cases to detect malignant tumors at an early stage. The course of even benign tumors is sometimes complicated. A not insignificant group of local, aggressive or intermediary tumors tend to recur and in exceptional cases can be fatal. Benign soft tissue tumors are subdivided according to the current WHO classification from 2002. They are classified by the tissue they mimick. In clinical practice they are additionally grouped according to aggressiveness. Some benign soft tissue tumors occur in the context of a syndrome, leading to multiple tumors. In these cases there is the threat of a tumor becoming malignant (neurofibromatosis, Maffucci syndrome).

Pigmented villonodular synovitis of the hip presenting as a buttock mass treated by total hip arthroplasty

Pigmented villonodular synovitis (PVNS) of the hip is a relatively uncommon benign but locally aggressive disease that should be considered in younger patients presenting with monoarticular joint symptoms. Pigmented villonodular synovitis begins in and usually remains confined within a synovium-lined joint, but rarely, it may extend beyond the joint capsule and present as a soft tissue mass. The authors report a previously unrecognized presentation of PVNS of the hip in a 36-year-old man, who presented with a buttock mass arising from the right hip joint. The patient was treated by synovectomy and total hip arthroplasty.

Tenosynovial giant cell tumors as accidental findings after episodes of distortion of the ankle: two case reports

INTRODUCTION

Tenosynovial giant cell tumors are benign tumors of uncertain pathogenesis. They occur in the joints, tendons and synovial bursas. Due to a high recurrence rate of up to 50%, some authors call a giant cell tumor a semimalignant tumor. To date, less than 10 cases of tenosynovial giant cell tumor of the ankle have been published in the international medical literature.

CASE PRESENTATION

In this case report, we present two patients with localized tumors that were detected accidentally after the occurrence of ankle sprains with persisting pain in the joint. The tumors were resected by open marginal surgery and regular follow-up examinations were carried out.

CONCLUSIONS

We present an unusual occurrence of a tumor along with a possible follow-up strategy, which has not been previously discussed in the international literature.

Giant cell tumour in the tendon sheath of the hand: Importance of the type of lesion

There are more diffuse giant cell tumours of the tendon sheath than we had expected, and we recommend excising them microscopically. We have treated 18 patients since 1988. They had two types of tumour: 10 nodular, and eight diffuse. We used a microscope to excise diffuse tumours. In the only case in which we did not use a microscope for a diffuse tumour, the tumour recurred. It spread to an adjacent joint in six diffuse tumours, but no nodular tumours. The detection of diffuse lesions was difficult without a microscope.

Pigmented villonodular synovitis: radiologic-pathologic correlation

Pigmented villonodular synovitis (PVNS) represents an uncommon benign neoplastic process that may involve the synovium of the joint diffusely or focally (PVNS) or that may occur extraarticularly in a bursa (pigmented villonodular bursitis [PVNB]) or tendon sheath (pigmented villonodular tenosynovitis [PVNTS]). Pathologic specimens of the hypertrophic synovium may appear villous, nodular, or villonodular, and hemosiderin deposition, often prominent, is seen in most cases. The knee, followed by the hip, is the most common location for PVNS or PVNB, whereas PVNTS occurs most often in the hand and foot. PVNTS is also referred to as giant cell tumor of the tendon sheath (GCTTS). PVNTS is the most common form of this disease by a ratio of approximately 3:1. Radiographs reveal nonspecific features of a joint effusion in PVNS, a focal soft-tissue mass in PVNB or PVNTS, or a normal appearance. Extrinsic erosion of bone (on both sides of the joint) may also be seen and is most frequent with intraarticular involvement of the hip (>90% of cases). Cross-sectional imaging reveals diffuse involvement of the synovium (PVNS), an intimate relationship to the tendon (PVTNS), or a typical bursal location (PVNB), findings that suggest the diagnosis. However, the magnetic resonance (MR) imaging findings of prominent low signal intensity (seen with T2-weighting) and "blooming" artifact from the hemosiderin (seen with gradient-echo sequences) are nearly pathognomonic of this diagnosis. In addition, MR imaging is optimal for evaluating lesion extent. This information is crucial to guide treatment and to achieve complete surgical resection. Recurrence is more common with diffuse intraarticular disease and is difficult to distinguish, both pathologically and radiologically, from the rare complication of malignant PVNS. Recognizing the appearances of the various types of PVNS, which reflect their pathologic characteristics, improves radiologic assessment and is important for optimal patient management.

Pigmented villonodular synovitis of the temporomandibular joint: a rare tumor of the temporal skull base

Musculoskeletal tumors are not usually encountered at the skull base. Benign lesions such as cholesterol granuloma, cholesteatoma, fibrous dysplasia, and Paget disease are common examples of such tumors arising from the bone of the cranial base. The authors report a case involving an adult male patient with the rare finding of pigmented villonodular synovitis of the temporomandibular joint. This case is reported as an example of another lesion to consider in the differential diagnosis. Due to the complexity of the anatomy at the cranial base, radical resection as recommended for the usual sites of occurrence in major joints is problematic. Because of the reported high recurrence rates at other sites, as radical excision as possible with vigilance for recurrence is recommended.

Infiltration of the pes anserinus complex by an extraarticular diffuse-type giant cell tumor (D-TGCT)

This report describes the case of a 26-year-old woman with a recurrent extraarticular diffuse-type tenosynovial giant cell tumor (D-TGCT) of the medial region of the knee affecting the pes anserinus and hamstring tendons. Presurgical MRI did not exclude infiltrative properties of the tumor. In the histological evaluation, the tumor showed an aggressive dispersion by infiltrating the collagenous tissue of the hamstring tendons. The treatment included a resection of the pes anserinus complex with distal semitendinosus and gracilis tendons. Regarding extraarticular D-TGCT a review of the literature showed a predominant affection of the medial region of the knee and thigh.

Multicentric diffuse-type giant cell tumor of the hand

Diffuse-type giant cell tumor (D-TGCT) is relatively rare. We report a case of multicentric D-TGCT located in the finger and wrist. A 79-year-old man presented with a more than two-year history of tumors. Marginal resection was performed. Histological study of the specimens disclosed D-TGCT. Recurrence occurred two years and five months postoperatively and was again excised. Clinical presentation, radiological features and histopathological findings are discussed with reference to the literature.

The value of sonography in diagnosing giant cell tumors of the tendon sheath

OBJECTIVE

The purpose of this study was to evaluate the diagnostic value of sonography in giant cell tumors of the tendon sheath.

METHODS

Sonographic findings and other clinical records were retrospectively reviewed and analyzed in 30 patients (45 lesions) with pathologically proven giant cell tumors of the tendon sheath. The sonographic findings were compared with those found at surgery.

RESULTS

The locations of the tumors included the hand (53.33%), wrist (10%), elbow (3.33%), knee (10%), and foot (23.33%). The sizes of the tumors ranged from 0.4 to 8 cm, with a mean size of 2.6 cm. All the lesions were shown as hypoechoic nodules with homogeneous or heterogeneous echogenicity. Thirty-two lesions (71.11%) had substantial flow, and 13 lesions (28.89%) had minimal flow. Thirty-four lesions were in contact with the tendon sheath; 5 were in contact with the joint; and 6 were in contact with both the tendon sheath and the joint. Bone erosions were found in 4 cases, and bone impressions were found in another 3 cases.

CONCLUSIONS

Sonography can provide exact information about a tumor and its relationship with the surrounding tissue, which indicates that it can be used as the first method to diagnose a giant cell tumor of the tendon sheath.

Diffuse-type giant cell tumor/pigmented villonodular synovitis arising in the sacrum: Malignant form

Diffuse-type giant cell tumor (GCT)/pigmented villonodular synovitis (PVNS) in the axial skeleton or spine is rare. Herein is reported a case of diffuse-type GCT/PVNS involving the sacrum and the fifth lumbar vertebra, in which the patient developed regional lymph node swelling after recurrence. The recurrent tumor was found to have atypical histological features such as spindle cell morphology, cytological atypia and high mitotic rate, which are compatible with the diagnostic criteria of secondary malignant diffuse-type GCT/PVNS. Although the nodal lesions were not sampled histologically, the clinical and histological features indicate that the current case is an example of malignant diffuse-type GCT/PVNS. This case is considered to be the first case of malignant diffuse-type GCT/PVNS in the spine, because no such lesions have been previously reported in the axial skeleton or spine. Careful surveillance should be required for diffuse-type GCT/PVNS arising at unusual site.

Extraarticular paravertebral diffuse-type giant cell tumor

A diffuse-type giant cell tumor (DGCT) of the paravertebral region is a rare condition characterized by an ill-demarcated mass with facet joint involvement. We describe a case of extra-articular DGCT of the paravertebral cervical region without association to the facet joint. A 51-year-old male presented with a headache. Diagnostic imaging showed a dumbbell-shaped mass with enlargement of the right intervertebral foramen between C6 and C7. The tumor was completely resected in multiple fragments with the suspicion that it was a schwannoma. Histologically the tumor consisted chiefly of mononuclear histiocytoid cells, foamy macrophages and multinucleated giant cells, which led to a diagnosis of DGCT. The case alerts one to be aware that DGCT may originate from a paravertebral location as a soft-tissue mass without facet joint involvement.

Diffuse-type giant cell tumor of the subcutaneous thigh

Diffuse-type giant cell tumor is an extra-articular form of pigmented villonodular synovitis. The localized form of this lesion (tenosynovial giant cell tumor) is frequent, representing the most common subset arising from the synovium of a joint, bursa or tendon sheath, with 85% of cases occurring in the fingers. The less frequent diffuse-type giant cell tumors are commonly located in the periarticular soft tissues, but on rare occasions these lesions can be purely intramuscular or subcutaneous We report the case of a 26-year-old female with diffuse-type giant cell tumor of the subcutaneous thigh, remote from a joint, bursa or tendon sheath. A review of the literature did not reveal any similar description of a diffuse-type giant cell tumor completely within the subcutaneous thigh, remote from a joint, bursa or tendon sheath. These lesions were initially regarded as inflammatory or reactive processes, but since the identification of clonal abnormalities in these patients, and in view of their capacity for autonomous growth, they are now widely considered to represent benign neoplasms.

Intramuscular diffuse-type giant cell tumor within the hamstring muscle

Diffuse-type giant cell tumor (D-TGCT) is known as a synonym for pigmented villonodular synovitis (PVS), a condition usually found in the large joints. We report an extremely rare case of D-TGCT which was located within the hamstring muscle. The lesion was an incidental finding in a 62-year-old man who underwent positron emission tomography (PET) as part of a staging evaluation for gastric cancer. The lesion was resected. There has been neither metastasis nor recurrence during the 6-month period since resection. This case demonstrates that PVS/D-TGCT may have a high SUV on PET imaging, and for this reason PET may be useful for detecting both the tumor and any recurrence.

A rare presentation of pigmented villonodular synovitis

Tenosynovial giant cell tumours are of two types, localised and diffuse. The diffuse type is also known as pigmented villonodular synovitis (PVNS). There have been 42 previously reported cases of PVNS in the axial skeleton, seven of which were reported in the thoracic spine. A young patient found to have thoracic PVNS and who presented with progressive lower limb weakness and parasthesiae over 3 weeks is reported. Computed tomography and magnetic resonance imaging demonstrated a posterior lesion at T6/7 with local bone invasion. The patient underwent complete resection of the tumour and has had an unremarkable postoperative convalescence with resolution of his signs and symptoms. Total surgical resection is the treatment of choice for this condition and close postoperative follow-up with serial imaging is important to monitor for local recurrence.

External beam radiotherapy as postoperative treatment of diffuse pigmented villonodular synovitis

PURPOSE

Diffuse pigmented villonodular synovitis is a rare proliferative disorder of synovial membranes with invasive and expansive growth patterns. Radical synovectomy is regarded as the treatment of choice. However, because of the high recurrence rates, additive treatment might be useful. Radiotherapy (RT) has been evaluated with positive results, but the optimal treatment schedules are vague. We have reviewed our experience with postoperative RT in cases of suspected or proven residual disease.

METHODS AND MATERIALS

Between December 1996 and January 2006, 7 diffuse pigmented villonodular synovitis patients underwent RT at our institution. The most common location was the knee joint (5 patients). All patients underwent radical surgery and were treated subsequently with 6-MV photon RT. The total doses applied were 30-50 Gy, depending on the resection status and estimated risk of relapse. For analysis, we retrospectively reviewed all patients in April 2006.

RESULTS

The mean follow-up time was 29 months (range, 3-112 months). RT had no acute adverse effects. At the assessment, no evidence was found of recurrent or persisting disease in any patient. Of the 7 patients, 6 reported asymptomatic limb function and excellent quality of life; 1 patient had persistent restriction of joint movement after repeated surgery. No radiotherapeutic late effects were seen.

CONCLUSION

The results of our series have confirmed the efficacy and safety of postoperative RT for diffuse pigmented villonodular synovitis. Hence, this treatment should be considered for patients with suspected or proven residual disease.

What affects the recurrence and clinical outcome of pigmented villonodular synovitis?

Studies investigating the outcome of pigmented villonodular synovitis have been restricted to certain locations or types of the disease and have not provided adequate documentation of followup. We asked the following questions: What were the recurrence rates especially when considering location and type of pigmented villonodular synovitis?; What was the long-term clinical outcome?; and Was MR imaging essential for the correct diagnosis? We retrospectively reviewed 42 of 53 consecutive patients primarily treated at our institution (19 diffuse lesions and 23 nodular lesions in 19 large joints and 23 digits of the hands or feet). Ten patients had recurrences after an average followup of 80 months (range, 26-293.8 months). Recurrences were more frequent for the diffuse type than the nodular type and in large joints rather than in digits. The average Enneking score was 92% of normal limb function indicating that surgical treatment led to good functional results. Preoperative magnetic resonance imaging results corresponded well with histologic diagnoses and intraoperative findings.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Pigmented villonodular synovitis of the foot and ankle: Forty years of experience from the Scottish bone tumor registry

Fourteen cases of pigmented villonodular synovitis (PVNS) of the foot and ankle accrued from the Scottish Bone Tumor Registry are presented with an average follow-up of 4.6 years. This study analyzed the clinical, radiological, and histopathological features and investigated their clinical behavior and the factors influencing recurrence. The mean age of the patients was 26.4 years (range, 8-52 years). There were 8 women and 6 men. The mean delay in presentation was 10.3 months. The anatomical sites were phalanges (n = 2), tarso-metatarsal area (n = 3), and hindfoot (n = 9) (6 extraarticular soft tissue swellings around the ankle, 2 ankle, 1 subtalar joint). Eight (57.1%) cases presented with a painless lump, 5 (35.7%) patients had painful masses, and 1 case had a lump associated with toe deformity. Peri-articular tissue invasion and cortical infiltration were found in one third on plain films. Magnetic resonance imaging findings were suggestive of synovial sarcoma in 2 cases because of extensive low-signal soft tissue hypertrophy and bone erosion. Excision of the lump was performed in 4 cases with a complete recovery. Phalangeal lesions were treated with toe amputation through the metatarsophalangeal joint, and no cases had recurrence. There were 2 recurrences affecting the ankle and the subtalar joint. There was a 14.3% recurrence rate, while complete recovery was achieved in 85.7% cases (12/14). A high index of suspicion for PVNS should be observed for cases presenting with a painless or painful mass in the foot and ankle region. Complete recovery can be achieved in the majority by complete excision. Toe amputation may be considered for foot phalangeal PVNS.

Diffuse-type tenosynovial giant cell tumor in association with neurofibromatosis type 1-Noonan syndrome: possibly more than a chance relationship

A case of diffuse-type tenosynovial giant cell tumor arising in the left upper extremity is reported in a 23-year-old man with neurofibromatosis type 1 (NF1)-Noonan syndrome. The predominately mononuclear cellular proliferation with psammomatous calcifications had the immunohistochemical and ultrastructural features of a fibrohistiocytic neoplasm. This uncommon type of soft tissue neoplasm occurring in this unique clinical setting served to open an inquiry into the subject of non-neurogenic tumors in association with NF1 and Noonan syndrome, both manifested in our patient. Nonossifying fibroma of bone as a presumptive fibrohistiocytic tumor is an uncommon but well-documented manifestation in NF1, whereas in Noonan-like syndrome, both giant cell granuloma and pigmented villonodular synovitis are recognized as associated lesions with histologic and immunophenotypic similarities with the diffuse-type tenosynovial giant cell tumor.

Pigmented villonodular synovitis of the hip mimicking soft-tissue sarcoma: a case report

Pigmented villonodular synovitis is a rare and benign but potentially locally aggressive disease that should be considered in younger patients who present with monoarticular joint symptoms and pathology. We present a 30-year-old Sudanese woman with a huge mass arising from the right hip joint. A multimodality radiological approach to investigation and diagnosis is demonstrated and discussed. Histopathological examination of the resected specimen confirmed the diagnosis of pigmented villonodular synovitis with the mass consisting of a proliferation of fibrohistiocytic cells, abundant haemosiderin, foamy histiocytes, and occasional giant cells. The patient made a good recovery, with mobility aided by arm crutches and a hip abduction brace.

Tenosynovial giant cell tumour of the neck

We report the case of a diffuse tenosynovial giant cell tumour to be found adjacent to the thyroid gland. These tumours, also known as extra-articular pigmented villonodular synovitis, are found more commonly in the fingers, wrist, knee thigh and foot, rarely in the head and neck. These tumours are prone to local recurrence, require a high clinical index of suspicion and if they have atypical features may be extremely difficult to obtain a histological diagnosis.

Pigmented villonodular synovitis

Pigmented villonodular synovitis is a benign proliferative lesion of the synovium with unclear etiology. It is a locally aggressive lesion that may invade and destroy surrounding bone and soft tissues and represents a high rate of recurrence despite aggressive treatment modalities. This article describes the new developments in etiology and outlines current approaches for diagnosis and treatment.

Recurrence potential of diffuse-type giant cell tumor in the foot: radiologic and pathologic features

BACKGROUND

Aggressive musculoskeletal tumors in the foot, such as diffuse-type giant cell tumors or extra-abdominal desmoid tumors, are difficult to treat because the foot does not have enough soft tissue to allow wide tumor resection. We reviewed the clinical behavior of diffuse-type giant cell tumor in the foot and evaluated the recurrence potential of these tumors from radiologic and pathologic perspectives.

METHODS

Six patients with a mean age of 37.6 years were included in this study. Radiologic studies, including sonography, computed tomography (CT), magnetic resonance imaging (MRI), and bone and gallium citrate scintigraphy, were obtained followed by surgical treatment and histologic evaluation of the tumor.

RESULTS

Recurrence occurred in three patients. Although CT and MRI findings were similar in the recurrent and nonrecurrent tumors, marked differences were found between the two by scintigraphy; positive radiotracer uptake to the affected foot with gallium citrate scintigraphy was noted only in recurrent tumors, although positive accumulation was seen in all patients with bone scintigraphy. Histologically, the necrotic area and mitotic activity were more apparent in recurrent than in the nonrecurrent tumors, and tumor cell dyscohesion was noted in the former, (the intercellular space was increased).

CONCLUSIONS

Repeated recurrence with tumor invasion into tarsal bone resulted in breakage of the tarsal arch that supports the body's weight. Amputation would be necessary for patients in whom the disease had progressed to obtain local cure and relief of pain. In the present study, we found two features of the recurrence potential of diffuse-type giant cell tumors: sparse cell to cell contact on pathologic examination and positive accumulation in the tumor on gallium citrate scintigraphy. We concluded that giant cell tumors with these two features have a strong potential for local recurrence, and thus require intensive followup.

Molecular cytogenetic characterization of tenosynovial giant cell tumors

Tenosynovial giant cell tumor (TSGCT) is a disease of disputed etiology and pathogenesis. Some investigations indicate a neoplastic origin of the tumors; others indicate that they are polyclonal and inflammatory. The cytogenetic and molecular genetic features of TSGCTs are largely unknown, as only some 20 localized and 30 diffuse tumors with cytogenetic aberrations have been reported. The most common karyotypic aberrations have been trisomy for chromosomes 5 and 7 and translocations involving chromosomal area 1p11-13. We decided to screen the genomes of TSGCTs by comparative genomic hybridization (CGH) to perform interphase fluorescence in situ hybridization (IP-FISH), looking for numerical aberrations of chromosomes 1, 5, and 7, and to analyze the tumors for microsatellite instability. Except for two diffuse TSGCTs that came fresh to us, and which, by karyotyping, exhibited t(1;22)(p13;q12) and a t(1;1)(q21;p11) and +7, respectively, all studies had to be performed on formalin-fixed, paraffin-embedded material. DNA was extracted from 51 localized and nine diffuse TSGCTs. CGH was successful for 24 tumors, but none of them showed copy number changes. The IP-FISH studies showed trisomy 7 in 56% of the tumors (15/27), whereas chromosomes 1 and 5 seemed to be disomic in all TSGCTs. All informative tumors were wild-type by microsatellite instability analysis.

Tenosynovialer Riesenzelltumor

Morphological, ultrastructural, and immunohistochemical findings of 12 diffuse type-tenosynovial giant cell tumors/pigmented villonodular synovitis are presented compared to 30 localized tenosynovial giant cell tumors (giant cell tumor of tendon sheath). Diffuse-type-tenosynovial giant cell tumor is characterized by a striking vascularisation pattern composed of densely arranged thin-walled, partly slit-like and partly hyalinized small blood vessels within the papillary synovial fronds. These vessels may show abnormal structures with incompletely arranged endothelial cells/pericytes. The fibrohistiocytic tumor cells probably cause considerable compression/distortion or destruction of the small vessels which might be responsible for an increased blood deposition and massive hemosiderosis. Accompanying multinucleated osteoclast-like giant cells seemingly are recruited from circulating blood monocytes. Microhemorrhagic foci with multinucleated giant cells could be detected in 83% of diffuse-type and 67% of localized-type tumors. Apart from the described vessels, typical morphological findings in diffuse-type tenosynovial giant cell tumors included "giant" hemosiderotic granules, (at least 2-3 times the diameter of an erythrocyte) "giant" siderophages, pseudoalveolar clefts and irregularly anastomosing synovial fronds. Neither mitotic rate nor the amount of giant cells/amount of nuclei of giant cells revealed statistically significant differences between localized-type and diffuse-type of tenosynovial giant cell tumor. Immunohistochemically, the diffuse-type exhibited focal expression of CD31 (in 75% of tumors) and calretinin (in 63%) besides CD68-staining.

Increased expression of humanin peptide in diffuse-type pigmented villonodular synovitis: implication of its mitochondrial abnormality

OBJECTIVES

To define the pathogenesis of pigmented villonodular synovitis (PVNS), by searching for highly expressed genes in primary synovial cells from patients with PVNS.

METHODS

A combination of subtraction cloning and Southern colony hybridisation was used to detect highly expressed genes in PVNS in comparison with rheumatoid synovial cells. Northern hybridisation was performed to confirm the differential expression of the humanin gene in PVNS. Expression of the humanin peptide was analysed by western blotting and immunohistochemistry. Electron microscopic immunohistochemistry was performed to investigate the distribution of this peptide within the cell.

RESULTS

68 highly expressed genes were identified in PVNS. Humanin genes were strongly expressed in diffuse-type PVNS, but were barely detected in nodular-type PVNS, rheumatoid arthritis, or osteoarthritis. Humanin peptide was identified in synovium from diffuse-type PVNS, and most of the positive cells were distributed in the deep layer of the synovial tissue. Double staining with anti-humanin and anti-heat shock protein 60 showed that humanin was expressed mainly in mitochondria. Electron microscopy disclosed immunolocalisation of this peptide, predominantly around dense iron deposits within the siderosome.

CONCLUSIONS

Increased expression of the humanin peptide in mitochondria and siderosomes is characteristic of synovial cells from diffuse-type PVNS. Humanin is an anti-apoptotic peptide which is encoded in the mitochondrial genome. Present findings suggest that mitochondrial dysfunction may be the principal factor in pathogenesis of diffuse-type PVNS and that humanin peptide may play a part in the neoplastic process in this form of PVNS.

Arthroscopic excision of juxta-articular giant-cell tumor arising from the patellar tendon sheath

Most giant-cell tumors of the tendon sheath are found on the flexor surface of the hand, in the fingers, wrist, or palm. The isolated discrete lesion involving tendon sheaths (localized giant-cell tumor of the tendon sheath) is rarely located intra-articularly, especially in the knee joint. To the best of my knowledge, this is the first reported case of a large, localized, juxta-articular giant-cell tumor of the patellar tendon sheath that was treated successfully with arthroscopic excision.

Immunohistochemistry in the diagnosis of soft tissue tumours

Immunohistochemistry is particularly important in the field of soft tissue tumours because of their variety and the frequent difficulty of diagnosis. The first part of this paper discusses useful or new antibodies, together with others that are no longer of use. The second part is devoted to the role of immunohistochemistry in the diagnosis of soft tissue tumours: identification of some rare or atypical benign lesions, identification of non-mesenchymal malignant tumours, and classification of sarcomas. The respective roles of immunohistochemistry and molecular biology are underlined.

Fine-needle aspiration cytology of chondroblastoma of soft parts: case report and differential diagnosis with other soft tissue tumors

Chondroblastoma is a benign tumor arising in the epiphysis of long bones. The extraskeletal presentation is most unusual. We report the first cytological description of a soft tissue chondroblastoma. It was a subcutaneous mass in the leg of a 62-yr-old man. Fine-needle aspiration (FNA) rendered a highly cellular material with grouped and single polygonal or round cells with a uniform, sometimes eccentric nucleus. Microvacuolated cytoplasm and hemosiderin pigment were frequent findings. There were rare nuclear grooves and mitoses. A metachromatic, focally calcified stroma was present, occasionally surrounding the cells. There were also numerous multinucleated osteoclast-like giant cells. Histological evaluation was diagnostic of chondroblastoma. The tumor was locally aggressive. A review of other soft tissue masses with similar cytological findings is included in the discussion. FNA cytology is very helpful in the diagnosis of soft tissue chondroblastoma, but additional studies may be necessary for a definitive diagnosis.

Fine-needle aspiration cytology of articular and periarticular lesions

BACKGROUND

The cytologic diagnosis of joint and articular surface-based lesions traditionally has been accomplished by examination of fluids or effusions. Although exfoliative cytology remains an accurate diagnostic test, not all joint-based lesions will produce effusions that are amenable to this type of examination. Fine-needle aspiration (FNA) represents an excellent alternative to traditional cytologic or histologic methods of diagnosis in joint pathology.

METHODS

The authors reviewed FNA materials for the period 1992-2001 from lesions of joint spaces and periarticular soft tissues. All diagnoses based on cytologic materials that were included in this study were confirmed with histologic follow-up. Cytologic and histologic materials were prepared using standard methods.

RESULTS

The authors found six relatively common lesions that were amenable to diagnosis by FNA. These included rheumatoid nodule, gouty tophi, ganglion cysts, pigmented villonodular synovitis, synovial chondromatosis, and synovial sarcoma. There are potential pitfalls in discriminating gout from pseudogout and synovial chondromatosis from chondrosarcoma.

CONCLUSIONS

In most instances, mass-producing lesions of the joint space or the periarticular soft tissues can be diagnosed successfully by FNA. The common lesions are easily recognizable and are cytologically distinctive.

Benign fibrohistiocytoma (xanthomatous variant) of the acromion. A case report and review of the literature

A number of fibrous lesions involving bone display almost identical histologic appearances yet may represent either reactive or neoplastic conditions, resulting in a confusing nomenclature and possible diagnostic confusion. We report the case of a young man with no significant previous medical history who presented with a painful lesion in the left shoulder, which consisted almost entirely of xanthomatous material. We discuss the possible differential diagnosis of this lesion and why benign fibrous histiocytoma is the preferred terminology for this lesion. To our knowledge, this is the first reported case of a benign fibrous histiocytoma involving the acromion in an adult.

Fine-needle aspiration biopsy diagnosis of "invasive" temporomandibular joint pigmented villonodular synovitis

The clinical and aspiration cytologic details of a case of temporomandibular joint pigmented villonodular synovitis are presented and correlated with imaging, surgical, histopathologic, and clinical follow-up findings; the origin of such lesions is discussed. The lesion originally presented in a 36-year-old, otherwise healthy, white man as a unilateral mass involving the temporal fossa and temporomandibular joint region. The tumor's extent was defined by magnetic resonance imaging and computed tomographic scan; there was destruction of the temporomandibular joint and erosion of the temporal cranial bones by a lesion whose maximum dimensions were estimated by imaging to be 2.75 x 3.25 cm. The lesion was initially sampled and classified by computed tomography-guided fine-needle aspiration biopsy. Following complete resection, the original diagnosis was confirmed with both hematoxylin-eosin-stained paraffin sections and immunohistochemical staining. The patient remains free of disease 7 years postoperatively.