Induction of Myogenic Differentiation Improves Chemosensitivity of Chemoresistant Cells in Soft-Tissue Sarcoma Cell Lines.

Rhabdomyosarcoma (RMS) and rhabdoid tumors (RT) are rare soft-tissue malignancies with the highest incidence in infants, children, and adolescents. Advanced, recurrent, and/or metastatic RMS and RT exhibit poor response to treatment. One of the main mechanisms behind resistance to treatment is believed to be intratumoral heterogeneity. In this study, we investigated the myogenic determination factor 1 (MYOD1) and Noggin (NOG) markers in an embryonal RMS (ERMS) cell line and an RT cell line and the differential response of the MYOD1 and NOG expressing subpopulations to chemotherapy. Importantly, we found that these markers together identify a subpopulation of cells (MYOD1+ NOG+ cells) with primary resistance to Vincristine and Doxorubicin, two commonly used chemotherapies for ERMS and RT. The chemoresistant MYOD1+ NOG+ cells express markers of undifferentiated cells such as myogenin and ID1. Combination of Vincristine with TPA/GSK126, a drug combination shown to induce differentiation of RMS cell lines, is able to partially overcome MYOD1/NOG cells chemoresistance.

The measurement of physical functioning among patients with Tenosynovial Giant Cell Tumor (TGCT) using the Patient-Reported Outcomes Measurement Information System (PROMIS).

BACKGROUND: Tenosynovial giant cell tumor (TGCT), a rare, locally aggressive neoplasm of the synovium of joints and tendon sheaths, is associated with joint destruction, pain and swelling. Impacts on physical function (PF) vary depending on tumor size and location. The aim of this study was to identify relevant items, and demonstrate the content validity of custom measures of lower extremity PF from the Patient-Reported Outcomes Measurement Information System Physical Function Physical Function (PROMIS-PF) item bank among patients with TGCT. METHODS: Patients were recruited for qualitative research interviews to identify predominant TGCT symptoms and impacts. Patients completed a checklist to evaluate the relevance of each PROMIS-PF item. The publicly available PROMIS-PF item response theory (IRT) parameters were used to select items representing the range of the latent PF trait. RESULTS: Participants (n = 20) were 75% female, mean age 42.5 years. TGCTs were located in the knee (n = 15), hip (n = 3), and ankle (n = 2). Fifty-four PROMIS-PF items were identified as relevant by ≥20% of the participants. PF concepts discussed by participants during the qualitative interviews were also used to select relevant items. Selected items (n = 13) were used to create a physical function subscale specific to lower extremity tumors. CONCLUSIONS: We describe a novel method of combining qualitative research and IRT-based item information to select a relevant and content valid subset of PROMIS-PF items to assess heterogeneous impacts on PF in TGCT, a rare disease population.

Aspirin for Prophylaxis Against Venous Thromboembolism After Orthopaedic Oncologic Surgery.

BACKGROUND: Patients who undergo orthopaedic oncologic surgical procedures are at increased risk of developing a venous thromboembolism (VTE). Guidelines from surgical societies are shifting to include aspirin as a postoperative VTE prophylactic agent. The purpose of this study was to review our experience using aspirin as postoperative VTE prophylaxis for orthopaedic oncologic surgical procedures. METHODS: This study was a retrospective review of patients diagnosed with a primary malignant soft-tissue or bone tumor or metastatic carcinoma. Demographic information, histopathologic diagnosis, VTE history, surgical procedure, and VTE prophylaxis were analyzed. VTE rates in the overall and prophylactic-specific cohorts were recorded and compared. RESULTS: A total of 142 distinct surgical procedures in 130 patients were included. VTE prophylaxis with aspirin was used after 103 procedures, and non-aspirin prophylaxis was used after 39. In 33 cases, imaging was used to investigate for VTE because of clinical signs and symptoms. VTE developed after 7 (4.9%) of the 142 procedures. There were 6 deep venous thromboses (DVTs) and 1 pulmonary embolism, and 2 of the VTEs presented in patients with a VTE history. VTE developed in 2.9% (3) of the 103 aspirin cases and 10.3% (4) of the 39 non-aspirin cases. No patient in the aspirin group who had been diagnosed with metastatic carcinoma, malignant soft-tissue sarcoma, lymphoma, or multiple myeloma developed a VTE. Risk factors for VTE development included diabetes mellitus (odds ratio [OR] = 10.40, 95% confidence interval [CI] = 1.61 to 67.30), a history of VTE (OR = 7.26, 95% CI = 1.19 to 44.25), postoperative transfusion (OR = 34.50, 95% CI = 3.94 to 302.01), and estimated blood losses of 250 mL (OR = 1.50, 95% CI = 1.11 to 2.03), 500 mL (OR = 2.26, 95% CI = 1.23 to 4.13), and 1,000 mL (OR = 5.10, 95% CI = 1.52 to 17.04). CONCLUSIONS: Aspirin may be a suitable and effective option for VTE chemoprophylaxis in patients treated with orthopaedic oncologic surgery, especially those diagnosed with a soft-tissue sarcoma. Research with a more advanced study design is required. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Novel case of Trevor's disease: Adult onset and later recurrence.

Dysplasia epiphysealis hemimelica (DEH), or Trevor's disease, is an osteocartilaginous epiphyseal overgrowth typically occurring in children. The literature reports 6 adult cases and none describe recurrence requiring additional procedures. We present a new-onset proximal tibial DEH in an adult recurring approximately 3 years after open excision. A 39-year-old female presented with a history of right knee pain, swelling, and instability. Physical examination revealed a firm proximal tibial mass. Computed tomography (CT) imaging showed an exophytic, lobulated, sclerotic mass involving the anterolateral margin of the lateral tibial plateau. Magnetic resonance imaging was suggestive of an osteochondroma. The patient underwent curettage of the lesion due to its periarticular location. Histology revealed benign and reactive bone and cartilage consistent with periosteal chondroma. Two and a half years later, the patient presented with a firm, palpable mass larger than the initial lesion. CT revealed a lateral tibial plateau sclerotic mass consistent with recurrent intra-articular DEH. A complete excision was performed and histology showed sclerotic bone with overlying cartilage consistent with exostosis. DEH is a rare epiphyseal osteocartilaginous outgrowth frequently occurring in the long bones of children less than 8 years old. DEH resembles an osteochondroma due to its pediatric presentation and similar histologic appearance. Adult-onset cases comprise less than 1% of reported cases. Recurrence rate after surgical intervention is unknown. Only 1 such case, occurring in a child, has been described. Clinicians contemplating operative treatment for DEH should note the potential for recurrence and consider complete excision. A follow-up period of several years may be warranted to identify recurrent lesions.

Patient-reported Symptoms of Tenosynovial Giant Cell Tumors.

PURPOSE: Tenosynovial giant cell tumor (TGCT), a rare locally aggressive neoplasm of the synovium of joints and tendon sheaths, is associated with joint destruction, inflammation, pain, and swelling, in part due to colony-stimulating factor 1 receptor-bearing macrophages recruited to the tumor by genetic elevation of colony-stimulating factor 1 activity. The most common treatment is surgery, although promising pharmacologic treatments are in development. Patient-reported outcome (PRO) instruments are critical end points in demonstrating the clinical relevance of standard oncologic outcome measures and the overall impact of novel pharmacologic therapies in nonmalignant neoplastic conditions such as TGCT. The content validity of PROs relevant to patients with TGCT has not been formally investigated, and instruments to evaluate such outcomes do not exist for this condition. METHODS: PRO instruments of potential relevance were evaluated by using a literature review and by clinical and PRO experts. Patients with TGCT were recruited through clinical sites and the Internet for participation in qualitative research interviews to identify predominant symptoms and to test the relevance and content validity of several PRO measures. Select PRO measures were included in a Phase I clinical trial, and preliminary results of the PRO end points are reported descriptively. FINDINGS: Of the 22 subjects who participated in qualitative interviews, 73% were female, and their mean age was 42.5 years (range, 27-56 years). The TGCTs (19 diffuse and 3 localized) were located in the knee (n = 15), hip (n = 3), ankle (n = 2), elbow (n = 1), and forearm (n = 1). The most common symptoms cited were pain (82%), swelling (86%), stiffness (73%), reduced range of motion (64%), and joint instability (64%), which were consistent with clinical expert input and with the content of instruments chosen by PRO experts. The worst pain numeric rating scale, Patient Reported Outcomes Measurement Information System physical functioning items, and the Western Ontario and McMaster Universities Osteoarthritis Index, as well as a worst stiffness numeric rating scale developed for TGCT, were confirmed as meaningful measures of TGCT patient symptoms and were well understood in qualitative interviews. Results from the Phase I trial showed trends of improvement in both pain and stiffness over time. IMPLICATIONS: This study is the first to gather information directly from patients with TGCT regarding their symptom experiences. Pain, stiffness, and physical functioning are important treatment outcomes in patients with TGCT. We have identified content-valid PRO measures of these concepts, which are included in an ongoing Phase III TGCT clinical trial with pexidartinib (PLX3397) (NCT02371369).

A simplified approach to reconstruction of hemipelvectomy defects with lower extremity free fillet flaps to minimize ischemia time.

External hemipelvectomy associated with trauma or during the operative management of musculoskeletal sarcomas may yield a soft tissue defect that can only be sufficiently covered by free tissue transfers. The application of "spare-parts surgery," such as a fillet of leg or thigh flap, uses distal uninvolved parts that are otherwise viable tissues as donor tissues to cover defects. This concept has great utility to achieve soft tissue coverage in challenging cases, such as hemipelvectomy. However, during such complicated and time-consuming cases, prolonged ischemia time of the proposed donor tissues can be problematic. We describe a technique developed by the senior author (SJK) that minimizes the ischemia time of donor free tissues during external hemipelvectomy. This technique is applicable to other surgeries where filleted spare parts are the donor-site source for free tissue transfer.

Angiosarcoma Arising in Chronic Expanding Hematoma: Five Cases of an Underrecognized Association.

Little is known about the etiology or pathogenesis of angiosarcoma (AS). We describe a series of 5 cases of AS arising in chronic expanding hematomas. Inclusion criteria were the presence of a hematoma of at least 1-year duration and a thick fibrous wall surrounding the hematoma. Patients were 4 men and 1 woman; ages ranged from 43 to 71 years. Locations were the thigh (3), chest wall (1), and pelvic soft tissue involving the ischial bone (1). Hematoma duration ranged from 2 to 25 years. All cases had large cystic hematomas >10 cm; 2 had prior radiation. Thick fibrous walls surrounded the hematomas, with foci of hemosiderin and foamy histiocytes. Wall thickness ranged from 0.2 to 1.0 cm and varied within lesions. All AS were epithelioid, and in 3 cases the tumor invaded through the cyst wall. Immunoreactive nuclear c-myc was noted in 3/3 cases available for testing. Follow-up disclosed 4 patients developed metastatic disease, 3 of whom died of disease, 4, 8, and 15 months after diagnosis; the fourth patient is alive without disease after chemotherapy at 59 months. One patient without metastases is alive without disease 18 months after diagnosis; this tumor was confined to the cyst without penetration through the wall. We identified 4 similar cases in the literature, 3 as individual case reports (all epithelioid AS), and 1 as part of a series of AS. To our knowledge, this is the first series of AS arising in chronic expanding hematomas. Recognition of this unusual complication should alert clinicians to provide periodic clinical follow-up to these patients and to biopsy any case with sudden or uncontrolled enlargement. We recommend that excised chronic hematomas be well sampled histologically to search for AS and, if identified, to determine its extent and invasiveness.

Surgical management of metastatic long bone fractures: principles and techniques.

Management of metastatic long bone fractures requires identification of the lesion and the use of sound fracture fixation principles to relieve pain and restore function. The treating surgeon must understand the principles of pathologic fracture fixation before initiating treatment. Because these fractures occur in the context of a progressive systemic disease, management typically involves a multidisciplinary approach. When considering surgical stabilization of these fractures, the abnormal (or absent) healing environment associated with diseased bone and the overall condition of the patient must be taken into account. The goal of surgery is to obtain a rigid mechanical construct, which allows for early mobility and weight bearing. This can be achieved using internal fixation with polymethyl methacrylate cement or segmental resection and joint reconstruction. Prosthetic joint arthroplasty is a more reliable means of fracture management when insufficient bone is present for fixation. Prophylactic stabilization of impending pathologic fractures can reduce the morbidity associated with metastatic lesions.

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.

Impact of close surgical margin on local recurrence and survival in osteosarcoma.

PURPOSE: Whether neoadjuvant chemotherapy safely allows close margins in osteosarcoma patients is still unknown. This study investigates the impact of close margins on local recurrence (LR) and overall survival (OS) for osteosarcoma patients treated with neoadjuvant chemotherapy. METHODS: We retrospectively reviewed 47 cases of conventional osteosarcoma who were treated at our institution. Patient and treatment factors such as age, gender, MSTS stage, tumour site, surgery type, pathological type, tumour size, surgical margin, tumour necrosis rate, chemotherapy regimens and cycles were recorded. A close margin was defined as tumour present less than 5 mm from the closest resection margin. The average followup was 87.6 months (range, 25-135 months). RESULTS: Twenty-five patients were alive, 22 patients had died, and eight had LR. Twenty-eight patients had wide margins, seven had positive margins and 12 had close margins. Positive margins had a greater risk of LR (57.1%) than wide margins and close margins. There was no difference in LR (8.3% vs 10.7%) between close margins and wide margins. Margin status was not correlated with OS. CONCLUSION: Compared with wide margins, close margins did not lead to increased local recurrence in our study group. Whether close margins, as defined in our study, are just as acceptable as wide margins in terms of patient outcomes for osteosarcoma patients with neoadjuvant chemotherapy needs to be further confirmed in the future.

Perioperative infection rate in patients with osteosarcomas treated with resection and prosthetic reconstruction.

BACKGROUND: The incidence of perioperative infection after segmental tumor endoprosthetic replacement in previous reports varies from a high of 7.4% to a low of 2.6%. Appropriate antibiotic use for this group is unknown and controversial, whereas the relationship of antibiotic use and perioperative infection is unclear. QUESTIONS/PURPOSES: We determined the incidence of perioperative infection in patients with osteosarcoma treated with segmental prosthetic replacement using a standard perioperative antibiotic regimen and the incidence of late infections and wound complications. PATIENTS AND METHODS: We retrospectively reviewed the records of 53 patients with osteosarcoma undergoing segmental prosthetic replacements from 1993 to 2008. There were 30 males and 23 females ranging from 10 to 78 years of age. All patients were given intraoperative antibiotics (intravenous cefazolin), continued for 3 days postoperatively and then given orally for 5 days. Patients who were allergic to penicillin or cefazolin were given vancomycin followed by clindamycin. A perioperative infection was defined as a deep infection within 2 months after prosthetic reconstruction. The minimum followup was 1 year (range, 1-15 years). RESULTS: We identified one confirmed perioperative prosthetic infection (1/53; 1.9%) (Enterobacter cloacae and methicillin-resistant Staphylococcus) in a 78-year-old woman after proximal tibial replacement, gastrocnemius flap, and skin graft. Her infection was controlled with débridement, drainage, and intravenous antibiotics. Three patients had late infections, two of which were culture negative. Four patients had wound complications that required further surgery. CONCLUSION: The antibiotic regimen we used is longer than that recommended for patients having routine total joint arthroplasty. Its appropriateness will require comparison with alternate regimens, including those of shorter duration. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The relation of tumour necrosis and survival in patients with osteosarcoma.

PURPOSE: We investigated whether tumour necrosis was associated with disease-free survival (DFS) and overall survival (OS) of osteosarcoma patients treated in our institution. METHODS: We retrospectively studied the predictive value of percentage of necrosis in 40 cases of IIB osteosarcoma treated from 1999 to 2008 in our institution. Patient and treatment factors such as age, gender, tumour site, surgery type, pathological type, tumour size, margin status, percentage of tumour necrosis, chemotherapy regimens and cycles were recorded. The average follow-up was 85.9 months (range, 25-135 months). RESULTS: Two patients had local recurrence (LR) alone, five patients had both LR and metastasis, 14 patients had metastasis alone. Twenty-four patients were alive and 16 had died. The five-year DFS and OS were 47.8% and 65.9%, respectively. Tumour necrosis grouped by 90% was not associated with DFS and OS. Patients with greater than 70% necrosis rate had a significantly higher DFS than those with less than 70%. CONCLUSION: We found no survival advantage at 90% tumour necrosis in our study. Further study with more patients should be performed to evaluate the predictive value of necrosis rate at the cutoff of 70%.

When should we biopsy a solitary central cartilaginous tumor of long bones? Literature review and management proposal.

Differentiation between benign and low-grade malignant cartilaginous tumors is a radiological and pathological challenge. Based on a literature review, we propose the following guidelines for the management of a solitary central cartilaginous tumor of long bones distinguishing three situations: 1. The tumor is considered to be aggressive and requires surgery if one of the following criteria is present: cortical destruction, Moth-eaten or permeative osteolysis, spontaneous pathologic fracture, periosteal reaction, edema surrounding the tumor on MR images, and soft tissue mass. Tumor biopsy followed by complete intralesional treatment is indicated. 2. The tumor is classified as active if two of the following active criteria are present: pain related to the tumor, endosteal scalloping superior to two-thirds of the cortical thickness, extent of endosteal scalloping superior to two-thirds of the lesion length, cortical thickening and enlargement of the medullary cavity. Tumor biopsy or excision is indicated. 3. The tumor is classified as possibly active if one of the previous active criteria is present. In such cases, bone scintigraphy and dynamic-enhanced MR imaging should be obtained. Radionuclide uptake superior to the anterior iliac crest at bone scintigraphy and early and exponential enhancement at dynamic-enhanced MR are considered as two additional active criteria. After these two examinations, if only one criterion is still present, the lesion can be regarded as possibly quiescent, and the following monitoring is suggested: first follow-up at three to six months and then once a year. Otherwise, if two or more active criteria are present, biopsy is recommended. 4. The tumor is considered quiescent and does not require surgery if no active or aggressive criterion is present. A radiological follow-up can be proposed.

Early outcomes for malignant peripheral nerve sheath tumor treated with chemotherapy.

OBJECTIVES: Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue sarcomas with a tendency for recurrence and metastasis. Treatment using chemotherapy is controversial, but benefit with some agents has been described. This study aimed to analyze early survival outcomes using doxorubicin and ifosfamide chemotherapy for MPNST. METHODS: Pathology records at our musculoskeletal tumor center were searched for patients with a new diagnosis of MPNST between 2003 and 2008. Treatment involved surgical resection, radiation, and chemotherapy with doxorubicin and ifosfamide. Ten patients met inclusion criteria, with mean age 40 years (range, 20-70). Four patients had metastatic disease on presentation. Four patients had neurofibromatosis type I (NF1). RESULTS: Of 6 patients with nonmetastatic disease on presentation, 5 had no evidence of disease post-treatment. The sixth had positive margins after surgery and initially received no further treatment due to noncompliance. Three from this subgroup developed local recurrence, but none developed distant metastases and 1 died of disease at last follow-up. One- and 2-year disease-free survival (DFS) for this subgroup was 80% and 60%, respectively. One- and 2-year overall survival (OS) for the subgroup was 100%. Of 4 patients with metastatic disease on presentation, 2 had no evidence of disease post-treatment. One of these 2 developed local recurrence, but none from the subgroup developed new metastatic disease. Two of these 4 died of disease at last follow-up. One- and 2-year DFS for this subgroup was 100% and 50%, respectively. One- and 2-year OS was 75% and 50%, respectively. Two of the 4 patients presenting with metastatic disease had NF1. All 3 local recurrences and 2 of the 3 deaths in this study occurred in NF1 patients. CONCLUSIONS: For all patients, when combined with surgery and radiation, chemotherapy using doxorubicin and ifosfamide yielded 57% DFS and 80% OS at 2 years. NF1 patients appeared to have worse outcomes, with a statistically significantly lower DFS than non-NF1 patients. Limitations of this study include a small sample size, retrospective design, and use of different chemotherapy regimens.

Curettage and graft alleviates athletic-limiting pain in benign lytic bone lesions.

BACKGROUND: Solitary bone cysts (SBC), nonossifying fibromas (NOF), and fibrous dysplasia (FD) create benign intramedullary lytic bone lesions. They are typically asymptomatic and treated conservatively. We present a series of lesions that caused performance-limiting pain in young athletes, a symptom phenomenon and possible treatment indication that has been poorly described in the literature. QUESTIONS/PURPOSES: We asked whether intralesional curettage and defect grafting of these lesions would alleviate pain in young athletes and permit their return to unrestricted athletic activities. PATIENTS AND METHODS: We retrospectively identified 29 patients (30 lesions) who underwent curettage and grafting for SBC (12 patients), NOF (nine), or FD (eight). All patients had pain predominantly with athletic involvement. The mean age of the patients was 18 years (range, 12-31 years). Tumor locations were the femur (eight lesions), humerus (seven), tibia (six), fibula (five), pubic ramus (two), ulna (one), and calcaneus (one). Signs/symptoms were pain alone (24 patients) and pain plus fracture (five). Surgery involved curettage and packing with allograft cancellous chips, bone substitute, or demineralized bone matrix. Two patients required internal fixation. The mean followup was 21 months (range, 2-114 months). RESULTS: Twenty-four patients had no pain and five had occasional mild pain at last followup. All patients resumed full activity at a mean of 3.3 months (range, 1.5-8.3 months), excluding two who required repeat surgery. CONCLUSIONS: Our observations suggest curettage and packing with bone graft/substitute can provide pain relief and allow full athletic recovery for young athletes with benign lytic bone lesions. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Recurrent lipoma-like hibernoma.

This is the fifth report of the rare lipoma-like variant of hibernoma, the 19th case reported, and the first documented as recurring after excision. Our patient was a 56-year-old man whose painful lipoma-like hibernoma (LLH) in the pelvis/buttock was initially treated with marginal excision 15 years earlier. Nine years after treatment, the LLH recurred locally. The recurrence was treated with partial excision and embolization, which alleviated symptoms. The disease was stable 26 months after repeat excision and 202 months after initial treatment. LLH is 1 of the 4 histologic variants of hibernomas, which are rare benign lipomatous tumors distinguished from other lipomas by their brown-fat component. Only minimal information is available regarding the clinicopathologic characteristics of the individual variants. Reviewing the literature, we found that LLH predominantly develops in the fifth and sixth decades, and mean age at diagnosis is 41 years (age range, 2-66 years). LLH has a slight male predilection of 10:9. It most commonly develops in the thigh, with other occurrences reported in the hip, trunk, knee, and calf. The magnetic resonance imaging signal of LLH mirrors fat in all sequences. Presence of internal septations and enhancement with contrast are variable. Histologically, LLH is defined as a hibernoma composed predominantly of univacuolated white-fat cells and only scattered granular or pale hibernoma cells. The literature provides only a few treatment details regarding this variant.

Early pleomorphic hyalinizing angiectatic tumor: precursor or distinct lesion?

Early pleomorphic hyalinizing angiectatic tumor is a rare and recently described soft tissue lesion. Originally believed to be a precursor lesion to neoplastic pleomorphic hyalinizing angiectatic tumor, and possibly identical to hemosiderotic fibrohistiocytic lipomatous lesion/tumor, there have been recent suggestions that it is distinct from pleomorphic hyalinizing angiectatic tumor and is instead a reactive process. This article reports a case of a mass in the foot of a 45-year-old woman, which is 1 of only 15 published cases of early pleomorphic hyalinizing angiectatic tumor and is the first case to describe its radiographic appearance. Early pleomorphic hyalinizing angiectatic tumor predominantly develops in the fourth to sixth decades (average age, 45 years, range, 10-67 years). Females predominate 4 to 1. The foot/ankle is the most common site (67%). On magnetic resonance imaging (MRI), the mass appeared inhomogeneously dark on T1-weighted sequences and inhomogeneously bright on fat-suppressed T2-weighted sequences. Forty-four percent of resected lesions recur locally, but no early pleomorphic hyalinizing angiectatic tumor lesion has ever metastasized. These clinical characteristics of early pleomorphic hyalinizing angiectatic tumors closely mirror those of hemosiderotic fibrohistiocytic lipomatous lesions/tumors and are dissimilar to those for classic pleomorphic hyalinizing angiectatic tumors. Therefore, although the 3 entities share several histologic features, we believe early pleomorphic hyalinizing angiectatic tumor is equivalent to hemosiderotic fibrohistiocytic lipomatous lesion/tumor and is not a true precursor to classic pleomorphic hyalinizing angiectatic tumor.

Fibroma of tendon sheath in the knee: a report of three cases and literature review.

Fibroma of tendon sheath (FTS) is a rare and benign soft-tissue tumor. It is predominantly found in the fingers, hands, and wrists of young, adult males. We describe a series of three cases all presenting in the atypical knee location. We also review the literature on FTS, located both in the knee and elsewhere, looking for common clinical, imaging, and histologic patterns to help differentiate it from similar knee lesions. FTS typically presents as a painless, slow-growing, solid nodule. In the knee though, 71% of lesions present with pain/discomfort and 31% present with a palpable mass. Physical exam for knee FTS commonly reveals painful range of motion (50%), decreased range of motion (42%), and a palpable non-tender mass (33%). MRI of FTS usually reveals a well-defined soft-tissue mass, with low signal on T1, variable signal on T2, and variable enhancement. Histologically, the tumors are composed of a dense fibrocollagenous stroma with scattered spindle-shaped fibroblasts and narrow slit-like vascular spaces. Most FTS are removed by marginal excision, with 24% of lesions subsequently recurring. No lesion has ever metastasized. Despite its rarity, this lesion should be included in the differential diagnosis of a knee mass on physical exam or imaging, especially if it is painful, benign appearing, and present in a middle-aged male.

Spindle-cell hibernoma: a clinicopathologic comparison of this new variant.

Spindle-cell hibernoma is 1 of 4 histologic variants of hibernomas, which are rare lipomatous tumors distinguished from other lipomas by their brown fat component. This article presents a case of a spindle-cell hibernoma that developed in the groin of a 58-year-old man, and is 1 of only 5 known cases of spindle-cell hibernoma published in the scientific literature. Minimal information is available regarding the clinicopathologic characteristics of the 4 hibernoma variants: typical, lipoma-like, myxoid, and spindle-cell. Spindle-cell hibernoma is believed to be the rarest variant, accounting for approximately 2% of hibernomas. The spindle-cell variant predominantly develops in the fourth and fifth decades, with an average age at diagnosis of 42.5 years (range, 28-59 years). It has a male predilection of 4:1. Previously reported only in the posterior neck and scalp, the groin is now added to the sites of spindle-cell hibernoma occurrence. Our patient's tumor demonstrated low-attenuation on computed tomography and contained moderately-attenuating internal septae. Histologically, in addition to the multivacuolated brown fat component common to all hibernomas, spindle-cell hibernoma has a spindle-cell element without vacuolization that is CD34 positive. No prior treatment details are available on this particular variant. Our patient was treated by marginal excision and was disease free through 13 months of follow-up.