Letter to the Editor: Synovial Sarcoma Mimicking Desmoplastic SmallRound-Cell Tumor: Critical Role for Molecular Diagnosis

To the Editor: The article by Cole et al. [1] is timelyand is to be welcomed as stressing the current impact ofmolecular diagnosis in the accurate diagnosis of solidtumors, especially sarcomas. Our experience is in agree-ment with the authors’ contention that “synovial sarcomawith atypical clinical presentations and without classicalbiphasic histology may be underdiagnosed.”

Two recent cases that we have seen had the additionalmisleading finding that MIC-2 (013) staining was alsopositive. It is not widely appreciated that MIC-2 positiv-ity in synovial sarcoma is not uncommon. MIC-2 prod-ucts have been detected by immunohistochemistry in sy-novial sarcoma in two series in a significant proportionof cases (42% of 123 patients [2] and 62% of 50 cases[3]).

In addition to the unusual sites mentioned in this ar-ticle and those mentioned in the “Tumor Board” in thesame issue of the journal [4], we recently reported on apatient with a synovial sarcoma of the proximal tibia[5]. The other patient was referred after a biopsy of alarge thigh tumor. Pulmonary metastases were present inboth lungs. In view of the small round-cell histology andthe MIC-2 positivity, the patient had been diagnosed ashaving a primitive neuroectodermal tumor. Rebiopsy,performed when a central line was being inserted,showed the specific SYT-SSX chimeric transcript of sy-novial sarcoma. A complex translocation that includedt(x:18) was also found using spectral karyotyping; analy-sis was not possible with conventional cytogenetic meth-ods. The importance of these techniques in the accuratediagnosis of solid tumors, even bone tumors, is self-evident.

REFERENCES

1. Cole P, Ladanyi M, Gerald WL, et al. Synovial sarcoma mimick-ing desmoplastic small round-cell tumor: critical role for molecu-lar diagnosis. Med Pediatr Oncol 1999;32:97–101.

2. Meis-Kindblom J, Steuman G, Kindblom LG. Differential diag-nosis of small round-cell tumors. Semin Diagnost Pathol 1996;13:213–241.

3. Dei Tos AP, Wadden C, Caouje E, et al. Immunochemical dem-onstration of glycoprotein p30/32mic-2 (CD-99) in synovial sar-coma. Appl Immunochem 1995;3:168–173.

4. Hall TC, Jensen DA, Lohse JR, Shokeir MO. Synovial sarcomawith t(x:18) chromosomal translocation, cardiac involvement andperipheral embolus. Med Pediatr Oncol 1999;32:141–145.

5. Cohen IJ, Issakov J, Avigad S, et al. Synovial sarcoma of bonedelineated by spectral karyotyping. Lancet 1997;350:1679–1680.

Ian J. Cohen,MB, ChB

Department of Pediatric Hematology-OncologySchneider Children’s Medical Center of Israel

Petah Tiqva 49 202 and Sackler School of MedicineTel Aviv University

Tel Aviv 69978Israel

B. Stark,MD

Department of Pediatric Hematology-Oncologyand Cancer Cytogenetic Laboratory

Schneider Children’s Medical Center of IsraelPetah Tiqva 49 202 and Sackler School of Medicine

Tel Aviv UniversityTel Aviv 69978

Israel

Smadar Avigad,PhD

Felsenstein Medical Research CenterCampus Beilinson

Petah Tiqva 49 202 and Sackler School of MedicineTel Aviv University

Tel Aviv 69978Israel

Medical and Pediatric Oncology 34:234 (2000)

© 2000 Wiley-Liss, Inc.