[1087] Undifferentiated Carcinomas of the Endomentrium and Ovary: A Clinicopathologic Correlation

LJ Tafe, K Garg, C Tornos, RA Soslow. Memorial Sloan Kettering Cancer Center, New York, NY; Stony Brook University Medical Center, Stony Brook, NY

Background: Undifferentiated carcinomas (UCs) of the endometrium and ovary are rare and under diagnosed. They are important to recognize since they have been shown to pursue a more aggressive clinical course than usual high grade endometrioid carcinomas (EC). Given the scant clinical and pathologic data, we reviewed our experience with these rare tumors.
Design: We reviewed our pathology database between 2001-2008 to identify 29 cases of UCs. Clinical information was obtained from electronic medical records.
Results: The patient age ranged from 27-83 years (median 54). Many patients (pts) were of young age (24% <40 yrs, 17% 40-50 yrs, and 59% >50 yrs). Thirteen (45%) pts presented with stage I/II disease and 16 (55%) with advanced stage III/IV disease. Most UCs were of endometrial origin and 1 was ovarian. The lower uterine segment (LUS) was involved in 16/29 cases. Ten (35%) UCs were associated with a low grade EC, consistent with so-called de-differentiated carcinoma. Histologically, they evoked a broad differential diagnosis including FIGO grade 3 EC, neuroendocrine carcinoma, cervical carcinoma, lymphoma and sarcoma. The tumors consisted of sheets of ovoid cells with uniform, large vesicular nuclei and variable amount of necrosis. A few cases showed foci of nuclear pleomorphism. Many UCs also showed focal to large areas of rhabdoid cells in a background of myxoid stroma. BAF-47 (INI-1) stain was retained where performed. These tumors showed only focal EMA and keratin staining, and CK18 was the most frequently positive keratin stain. They were negative for neuroendocrine markers, smooth muscle markers and ER/PR. Mismatch repair (MMR) protein expression by IHC was evaluated in 12 cases (40%), and 8 (67%) were abnormal (6 with loss of MLH1/PMS2 and 2 with MSH2/MSH6 loss). Follow-up (F/U) information is available for 24 pts. Nine pts died of disease in 1 to 9 months, 6 are alive with disease (F/U of 1-45 mths), 9 pts have no evidence of disease at 18-85 mths.
Conclusions: UCs of the endometrium and ovary can occur in young women and should be diagnosed correctly as they can pursue a fulminant clinical course. They frequently occur in the LUS. Histologically, they have a broad differential diagnosis and can sometimes be associated with a low grade EC. Rhabdoid cells can be frequently seen in UCs and CK18 may be particularly helpful to demonstrate epithelial differentiation. These tumors frequently show loss of DNA-MMR proteins, particularly MLH1/PMS2.
Category: Gynecologic

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 144, Wednesday Afternoon