Imaging of giant cell tumour of the tendon sheath.

Giant cell tumours of the tendon sheath (GCTTS) and pigmented villonodular synovitis (PVNS) are part of a spectrum of benign proliferative lesions of synovial origin that may affect the joints, bursae and tendon sheaths. This review article describes the clinicopathological features and imaging findings in patients with GCTTS. GCTTS usually presents as a soft tissue mass with pressure erosion of the underlying bone. Magnetic resonance (MR) imaging of GCTTS typically shows low to intermediate signal on T1- and T2-weighted spin-echo sequences due to the presence of haemosiderin, which exerts a paramagnetic effect. On gradient-echo sequences, the paramagnetic effect of haemosiderin is further exaggerated, resulting in areas of very low signal due to the blooming artefact. Ultrasonography shows a soft mass related to the tendon sheath that is hypervascular on colour or power Doppler imaging.

Sarcomatous transformation in diaphyseal aclasis.

Multiple hereditary exostosis (or diaphyseal aclasis) is a condition characterized by the development of multiple osteochondromas. The tendency for malignant transformation into chondrosarcoma is well known. Malignancy typically arises from the cartilaginous cap of the osteochondroma. Radiographs supplemented by computed tomography have an important role in the diagnosis of this condition. Magnetic resonance imaging shows the features of sarcomatous change and aids in differentiating malignancy from pseudotumours.

Magnetic resonance imaging appearances of fibrous dysplasia.

Fibrous dysplasia is a developmental disorder in which normal bone marrow is replaced by fibro-osseous tissue. The radiographic, CT and scintigraphic appearances of this condition are well known. The MRI appearances of fibrous dysplasia have not been widely published. The lesions are largely isointense with areas of hypointensity on T(1) weighted images and appear heterogeneously hyperintense on T(2) weighted images. The enhancement pattern is patchy central, rim, homogeneous, or a combination. The MRI features reflect the variable tissue components of this entity. This pictorial review aims at highlighting the MRI appearances, with pathological correlation.

Local recurrence of parosteal osteosarcoma adjacent to a prosthesis after 20 years: a case report.

We describe the treatment of an uncommonly late presentation of a recurrent parosteal osteosarcoma of the distal femur. The osteosarcoma had originally been detected 20 years earlier, and had been treated with wide excision and mega-prosthesis to reconstruct the femur. The tumour recurred in close proximity to the femur prosthesis and encased half the femoral stem. Because there was a large piece of metal at the site of recurrence, which might have interfered with computed tomography and magnetic resonance imaging, ultrasonography was used to locate the lesion. The tumour was successfully treated with wide local re-excision. This case emphasises the importance of the long-term follow-up of patients with parosteal osteosarcoma.

Nonhematologic malignancies after allogeneic hematopoietic stem cell transplantation: incidence and molecular monitoring.

Survivors of allogeneic hematopoietic stem cell transplantation (HSCT) are at a life-long increased risk of secondary nonhematologic malignancies. In 615 adult Chinese allogeneic HSCT patients, nine developed nonhematologic malignancies. The 5-year cumulative incidence was 6.1%, 4.5 times the background cancer incidence. Early-onset (within first 6 months) and late-onset (>3 years) subtypes were observed. Secondary cancers included hepatocellular carcinoma, oral and esophageal squamous cell tumors and lung adenocarcinoma in a female nonsmoker. The spectrum reflected local cancer epidemiology, which was different from Western populations. The pathogenesis might be related to acceleration of pre-existing cancers (early-onset type), or prolonged immunosuppression (late-onset type). DNA chimerism studies showed that all tumors were recipient-derived. In the plasma, DNA in all cases was apparently donor-derived, although aberrantly methylated p15 was detectable in a patient with a p15-methylated secondary cancer, implying that minute quantities of tumor (and therefore recipient) derived DNA might be present.

Delayed portal vein thrombosis after experimental radiofrequency ablation near the main portal vein.

BACKGROUND: Portal venous blood flow may protect adjacent tumour cells from thermal destruction with radiofrequency ablation (RFA). This study aimed to investigate the local effect of RFA on the main portal vein branch, and the completeness of cellular ablation in its vicinity, with or without a Pringle manoeuvre using a porcine model. METHODS: This was an in vivo study on 23 domestic pigs. RFA using a cooled-tip electrode was performed 5 mm from the left main portal vein branch under ultrasonographic guidance for 12 min with (n = 10) or without (n = 10) a Pringle manoeuvre. Ten pigs were killed 4 h after the procedure to study the early effects of RFA and ten others were killed 1 week later to determine any delayed effect. As a control, sham operations with a Pringle manoeuvre for 12 min were performed on three pigs. The flow velocity changes of portal vein and hepatic artery were measured using Doppler ultrasonography, and the completeness of cellular ablation around the portal vein was assessed qualitatively by histochemical staining and quantitatively by measuring intracellular levels of adenosine 5'-triphosphate (ATP). RESULTS: In the absence of the Pringle manoeuvre, there was no significant change in mean(s.d.) portal vein flow velocity before RFA (20.0(3.5) cm/s) and at 4 h (18.5(2.5) cm/s) (P = 0.210) and 1 week (19.5(2.2) cm/s) (P = 0.500) after the procedure. Gross and histological examination of the portal vein branches showed no damage without the Pringle manoeuvre. In all pigs that underwent RFA with a Pringle manoeuvre, the portal vein was occluded 1 week after the operation; histological examination of the affected portal vein showed severe thermal injury and associated venous thrombosis. The local effect of RFA on the hepatic artery was similar. With intact portal blood flow during RFA, complete ablation of liver tissue around the pedicle was demonstrated by histochemical staining and measurement of the intracellular ATP concentration. CONCLUSION: RFA was safe when applied close to the main portal vein branch without a Pringle manoeuvre, with complete cellular destruction. Use of the Pringle manoeuvre resulted in delayed portal vein and hepatic artery thrombosis and injury to the hepatic artery and bile duct.

Cholestatic jaundice caused by sequential carbimazole and propylthiouracil treatment for thyrotoxicosis.

A 36-year-old Chinese man presented to the Queen Mary Hospital in August 1999 with a 2-week history of jaundice due to propylthiouracil treatment for thyrotoxicosis. He had previously received carbimazole but had developed an urticarial skin rash after 2 weeks of treatment. The patient developed liver failure and fulminant pneumonitis shortly after hospital admission. Despite receiving treatment with broad-spectrum antibiotics and intravenous immunoglobulin, he died 11 days after the onset of the respiratory symptoms. Postmortem examination using electron microscopy showed typical glycogen bodies within the cytoplasm of the hepatocytes, which corresponded to eosinophilic cytoplasmic inclusion bodies visible under light microscopy. Immunohistochemical studies of the inclusion bodies were positive for carcinoembryonic antigen and albumin, and negative for fibrinogen, complement protein C3, immunoglobulins G, M, and A, alpha-fetoprotein, and alpha-1-antitrypsin. This is the first report of a patient who received two sequential antithyroid drugs and developed predominate cholestasis with unique histological features. Extreme caution should be taken when a patient develops allergy to one type of antithyroid drug, because cross-reactivity may develop to the other type.

Use of bisphosphonate to manage avulsion fracture of tibial tuberosity with underlying angiomatosis: a case report.

An unusual case of avulsion fracture of the tibial tuberosity with underlying angiomatosis in a middle-aged man is described, with particular emphasis on the successful use of bisphosphonate in its treatment and the value of serial dual energy X-ray absorptiometry in its subsequent disease monitoring. This case illustrates the importance of careful correlation of the clinical, radiological, and histological findings in the management of skeletal tumour and tumour-like lesions. The differential diagnosis of osteolysis with vascular ectasia is discussed.

Analysis of Clonality in Kimura's Disease.

Kimura's disease is a chronic inflammatory disorder of unknown etiology. A 62-year-old man presented with asymptomatic cervical lymphadenopathy associated with eosinophilia and increased serum immunoglobulin E. Excision biopsy showed Kimura's disease. Three years later another groin lymph node appeared and showed similar pathologic features. Polymerase chain reaction for Ig heavy chain and T-cell receptor (TCR) genes on DNA extracted from the cervical lymph node showed smear patterns. However, polymerase chain reaction for TCRdelta gene showed a clonal rearrangement. Sequencing showed a complete VDJ rearrangement (Vdelta1-N-Ddelta2-N-Jdelta), confirming the presence of a clonal T cell population. The same clonal TCRdelta rearrangement was amplified by polymerase chain reaction from the groin lymph node biopsied 3 years later. These results showed that the primary and recurrent lesions were biologically related. Furthermore, the presence of identical T cell clones in different sites and at different times suggested that a clonal T cell population might have contributed to the pathogenesis in this case of Kimura's disease.

Imaging of peripheral PNET: common and uncommon locations.

AIM: We present the imaging features of peripheral primitive neuroectodermal tumour (PNET) in eight children, highlighting the unusual locations of this tumour in three children. MATERIALS AND METHODS: At presentation, the tumours were studied with magnetic resonance imaging (MRI; n = 6), computed tomography (CT; n = 7) and ultrasound (US; n = 1). The diagnoses were confirmed histologically (n = 8), immunohistochemically (n = 8), by cytogenetics (n = 3) and electron microscopy (n = 1). Correlation with gross pathology, histology, treatment and outcome were obtained. RESULTS: The tumours were located in the chest wall (n = 2), shoulder, pelvis, small bowel mesentery, adrenal gland, dura mater and skin and subcutaneous tissue of the abdominal wall (n = 1 each). Peripheral PNET arising from the small bowel mesentery, adrenal gland and dura mater have not been previously reported in the English literature. The tumours were mainly large (mean size: 10.6 cm) and infiltrative. All tumours were heterogeneously hyperintense on T2-weighted MRI, heterogeneously iso/hypodense on CT and had variable contrast enhancement. Most tumours were heterogeneously hypointense to muscle on T1-weighted MRI. US showed a hypoechoic mass with a cystic component. CONCLUSION: Peripheral PNET can occur in unusual locations. The clinical and imaging features of peripheral PNET are non-specific, making tissue diagnosis essential. PNET should be included in the differential diagnosis of aggressive soft tissue tumours in children.