[Morphology of the cells in myxoid tumors]

We describe a morphologic study of myxoid cells in myxoid tumors or with myxoid regions: myxoid fibrosarcoma, myxoma, myxoid liposarcoma, embryonal rhabdomyosarcoma, chondroma, chondrosarcoma, myxoid leiomyosarcoma, schwannoma, and odontoameloblastoma; and we compare with fibroblasts of umbilical cord, embryonal mesenquima and loose connective tissue in inflammatory conditions. Histologic techniques: H-E, PAS, Masson's trichrom, and Del Río Hortega's panoptic silver staining. Histologically Del Río Hortega's technique reveals bipolar fibroblasts with long processes. In myxoma and myxoid fibrosarcoma they are stellated with abundant processes and mucin cytoplasm secretion contained in bowls that slides through cytoplasmic expansions and discharge into intercellular space. The lipoblasts of myxoid liposarcoma are also stellated with abundant processes and contain drops of lipids. The rhabdomyoblasts are raquetoid cells with cross striated cytoplasm, myofibrils and cigar-shaped nuclei. Schwannomas are composed of spindle and bipolar cells with long and thin cytoplasmic extensions. The chondroblasts in chondromas and chondrosarcomas have wide cytoplasm with short processes. The odontoblasts in odontoameloblastomas have wide cytoplasm and long processes directly extended toward adjacent dentinal. These morphologic details can help in the differential diagnosis associated with immunoperoxidase stains.