Synovial sarcoma arising in association with a popliteal cyst

Synovial sarcoma is a relatively common soft tissue sarcoma particularly in the adolescent and young adult. We report an unusual case of a synovial sarcoma arising within a popliteal cyst in a 13-year-old female presenting with bilateral popliteal cysts. MR imaging demonstrated the cyst with evidence of subacute haemorrhage and a discrete nodule of tumour. Received: 20 July 2000 Revision requested: 10 August 2000 Revision received: 24 August 2000 Accepted: 28 August 2000     

Rapid chondrolysis after an intra-articular leak of bone cement in treatment of a benign acetabular subchondral cyst: an unusual complication of percutaneous injection of acrylic cement

Percutaneous injection of methylmethacrylate is now increasingly employed to treat bone lesions, both malignant and benign. However, the risks of this procedure are still to be fully established. In this report, we describe a case of rapid chondrolysis appearing after the intra-articular leakage of cement during injection of an acetabular subchondral cyst, resulting in hip replacement. Although the mechanism of such chondrolysis is unknown, this event suggests a chondrolytic effect of the acrylic cement. Thus, it is essential to systematically search for the presence of an intra-articular passage before injecting bone cement into a peri-articular cyst. This unusual complication highlights the need for rigorous evaluation of the benefits and risks of percutaneous injection of acrylic cement in the treatment of benign lesions, especially close to an articulation. Received: 30 September 1999 Revision requested: 1 December 1999 Revision received: 27 December 1999 Accepted: 27 December 1999     

MRI of spinal hardware: comparison of conventional T1-weighted sequence with a new metal artifact reduction sequence

Objective. This study was designed to compare diagnostic quality of MR images of patients with spinal hardware acquired using a conventional T1-weighted spin-echo sequence and a new metal artifact reduction sequence (MARS). Conclusion. The new MARS sequence effectively reduces the degree of tissue-obscuring artifact produced by spinal fixation hardware and subjectively improves image quality compared with the conventional T1-weighted spin-echo sequence. Received: 30 May 2000 Revision requested: 12 September 2000 Revision received: 27 September 2000 Accepted: 27 November 2000     

Percutaneous Ethibloc injection in aneurysmal bone cysts

Objective. To investigate whether the injection of Ethibloc into aneurysmal bone cysts can be an effective treatment modality. Design and patients.Ethibloc is an alcoholic solution of zein (corn protein) which has thrombogenic and fibrogenic properties. Ten patients with aneurysmal bone cysts were treated with CT-guided percutaneous injection of Ethibloc into the cyst cavity. Ethibloc injection was the primary treatment in five patients. Four patients had recurrence following previous curettage and bone grafting and one patient had not responded to injection into the lesion of autologous iliac crest bone marrow aspirate. Three patients needed a second injection. The median follow-up was 27 (6–60) months. Results and conclusion.Symptoms were relieved in all patients. At imaging, seven patients had resolution of the lesion and three had partial response at the most recent follow-up. Complications consisted of a local transitory inflammatory reaction in two patients and an aseptic abscess in one patient. This relatively simple, minimally invasive procedure makes an operation unnecessary by stopping the expansion of the cyst and inducing endosteal new bone formation. This technique may be used as the primary management of aneurysmal bone cysts excluding spinal lesions. Received: 19 July 1999 Revision requested: 20 September 1999 Revision received: 9 November 1999 Accepted: 6 December 1999     

Solid aneurysmal bone cyst in the humerus

We report on a 69-year-old woman with a solid variant of aneurysmal bone cyst (solid ABC) in the left humerus with a pathological fracture. Radiographically, the lesion exhibited a relatively well-defined osteolytic lesion in the diaphysis of the left humerus. On magnetic resonance (MR) imaging, the medullary lesion exhibited a homogeneous signal intensity isointense with surrounding normal muscles on the T1-weighted images and a mixture of low and high signal intensity on the T2-weighted images. Contrast-enhanced T1-weighted images revealed diffuse enhancement of the entire lesion. The pathological study showed a proliferation of fibroblasts, histiocytes, chronic inflammatory cells and numerous multinucleated giant cells in a collagenous matrix. Abundant osteoid formation in the matrix was observed, but the cells were devoid of nuclear atypia. Aneurysmal cystic cavities were absent. A review of the English literature found 22 cases of solid ABC of the long bones. Received: 15 February 2000 Revision requested: 18 March 2000 Revision received: 17 April 2000 Accepted: 19 April 2000     

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease

Objective. Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease. Design. Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease. Results. Five percent (46/890) of lumbar pedicles in 23 patients had marrow signal intensity changes. Ninety-one percent (42/46) of the abnormal pedicles had adjacent degenerative joint disease of the facets, while only 21% (189/890) of normal pedicles had adjacent facet degenerative joint disease (p<0.001). Eighty-nine percent (41/46) of the pedicles with marrow signal intensity changes had adjacent degenerative disc disease. Conclusions. Pedicle marrow signal intensity changes are not a specific sign of spondylolysis; they are commonly seen with adjacent facet degenerative joint disease in the absence of spondylolysis. Pedicle marrow signal intensity changes are probably a response to abnormal stresses related to abnormal motion or loading caused by the degenerative changes in the spinal segment. Received: 2 May 2000 Revision requested: 18 July 2000 Revision received: 25 August 2000 Accepted: 1 September 2000     

Posteromedial subtalar coalition: imaging appearances in three cases

Objective. To define the imaging appearances in three cases of posteromedial subtalar coalition. Design. Three patients who presented with hindfoot pain were found to have non-osseous coalition involving the posteromedial hindfoot. This entity is distinct from conventional middle facet coalition as the sustentaculum is uninvolved. Results. Plain radiographs, available in two cases, demonstrated subtle irregularity of the posterior facet. MRI (three cases) demonstrated a mixed bony and cartilaginous mass lying posterior to the sustentaculum. There was trabecular oedema within the mass and adjacent talus, and narrowing of the space between the middle and posterior facets. Prominence and dilatation of the posterior tibial veins with tenosynovitis of the adjacent tibialis posterior tendon was seen. CT demonstrated the bony mass but did not detect the adjacent bony oedema. Conclusion. Posteromedial subtalar coalition may present with hindfoot pain and stiffness. The presence of a pseudarthrosis posterior to a normal middle facet is characteristic. The abnormality can be difficult to detect on plain radiographs. Received: 2 June 1999 Revision requested: 6 August 1999 Revision received: 13 September 1999 Accepted: 21 September 1999     

Intraosseous glomus tumor of the fibula

Glomus tumor is a rare, benign vascular tumor and intraosseous glomus tumor, which arises primarily within bone, is even rarer. Fewer than 20 cases have been reported in the literature. We present the case of a 34-year-old woman with glomus tumor primarily in the midshaft of the fibula that radiologically mimicked chondromyxoid fibroma, aneurysmal bone cyst or adamantinoma, together with a review of other reported cases. Received: 5 July 2000 Revision requested: 10 August 2000 Revision received: 28 August 2000 Accepted: 28 August 2000     

Spinal epidural hemangioma related to pregnancy

We report the case of a 39-year-old woman with adolescent idiopathic scoliosis presenting with myelopathy secondary to a spinal epidural hemangioma. MRI showed an epidural soft tissue mass within the spinal canal between T5 and T9 with severe spinal cord compression. Symptoms had a temporal relationship to her pregnancy. Surgical removal of the epidural hemangioma rapidly relieved her symptoms and neurologic deficits. Follow-up examination 2 years later demonstrated normal motor and sensory function, without any neurologic sequelae or progression of deformity. Received: 16 June 2000 Revision requested: 2 June 2000 Revision received: 13 September 2000 Accepted: 25 September 2000     

Phalangeal microgeodic syndrome: MR appearance

The authors describe the MR features of a case of microgeodic phalangeal syndrome in a 9-year-old boy. Roentgenograms showed multiple small areas of osteolysis in the middle phalanx of the right index finger. T1-weighted MR images showed lesions with diffuse low signal intensity not only in this phalanx but also in other phalanges. These lesions exhibited high signal intensity on T2-weighted images. Contrast- enhanced T1-weighted images showed a wide non-enhancing area in the middle phalanx of the index finger. Received: 26 September 2000 Revision requested: 2 November 2000 Revision received: 25 November 2000 Accepted: 27 November 2000     

TRUS, CT and MRI findings of hydatid disease of seminal vesicles

Hydatid disease of the urogenital system, especially seminal vesicles and prostate, or retroperitoneum is a very rare condition. Secondary dissemination of seminal vesicles has not been described before. We describe the transrectal ultrasonography (TRUS), CT and MRI findings of a secondary solitary hydatid cyst of the left seminal vesicle, in a patient with disseminated hydatid disease involving all abdominal organs except for right kidney. We obtained typical findings of hydatid cyst at all modalities. Received 13 June 1997; Revision received 23 September 1997; Accepted 14 November 1997     

Spontaneous osteonecrosis of the knee associated with ipsilateral tibial plateau stress fracture: report of two patients and review of the literature

Two cases are presented of spontaneous osteonecrosis of the knee (SONK) associated with stress fractures of the tibial plateau. This association lends further credence to the postulate that SONK has a traumatic etiology. Received: 9 May 2000 Revision requested: 15 June 2000 Revision received: 31 August 2000 Accepted: 4 September 2000     

Intra-articular membranous interposition detected by MRI in developmental dysplasia of the hip

Intra-articular membranous interposition was detected by MRI in the hip joint with residual subluxation of a girl aged 5 years 10 months. This structure, which had low signal intensity on both T1- and T2-weighted images, separated the femoral head from the acetabulum. Histological examination revealed chondrometaplasia, which suggested that this interposition might be transformed to a surface cartilaginous tissue of the secondary acetabulum often observed in residual subluxation of the hip. Received: 20 July 2000 Revision requested: 18 August 2000 Revision received: 8 September 2000 Accepted: 8 September 2000     

Radiologic and histopathologic findings in a rare case of complex occult spinal dysraphism with association of a lumbar fibrolipoma, neurenteric cyst and tethered cord syndrome

We present the case of a 60-year-old farmer who reported non-specific back pains for the past 30 years. Increasing paralysis of the left leg led to hospitalization. A complex occult spinal dysraphism comprising a fibrolipoma of the conus medullaris, an neurenteric cyst, and a tethered cord syndrome was diagnosed and operated on. The radiological and histological findings are demonstrated. Received 19 March 1997; Revision received 18 July 1997; Accepted 3 September 1997     

Synovial osteochondromatosis complicating pilon fracture of the tibia

A case of previously undiagnosed synovial osteochondromatosis complicating a tibial pilon fracture is presented. The entrapment of osteochondral bodies within the fracture margin prevented complete reduction of the fracture and necessitated surgical intervention. Received: 27 December 2000 Revision requested: 26 January 2001 Revision received: 19 March 2001 Accepted: 21 March 2001     

Paravertebral neurinoma associated with aggressive intravertebral extension

Neurinomas are relatively common benign tumors thought to arise from nerve sheath cells. Although intraosseous neurinomas may destroy the bone, extraosseous neurinomas with extensive destruction and invasion of bone are considered rare. We present two unusual cases of a benign extraosseous neurinoma that extensively invaded the vertebral body through the nutrient canal. Received: 1 September 2000 Revision requested: 3 November 2000 Revision received: 4 December 2000 Accepted: 5 December 2000     

Concomitant pituitary adenoma and Rathke's cleft cyst

We reviewed the clinical, radiological and surgical findings in patients with both pituitary adenoma and Rathke's cleft cyst. We retrospectively selected patients with both lesions from the 374 patients in whom a sellar/juxtasellar lesion was detected on MRI at 1.5 tesla. All patients received intravenous contrast medium. Concomitant pituitary adenoma and Rathke's cleft cyst were found in eight patients (2.1 %). The frequency of the combination was 3.5 % of pituitary adenomas and 11 % of Rathke's cleft cysts. Symptoms were always due to the adenoma, secreting adrenocorticotrophin in two patients and growth hormone in six. The adenoma was larger in five patients, and the cyst in three. The cysts gave variable signal. The adenoma was adjacent to the cyst in seven patients, and enclosed it in the other patient. As a result of experience with MRI, concomitant pituitary adenoma and Rathke's cleft cyst are now known not to be as rare as thought previously. When a nonenhancing cyst-like structure is demonstrated in a patient with pituitary adenoma, the possibility of a coexisting Rathke's cleft cyst should be considered. Received: 23 March 2000/Accepted: 12 July 2000     

L5 radicular pain related to a cystic lesion of the posterior longitudinal ligament

A 35-year-old man with a long history of left L5 radicular pain was found to have an intraspinal cystic lesion causing radicular compression. Magnetic resonance imaging demonstrated a round lesion situated in the anterior epidural space, with uniform high signal intensity on T2-weighted sequences characteristic of a cystic lesion. During surgery a liquid-containing cyst originating from the posterior longitudinal ligament was punctured and resected. The histologic aspect was that of a ganglion cyst without synovial layers. The radiologic differential diagnoses are discussed. Received: 20 December 1999; Revised: 15 March 2000; Accepted: 16 March 2000     

Telangiectatic dedifferentiation of a parosteal osteosarcoma

A unique case of parosteal osteosarcoma (POS) of the proximal femur, with areas of telangiectatic dedifferentiation, in a 28-year-old woman is reported. The patient had a 7-week history of pain and swelling in her right thigh. A biopsy diagnosis of POS was established. The patient was treated with two cycles of intra-arterial chemotherapy, followed by limb salvage surgery. Histological examination of the resected specimen showed POS with areas of dedifferentiation composed of high-grade telangiectatic osteosarcoma with associated secondary aneurysmal bone cyst change. Received: 17 April 1998 Revision requested: 11 May 1998 Revision received: 9 May 2000 Accepted: 11 May 2000     

The clinical significance of gall-bladder non-visualization in cholescintigraphy of patients with choledochal cysts

Intravenous radionuclide cholescintigraphy (IVRC) provides a very specific picture for choledochal cysts. However, the clinical significance of the non-visualization of the gall-bladder (GB) activity in these cases is unclear. In this study, we reviewed 27 patients with choledochal cysts who underwent IVRC within 7 days prior to operation and correlated the GB findings on IVRC with the histopathological results. In 18 of the 27 patients (66.7%), there was non-visualization of the GB at 4 h post injection. Among these, two had histopathological features of acute cholecystitis (AC), 11 had chronic cholecystitis (CC), and five had normal GBs. In the other nine patients with visualization of the GB, there were five cases of CC and four normal GBs. If we apply the finding of non-visualization of the GB at 4 h post injection as the criterion for the diagnosis of AC, the diagnostic accuracy was only 40.7% (11/27). We concluded that: (1) GB disease (AC and CC) was common (66.7%: 7.4% and 59.3% respectively) in choledochal cyst patients. (2) Non-visualization of the GB on IVRC did not necessarily indicate AC in choledochal cyst cases, and the diagnostic accuracy was low. (3) GB disease is not the only cause of GB non-visualization on IVRC. A huge choledochal cyst causing a mass or reservoir effect may be a cause of GB compression and result in non-visualization of the GB.