[A case of metastatic rectal cancer showing a sustained complete response to chemotherapy with FOLFIRI followed by UFT].

The FOLFIRI regimen (irinotecan in combination with bolus and continuous infusion of 5-FU and l-LV) and FOLFOX regimen (oxaliplatin/5-FU/LV therapy) are now standard chemotherapy for metastatic colorectal cancer in Western countries. Combining those regimens, a median overall survival time (MST) of over 20 months has been reached. However, adverse reactions related to those regimens have included deteriorating patient quality of life (QOL). Here, we report a case of metastatic rectal cancer showing a complete response (CR) to cycle 4 in FOLFIRI regimen, while maintaining a CR status for over 11 months and good QOL, as a result of chemotherapy with 4 cycles of FOLFIRI followed by UFT.

Undifferentiated (embryonal) sarcoma of the liver in middle-aged adults: smooth muscle differentiation determined by immunohistochemistry and electron microscopy.

Undifferentiated (embryonal) sarcoma of the liver (UESL) is a rare pediatric liver malignancy that is extremely uncommon in middle-aged individuals. We studied 2 cases of UESL in middle-aged adults (1 case in a 49-year-old woman and the other in a 62-year-old man) by histology, immunohistochemistry, and electron microscopy to clarify the cellular characteristics of this peculiar tumor. One tumor showed a mixture of spindle cells, polygonal cells, and multinucleated giant cells within a myxoid matrix and also revealed focal areas of a storiform pattern in a metastatic lesion. The other tumor was composed mainly of anaplastic large cells admixed with few fibrous or spindle-shaped components and many multinucleated giant cells. In both cases, some tumor cells contained eosinophilic hyaline globules that were diastase resistant and periodic acid-Schiff positive. Immunohistochemically, the tumor cells showed positive staining for smooth muscle markers, such as desmin, alpha-smooth muscle actin, and muscle-specific actin, and also for histiocytic markers, such as alpha-1-antitrypsin, alpha-1-antichymotrypsin, and CD68. Electron microscope examination revealed thin myofilaments with focal densities and intermediate filaments in the cytoplasm of tumor cells. Our studies suggest that UESL exhibits at least a partial smooth muscle phenotype in middle-aged adults, and this specific differentiation may be more common in this age group than in children. Tumor cells of UESL with smooth muscle differentiation in middle-aged adults show phenotypic diversity comparable to those of malignant fibrous histiocytoma with myofibroblastic differentiation.