Journal of Cytology & Histology

Extraskeletal Myxoid Chondrosarcoma-like Features in Metastasizing Lung Adenocarcinoma: Unique Morphological Changes after Chemo-radiotherapy

Abstract

Susumu Matsukuma, Hiroaki Takeo, Kimiya Sato, Aoi Yamashiro and Kimi Kato

Lung cancer closely resembling Extraskeletal Myxoid Chondrosarcoma (EMC), called “primary pulmonary myxoid sarcoma (PPMS),” is an extremely rare tumor. This report is presented here of a unique case showing EMC-like changes only in metastases from conventional lung adenocarcinoma in an 81-year-old man. After lung tumor resection and chemo-radiotherapy, he underwent the resection of right adrenal metastasis composed of carcinomatous and EMC-like components. There were multifocal transitions between these components. He was treated with additional chemo-radiotherapy for newly developed liver and brain metastases, but he died 3.3 years after the initial surgery. Autopsy revealed EMC-like tumors, with or without minute adenocarcinomatous components, extensively involving widespread organs. Reverse transcription-polymerase chain reaction did not detect EWSR1- CREB1 fusion in the primary tumor or metastases. These features indicated that the current tumor was different from PPMS characterized by EWSR1-CREB1 fusion. We concluded that such EMC-like features represent morphological changes of metastatic lung adenocarcinoma. We believe that this possible occurrence should be recognized for accurate diagnosis of metastatic lung carcinoma.