Clinicopathological features of lymph node metastatic EMPNST: a case report and review of literatures

Abstract

Background Mesenchymal malignancies prefer hematogenous spread, while epithelial malignancies tend to prefer lymphatic spread. However, mesenchymal malignancies occasionally generate lymphatic metastases. Objective To investigate the clinicopathological features of the epithelioid malignant peripheral nerve sheath tumor (EMPNST). Methods The clinical data, histopathological, histochemical and immunohistochemical features in one case of EMPNST with lymph node metastases were retrospectively analyzed, and the related literatures were reviewed. Results A 42 ⁃ year ⁃ old woman presented right upper arm and shoulder numbness with a right axillary nodule measuring 4 cm × 4 cm × 3 cm for 2 months. Type⁃B ultrasonic examination showed substantive lesions in right axillary which appeared to be a neurofibroma. CT scan showed soft tissue masses in right axillary with multiple enlarged lymph nodes were considered to be malignant lesions. MR image showed nodules in right armpit muscles were considered to be malignant tumor. The multiple nodules were identified in right axillary and the largest one was about 5 cm × 3 cm × 3 cm intraoperatively. The section of specimen was hard, gray⁃red and sallow in color with focal necrosis. The nodules were partly circumvoluted with blood vessel and without distinct border. The surrounding nerves were not obviously compressed. Microscopically, the structure of lymph node was damaged. The tumor invaded the surrounding fibrous connective tissue and adipose tissue with focal hemorrhage and necrosis. Tumor cells arranged in sheets, nests, and were separated by thin fibrous and blood vessels tissue. Most tumor cells were epithelioid. They were large in size with abundant cytoplasm. Cell border was indistinct, and the cytoplasm consisted of fine granules. Nuclei were invariably intensely hyperchromatic with coarse chromatin, and were vacuolated with prominent nucleoli in the center of the nuclei. Tumor cells showed frequent mitotic activity. Multinucleated giant cells and interstitial mucous degeneration were presented. Immunohistochemical staining showed that tumor cells were positive for S⁃100 protein, strong nuclear reactivity for Sox⁃10, and were positive for vimentin and Col⁃Ⅳ, and were negative for CK, CEA, EMA, Melan⁃A, CD56, CD3 and CD20. P53 positive revealed by 40% nuclear of tumor cells. Ki⁃67 labeling index was above 90%. Histochemical staining showed that the tumor cells were surrounded by reticular fibers. The patient had a medical history which recorded a tumor at the right wrist was removed in other hospital 8 years ago, and the wrist tumor recurred 5 years ago. The pathological diagnosis of the recurred wrist tumor was EMPNST with focal hemorrhage and necrosis. According to the history and the final pathological diagnosis, axillary tumor was diagnosed as lymph node metastasis of EMPNST in right axillary. Conclusion The metastasis of MPNST is mostly through the blood channel. This is the first case of the lymph node metastasis of EMPNST. In clinical work, it should be differentiated from other tumors with similar histopathology.

DOI：10.3969/j.issn.1672⁃6731.2012.02.017