The usefulness of diffuse pattern of distribution in ^99mTc-(V) DMSA scintimammography in the evaluation of in situ breast carcinomas

Aim

To evaluate retrospectively the diagnostic accuracy of diffuse (V) DMSA concentration in the detection of in situ carcinomas of the breast.

Materials and methods

A total of 71 women with mean age 62.5 years that were referred to us for suspicious breast lesions on physical examination and/or an abnormal mammogram underwent ^99mTc-(V) DMSA scintimammography prior to any surgical intervention. The presence of focal (V) DMSA increased activity, as compared with surrounding tissue, was characterized as a positive study for invasive cancer, and diffuse increased activity was considered as suggesting noninvasive lesions. We evaluated retrospectively this kind of distribution in relation with the histopathology of the specimens obtained surgically. Scintigraphic results were compared with mammograms.

Results

Breast cancer was histologically confirmed in 43/71 patients (invasive cancer in 24 patients and in situ cancer [with or without invasive component] in 19 patients). A diffuse (V) DMSA pattern was presented in 30 patients: in 18/19 patients with in situ carcinomas (16 ductal in situ, two lobular in situ), in 2/24 patients with invasive cancer (microcentric ductal carcinoma) and in 10/28 patients with benign lesions associated with epithelial hyperplasia. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value for in situ carcinoma were 94.7%, 76.9%, 81.7%, 60% and 97.6%, respectively.

Mammograms depicted suspicious branching or clustered coarse granular type microcalcifications in 10/19 patients with in situ cancer. In the remaining 12/30 patients with a diffuse (V) DMSA pattern, only two patients had suspicious microcalcifications (both of them with invasive cancer).

Conclusion

The diffuse pattern of (V) DMSA concentration seems to have an excellent sensitivity in detection of in situ breast carcinoma. In combination with a mammogram this could provide useful preoperative information.