Unusual Myoid Differentiation in a Canine Benign Mixed Mammary Tumour

Figure 1

(a) Tubules of epithelial cells without feature of atypia (left) and scattered myoid spindle cells (right), HE, 10x, scale bar 100 micron. (b) Lobules of hyaline cartilage with well-differentiated chondrocytes, surrounded by a moderate cellular population of elongated myoid cells embedded in a moderate amount of myxoid extracellular matrix, HE, 10x, scale bar 100 micron. (c) Giant spindle multinucleate cells, 50-70 micron, with abundant eosinophilic cytoplasm and cross striation (strap-like cells or rhabdomyoblasts), HE, 40x, scale bar 100 micron. (d) Striated muscles are highlighted in blue, with prominent cross striations, PTAH, 40x, scale bar 100 micron.

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