Our case, a 63-year-old female patient, was admitted to Akdeniz University, Faculty of Medicine, Department of Pathology with consultation of 5 paraffin blocks and 5 Hematoxylin-eosin stained preparations. The serial sections of the paraffin blocks showed tumor cells in the entire tissue. The tumor was lobular in architecture and contained central necrosis in some regions. The tumor cells were large with eosinophilic cytoplasm and prominent nucleoli (Figure 1
). The differential diagnosis included malignant melanoma, malignant epithelial tumor, epitheloid sarcoma and other malignant mesenchymal tumors. The histochemistry and immunohistochemistry aided in the differential diagnosis. The reticulin stain showed reticular fibers surrounding the tumor cells in groups (Figure 2
Fig 1: Epitheloid cells with large, eosinophilic cytoplasm and prominent nucleoli (H&E, x200)
Fig 2: Reticular fibers surrounding tumor cells in groups (Reticulin, x200)
There was positive immune reaction for S-100, vimentin and high molecular weight keratin in the cytoplasm of the tumor cells and also for desmin and HMB-45 in the dedifferentiated areas of the tumor (Figures 3 4 5 6 7 8). The tumor cells did not show immunoreactivity for CD34 and Factor VIII. About 2 months later, the patient underwent an operation and we examined a specimen including the mass and the inguinal lymph nodes. The gross examination revealed a tumor of 6 cm in diameter with no relation with the epidermis over the specimen. The tumor was pink in color and lobulated in appearance. Cysts, hemorrhage and necrosis were detected in some areas.
Fig 3: S-100 (DAB, x400)
Fig 4: Vimentin (DAB, x400)
Fig 5: EMA (DAB, x400)
Fig 6: High molecular weight keratin (DAB, x400)
Fig 7: Desmin (DAB, x400)
Fig 8: HMB-45 (DAB, x400)
The hematoxylin-eosin stained sections of this tumor revealed a tumor identical with the previous one. The immunohistochemical findings of both tumors were also common. The tumor had no connection with the epidermis, it was located in the soft tissue. With all these findings, the case was reported as epitheloid type MPNST. The patient underwent whole body scan for primary focus and no other focus could be identified. The patient was accepted as primary MPNST of the vulva.