title: Subcutaneous soft tissue sarcoma with rhabdoid features in a dog.
abstract: A nine-year-old male beagle dog had a white spherical mass in the subcutis of the left lumbar region. Microscopically, spindle to oval cells diffusely proliferated in the fibrous and myxoid stroma. Many neoplastic cells showed rhabdoid features or vacuolated cytoplasm. Immunohistochemically, the neoplastic cells were positive for vimentin and S100 and partly positive for neuron-specific enolase and glial fibrillary acidic protein but were negative for von Willebrand factor, desmin and α-smooth muscle actin. Ultrastructurally, the neoplastic cells had abundant cytoplasmic processes and desmosome-like structures. Cytoplasmic inclusions of rhabdoid-featured cells in HE sections were composed of aggregates of intermediate filaments, and cytoplasmic vacuoles were identified as an invagination of cytoplasm. Although malignant peripheral nerve sheath tumor was suggested according to these results, the present case was diagnosed as a soft tissue sarcoma with rhabdoid features due to a lack of identification of the basal lamina under electron microscopy.
authors.affiliation: Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Sayama
authors.affiliation: Biological Research Department, Daiichi Sankyo RD Novare Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Okado
authors.affiliation: Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Imaoka
authors.affiliation: Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yokouchi
authors.affiliation: Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Jindo
authors.affiliation: Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 16-13 Kita-Kasai 1-Chome, Edogawa-ku, Tokyo 134-8630, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Takasaki
keywords: canine; canine hemangiopericytoma; peripheral nerve sheath tumor; rhabdoid features; soft tissue sarcoma