PMC4327403_01
Macroscopic view of the 2.0-cm subcutaneous tumor on the right elbow.
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F1
The tumor was 2.0 cm in size and revealed a hard consistency (fig. 1).
Histological appearance of the lesion. a Dermal-to-subcutaneous tumor with extension into the subcutaneous tissue. The epidermis appeared hyperplastic (HE, x1). b The tumor extended into subcutaneous fat with an irregular lace-like pattern (HE, x400). c Tumor cells appeared spindle-shaped and monomorphic and had a mixed fascicular and storiform growth pattern (HE, x400). d-f Immunohistochemistry of the tumor cells. The cells were positive for CD163 (d) and CD44 (e), but negative for CD34 (f).
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F2
Microscopic examination of the specimen revealed a well-defined lesion located in the dermis and extending to the subcutaneous fat (fig. 2a), exhibiting an irregular lace-like pattern between the fat cells (fig. 2b). The lesion was composed of monomorphic spindle cells with a mixed fascicular and storiform growth pattern (fig. 2c). Immunohistochemical staining revealed positivity for vimentin, factor XIIIa, CD68, CD163 (fig. 2d) and CD44 (fig. 2e), but no reactivity for CD34 (fig. 2f), desmin, AE1/AE3 or S100 protein.
a-c Cell morphology of the primary and recurrent tumors. a The primary tumor showed irregularly arranged collagen fibers mixed with scattered proliferating fibroblast. b The first recurrent tumor, composed of slimmer spindle cells. c The second recurrent tumor, composed of slimmer spindle cells. Cells in the recurrent tumors were more monomorphic and showed higher cellularity. d-f Immunostaining for Ki-67. The Ki-67 labeling index of the primary tumor was 2% (d) and that of the first and second recurrent tumors 10% (e) and 7% (f), respectively.
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F3
We compared the cell morphology of the primary lesion (fig. 3a) with that of the first (fig. 3b) and second (fig. 3c) recurrences. The primary tumor showed 2% positivity for Ki-67 (fig. 3d), whereas the first and second recurrent tumors showed 10% (fig. 3e) and 7% (fig. 3f) positivity.