Benign vascular lesions of bone: radiologic and pathologic features

 The benign vascular tumors of bone represent a diverse group of tumors that can present with a broad spectrum of clinical signs and symptoms. They can also present a significant diagnostic challenge due to their widely variable radiographic imaging and histologic features. Some of the tumors manifest as clearly benign lesions with tissue-specific diagnostic imaging features, while others have non-specific imaging features that may simulate malignant neoplasm. This article will provide a review of the nomenclature and the characteristic radiographic and pathologic features of the benign vascular lesions of bone. The information will aid in improving our diagnostic accuracy and enhance our understanding of the biologic potential of this diverse group of osseous lesions. Received: 14 May 1999 Revision requested: 17 June 1999, 6 October 1999 Revision received: 27 October 1999 Accepted: 27 October 1999     

Metastatic bone tumor mimicking spontaneous osteonecrosis of the medial condyle of the femur: misleading appearance on MR imaging

We report a case of a metastatic bone tumor that mimicked spontaneous osteonecrosis of the medial condyle of the femur on magnetic resonance imaging. Received: 5 October 1999 Revision requested: 11 November 1999 Revision received: 10 January 2000 Accepted: 17 January 2000     

Desmoplastic fibroma of bone: MRI features

Desmoplastic fibroma of bone is a very rare benign tumor, which may be locally aggressive. In contrast to the well-documented radiological appearance, the literature on MR imaging features of this tumor is scarce. The MR imaging characteristics in our case are compared to those previously reported. Although there is a considerable overlap in the MR imaging features with other bone tumors, an interesting MR feature of desmoplastic fibroma is the presence of low to intermediate signal intensity foci on T2-weighted images, which radiographically does not correspond to calcifications. This feature may help narrow the differential diagnosis. Received: 24 May 1999 Revision requested: 30 June 1999 Revision received: 8 October 1999 Accepted: 14 October 1999     

MR appearances in a case of femoral ecchinococcosis

Magnetic resonance (MR) findings of a rare case of osseous echinococcosis with involvement of the femur are described. Attention is drawn to the typical MR appearances and therapeutic management. Received: 4 October 1999 Revision requested: 28 October 1999 Revision received: 20 November 1999 Accepted: 1 December 1999     

Imaging of plant-thorn synovitis

We describe a case of plant-thorn synovitis of the elbow resulting from a thorn injury. This caused recurrent pain and swelling of the elbow over a 3-month period. A magnetic resonance imaging examination was initially requested to exclude septic arthritis, and demonstrated a joint effusion, synovitis, and a 2-cm linear opacity embedded in the synovium. Ultrasound was performed prior to surgery to confirm these findings and provide accurate localization of the thorn fragment, later removed at surgery. To our knowledge this is the first example of this condition that has been confirmed by radiological imaging prior to surgery. Received: 12 August 1999 Revision requested: 31 October 1999 Revision received: 1 May 2000 Accepted: 11 May 2000     

Intra-articular regional migratory osteoporosis of the knee

We report a case of lntra-articular regional migratory osteoporosis of the knee in a 53-year-old man. The case demonstrates an unusual pattern of migration of the marrow edema within the knee joint. This phenomenon has received scant attention in the radiological literature. Received: 9 July 1999 Revision requested: 24 August 1999 Revision received: 6 October 1999 Accepted: 8 October 1999     

Complete rupture of the distal semimembranosus tendon with secondary hamstring muscles atrophy: MR findings in two cases

Complete rupture of the hamstring muscles is a rare injury. The proximal musculo-tendinous junction is the most frequent site of rupture. We present two cases of complete rupture of the distal semimenbranosus tendon, which clinically presented as soft-tissue masses. MR imaging permitted the correct diagnosis. There has been only one other such case reported. Received: 15 October 1999 Revision requested: 6 February 2000 Revision received: 8 March 2000 Accepted: 13 March 2000     

The magnetic resonance imaging of musculoskeletal hemorrhage

Hematomas in the extremities can present clinically as a soft tissue mass. Hematomas can usually be distinguished from neoplasia on MR by the signal patterns of hemoglobin breakdown products, which are dependent on the chemical bonding and oxidation state of hemoglobin iron. Beginning with a discussion of relevant atomic electronic structure, this review will examine how oxyhemoglobin, deoxyhemoglobin, methemoglobin, and hemosiderin, the principal iron compounds occurring in the various stages of a hematoma, affect its appearance on MRI. Received: 26 August 1999 Revision requested: 6 October 1999 Revision received: 27 October 1999 Accepted: 27 October 1999     

Angiosarcoma associated with chronic lymphedema (Stewart-Treves syndrome) of the leg: MR imaging

Magnetic resonance (MR) imaging findings of two patients with Stewart-Treves syndrome are presented. MR imaging showed edematous changes in the subcutaneous fat and skin masses that proved to be angiosarcomas. MR signal intensity of the tumor was low compared with fat on T1-weighted images and intermediate and heterogeneous on T2-weighted images. In one patient, administration of intravenous Gd-DTPA showed marked enhancement in the early phase, which persisted until the delayed phase. These finding on dynamic MR imaging may reflect the abundant vascular spaces seen in these tumors. Received: 20 August 1999 Revision requested: 28 October 2000 Revision received: 31 January 2000 Accepted: 8 February 2000     

Premature epiphyseal fusion and degenerative arthritis in chronic recurrent multifocal osteomyelitis

A 9-year-old boy was diagnosed with chronic recurrent multifocal osteomyelitis affecting multiple sites. During an 8-year follow-up he developed premature closure of a distal radial epiphysis and degenerative changes in the adjacent radiocarpal joint. Received: 26 July 1999 Revision requested: 24 August 1999 Revision received: 27 September 1999 Accepted: 8 October 1999     

Chronic ulceration of the leg following extensive scarring due to a snake bite complicated by squamous cell carcinoma

Chronic ulcers of the leg are common in Brazil, perhaps more common than in the developed world. We report a case of a chronic ulcer of the leg following extensive scarring due to a bite by a venomous snake, which eventually led to a squamous cell carcinoma. Received: 16 August 1999 Revision requested: 8 October 1999 Revision received: 10 December 1999 Accepted: 15 December 1999     

Magnetic resonance imaging findings in anterolateral impingement of the ankle

Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle. Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group. Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter. Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. Received: 22 July 1999 Revision requested: 20 September 1999 Revision received: 7 October 1999 Accepted: 8 October 1999     

Intraosseous schwannoma of the metacarpal

Intraosseous schwannoma (neurilemmoma) is an extremely rare, benign neoplasm, constituting less than 0.2% of primary bone tumors. It infrequently involves the bones of the hand. We present a case of intraosseous neurilemmoma of the metacarpal. Received: 26 July 1999 Revision requested: 16 August 1999 Revision received: 16 September 1999 Accepted: 4 October 1999     

Dumb-bell-type teratoma in the lumbar spine

We report a case of a lumbar teratoma in a 50-year-old woman. The teratoma showed a dumb-bell-type expansion at the level of the left L3/4 foramen with massive erosion of the L3 vertebral body. MRI revealed inhomogeneous signal changes in the tumor, which were histologically compatible with a mixture of bone, muscle, fat, and cyst containing sebaceous material. Complete resection of the tumor and spinal arthrodesis with pedicle screw fixation was necessary to obtain stability of the affected spinal segment. Received: 30 July 1999 Revision requested: 24 August 1999 Revision received: 11 October 1999 Accepted: 12 October 1999     

Proteus syndrome: MRI characteristics of plantar cerebriform hyperplasia

Proteus syndrome is a rare congenital hamartomatous syndrome with a variety of abnormalities. It shares many features with other congenital hamartomatous disorders, but cerebriform hyperplasia of the soles and the palms is known as a quite distinctive characteristic in the dermatologic literature. The purpose of this case report is to demonstrate the MRI features of plantar cerebriform hyperplasia in a 9-year-old boy with known Proteus syndrome. Received: 8 July 1999 Revision requested: 8 September 1999 Revision received: 27 September 1999 Accepted: 8 October 1999     

Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging

Pulmonary perfusion defects can be demonstrated with contrast-enhanced dynamic MR perfusion imaging. We present the case of a patient with a pulmonary artery sarcoma who presented with a post-operative pulmonary embolus and was followed in the post-operative period with dynamic contrast-enhanced MR perfusion imaging. This technique allows rapid imaging of the first passage of contrast material through the lung after bolus injection in a peripheral vein. To our knowledge, this case report is the first to describe the use of this MR technique in showing the evolution of peripheral pulmonary perfusion defects associated with pulmonary emboli. Received: 27 July 1998; Revision received: 28 October 1998; Accepted: 20 January 1999     

Marginal erosive discovertebral ”Romanus” lesions in ankylosing spondylitis demonstrated by contrast enhanced Gd-DTPA magnetic resonance imaging

Objective. To assess the value of Gd-DTPA magnetic resonance (MR) imaging in the demonstration of marginal destructive discovertebral Romanus lesions in ankylosing spondylitis. Design and patients. A prospective study of Gd-DTPA MR imaging was performed in 39 patients with a clinical diagnosis of ankylosing spondylitis and typical Romanus lesions seen on radiographs of the thoracolumbar spine. MR morphological appearances and signal intensity changes at the discovertebral junctions were analysed and compared with the radiographic findings. Results. Ninety-nine discovertebral junctions with Romanus lesions showed low signal intensity on T1-weighted and high signal on T2-weighted and T1-weighted postcontrast images at the vertebral corners consistent with oedematous hyperaemic inflammatory tissue. There were nine discovertebral junctions with similar MR findings but normal radiographs. Fifty-three discovertebral junctions showed syndesmophyte formation with increased signal intensity on both T1- and T2-weighted images with no contrast enhancement. Sixty-five discovertebral junctions showed a mixture of radiographic features and varied high and low signal changes at the vertebral rim on MR imaging with rims of enhancement in the vertebral body following contrast administration. Conclusion. Gd-DTPA MR imaging demonstrates a variable signal pattern and degree of contrast enhancement which may reflect the evolutionary stages of discovertebral enthesitis in ankylosing spondylitis. MR imaging may identify early erosive changes in radiographically normal vertebra. The role of MR imaging needs further investigation. Received: 6 April 1998 Revision requested: 7 May 1998 Revision received: 26 October 1999 Accepted: 27 October 1999     

Erdheim-Chester disease with intramuscular lipogranuloma

We report on a rare manifestation of Erdheim-Chester disease with intramuscular lipogranuloma. The patient was a 66-year-old man who noted a soft tissue mass in the right quadriceps femoris muscle. Radiographs revealed symmetrical osteosclerosis in the diametaphysis of both femora and tibiae. An open biopsy revealed a proliferation of lipid-laden histiocytes in the femoral bone marrow and the quadriceps femoris muscle. To our knowledge, this is the second case of Erdheim-Chester disease involving muscle. Received: 4 October 1999 Revision requested: 18 November 1999 Revision received: 1 December 1999 Accepted: 2 December 1999     

Muscle hernias of the lower leg: MRI findings

Muscle hernias of the lower leg involving the tibialis anterior, peroneus brevis, and lateral head of the gastrocnemius were found in three different patients. MRI findings allowed recognition of herniated muscle in all cases and identification of fascial defect in two of them. MR imaging findings and the value of dynamic MR imaging is emphasized. Received: 1 March 1999 Revision requested: 24 March 1999 Revision received: 19 April 1999 Accepted: 20 April 1999     

Retroisthmic cleft: a stress fracture of the lamina

The retroisthmic cleft is a rarely diagnosed defect in the lamina of the lumbar spine. It has always been considered a congenital anomaly. This is the first report we are aware of showing radiological changes in a retroisthmic cleft over a period of time. The follow-up of this patient over a period of 6 years, the radiological and scintigraphic appearances and a review of the literature suggests that the retroisthmic cleft is a stress fracture of the lamina. Received: 9 September 1999 Revision requested: 12 October 1999 Revision received: 1 December 1999 Accepted: 2 December 1999