EWS-ATF1 fusion transcripts in gastrointestinal tumors previously diagnosed as malignant melanoma.
BACKGROUND
Clear cell sarcoma (CCS) is classically a deep soft tissue tumor associated with tendons or aponeuroses, although cases of primary CCS of the gastrointestinal (GI) tract have recently been reported. Because it is difficult to distinguish CCS from metastatic melanoma based on morphology, immunohistochemical profile, and ultrastructural features, it is possible that some GI tumors diagnosed as metastatic melanoma actually represent primary GI CCS. Because the EWS-ATF1 fusion transcript and the associated t(12;22)(q13;q12) translocation occur in CCS but not cutaneous melanoma, we investigated the use of molecular-based testing for discriminating CCS from metastatic melanoma (MM) in GI tumors.


METHODS
Patients with GI tumors diagnosed as MM were identified from departmental files. The tumors were tested for the EWS-ATF1 fusion transcript by RT-PCR and for t(12;22)(q13;q12) by fluorescence in situ hybridization.


RESULTS
Detailed review of medical records revealed that 16 (80%) of the 20 had a documented history of cutaneous melanoma. Two cases (10%) harbored the EWS-ATF1 fusion transcript, and fluorescence in situ hybridization confirmed the presence of t(12;22) in both cases. Of the 2 positive tumors, 1 developed in a patient who had no history of cutaneous melanoma, and the other developed in a patient with a remote history of vulvar melanoma.


CONCLUSIONS
Based on molecular genetic findings, a subset of GI tumors diagnosed as MM by routine histopathologic evaluation represents CCS.
Covinsky
Michael
M
Lauren V. Ackerman Laboratory of Surgical Pathology, Washington University School of Medicine, St. Louis, MO 63110-1093, USA.
Gong
Steven
S
Rajaram
Veena
V
Perry
Arie
A
Pfeifer
John
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D003937:Diagnosis, Differential; D005770:Gastrointestinal Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000473:pathology; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018227:Sarcoma, Clear Cell / Q000235:genetics* / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology; D014157:Transcription Factors
C111598:EWS-ATF1 fusion protein, human; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors