BREAST CYTOPATHOLOGY

162 6. Breast Ductal Lavage
carcinoma in situ (ductal or lobular type) were identified in
six cases, and ducts or lobules in tissue sections also containing
carcinoma in situ were found in seven. These findings
demonstrate that DL had sampled a duct involved by carcinoma
in situ or an area of the breast spatially close to carcinoma
in about 80% of cases. Nonetheless, DL has low
sensitivity for the detection of carcinoma, and a benign sample
cannot exclude malignancy. Khan et al. have obtained similar
results and noted that the location of carcinoma in situ in
relation to the nipple may affect the ability to detect atypical
cells in the DL fluid. In both studies, the results of DL in the
cancer-affected breast may have been limited due to possible
distortion of the ducts caused by invasive carcinoma in some
cases.
Lobular carcinoma in situ, an alteration of the mammary
epithelium associated with high risk of breast carcinoma,
was the only morphologic alteration in three mastectomy
specimens in one correlative study. Two of the corresponding
DL samples showed mild atypia with morphologic features
compatible with lobular carcinoma in situ. Injected blue
dye identified a duct and a few lobules involved by lobular
carcinoma in situ in one case. This is, to date, the only
documented example of DL sampling lobular carcinoma
in situ.
Because of some limitations in the cytologic interpretation
of DL samples, future evaluation of this type of sample may
combine cytology with other techniques, such as methylationspecific
polymerase chain reaction, analysis of loss of heterozygosity,
chromosome copy number determination, and/or
proteomic analysis.
Studies are in progress to investigate the clinical
significance of the new methodologies summarized in
this chapter. “Intraductal” investigation of mammary carcinoma
and its precursor lesions can provide insight into
the biology of this disease and its clinical management.
Cytology has had a determinant role in the development
of this novel approach and will most certainly continue
to play a critical role in their future development and
application.