[237] Neuroendocrine Ductal Carcinoma In Situ (NE-DCIS) of the Breast – A Distinct Variant of DCIS

T Kawasaki, G Sakamoto, T Kondo, T Nakazawa, T Yamane, K Mochizuki, D Niu, D Ma, Y Ishii, M Inoue, S Inoue, H Tsunoda-shimizu, S Nakamura, R Katoh. University of Yamanashi, Yamanashi, Japan

Background: The World Health Organization (WHO) classifies neuroendocrine tumors (NETs) of the breast as a special tumor entity. However, neuroendocrine ductal carcinoma in situ (NE-DCIS) of the breast, which could be considered a precursor lesion of breast NETs, has not been adequately studied and its clinicopathological significance remains poorly understood. Therefore, we investigated the clinical and pathological characteristics of NE-DCIS in comparison with those of non-NE-DCIS.
Design: NE-DCIS was diagnosed according to the WHO classification criteria for breast NETs, i.e. DCIS tumors in which more than 50% of the cell population immunohistochemically expressed NE markers (chromogranin A and/or synaptophysin) were diagnosed as NE-DCIS. We clinicopathologically analyzed 20 NE-DCIS and 274 non-NE-DCIS cases.
Results: NE-DCIS accounted for 6.8% of all DCIS. The mean patient age was 50.4 years for NE-DCIS and 49.6 years for non-NE-DCIS (p=0.66). The main clinical presentation of NE-DCIS patients was bloody nipple discharge, seen in 72% (13/18) of cases, significantly different from the 5% in non-NE-DCIS patients (p<0.01). Neither metastasis nor recurrence was seen in the NE-DCIS cases (mean 67 months post surgery). Carcinoma was preoperatively diagnosed in 67% (12/18) of NE-DCIS, significantly less than the 95% in non-NE-DCIS (p<0.01). Characteristically, the histological architecture of NE-DCIS was a predominantly solid growth of cancer cells, frequently with well-developed vascular networks. Cancer cells in NE-DCIS had fine-granular cytoplasm and ovoid, occasionally spindle-shaped, nuclei. The nuclear grades and Van Nuys classification were significantly lower for NE-DCIS than for non-NE-DCIS (p<0.01). Immunohistochemically, the mean MIB-1 labeling index of NE-DCIS was 4.3%, significantly lower than the 8.1% in non-NE-DCIS (p<0.01). Furthermore, NE-DCIS scored significantly higher for estrogen and progesterone receptors in the Allred scoring system and lower for HER2, compared with non-NE-DCIS (p<0.01).
Conclusions: NE-DCIS of the breast has characteristic clinical and histological features and could therefore be regarded as a distinctive entity, a NE variant of DCIS. We advocate careful consideration of diagnosis and treatment for this presumably indolent breast cancer. NE-DCIS is the significant disease entity in clarifying and understanding a natural history of breast NETs.
Category: Breast

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 44, Tuesday Morning


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