Metastatic Melanoma of the Gallbladder in an Asymptomatic Patient

Figure 4

(a) Gallbladder mucosa with dark brown pigmented polypoid lesion measuring 2.7 × 1.5 × 1.3 cm. (b) Sheets of malignant epithelioid cells are seen with eosinophilic cytoplasm and prominent nucleoli. Gallbladder epithelium can be seen (arrow). (c) Higher power showing malignant cells with hyperchromatic large atypical nuclei with eosinophilic cytoplasm and scattered brown pigment. (d) Immunohistochemistry for melanocytic marker HMB-45 showing diffuse and strong staining.

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