Synovial sarcoma, histologically mimicking primitive neuroectodermal tumor/Ewing's sarcoma at distant sites

Fumiaki Masui, Yoshihiro Matsuno, Ryohei Yokoyama, Yukihiro Nakanishi, Tadashi Hasegawa, Yae Kanai, Yasuo Beppu, Setsuo Hirohashi, Katsuyuki Fujii, Tadakazu Shimoda

研究成果: Article査読

20 被引用数 (Scopus)


We report a case of synovial sarcoma (SS) showing unusual histology at distant sites. A 47-year-old man was aware of a tumor on the sole of his left foot. After preoperative chemotherapy with a diagnosis of SS, wide excision was performed. During postoperative chemotherapy, multiple tumorous lesions developed in the bone (including the whole spine) and both lungs. The patient died 1 year later. Histologically, the excised tumor of the foot showed a biphasic cellular pattern typical of SS, whereas at autopsy the bone and lung lesions were composed only of undifferentiated small round cells with cytoplasmic fibrillar processes. Homer-Wright rosettes were also observed. Immunohistochemically, 80% of the bone and lung tumor cells expressed MIC2 protein homogeneously. To clarify whether the bone and lung round cell tumors were metastatic lesions or second malignancies, especially primary primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES), we performed reverse transcription-polymerase chain reaction (RT-PCR) analysis of tumor type-specific fusion gene transcripts. The SYT/SSX fusion transcript was identified in both the foot and lung lesions, whereas the EWS/FLI1 transcript was not detected in either lesion. Therefore, we concluded that the multiple bone and lung tumors were poorly differentiated metastatic tumors, which arose from the SS of the foot. We also conclude that the identification of chimeric fusion transcripts can be successfully applied to poorly differentiated sarcomas and will help in the differential diagnosis of tumors that cannot be distinguished by conventional morphological examinations. Also, it should be remembered that cytoplasmic staining for MIC2 protein may occur in sarcomas other than PNET/ES.

ジャーナルJapanese journal of clinical oncology
出版ステータスPublished - 1999 9月

ASJC Scopus subject areas

  • 腫瘍学
  • 放射線学、核医学およびイメージング
  • 癌研究


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