Mammary ductal carcinoma in Situ with microinvasion

Authors

  • Susan A. Silver M.D.,

    Corresponding author
    1. Department of Gynecologic and Breast Pathology, Armed Forces Institute of Pathology, Washington, DC
    • Department of Gynecologic and Breast Pathology, Armed Forces Institute of Pathology, 6825 16th Street N.W., Washington, DC 20306-6000
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  • Fattaneh A. Tavassoli M.D.

    1. Department of Gynecologic and Breast Pathology, Armed Forces Institute of Pathology, Washington, DC
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  • Presented in part as a platform session at the annual meeting of the United States and Canadian Academy of Pathology, Orlando, Florida, March 1997.

Abstract

BACKGROUND

The natural history of patients with intraductal carcinoma (DCIS) and microinvasion is poorly defined, and the clinical management of these patients, with particular reference to management of the axilla, has been controversial. Previous studies of this lesion have used varied and/or arbitrary criteria for the evaluation of microinvasion.

METHODS

Thirty-eight DCIS lesions with microinvasion (n = 29) or probable microinvasion (n = 9), diagnosed during the period 1980-1996, were retrospectively analyzed after cases not treated with mastectomy and axillary lymph node dissection were excluded. Microinvasion was defined as a single focus of invasive carcinoma ≤2 mm or up to 3 foci of invasion, each ≤1 mm in greatest dimension.

RESULTS

The patients were all females with a mean age of 56.4 years. DCIS was of comedo (n = 31) or papillary (n = 7) subtype. Microinvasion was often associated with an altered, desmoplastic stroma (55%) or a lymphocytic infiltrate (39%). The foci of microinvasion ranged from 0.25 to 1.75 mm (mean, 0.6 mm), with an aggregate mean size of 1.1 mm (range, 0.25-2.25 mm). Foci of microinvasion, ranging from 1 to 3 (mean, 1.7), were adjacent to DCIS in 95.3% of cases. The extent of DCIS did not correlate with the number of foci of microinvasion. Axillary lymph node dissections yielded a mean of 19.3 lymph nodes (range, 7-38), and all lymph nodes were negative for metastasis. None of 33 patients, followed for a mean of 7.5 years (range, 1.0-14.4 years), developed local recurrence or metastasis.

CONCLUSIONS

The cases of microinvasive carcinoma examined in this study, as defined above, were not associated with axillary lymph node metastases and appeared to be associated with an excellent prognosis. Further study is indicated to determine the appropriate management and long term prognosis of patients with this lesion. Cancer 1998;82:2382-2390. © 1998 American Cancer Society.

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