Dedifferentiated liposarcoma of the lower extremity with low-grade dedifferentiation and low-grade osteosarcomatous component.

Dedifferentiated liposarcoma can arise de novo or as a complication of a preexisting well-differentiated liposarcoma. We describe the radiologic and pathologic features of a long-standing liposarcoma with multiple recurrences in a 59-year-old male. Imaging demonstrated a heterogeneous fat-containing mass in the anterior thigh. The adjacent proximal femur showed irregular cortical new bone, eventually followed by intramedullary osteoblastic involvement and pathologic fracture. Histologic assessment at resection revealed dedifferentiated liposarcoma with low-grade osteosarcomatous component. The patient subsequently developed metastatic lesions in the lungs containing osteoid and osteoblastic bone metastases. We discuss the radiologic and pathologic features of this rare entity that, to our knowledge, has previously been reported to directly involve osseous structures in only one other case and discuss the potential pitfalls in diagnosis.

The association of incomplete glenoid component seating and periprosthetic glenoid radiolucencies after total shoulder arthroplasty.

BACKGROUND: Radiolucent lines surrounding prosthetic glenoid components are commonly seen after unconstrained total shoulder arthroplasty and can be a harbinger of subsequent glenoid component failure. Whether less than 100% glenoid seating is associated with the development of radiolucent lines around glenoid prostheses is unknown. This study investigated the association between incomplete glenoid component seating and periprosthetic glenoid radiolucencies. METHODS: Thirty-six unconstrained total shoulder arthroplasties were performed in 29 patients for primary glenohumeral osteoarthritis with a minimum 2-year follow-up. All were implanted with a partially cemented all-polyethylene glenoid prosthesis. Patients were evaluated with standardized plain films preoperatively and postoperatively and with thin-cut computed tomography (CT) scans at the latest follow-up. The Lazarus and Yian classifications were used to assess radiolucency and seating on radiographs and CT scans. Ratings were calculated for intraobserver and interobserver reliability and given κ, the Kendall coefficient, and interclass correlation coefficient values. RESULTS: At a mean of 43 months (range 24-26 months) after surgery, neither Lazarus plain film radiolucency scores (P = .78) nor Yian CT radiolucency scores (P = .68) were associated with Lazarus plain film seating scores. Neither Lazarus plain film radiolucency scores (P = .25) nor Yian CT radiolucency scores (P = .91) were associated with modified Lazarus CT scan seating scores. CT allowed for better intraobserver and interobserver reliability in all categories. CONCLUSION: Radiolucencies around a partially cemented glenoid component were not associated with the degree of component seating. Complete seating of the glenoid component is not necessary to achieve radiographic implant stability at a mean follow-up of 43 months.

Bone presence between the central peg's radial fins of a partially cemented pegged all poly glenoid component suggest few radiolucencies.

BACKGROUND: Cement penetration problems and/or cement-induced bone necrosis may contribute to glenoid component failures. An all polyethylene component was developed that promotes biologic fixation between radial fins of its central peg and utilizes minimal cement fixation for its peripheral pegs, but it has little published data. We hypothesized better bone presence between the radial fins would be associated with less overall radiolucencies. This study's purpose was to utilize computed tomography (CT) and plain films to assess for bone between the central peg's radial fins and to assess overall component radiolucencies. MATERIALS AND METHODS: Thirty-five of 48 consecutively performed total shoulder arthroplasties (TSA) for primary glenohumeral osteoarthritis were in patients able to participate a minimum 2 years after surgery. All had reamed humeral head bone packed between radial fins of the central peg and minimal cement for the peripheral pegs. Thin cut (0.625 mm) CT scans, standardized plain films, Simple Shoulder Tests (SST), and Constant scores were obtained. A musculoskeletal radiologist calculated Yian CT scores, bone presence between fins on CT, and Lazarus radiolucency scores. RESULTS: At a mean of 43 months, by CT: 1) better Yian scores correlated with more bone between fins, and 2) bone was present in 6/6 inter-fin compartments in 23/35 shoulders, averaging 4.5/6 overall. Mean Lazarus radiolucency score was 0.45. Mean SST and Constant scores were 10.3 and 81.3, respectively. CONCLUSION: TSA utilizing autologous bone in inter-fin compartments of the central peg and minimal peripheral peg cement maintained bone presence a minimum 2 years post-op. More bone imparted fewer overall component radiolucencies.

MR imaging of hepatocellular carcinoma: relationship between lesion size and imaging findings, including signal intensity and dynamic enhancement patterns.

PURPOSE: To assess the relationship between lesion size and MR imaging findings of pathologically-proven hepatocellular carcinoma (HCC). MATERIALS AND METHODS: In a retrospective, single-center study, 37 consecutive patients were identified between 1999 and 2005 that underwent preoperative MRI and surgical resection of HCC. A total of 47 lesions (mean size = 6.85 cm, range = 1-25 cm) were assessed for signal intensity (SI), enhancement patterns, and secondary morphologic features. Interobserver rating, percentage enhancement, and contrast-to-noise-ratio (CNR) were determined. Lesions were assessed for combinations of typical MRI features. Regression analysis was used to assess relations between MRI findings and tumor size. RESULTS: On fat-suppressed T2-weighted (T2w) fast-spin-echo, smaller lesions had lower SI compared to larger lesions (P < 0.05). In the arterial phase, smaller lesions showed significantly higher percentage enhancement compared to larger lesions (P < 0.05). In the delayed phase, smaller lesions showed less pronounced washout (P < 0.05). Heterogeneity of the lesions, including fatty infiltration, internal nodules, or mosaic pattern, was observed significantly more frequently in larger lesions (P < 0.001). The classic combination of high T2w signal, strong arterial enhancement, and delayed phase washout was present in 23 of 44 lesions (52%). CONCLUSION: Smaller HCC often showed lower SI on T2w, more intense arterial enhancement, and less pronounced delayed washout compared to larger HCC.

Heel ultrasonography is not a good screening tool for bone loss after kidney and pancreas transplantation.

BACKGROUND: Solid organ transplant recipients, particularly simultaneous pancreas kidney recipients, are at high fracture risk. We tested whether quantitative ultrasonography (QUS) of the heel predicts bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA) in solid organ transplant recipients. METHODS: Thirty-eight transplant recipients (22 Female/16 Male) were studied. Spine and hip BMD was measured with a Hologic DXA scanner. 'Stiffness' of the heel was measured with a Lunar Ultrasound densitometer and compared with BMD by DXA. Contributing factors to bone loss were also assessed. RESULTS: Mean age was 43.1 +/- 1.3 yr. Simultaneous pancreas-kidney, kidney, and pancreas alone transplant recipients were assessed. Mean time post-transplantation was 3.0 +/- 0.6 yr. Mean DXA spine T-score was -1.15 +/- 0.22 (mean +/- SEM) and hip T-score was -1.22 +/- 0.20. There was no difference in mean T-score between women and men at the hip or spine. Mean right heel stiffness T-score was -0.97 +/- 0.25. There was no correlation between QUS and DXA at either the hip or spine in women or men. QUS had a false negative rate for identifying osteopenia or osteoporosis of 17% compared with DXA. The false positive rate for identifying osteopenia was 61%. CONCLUSIONS: The QUS is an unacceptable tool for identifying those at risk for bone loss after kidney or pancreas transplantation.