[446] Clusterin Expression Correlates with Tumor Progression in Mycosis Fungoides

P Chandra, Z Zuo, JA Plaza, H Koeppen, AH Diwan, LJ Medeiros, VG Prieto. University of Texas MD Anderson Cancer Center, Houston, TX; Medical College of Wisconsin, Milwaukee, WI

Background: Clusterin is a ubiquitously expressed glycoprotein and a diagnostic marker of anaplastic large cell lymphoma (ALCL). Mycosis fungoides (MF) with progression to large cell transformation (LCT) may histologically resemble ALCL. We therefore evaluated clusterin expression in MF and compared the results with clinical stage and number of large cells. We also assessed morphologically similar cutaneous T-cell lymphoproliferative disorders (T-LPD).
Design: Paraffin blocks of 97 cutaneous T-LPD specimens were identified including 70 cases of MF (19 patch, 28 plaque, 21 tumor stage, and 2 with erythroderma), 18 ALCL (16 cutaneous and 2 systemic), 6 peripheral T-cell lymphomas (PTCL), and 3 lymphomatoid papulosis (Lyp). Cases were classified according to World Health Organization criteria. Cases of MF with increased large cells (MF-LC) had greater than 10% but less than 25% large cells. Cases of MF in large cell transformation (MF-LCT) had at least 25% large cells. Clusterin expression was assessed using immunohistochemical methods on prepared unstained tissue sections. A case was scored as positive when at least 5% of the infiltrate expressed clusterin. Statistical differences were calculated using Chi-squared analysis.
Results: Clusterin was positive in 36/70 (51%) of MF specimens. Expression was noted by both small and large lymphocytes and stromal cells. According to clinical stage, 3/19 (16%) patch, 13/28 (46%) plaque, and 20/23 (87%) tumors/erythroderma were clusterin positive. Histologically, 43% of MF cases showed predominantly small cells, 26% were MF-LC, and 31% were MF-LCT. According to cytologic composition, 6/30 (20%) small cell MF were clusterin positive versus 12/18 (67%) MF-LC and 18/22 (82%) MF-LCT. With the exception of MF-LC versus MF-LCT, differences in clusterin expression were statistically significant (p less than 0.0001 to 0.03). Clusterin was also positive in all cases of LyP and systemic ALCL, 7/16 (43%) cases of cutaneous ALCL, and 1/6 cases of PTCL (17%).
Conclusions: Clusterin expression is common in MF, ALCL, and Lyp and uncommon in PTCL. In MF, clusterin expression correlates with clinical stage and increased large cells.
Category: Dermatopathology

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 74, Monday Morning