Recent clinical studies have reported that microsatellite instability (MSI) colorectal cancers show a high sensitivity to 5-FU, but these reports are contradictory to findings from in vitro analyses. In this study, we analyzed the relationship between MSI phenotypes and the expression of 5-FU metabolic enzymes in human colorectal cancer specimens. MSI phenotypes in 174 sporadic colorectal carcinomas were determined and grouped into the following three categories based on the Bethesda guidelines: high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and stable microsatellite (MSS). The expressions of dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) in tumor specimens were measured by enzymelinked immunosorbent assays. The ratio of TP to DPD expression (TP/DPD ratio) was calculated for each tumor. These three factors were compared with regard to MSI phenotypes by non-parametric and logistic regression analyses using cut-off values at their medians. MSI-L tumors were excluded from statistical analyses. Thirteen tumors were classified as MSI-H, 8 tumors as MSI-L, and 153 tumors as MSS. DPD expression did not differ between MSI-H tumors and MSS tumors. TP expression and the TP/DPD ratio were significantly higher in MSI-H tumors than in MSS tumors [TP, 160.1± 104.0 vs 97.3 ± 53.7 (Units/mg protein) (P=0.009); TP/DPD ratio, 3.04 ± 1.62 vs 2.07 ± 1.08, (P=0.016)]. These differences were also significant in multivariate analysis. In conclusion, these data suggest that 5-FU catabolic activity in cancer tissue does not differ between MSI-H and MSS tumors. However, 5-FU anabolic activity in cancer tissue is higher in MSI-H than in MSS colorectal carcinomas.

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We present a case of ovarian plasmacytoma results in the patient's death by very quick progression after the operation, radiation and chemo therapy. As reported cases of primary ovarian plasmacytoma are very rare, its prognosis remains unknown. To date, we found seven reports of solitary ovarian plasmacytoma. Except for our case, most cases showed relatively slow progression or need only strict observation without recurrence. Although post-surgical therapy of ovarian plasmacytoma is not clearly established, our case was needed to use radiation and chemo therapy against the very rapid recurrent tumor. In this case, ovarian plasmacytoma relapsed very quickly, suggesting that some cases of ovarian plasmacytoma may require an aggressive adjuvant therapy.

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Purpose: To study the relationship between bone marrow edema (BME) and subchondral fracture in osteonecrosis of the femoral head (ONFH), and to analyze MRI findings of subchondral fracture and correlate them with those of CT. Materials and Methods: Fifty seven hips in 38 patients with ONFH were studied retrospectively. Images were obtained with 1.5-T MRI unit and multidetector helical CT. Selected hips were divided into edema positive and edema negative groups. In each group presence or absence of subchondral fracture and/or collapse of femoral head was assessed, and the MR findings were compared with those of CT. Results: Thirty (52.6%) of 57 hips showed BME during the course of ONFH. In these edema positive group, 29 (96.7%) of 30 hips showed subchondral fracture and/or femoral head collapse, whereas only 7 (25.9%) of 27 hips in edema negative group showed subchondral fracture and/or FH collapse (P < 0.0001). A low-signal intensity line on T1 and T2 weighted MR images and linear lucency on CT were the most common patterns of subchondral fracture. Conclusion: Our study showed significant relationship between BME and subchondral fracture/ femoral head collapse and supported the results of previous studies in considering BME as a marker for potential progression of osteonecrosis.

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Gastrointestinal stromal tumors (GISTs) in the liver are exceedingly rare. We report a case of hepatic GIST with myxoid changes and hemangiopericytoma-like patterns. A 69-year-old woman presented with epigastric discomfort, and underwent laparotomy for an extruded tumor in the liver. Five years later, recurrent tumor was excised. The primary tumor contained extensive necrotic and myxoid areas. Spindle and epithelioid cells plus a few giant cells with abundant myxoid matrix surrounded the necrotic areas. Immunohistochemically, the spindle cells were distinctly positive for KIT as well as vimentin and smooth muscle actin, leading to a diagnosis of hepatic GIST. The second excised tumor showed increased cellularity and nuclear atypia of epithelioid cells with hemangiopericytoma-like patterns. Although rare, we should consider GIST as a differential diagnosis for a hepatic mesenchymal tumor.

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Background Acinar cell carcinoma (ACC) is a very rare malignancy and represents only 1% to 2% of pancreatic exocrine carcinomas. At the time of diagnosis, 75% of ACC are resectable. Reliable data concerning effective adjuvant chemotherapy has not been established. Case presentation A 30-mm tumor in the pancreatic tail was incidentally discovered by computed tomography in a 71-yearold man. Several swollen lymph nodes were seen around the main tumor. Endoscopic retrograde cholangiopancreatography (ERCP) revealed disruption of the main pancreatic duct. The patient underwent curative resection (R0) with distal pancreatectomy and node dissection. Histopathological examination revealed ACC with lymph node metastases; adjuvant chemotherapy was performed with gemcitabine after surgery. Twelve months later, the patient showed no sign of recurrence. Conclusion The prognosis of ACC is dismal, although compared to ductal adenocarcinoma, the mean survival appears to be longer. Patients with advanced-stage ACC might benefit from gemcitabine-based adjuvant chemotherapy.

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Chorioangioma is the most common benign placental tumor arising from the chorionic stroma and capillaries, and histologically accounts for about 1% of placental tumors¹⁾. It rarely exceeds 5 cm in diameter, and is clinically diagnosed in 1 out of every 8,000-50,000 patients¹⁾. We report a patient with a relatively large chorioangioma (10 cm in diameter) accompanied by polyhydramnios.

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