Fibroma of tendon sheath

Equine non-septic tenosynovitis: A systematic literature review of site-specific pathological lesions, outcomes and surgical complications

BACKGROUND

Non-septic tenosynovitis is a clinically relevant and often performance limiting musculoskeletal injury in the horse.

OBJECTIVES

To review the published literature to determine which tendon sheaths are commonly affected by non-septic tenosynovitis and to describe the most frequently reported pathological lesions, outcomes, and surgical complications in equine non-septic tenosynovitis.

STUDY DESIGN

Systematic review.

METHODS

Literature searches were conducted in July 2021 from the online search engines PubMed, Scopus, Web of Science Core, VetMed Resource and ProQuest Theses & Dissertations. The inclusion criteria followed a participants, interventions, comparisons, outcome and study design (PICOS) approach. For inclusion, studies had to include live equids with non-septic tenosynovitis of any tendon sheath. Studies were excluded if they only described non-equine species, if they included data only on non-tendon sheath structures, or if they included data exclusively on cases of septic or contaminated tendon sheaths. Determination of non-sepsis relied on the diagnosis of the original authors; however, if non-sepsis was not explicitly specified, then cases that had a history of contamination of the sheath, a wound near the sheath or a positive bacterial culture were excluded from analysis. Data analysed included the distribution of structures affected by non-septic tenosynovitis, the most common pathological lesions identified within each sheath, and the most frequently reported surgical complications of non-septic tenosynovitis. The quality of each study was assessed using a methodological quality analysis.

RESULTS

A total of 85 studies describing non-septic tenosynovitis in the horse were included. Across all 85 studies, there were a total of 2449 tendon sheaths in 2101 horses reported to be affected by non-septic tenosynovitis. The digital flexor sheath was the most reported structure to be diagnosed with non-septic tenosynovitis: 41/85 (48%) studies examined the digital flexor sheath exclusively, followed by the carpal flexor sheath, tarsal flexor sheath, carpal extensor sheaths, tarsal extensor sheaths, and one case of biceps brachii non-septic tenosynovitis. For most tendon sheaths, the most common pathological lesion was an intrathecal tear of a soft tissue structure, including tears of the deep digital flexor tendon and tears of the manica flexoria. Bilateral disease was most common in the carpal flexor sheath, where distal radial physeal exostoses were the most common pathological lesions. Less common causes of non-septic tenosynovitis included neoplasia, fracture of a bone adjacent to a tendon sheath, and mineralisation of an intrathecal tendon. The likelihood of return to previous level of athletic function following non-septic tenosynovitis of most structures was approximately 50%, and the most common complication was persistent effusion following tenoscopy. While iatrogenic infection following surgery was uncommon, it was most likely following tenoscopy of the digital flexor sheath.

CONCLUSION

Non-septic tenosynovitis is commonly reported in equine athletes, with intra-thecal tears of the deep digital flexor tendon, superficial digital flexor tendon and manica flexoria frequently reported. Directions for future research include more thorough assessment of and reporting of complications following non-septic tenosynovitis and correlation of characteristics of intrathecal pathological lesions with clinical outcomes.

Arthroscopic treatment for intra-articular fibroma of the tendon sheath in a teenager

An adolescent female patient presented with atraumatic left knee pain and limited flexion. MRI demonstrated evidence of a soft tissue lesion abutting the posterior cruciate ligament. Differential diagnosis included pigmented villonodular synovitis (PVNS) and fibroma of the tendon sheath (FTS). Following arthroscopic biopsy, histopathological evaluation confirmed FTS. The tumour was then excised via an arthroscopic approach. This case report provides a unique example of FTS abutting the cruciate ligaments in an uncommonly young female patient. It highlights the importance of including benign processes, such as FTS, in the differential with more aggressive-type diagnoses like PVNS. Furthermore, this case exemplifies an appropriate surgical indication for FTS. Finally, it emphasises the importance of communication and collaboration among orthopaedic subspecialists in providing safe and effective arthroscopic treatment of this unique tumour presentation.

Fibroma of tendon sheath is defined by a USP6 gene fusion-morphologic and molecular reappraisal of the entity

Fibroma of tendon sheath (FTS) is an uncommon benign myofibroblastic neoplasm that arises in association with tenosynovial tissue. Fusions of the USP6 gene have been recently documented in a proportion of so-called "cellular FTS" but not in "classic FTS". It remains unknown whether FTS can be defined by a USP6 fusion, regardless of cellularity, and what are USP6 fusion-negative "cellular FTS". Furthermore, FTS with low cellularity seems to be frequently confused with desmoplastic fibroblastoma. We performed a comprehensive analysis, including targeted RNA sequencing, of 58 consecutive cases originally diagnosed as FTS (n = 49), desmoplastic fibroblastoma (n = 6), or nodular fasciitis (n = 3); the latter two at the predilection sites for FTS. After review of the original slides, 28 lesions were morphologically classified as FTS (13 "classic" and 15 "cellular") and 23 as desmoplastic fibroblastoma. Among originally diagnosed FTS at the more cellular end of the spectrum, we identified seven lesions that shared many morphologic features of FTS but, in addition, showed several distinct morphologic features consistent with myofibroma, such as myoid appearance, branching thin-walled vessels, and perivascular growth. Targeted RNA sequencing showed a USP6 fusion in 17 of 18 analyzed FTS, regardless of cellularity, 0 of 5 desmoplastic fibroblastomas and 0 of 4 myofibromas. MYH9, COL1A1, and ASPN were identified as fusion partners in three cases each, and MIR22HG, CTNNB1, SPARC, CAP1, EMP1, LINC00152, NR1D1, and RAB1A in a single case each. FTS, regardless of cellularity, can be defined by a USP6 fusion with a variety of fusion partners. More cellular lesions exhibiting some morphologic features of FTS but lacking a USP6 fusion tend to be myofibromas.

Characterization of novel USP6 gene rearrangements in a subset of so-called cellular fibroma of tendon sheath

Fibroma of tendon sheath (FTS) is an uncommon benign fibroblastic/myofibroblastic neoplasm that typically arises in the tenosynovial tissue of the distal extremities. Histologically, it is a well-circumscribed proliferation of spindle cells within collagenous stroma with peripheral slit-like vessels. Most examples are relatively hypocellular and more densely collagenous than nodular fasciitis; however, a cellular variant has been described, which has considerable morphologic overlap with nodular fasciitis and has been shown to harbor USP6 translocations in a subset of cases. The incidence of these rearrangements and the identity of the USP6 fusion partners have not been described in detail. In this study we evaluate 13 cases of cellular fibroma of tendon sheath by anchored multiplex PCR/next generation sequencing in order to detect potential gene fusions. Nucleic acids of adequate quality were obtained in 11 cases, demonstrating gene fusions in 7/11 (64%), all of which involve USP6 with a variety of partners, including PKM, RCC1, ASPN, COL1A1, COL3A1, and MYH9. Some unusual histomorphologic findings were present in a subset of cases including palisading growth pattern, epithelioid cells, and osteoclast-like multinucleated giant cells, particularly in the tumors with PKM and ASPN gene partners. Overall, the findings support a biologic relationship between cellular fibroma of tendon sheath and other lesions within the spectrum of USP6-rearranged neoplasms, particularly nodular fasciitis.

Fibroma of the tendon sheath of the neck

INTRODUCTION

Fibroma of the tendon sheath (FTS) is a rare benign tumour typically occurring in the extremities, but very rarely involving in the neck.

CASE REPORT

A 22-year-old male presented with a large painless mass of the right oropharynx. Magnetic resonance imaging (MRI) showed a well-circumscribed 7cm lesion in the right prestyloid space. The lesion was completely removed surgically. Histopathological examination revealed a fibroma of the tendon sheath of the stylohyoid muscle.

DISCUSSION

These tumours generally arise in the extremities of adults. To our knowledge, this is the first reported case of FTS in the neck.

Is the Recurrence of Fibroma of the Tendon Sheath Underestimated? An Instructive Case Report and a Review of the Literature

We report a case of a 21-year-old healthy woman with a history of a painful growing mass in the palm of the right hand, with a trigger finger phenomenon. The mass was surgically entirely excised, and the histological findings of the tumor were those of a fibroma of the tendon sheath (FTS) starting from the flexor tendons. Although the initial outcome was good, the patient experienced the same symptoms at the same location 4.5 years later. The MRI demonstrated a 50 × 10 × 5 mm mass of low intensity on T1-weighted images and high intensity on T2-weighted images and gadolinium enhancement. A second complete excision of the tumor was performed by the same senior surgeon, and the histology confirmed the recurrence of the FTS. We also reviewed the scientific literature about FTS in the hand. Most recent studies show a low rate or no recurrence at all. We hypothesize that a lot of recurrences are missed because of a short follow-up and that the recurrence rate may be higher than thought.

Surgery on aggressive fibroma of the posterior compartment of the knee: A case report

INTRODUCTION

Fibroma is a benign tumor. More than 99% fibroma arises from tendon sheaths or tendons. Aggressive Fibroma at posterior compartment knee is a rare case. This report presents one case of fibroma at posterior compartment of the knee with the treatment.

CASE REPORT

A boy with 4-year history of knee discomfort and lump at posterior knee joint, no history of infection and trauma. Physical examination revealed a mass (10 × 9 × 7 cm) with limited Range of Motion extension 30°, flexion 70°. MRI revealed a soft tissue mass at posterior knee compartment. Histologic examination showed a circumscribed and lobulated hypo cellular mass containing spindle cells diagnosed as aggressive fibroma. The patient underwent popliteal resection. An ellipse incision was made 2 cm margin of skin around the biopsy site. Fasciocutaneous flaps were created and retracted to expose the posterior compartment. The tumor had a partial well-defined capsule, popliteal artery and vein embedded and pressing the sciatic nerve. The tumor and enveloping muscles were elevated from the base of the compartment. The sciatic nerve was preserved with epineurotomy. The popliteal artery was reconstructed with saphenous veins graft. After the tumor was resected, the heads of gastrocnemius were sutured to each other and to the hamstring muscles to cover popliteal space. After one year postoperative, there was a good vascularization, no recurrence and neurological deficit with Musculoskeletal Tumour Society Scoring System 80%.

CONCLUSION

One year postoperative with popliteal resection surgery yields a good result. A follow-up is needed for risk of recurrence and malignancy.

Fibroma of the patellar tendon sheath-a rare case in a young boy

Fibroma of the tendon sheath is a rare benign fibrocollagenous soft tissue tumor, arising predominantly from the synovium of tendon sheath. Fibromas occur most commonly in relation to the tendons of the fingers, hand, and the wrist. Fibromas related to large joints are rather rare and though amongst the large joints, the knee is a common site. Fibromas of the patellar tendon sheath, specifically, are very rare. To the best of our knowledge, only three cases of fibromas arising from the patellar tendon sheath have been reported in the relevant English medical literature. Herein we describe the fourth biopsy-proven case of fibroma of patellar tendon sheath in a 6-year-old boy.

Fibroma of tendon sheath around large joints: clinical characteristics and literature review

Background

Fibroma of tendon sheath (FTS) is a benign tumor arising from the synovium of the tendon sheath that occurs mostly around small joints such as the fingers, hands, and wrist. However, FTS rarely arises around a large joint (knee, shoulder, elbow, and ankle) with intra-articular or extra-articular involvement. The clinical characteristics of FTS arising around a large joint are unclear. An additional 3 cases of FTS arising around a large joint are presented. Furthermore, the published cases and the present cases are reviewed with respect to their clinical characteristics and imaging and histopathology findings.

Methods

The 43 reported cases including the present 3 patients were summarized, and the patients’ profiles, symptoms, sites and locations in the joint involved by FTS, magnetic resonance imaging (MRI) findings, surgical procedures, clinical courses, and cytogenetic analyses were reviewed.

Results

The average age of 26 cases was 40.9 years (range 13–69 years), and about 60% of the patients were male. About 10% of the patients had a past history of trauma to the knee joint. Of the present 3 cases, one case was extra-articular around the elbow joint, one case was extra-articular around the knee joint, and one case was intra-articular involving the knee joint. The common symptoms were pain (62.5%), swelling or palpable mass (54.2%), and limited range of motion of the involved joint (50%). The most commonly involved joint was the knee, with 32 cases (74.4%), followed by the elbow in 5 cases (11.6%), ankle in 4 (9.3%), and shoulder in 2 (4.7%). The tumor typically exhibited iso to low signal intensity on T1-weighted MRI. T2-weighted images showed various patterns, but mostly low signal intensity relative to muscle. The surgical margin was marginal resection in all cases. There were no recurrences after surgery. On chromosomal analysis, only the present Case 3 showed an abnormality.

Conclusions

A total of 43 FTS cases that occurred around large joints were summarized. The most common site was around the knee joint. In FTS cases around large joints, it is necessary to distinguish between various fibroblastic and/or fibrohistiocytic tumors.

Fibroma of Tendon Sheath of the Hand: Clinical and Pathological Study

Presented are seven cases of the rare tumour known as fibroma of tendon sheath of the hand. Diagnosis was uncertain before surgery. When the lesions were removed, they resembled schwannomas. Immunohistochemistry helped distinguish these tumours from giant cell tumours of the flexor sheath and schwannomas. The authors recommend that fibroma of the tendon sheath be included in the differential diagnosis of soft tissue neoplasms of the hand.

Fibroma of Tendon Sheath Presenting Limited Flexion of the Fingers

A 35-year-old Japanese man presented with a 1-month history of limited flexion and radiating pain in the left middle and ring fingers. A physical examination revealed a hard nodular mass in his left palm. Magnetic resonance imaging showed a 2 × 1.5 × 1 cm mass of low intensity on T1-weighted images and high intensity on T2-weighted images and gadolinium enhancement. The tumor was marginally resected, adhering to the flexor digitorum profundus of both the third and fourth fingers. The histological diagnosis was fibroma of tendon sheath. After the surgery, the range of motion and hand function were improved. No recurrence has been observed. Fibroma of tendon sheath usually arises on the fingers and hands with strong attachment to the tendon or tendon sheath. The tumor in the present case probably limited the range of flexion of the fingers by obstruction of the transverse carpal ligament.

Fibroma of tendon sheath on the medial side of the knee: a case report

Fibroma of tendon sheath, which is a benign soft tissue tumor, primarily affects the finger, hand, or wrist. It rarely involves the knee and only a few cases appear in the literature. Here, we report a case of fibroma of tendon sheath on the medial side of the knee, in a previously hardly reported location, and provide detailed imaging and histological findings. A 54-year-old man presented with his right knee pain and a palpable mass that had developed 3 months earlier. Magnetic resonance imaging showed isointensity in the soft tissue tumor on T1-weighted images, variable intensity on T2-weighted images, and contrast enhancement. The specimen obtained by needle biopsy showed no histological findings of malignancy. Marginal resection was performed and the microscopic diagnosis was fibroma of tendon sheath. Since fibroma of tendon sheath is relatively rare, the radiological feature is not specific, and a rate of local recurrence following excision is high, careful diagnosis, surgical treatment and long-term follow-up are necessary. J. Med. Invest. 64: 173-176, February, 2017.

USP6 genetic rearrangements in cellular fibroma of tendon sheath

Fibroma of tendon sheath is a benign (myo)fibroblastic neoplasm of the tenosynovial soft tissues, typically affecting the distal extremities. It is classically described as a paucicellular, densely collagenized tumor; however, cellular variants have been described. A subset of cellular fibromas of tendon sheath shares similar histological features with nodular fasciitis. As nodular fasciitis very frequently harbors rearrangement of ubiquitin-specific peptidase 6 (USP6), we hypothesized that cellular fibromas of tendon sheath with nodular fasciitis-like features may also contain USP6 rearrangements. Cases of fibroma of tendon sheath (n=19), including cellular (n=9) and classic (n=10) variants, were evaluated for USP6 rearrangement by fluorescence in situ hybridization studies. A subset of cases was tested for MYH9 rearrangements and MYH9-USP6 and CDH11-USP6 fusion products. Classic fibroma of tendon sheath occurred in 5 males and 5 females (median age 67 years, range 23-77 years) as soft tissue masses of the hand (n=4), finger (n=3), forearm (n=1) and foot (n=2). Cellular fibroma of tendon sheath occurred in 5 males and 4 females in a younger age group (median age 32 years, range 12-46 years) as small soft tissue masses of the finger (n=5), hand (n=3) and wrist (n=1). USP6 rearrangements were detected in 6/9 cellular fibromas of tendon sheath. Among cellular fibromas of tendon sheath with USP6 rearrangements, no MYH9 rearrangements were detected. By RT-PCR, neither the MYH9-USP6 or the CDH11-USP6 fusion products were detected in any case. Neither USP6 nor MYH9 rearrangement were detected in any classic fibroma of tendon sheath. We report for the first time the presence of USP6 rearrangements in a subset of cellular fibroma of tendon sheath. Based on the similar morphological and molecular genetic features, we suspect that a subset of cellular fibromas of tendon sheath are under-recognized examples of tenosynovial nodular fasciitis, driven by alternate USP6 fusion genes. Further investigation will delineate how these lesions should best be classified.

Intra-articular fibroma of tendon sheath in a knee joint associated with iliotibial band friction syndrome

Iliotibial band (ITB) friction syndrome is a common overuse injury typically seen in the active athlete population. A nodular lesion on the inner side of the ITB as an etiology or an accompanying lesion from friction syndrome has been rarely reported. A 45-year-old male presented with recurrent pain and a movable nodule at the lateral joint area, diagnosed as ITB friction syndrome. The nodule was confirmed as a rare intra-articular fibroma of the tendon sheath (FTS) on the basis of histopathologic findings. We describe the MRI findings, arthroscopic and pathologic features, in this case of intra-articular FTS presenting with ITB friction syndrome.

Fibroma of tendon sheath of the hand: a series of 20 patients with 23 tumours

Fibroma of tendon sheath is an uncommon fibrous tumour that has a predilection for the hand. Large series from Histopathological Units report a local recurrence rate of 24% after surgical excision. In the hand/orthopaedic surgery literature, fibroma of tendon sheath was generally reported as isolated case reports with unusual presentations, such as triggering and carpal tunnel syndrome. The current article reports on a series of 23 tumours of the hands of 20 patients. These were all adults (mean age of 36 years) with a male to female ratio of 3:1. The thumb and index were the most common sites. A slow-growing painless mass was the clinical presentation in every case. Total surgical excision was ensured by excision of part of flexor sheath/palmar fascia to which the tumour was attached. Diagnosis was confirmed by the classic histological features of fibroma of tendon sheath. There were no recurrences at final follow-up 2-5 years after surgery.

Tendon sheath fibroma in the thigh

Tendon sheath fibromas are rare, benign soft tissue tumors that are predominantly found in the fingers, hands, and wrists of young adult men. This article describes a tendon sheath fibroma that developed in the thigh of a 70-year-old man, the only known tendon sheath fibroma to form in this location. Similar to tendon sheath fibromas that develop elsewhere, our patient's lesion presented as a painless, slow-growing soft tissue nodule. Physical examination revealed a firm, nontender mass with no other associated signs or symptoms. Although the imaging appearance of tendon sheath fibromas varies, our patient's lesion appeared dark on T1- and bright on T2-weighted magnetic resonance imaging. It was well marginated and enhanced with contrast.Histologically, tendon sheath fibromas are composed of dense fibrocollagenous stromas with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most tendon sheath fibromas can be successfully removed by marginal excision, although 24% of lesions recur. No lesions have metastasized. Our patient's tendon sheath fibroma was removed by marginal excision, and the patient remained disease free 35 months postoperatively. Despite its rarity, tendon sheath fibroma should be included in the differential diagnosis of a thigh mass on physical examination or imaging, especially if it is painless, nontender, benign appearing, and present in men.

An intraarticular fibroma of the tendon sheath in the knee joint

Fibromas that usually occur in the tendon sheaths of the wrist and hand are extremely rare in intra-articular locations. Only five such cases in the knee joint have been reported so far. This is a case report of an intra-articular fibroma of the tendon sheath of the knee joint arising adjacent to posterior cruciate ligament (PCL). Magnetic resonance imaging (MRI) revealed a well-defined intra-articular lesion in the region of the intercondylar notch of the femur behind the PCL. The mass was excised by arthrotomy. Histopathological study confirmed the diagnosis.

Intraarticular fibroma of tendon sheath

A 17-year-old male presented to us following a hyperflexion injury to his right knee sustained while playing soccer. Immediately after the traumatic event, he developed a large, tense knee effusion. Physical examination revealed limited range of motion. MRI revealed a lobulated mass in the posteromedial aspect of the knee joint. The mass was excised and sections submitted to pathology. A pathologic, microscopic, and immunohistochemical characteristics revealed the final diagnosis of fibroma of tendon sheath in the knee. At 12 months followup, the patient reported no subjective symptoms, such as pain or limitation of athletic activities and has full range of motion. Additionally, he has demonstrated no signs of recurrence. We report a case of fibroma of the tendon sheath originating from the synovial membrane of the joint capsule of the knee.

Fibroma of tendon sheath located within the ankle joint capsule

We report a very rare case of fibroma of the tendon sheath arising from the anteromedial ankle joint capsule, with no apparent connection to any tendon in the area, found in a 58-year-old patient complaining of progressive local swelling. This uncommon tumor has its usual localization in tendon sheaths, is extremely rare in joint capsules, and has never been described in this location previously. MRI showed nonuniform low signal intensity in T1- and T2-weighted images and high intensity in STIR images. The mass was completely excised by open surgery. Histopathological analysis later confirmed the diagnosis of a fibroma of the tendon sheath.

Fibroma of a tendon sheath at the wrist: a rare cause of compression of the median nerve

We report a case of fibroma of a tendon sheath, a rare benign tumour, which presented as a painless swelling at the wrist and caused symptoms of median nerve compression. We have also reviewed similar cases.

Intraarticular fibroma of the tendon sheath arising from the infrapatellar fat pad in the knee joint

We report a rare case of fibroma of the tendon sheath arising from the fat pad in the knee. To our knowledge, only four previous cases of fibroma of the tendon sheath in the knee have been reported in the English literature. In our case, magnetic resonance imaging showed low signal intensity in the mass on T1- and T2-weighted images. The mass was excised by mini arthrotomy.

Tumour and tumour-like lesions of the intercondylar notch of the knee: a pictorial review

A variety of tumours and tumour-like lesions are found in the intercondylar notch of the knee. MR imaging is the technique of choice in evaluating these conditions. Correlation with radiographs is important to identify those lesions containing calcification. This review article discusses the imaging features of tumour and tumour-like lesions involving the intercondylar notch with an emphasis on MR imaging features that suggest a specific diagnosis.

Dermatofibroma on the palmar surface of the hand

Case 1: A 58-year-old man presented with a solitary asymptomatic nodule on his thumb (Figure A). After trauma with a rusty nail approximately 20 years ago, he had developed a small papule, which had enlarged gradually for a few days initially before stabilizing. His personal and family medical histories were unremarkable. Dermatologic examination revealed a 1-cm crater-like nodule on the left palmar area. This was a firm and nontender lesion that was fixed to the overlying skin but moved freely from underlying structures. There were no similar lesions elsewhere on his body. Case 2: A 52-year-old man presented with a nodular lesion on the left palmar surface of his thumb. The 0.8-cm lesion was lightly colored, with a central cup-shaped epidermal depression and thin epidermis. The patient described an insect bite to the area 15 years earlier as the precipitating event. The firm and nontender lesion was fixed to the overlying skin but moved freely from underlying structures (Figure B). Case 3: A 36-year-old man consulted for a nodular lesion, located on his left palmar surface, that had not enlarged or changed since appearing 3 years ago. He described mechanical trauma to the area as precipitating the lesion. Clinical examination revealed a 0.6-cm, well-circumscribed nodule, with a dome shape and colored skin. Clinically, the nodular lesion appeared to be a benign tumor (Figure C). In each case, the nodule was excised totally and histopathologic examination revealed a well-circumscribed, nonencapsulated nodule within the mid-dermis. Thick, acellular collagen bundles were arranged randomly in short fascicles through the center of the lesion. Cellular areas consisting of histiocytes and fibroblasts with a storiform pattern at the periphery of lesion were observed, but nuclear atypia and mitotic activity were not. Results of immunohistochemical stain with CD34 were negative, but in all cases were strongly positive for Factor XIIIa. Slight epidermal hyperplasia was present with orthokeratotic hyperkeratosis and flattened rete ridges in the overlying epidermis (Figure A-1, Figure B-1, Figure C-1). The subcutaneous fat and adjacent skin were normal. No folliculosebaceous units at the periphery of the lesion were seen, but a few eccrine sweet glands were noted. No recurrence appeared in 18 months of follow-up.

Pathologic and MR Imaging Features of Benign Fibrous Soft-Tissue Tumors in Adults

Benign fibrous (fibroblastic or myofibroblastic) soft-tissue tumors are a heterogeneous group of fibrous lesions with widely varied anatomic locations, biologic behavior, and pathologic features. The four broad categories of fibrous proliferation are benign fibrous proliferations, fibromatoses, fibrosarcomas, and fibrous proliferations of infancy and childhood. The first two categories include nonaggressive fibroblastic lesions such as nodular fasciitis, as well as fibromatoses that demonstrate more aggressive biologic behavior (eg, desmoid tumors). In adults, fibrous tumors are among the most common soft-tissue lesions encountered in clinical practice. MR imaging can be useful for defining the intrinsic signal characteristics, size, and compartmental extension of these lesions. Histologic features of the tumor also may be depicted on T2-weighted MR images. Hypocellular fibrous tumors with dense collagenous components tend to have lower signal intensity on T2-weighted images than do lesions that are more cellular or that contain greater amounts of extracellular myxoid matrix. When interpreting MR images of soft-tissue masses in adults, radiologists should be aware of the clinical behavior, common sites of occurrence, and histopathologic and imaging features of the common benign fibrous soft-tissue tumors.

CASE REPORTS: intraarticular fibroma of the tendon sheath in the knee

We report a rare case of fibroma of the tendon sheath in the knee. To our knowledge, only three previous cases of fibroma of the tendon sheath in the knee have been reported in the English literature. In our case, T1-weighted magnetic resonance imaging revealed a low intensity signal, T2-weighted magnetic resonance imaging showed a mixed area of high and low signal intensity, and gadolinium-diethylene triaminepentaacetic acid-enhanced magnetic resonance imaging showed faint enhancement at the periphery of the lesion. Magnetic resonance imaging therefore was valid for detection of this intraarticular lesion. The lesion, which was located between the posterior capsule of the left knee and the posterior cruciate ligament, was excised arthroscopically.

Benign tumors of fibrous tissue and adipose tissue in the hand

This article presents the current understanding of soft tissue hand tumors and the best options for treating them. The majority of soft tissue hand tumors are benign. Discussion includes hand tumors of fibrous and adipose tissue origin, determining the diagnostic and therapeutic pathways for these tumors, and controversial treatment issues.

Fibroma of tendon sheath originating from the knee joint capsule

We present a rare case of fibroma of the tendon sheath originating from the posterior joint capsule of the knee in a 50-year-old man. Magnetic resonance (MR) imaging revealed a lesion posterior to the medial femoral condyle. The lesion showed hypointensity on all T1-weighted, T2-weighted, short tau inversion recovery (STIR), and contrast-enhanced T1-weighted images. Plain computed tomographic (CT) scans showed a lesion with isodensity to muscle. The lesion showed no enhancement on postcontrast CT scans.

Fibroma of a tendon-sheath presenting as toe deformity

We describe a rare manifestation fibroma in a tendon-sheath in an 83-year-old man. The patient complained initially of a slowly progressive spreading, apart of the right second and third toes. A mass was found in the plantar aspect of the foot. It was completely excised at surgery. Histological examination revealed sparse spindle or stellate cells with slit-like vessels in the dense collagenous matrix. There had been no recurrence at follow-up 17 months after surgery.

Achilles tendon nodule: inflammation, rupture, or tumor?

When an active patient has a mass on the Achilles tendon, fibroma of the tendon sheath should be in the differential diagnosis along with other tumors and benign conditions like inflammation or rupture. A case report demonstrates how the clinical characteristics of fibromas resemble other common tendon tumors, such as giant cell tumor of the tendon sheath. A histologic exam is needed to distinguish a fibroma of the tendon sheath from other tumors. Plain films should be considered to rule out bony involvement. Surgical excision is required. Patients should know that fibromas recur in 25% of those who have them removed.

Intraarticular fibroma of the tendon sheath of the knee

Fibroma of the tendon sheath is an uncommon soft-tissue tumor. Intraarticular localization has not been previously reported. The patient presented with unexplained recurrent swelling of the knee not associated with recent trauma. The soft-tissue tumor was identified by magnetic resonance imaging. Arthroscopy confirmed the diagnosis. Arthrotomy was performed because of the large size of the lesion.

Fibroma of tendon sheath in the hand

Seven cases of fibroma of tendon sheath in the hand are reviewed. These tumors are common enough to be considered in the differential diagnosis of a soft tissue tumor in the hand, as they comprised 7 of our series of 208 soft tissue hand tumors excised over a 15-year period. A marginal excision was performed in each case, and no tumor recurred after a mean follow-up interval of 8 years. The fibromas were adherent to tendons, tendon sheaths, and neurovascular structures, and thus were more difficult to excise without morbidity than other soft tissue hand tumors.

Tendon sheath tumours: a pathological study of the relationship between giant cell tumour and fibroma of tendon sheath

Thirty-nine soft tissue lesions occurring on the distal aspect of the limbs have been selected because of histological features consistent with those recognized for giant cell tumour of tendon sheath or fibroma of tendon sheath. In spite of the frequent occurrence of such lesions at the stated sites, they were rarely correctly diagnosed pre-operatively. Using a scoring system to grade specified histological features, a blind evaluation to re-classify these 39 lesions was undertaken. This resulted in 29 cases of giant cell tumour of tendon sheath, six fibromas of tendon sheath and four 'transitional stage' lesions. Despite the heterogeneous morphology of these categories, there were no significant differences in the clinical features of affected patients. The existence of a 'transitional stage' lesion, combined with the homogeneous clinical picture of all categories, supports the concept that fibroma of tendon sheath is the end and sclerosing stage of giant cell tumour of tendon sheath, probably consequent on progressive vascular impairment. There is a need for pathologists to recognize the transitional stage lesions so as to avoid their inclusion with other diagnostic entities. For this group the name 'giant cell tumour of tendon sheath--transitional stage lesion' is suggested.

Fibroma of Tendon Sheath with Bone Involvement

The case is reported of a 62-year-old man presenting with a fibroma of tendon sheath of the left little finger with bone involvement. This is only the third such case reported. A brief discussion of this benign soft tissue tumour follows.

Fibroma of tendon sheath: a tumor of myofibroblasts. A clinicopathologic study of 18 cases

A clinicopathologic study of 18 cases of fibroma of tendon sheath included an immunohistochemical survey of 7 cases and an electron-microscopic examination of one. The age of the patients ranged from 1 to 77 years, with a median of 34 years. The most common site of the tumors was the finger (7 cases), followed by the knee (3), the hand (2), and the foot (2). The median greatest diameter of the tumor was 2 cm. The tumors were attached or closely related to the tendon or tendon sheath, and usually well circumscribed, and multinodular or lobulated. Microscopically, spindle or stellate tumor cells with fuchsinophilic cytoplasm were embedded in a dense fibrous stroma with scattered small blood vessels. Most tumor cells have immunoreaction products for actin in the cytoplasm with accentuation along the cell membrane. Ultrastructurally, many of the tumor cells proved to be myofibroblasts.

Fibroma of tendon sheath

This report describes four patients with fibroma of tendon sheath. The tumors were slowly enlarging, firm nodules that were adherent to tendon sheaths of the volar aspect of the fingers or palm. One lesion was recurrent. Microscopically, they consisted of lobulated, hyalinized, collagenous masses that contained spindled and stellate fibroblasts and an array of slitlike spaces. There were small pseudopods and separate foci of tumor in adjacent connective tissue. These may explain the propensity of fibroma of tendon sheath to recur.

An unusual "giant" lipofibroma in the palm

A case is described of an unusually large lipofibromatous hamartoma arising from the tendon sheath of flexor pollicis longus.