PMC3861538_01
Histopathological and immunohistochemical features of the thigh nodule. (A) Signet-ring cell appearance of the neoplastic cells. The neoplastic cells exhibited eccentrically located enlarged nuclei and abundant pale cytoplasm (hematoxylin and eosin stain; magnification, x400). (B) Vimentin was expressed in the signet-ring cells (magnification, x400). (C) mTOR, 4E-BP1 and p4E-BP1 were diffusely expressed (magnification, x100). mTOR, mammalian target of rapamycin; p4E-BP1, phosphorylated 4E-BP1.
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In the lower section of the lesion, the neoplastic cells showing signet-ring cell appearance were identified (Fig. 1A). These cells exhibited eccentrically located enlarged nuclei with or without conspicuous nucleoli and abundant pale cytoplasm (Fig. 1A). Melan-A (Fig. 1B), but negative for HMB-45, cytokeratin (AE1/AE3 and CAM5.2), nestin, peripherin, alpha-internexin and GFAP. Moreover, mTOR, 4E-BP1 and p4E-BP1 were diffusely expressed in the tumor cells (Fig. 1C).
Histopathological features of the sentinel lymph node. Metastatic malignant melanoma was identified. Specific tumor cells showed signet-ring cell appearance as observed in the inset (magnification, x400) (hematoxylin and eosin stain; magnification, x100).
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The sentinel lymph node exhibited a metastatic malignant melanoma with signet-ring cell component (Fig. 2).