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Cytopathologic features of epithelioid inflammatory myofibroblastic sarcoma with correlation of histopathology, immunohistochemistry, and molecular cytogenetic analysis
Author(s) -
Lee JenChieh,
Wu JiannMing,
Liau JauYu,
Huang HsuanYing,
Lo ChengYu,
Jan IShiow,
Hornick Jason L.,
Qian Xiaohua
Publication year - 2015
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.21558
Subject(s) - pathology , epithelioid cell , epithelioid sarcoma , medicine , anaplastic lymphoma kinase , immunohistochemistry , sarcoma , dermatofibrosarcoma protuberans , fine needle aspiration , differential diagnosis , biopsy , malignant pleural effusion , lung cancer
BACKGROUND Epithelioid inflammatory myofibroblastic sarcoma (E‐IMS) is a recently established rare variant of inflammatory myofibroblastic tumor. It is characterized by a distinctive constellation of clinical, pathological, and molecular features, including a nearly exclusive intraabdominal location, strong male predilection, aggressive clinical course, predominance of epithelioid tumor cells, and Ran‐binding protein 2 ( RANBP2 ) ‐ anaplastic lymphoma kinase ( ALK ) fusion in the majority of cases. To the authors’ knowledge, the cytologic features of E‐IMS have not been described to date. METHODS Cases of E‐IMS that had corresponding cytology were searched. Six cytology samples (1 fine‐needle aspiration sample, 2 imprint samples, and 3 effusion fluids) containing tumor cells were identified in 5 patients with E‐IMS. RESULTS The cytomorphology included large monotonous epithelioid cells arranged in loose aggregates or singly, with admixed myxoid stroma, and an inflammatory background rich in neutrophils. The tumor cells had a large, round, eccentric nucleus with vesicular chromatin, prominent nucleoli, and moderate amounts of pale cytoplasm. Delicate thin‐walled branching vessels traversing tumor aggregates was a prominent feature in a fine‐needle aspiration sample. Immunohistochemically, ALK was positive in all 5 tumors, with a nuclear membranous staining pattern noted in 3 cases and a cytoplasmic pattern observed in the other 2 cases. ALK rearrangement was confirmed in all 5 tumors by molecular genetic studies. CONCLUSIONS The cytologic features of E‐IMS recapitulate its histologic characteristics. E‐IMS merits inclusion in the differential diagnosis of any intraabdominal, large epithelioid cell neoplasm. Confirmation of ALK rearrangement is advisable because patients may benefit from targeted therapies. Cancer (Cancer Cytopathol) 2015;123:495–504 . © 2015 American Cancer Society .