PMC3643369_01
(a) Cytology showing neoplastic cells containing cytoplasmic brown pigment (H and E, x400). (b) Vacuolated tumor cells containing brown pigment on histopathology (H and E, x400). (c) Immunohistochemical stain showing strong membrane positivity of tumor cells for HER-2/neu(IHC, x400)
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F1
The smears showed clusters and singly scattered, pleomorphic malignant epithelial cells exhibiting, hyperchromatic nuclei, with moderate amount of eosinophilic, vacuolated cytoplasm, with dark brown pigment [Figure 1a]. The microscopic sections showed epidermal expansion with clusters of large round to ovoid cells with clear to eosinophilic cytoplasm, pleomorphic nuclei, and prominent nucleoli devoid of intercellular bridges [Figure 1b]. Immunohistochemistry was carried out and showed strong membrane positivity of tumor cells for HER-2/neu and negative for both S-100 and HMB-45 [Figure 1c], thus excluding melanoma.