PMC4766521_01
Histological appearance of cutaneous mastocytosis. Hematoxylin and eosin staining (A-D). Toluidine blue staining (E). Immunostaining of mast cell tryptase (F). Diffuse extensive cellular infiltration of well-differentiated mast cells from the superficial to deep dermis in most parts of the skin around the fourth and fifth mammary papilla without nodule formation (A-B). Tumor cells were fairly monomorphic, well-differentiated mast cells with round nuclei of small distinct nucleoli and moderate to abundant, slightly eosinophilic and granular cytoplasm (C). A perivascular arrangement of mast cells was noted at the margin of the lesions, and these neoplastic cells were slightly small, like normal mast cells (D). Mast cells that infiltrated the dermis had cytoplasmic granules with metachromatic staining (E) and were immunopositive for mast cell tryptase (F). Bars: 1 mm (A), 500 mum (B), 100 mum (D-F), 50 mum (C).
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Microscopically, diffuse extensive cellular infiltration was observed from the superficial (nearly the epidermal-dermal junction) to deep dermis in most parts of the skin around the fourth and fifth mammary papilla without nodule formation (Fig. 1A, 1B). Tumor cells were fairly monomorphic, well-differentiated mast cells with round nuclei of small distinct nucleoli and moderate to abundant, slightly eosinophilic and granular cytoplasm (Fig. 1C). A perivascular arrangement of mast cells was noted at the margin of the lesions, and these neoplastic cells were slightly small, like normal mast cells (Fig. 1D). Toluidine blue staining revealed the typical metachromatic characteristics of cytoplasmic granules (Fig. 1E). Infiltrated mast cells were positive for CD117, histamine, and mast cell tryptase (Fig. 1F).
Sequence of the canine c-kit gene in exon 11. The deletion of Gln555 to Ile570 (c.1663_1710 del) in this case is denoted by a dotted dashed line.
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A sequence analysis of c-kit revealed the deletion of Gln555 to Ile570 within the protein sequence of the juxtamembrane domain in exon 11 (c.1663_1710del) (Fig. 2).