[257] Pleomorphic Carcinoma of the Breast: Is Severe Pleomorphism Associated with a Worse Clinical Outcome?

CV Nguyen, KK Hunt, KM Nayeemuddin, TR Lester, R Falcon-Escobedo, MZ Gilcrease. University of Texas M.D. Anderson Cancer Center, Houston, TX; M.D. Anderson Cancer Center, Houston, TX; Medical School, Autonomous University of San Luis Potosi, San Luis Potosi, Mexico

Background: The WHO classification of tumors of the breast includes a rare variant of high-grade ductal carcinoma termed pleomorphic carcinoma. These tumors characteristically contain multinucleated tumor giant cells and contain marked pleomorphism (>6-fold variation in nuclear size) at the highest end of the spectrum of grade 3 invasive ductal carcinomas. Although these tumors are reported to have an aggressive behavior, the WHO classification allows a focal spindle cell component, and it is unclear whether invasive carcinomas with severe pleomorphism without a metaplastic component have a worse clinical outcome than other high-grade invasive ductal carcinomas.
Design: We examined the clinicopathologic features of 37 cases of invasive carcinoma with severe pleomorphism (>6-fold variation in nuclear size), with or without a spindle cell component. Only cases with a striking degree of pleomorphism were included. Patients with invasive pleomorphic lobular carcinoma and those without at least a tissue biopsy prior to chemotherapy were excluded.
Results: Patients ranged in age from 23 to 78 yrs (median 49 yrs). Frequent histologic findings included multinucleated tumor giant cells in all 37 tumors, necrosis in 28 (patchy in 26 and extensive in 2), and at least a partial lymphocytic response in 26. The mitotic rate was <20 per 10 hpf in 6 tumors, between 20 and 50 in 19 tumors, and >50 in 12. A focal spindle cell component (<25%) was present in 14 tumors (38%). Fourteen cases had associated DCIS, and 18 had positive axillary lymph nodes. Clinical follow-up was available for 36 patients (median 17 months). Patients with a spindle cell component appeared to have decreased survival compared to those without a spindle cell component. Mean overall survival for patients with and without a spindle cell component was 41 9 mos and 65 6 mos, respectively. Overall five-year survival for patients with and without a spindle cell component was 38% 15% and 89% 7%, respectively.
Conclusions: Pleomorphic carcinoma as defined by the WHO classification is not a specific subtype of breast carcinoma. The distinctly aggressive clinical course appears limited to the subgroup of pleomorphic carcinomas with a spindle cell component. Severe pleomorphism by itself appears not to be prognostically significant.
Category: Breast

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 41, Monday Morning