Aspiration cytology of pulmonary small cell variant of poorly differentiated synovial sarcoma metastatic from the tongue: a case report.
BACKGROUND
Small cell variant ofpoorly differentiated synovial sarcoma (PDSS) is a great mimic of Ewing's sarcoma/primitive neuroectodermal tumor, with cytologic and immunohistochemical overlap.


METHODS
A 21-year-old male was admitted to our hospital because of a solitary pulmonary nodule that developed 22 months after resection of a tongue mass, small cell variant of PDSS. The nodule was biopsied via fluoroscopy-guided fine needle aspiration (FNA). At low power, the cytologic smears were highly cellular, consisting of a mixture of dispersed cells and loose or tight tissue fragments. The cells were characteristically uniform and monotonous, showing round to ovoid nuclei and scant cytoplasm. However, at high power, mild nuclear pleomorphism and frequent mitotic figures were noted. Blood vessels were often seen within the tumor cell aggregates. A diagnosis of metastatic sarcoma was rendered. Metastatectomy of the lung nodule was performed, and cytogenetic study showed t(X;18).


CONCLUSIONS
A diagnosis of small cell variant of PDSS is difficult on routinely stained smears, but in the appropriate clinical setting, especially when a prior history of a primary tumor is available, a confident diagnosis can be established by FNA cytology. Immunohistochemistry and identification of SYT/SSX fusion transcript are useful for confirmation.
Kwon
Mi Seon
MS
Department of Pathology, Dankook University College of Medicine, Chungnam, South Korea. mskwon@dankook.ac.kr
D000328:Adult; D044963:Biopsy, Fine-Needle; D002454:Cell Differentiation; D002887:Chromosomes, Human, Pair 18; D041321:Chromosomes, Human, X; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000556:secondary*; D008297:Male; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000175:diagnosis; D013584:Sarcoma, Synovial / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000556:secondary*; D014057:Tomography, X-Ray Computed; D014062:Tongue Neoplasms / Q000473:pathology*; D014178:Translocation, Genetic; D014746:Vimentin / Q000378:metabolism
D019253:Proto-Oncogene Proteins c-bcl-2; D014746:Vimentin