Malignancy in pigmented villonodular synovitis

Malignant pigmented villonodular synovitis is an extremely rare and controversial disease. We describe malignant change in pigmented villonodular synovitis of the ankle in a patient with an unusually long clinical history. Symptoms began at age 21, metastatic disease developed at age 85, and the patient died 1 year later. The histologic appearance of the malignant tumor differed from that in most reported cases, in that spindle-shaped cells predominated. Lymph node metastasis also developed, a feature uncommon to soft tissue sarcomas.     

Pigmented villonodular synovitis of the hip: review of radiographic features in 58 patients

Clinical and radiographic findings were retrospectively reviewed in a multicentric survey of 58 patients with histologically proven pigmented villonodular synovitis (PVNS) of the hip. The most common clinical features were mechanical pain (47 cases) and limitation of joint motion (47 cases). On plain films, a classic form with large and multiple lucencies was found in 36 cases, followed by an osteoarthritis-like form (9 cases), an arthritis-like form (8 cases), normal radiographic appearance (3 cases), osteonecrosis of the femoral head (one case) and joint destruction with acetabular protrusion (one case). Bilateral involvement of the hips was probable in two patients. In contrast to the knee, the hip showed a high prevalence of bony lesions and joint space narrowing. Although an uncommon disease, PVNS of the hip has to be considered when arthritis is associated with uncharacteristic clinical or radiographic findings.     

Cellular schwannoma: a benign neoplasm sometimes overdiagnosed as sarcoma

A case of cellular schwannoma originating in the left lumbar paraspinal region is described. The diagnosis was originally made on needle biopsy material. The histological examination is usually not sufficient to correctly diagnose this benign neoplasm. Bone erosion, neurological symptoms, caused by compression of the spinal roots, together with hypercellularity, pleomorphism and an occasional increase in mitotic activity, may lead to an erroneous diagnosis of malignancy. Immunohistochemistry and ultrastructural analysis are helpful in confirming the diagnosis. The recognition of this entity avoids unnecessary overtreatment of these patients. Received: 16 November 2000 Revision requested: 18 December 2000 Revision received: 5 February 2001 Accepted: 11 February 2001     

Magnetic resonance imaging: a cost-effective alternative to bone scintigraphy in the evaluation of patients with suspected hip fractures

Objective. To evaluate the cost-effectiveness of magnetic resonance imaging (MRI) compared with radionuclide bone scan in the evaluation of patients with clinically suspected hip fractures. Design. The medical records of all patients who had been seen in the emergency room over a 4-year period with a clinically suspected hip fracture, negative or equivocal plain films, and either a subsequent bone scan or MRI examination were retrospectively reviewed. The time to diagnosis, admission rate, and time to surgery were determined. A two-sample t-test was used to assess the statistical significance of the results. A theoretical cost analysis was performed using current charges to estimate all expenses. Patients. Forty patients (11 male, 29 female; age 28–99 years) satisfied our inclusion criteria. Results and conclusions. Twenty-one patients had bone scans (six with fractures), and 19 had MRI (four with fractures). The time to diagnosis was 2.24±1.30 days for bone scanning and 0.368±0.597 days for MRI (P<0.0001). Twenty patients in the bone scan group were admitted compared with 13 in the MRI group. The time to surgery was at least 1 day longer in patients undergoing bone scanning. Bone scanning resulted in higher patient costs compared with MRI because of the delay in diagnosis. In the evaluation of patients with suspected hip fractures, early MRI is more cost-effective than delayed bone scanning. Further prospective studies comparing the cost-effectiveness of early MRI with early bone scanning are needed.     

Unsuspected metastases presenting as solitary soft tissue lesions: a fourteen-year review

Objective. To describe a series of patients with no known primary malignancy who presented with a solitary unsuspected soft tissue metastasis masquerading as a soft tissue sarcoma, and secondarily to describe the imaging appearance of these lesions. Design. Records of two academic hospitals with active orthopedic oncology services were reviewed for patients meeting the above criteria. Clinical charts were examined, and the imaging appearance of the soft tissue lesions retrospectively reviewed. Patients. Of 1421 patients examined for soft tissue lesions, 11 were found who met the above criteria. Results. Of the 11 patients whose initial presentation was a solitary soft tissue metastasis, eight were found to have a primary lung cancer, two were diagnosed with adenocarcinoma of unknown primary, and adenocarcinoma of the colon was discovered in the remaining patient. Conclusions. The clinical presentation of a solitary soft tissue metastasis without a known primary malignancy is a rare occurrence, with an incidence of approximately 0.8%. Lung cancer is the primary neoplasm in a high percentage of these cases. Received: 13 Oktober 1999 Revision requested: December 1999 Revision received: 25 January 2000 Accepted: 28 January 2000     

Immunoglobulin D myeloma presenting as an extraosseous soft tissue tumor

We report a 69-year-old man who suffered an extraosseous tumor of immunoglobulin D myeloma (lambda type) in the shoulder girdle, mimicking a primary soft tissue sarcoma. The tumor was isointense with adjacent muscle on T1-weighted MR images, and hyperintense on T2-weighted images. No continuity with the neighboring bone was noted. After administration of gadolinium, the central part of the tumor showed marked contrast enhancement. Although the tumor showed a complete response to the initial chemotherapy, the patient died of the disease 31 months after its initial manifestation. Several bone marrow aspirations and biopsies of the ilium and sternum had shown no increase in plasma cells (range 0.6–1.2%) until the disease became advanced 19 months after its initial manifestation. Received: 1 September 2000 Revision requested: 9 October 2000 Revision received: 11 November 2000 Accepted: 15 November 2000     

Subcutaneous granuloma annulare: MR imaging findings

We present a case of subcutaneous granuloma annulare evaluated with MR imaging. The mass was poorly defined and showed thickened interconnecting strands with low signal intensity on T1- and T2-weighted MR images. When a poorly defined subcutaneous mass with low signal intensity on both T1- and T2-weighted MR images is observed in an otherwise healthy child, subcutaneous granuloma annulare should receive serious consideration. Subcutaneous granuloma annulare should be added to the list of tumors with short T2.     

Magnetic resonance imaging of dialysis-related amyloidosis of the shoulder and hip

 Objective. The purpose of this study was to evaluate the usefulness of MRI in identifying abnormalities of the periarticular structures in patients with symptoms of dialysis-related amyloid arthropathy. Design and patients. MR images of shoulders and hips in 5 dialysis patients with symptoms of amyloid arthropathy were compared to images of shoulders and hips in 4 asymptomatic dialysis patients, shoulders in 9 nondialysis patients, and hips in 12 nondialysis patients. These were evaluated for the presence of focal periarticular osseous lesions, tendinous and capsular thickening, and periarticular fluid. Results. Increased thickness of the supraspinatus tendon was found in both symptomatic and asymptomatic patients. Capsular thickening at the hip was present in all symptomatic patients, and in 3 of 8 asymptomatic hips. Joint and bursal fluid was common in the symptomatic group, and was present in some asymptomatic individuals. Osseous lesions were detected in the absence of plain film findings, and demonstrated variable signal intensity. Conclusions. MRI is useful in detecting signs of dialysis-related amyloidosis. Findings of a milder degree in asymptomatic dialysis patients suggests that MRI may also be valuable in the early diagnosis of this syndrome.     

Benign giant cell tumor of bone with osteosarcomatous transformation (”dedifferentiated” primary malignant GCT): report of two cases

 It is not uncommon for sarcomatous transformation of giant cell tumor (GCT) of bone to occur after radiation, but rarely does malignant transformation occur spontaneously, with less than 15 cases reported up to 1995. Only four of these cases have been documented in detail. We report two additional cases of GCT of bone spontaneously transforming or ”dedifferentiating” into osteosarcoma without radiation therapy. The first case is absolutely unique and most interesting in that the dedifferentiation process occurred in one of multiple GCT lung metastases 6 years after successful eradication of a primary tibial tumor. The right lung was resected due to development of a large tumor, and at pathologic examination, demonstrated several small nodules of conventional GCT and a much larger, 14-cm mass composed of a mixture of GCT and high-grade osteosarcoma. The second case involved a physician, who had a large tumor in the sacrum with vague symptoms for 8 years. Open biopsy revealed conventional, benign GCT of bone with a secondary aneurysmal bone cyst. Complete curettage 2 weeks later revealed, in addition to areas of conventional, benign GCT a second component of very high grade osteosarcoma. Both patients died less than 1.5 years from diagnosis. This report of osteosarcomatous transformation of a conventional GCT of bone strengthens the theory that there is a mesenchymal cell line in GCT that may spontaneously tansform to sarcoma.     

Luxatio erecta of the hip: a critical retrospective

 The term ”luxatio erecta” has been borrowed from the shoulder to identify rare traumatic hip dislocations in which there is inferior dislocation of the femoral head and inversion of the femoral shaft. A review of the literature is presented along with an additional illustrative case. The mechanism of injury, and the radiological and physical appearance of the patient, indicate that there are two subtypes of dislocation hitherto lumped together under the single term.     

MR arthrography of the shoulder and hip after fluoroscopic landmarking

Purpose. To describe a technique for intra-articular injection in the MR suite after conventional fluoroscopic landmarking in order to streamline MR arthrography. Design and patients. This technique was performed on 33 consecutive patients referred for MR arthrography of the shoulder to evaluate the glenoid labrum and on 15 consecutive patients referred for MR arthrography of the hip to evaluate the acetabular labrum. The patients were landmarked in the fluoroscopy suite, followed by a conventional MR examination. The intra-articular injection was then performed on the MR table and the MR arthrographic sequences obtained. Results. One of the 48 injections was extra-articular, requiring a second injection. The other injections were performed without incident, and the average total procedure time for all injections was 10 min. Conclusions. This technique is a reliable method of streamlining intra-articular injections when performing conventional MR imaging prior to the MR arthrographic portion of the examination. It shortens the total MR examination time by eliminating a visit to the fluoroscopy suite in the middle of the MR study, and its use of a straight anterior approach for both the shoulder and hip joints should be familiar to most people who perform conventional arthrography. Received: 27 August 1999 Accepted: 26 October 1999     

MR arthrography of the hip: normal intra-articular structures and common disorders

This pictorial review illustrates the anatomical features of normal intra-articular components of the hip and their common disorders on MR arthrography. On T1-weighted MR arthrograms, the normal contrast-filled joint cavity shows a homogeneous high signal intensity. Normal acetabular labrum appears as a well-delineated triangle showing a low signal intensity, surrounded by contrast material in the perilabral recess. Intra-articular paramagnetic contrast outlines labral tears, loose bodies, communicating labral cysts and cartilage lesions (traumatic tears, focal defects, degenerative fissures and thinning), and improves their detection. Overall, MR arthrography enables accurate detection and staging of hip intra-articular structure abnormalities. Received: 6 June 1998; Revision received: 2 January 1999; Accepted: 2 April 1999     

色素沉着绒毛结节性滑膜炎、腱鞘巨细胞瘤的 MRI表现及其应用价值

目的分析色素沉着绒毛结节性滑膜炎、腱鞘巨细胞瘤的MRI表现.方法回顾分析8例(色素沉着绒毛结节性滑膜炎7例,腱鞘巨细胞瘤1例)经手术病理证实病例资料.所有病例行MR平扫,2例同时增强扫描.本组资料中5例为术后复发,1例为手术后放疗前检查.结果病变位于膝关节6例,髋关节1例,胫腓上关节1例,病变呈弥漫型7例.MRI表现为关节腔内滑膜增生形成绒毛结节或肿块,结节内见长T1、短T2低信号6例,其中3例在T2WI上部分病灶呈低高混杂信号;1例腱鞘巨细胞瘤在T1WI、T2WI上呈稍高信号;增强后的病灶有强化;关节软骨、骨质受侵蚀6例;关节韧带受侵蚀4例;4例关节囊积液;关节囊肿胀5例;关节周围软组织受推移5例;半月板受累及1例.结论色素沉着绒毛结节性滑膜炎特征的MR表现为关节内滑膜增生形成绒毛结节,以及结节内含铁血黄素在T1WI、T2WI上呈低信号,典型表现呈"海绵垫样"、"苔藓状"、"菜花状".MRI是诊断、临床治疗和随访的重要手段,应作为首选的检查方法.     

Chromomycosis presenting as soft-tissue mass: report of a case with MRI features

Chromomycosis is primarily a skin disease that superficially presents as slowly growing, verrucous lesions, often warty or cauliflower-like in appearance. It may occasionally create a flat, plaque-like lesion in the skin but deep-seated tumorous presentation has not previously been reported. As the lesion is limited to the cutaneous and superficial subcutaneous tissues, hitherto reported cases have been described from the view point of dermatology and, so, without MRI study. We report a patient with pathologically proven chromomycosis that produced a subcutaneous mass in the dorsum of the hand with an emphasis on MRI features.     

Skeletal age as a determinant of bone mass in preadolescent females

 Objective. To evaluate the association between chronological age, skeletal age, pubertal stage, and basic anthropometry with bone mass of the total body, forearm, and second metacarpal bone in 456 healthy Caucasian females, aged 8–13 years. Design. Total body and forearm bone measurements were performed by dual X-ray absorptiometry, while bone mass of the second metacarpal was assessed by radiogrammetry. Skeletal age (SA) was assessed by the FELS method and pubertal stage was self-determined by selecting corresponding illustrations of breast and pubic hair development. The C _p criterion was used to select the best multiple regression model containing the subset of independent variables with the least bias and best predictive ability for each of the measured bone mass variables. Results. Of all the independent variables, weight, stature, and SA emerged as the most significant predictors for almost all the bone mass variables. Multiple regression models were created based on the C _p criterion with the resulting R ² (adjusted) for bone mineral content of total body, proximal forearm, ultradistal forearm, length of second metacarpal, as well as of total, medullary, and cortical areas: 0.793, 0.523, 0.390, 0.602, 0.232, 0.073, and 0.264, respectively. The measured bone variables were also regressed on SA using either quadratic or linear equations, depending on the shape of the cubic splines used for the best curve fitting. Significant positive association (p<0.0001) of SA and each of the bone variables was noted, the highest being with bone mineral density and content of total body (R ²=0.176, 0.338) and proximal and ultradistal forearm (R ²=0.216, 0.203, 0.106, 0.201), respectively, as well as with the length of the second metacarpal bone (R ²=0.339). Chronological age and pubertal stage did not have statistically significant predictive abilities for bone mass variables in the multiple regression models. Conclusions. We conclude that skeletal age is a powerful determinant of bone mass in children. It can be used as the criterion for the selection of a biologically homogeneous population with regard to bone mass. This may be important for the design of intervention studies targeting bone mass of children and adolescents.     

Collagenous fibroma of the arm: a report of two cases

A recently proposed addition to fibrous tumors in soft tissue was first described as desmoplastic fibroblastoma and later renamed collagenous fibroma. This tumor is clinically and morphologically distinct and benign. However, only a few series have been reported, and the clinicopathologic features are not widely recognized. We present two cases of collagenous fibroma of the arm. Both patients presented with an enlarging, well-circumscribed and mobile soft tissue mass. Magnetic resonance imaging showed areas of low signal intensity on both T1- and T2-weighted sequences. Needle aspiration cytology revealed nondiagnostic samples because of the low cellularity of the tumors. Each of the resected tumors was composed of low-cellular spindle- to stellate-shaped cells in a fibrous matrix with clear margination. After the marginal excisions, no recurrences were observed. Clinicians should be aware of this entity to prevent overtreatment, because imaging findings and cytologic features are similar to those of desmoid tumor. Received: 15 December 1999 Revision requested: 12 January 2000 Revision received: 31 March 2000 Accepted: 17 March 2000     

Extraskeletal osteochondroma of the foot

A case of pathologically proven extraskeletal osteochondroma is presented with magnetic resonance imaging (MRI), computed tomography (CT), bone scan and radiographic findings. The diagnosis of extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues of the distal extremities. Nomenclature surrounding this entity is controversial and is discussed. Received: 22 March 1999 Revision requested: 26 April 1999 Revision received: 22 May 1999 Accepted: 24 May 1999     

Giant cell tumor of bone with selective metastases to mediastinal lymph nodes

We report an unusual case of a recurrent giant cell tumor of the patella which presented with metastatic disease to the posterior mediastinal lymph nodes with no evidence of pulmonary metastases. The patient underwent chemotherapy with subsequent successful removal of the mediastinal mass. A review of the reported cases of mediastinal giant cell tumor metastases is provided.