[942] Spectrum of Cystic Changes in Translocation Associated Renal Cell Carcinoma (RCC): A Report of 5 Cases with Cystic Change and Special Emphasis on Tumors with Multilocular Appearance

RS Parakh, J Brown, S Suzigan, G Martignoni, DE Westfall, M Vankalakunti, AV Parwani, S Bastacky, MB Amin. Cedars- Sinai Medical Center, Los Angeles, CA; Larpac (Sa˜o Jose´ do Rio Preto), Sa˜o Paulo, Brazil; Universita' di Verona, Verona, Italy; University of Pittsburgh, Pittsburgh, PA

Background: A distinct subset of RCCs, more commonly occurring in young patients, have various translocations involving chr. Xp11.2 resulting in gene fusions that involve TFE3 transcription factor. These tumors exhibit a variable proportion of clear and eosinophilic cells with solid and papillary architecture, often with abundant voluminous cytoplasm and calcifications. The presence of prominent cystic change has been reported as case reports in two cases.
Design: The clinicopathologic features of five unique cases with variable, often prominent cystic change and TFE3 positivity are presented.
Results: The mean age was 27 years (range 17-54); all were women. Mean tumor size was 5.4 cm (range 1.3-11.2); macroscopically, two were multilocular, one predominantly cystic, one unilocular with mural nodules and one was a solid and cystic tumor. Microscopically, the cystic component varied from 40% to almost 100%; non-cystic patterns included nested, alveolar, papillary, tubular and tubulocystic. The cytoplasm was clear to eosinophilic with variations of both cell types within the same case. All tumors were Fuhrman grade 3; four were organ confined and one was adherent to the liver. All tumors showed strong positivity for TFE3, racemase and PAX2; MiTF was positive in all (focal in two). Melan A (1/5), Cathepsin K (2/4) and AE1/AE3 (2/5) were other positive markers. Follow up of 14.4 months (range 4-27) showed no evidence of disease progression. Two patients were pregnant at the time of diagnosis, one delivered a stillborn infant with Turner's syndrome and the other pregnancy was uneventful. One patient had a sibling with clear cell RCC and the mother of one patient died of "RCC" (histology unconfirmed).
Conclusions: 1) Recognition of prominent cystic change including multiloculated appearance resembling multiloculated cystic RCC is an important morphologic surrogate to recognize translocation associated RCC. 2) The strong predilection in women, with further proclivity for those in pregnancy, is unique from other translocation associated carcinomas. 3) Accurate histologic subtyping of translocation associated carcinomas is important as preliminary evidence suggests a role for emerging targeted therapy.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 153, Tuesday Morning


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