Aims: To evaluate the risk of having occult ductal carcinoma in situ or invasive carcinoma in the region of a focus of lobular (in situ) neoplasia (LN) diagnosed on needle core biopsy (NCB) of breast.
Methods: All cases of LN diagnosed on NCB of breast over 10 years (2000-2009 inclusive) were reviewed. The clinical presentation, radiological appearances and final pathological diagnosis on open diagnostic biopsy (ODB) were correlated.
Results: 125 cases of LN on NCB were identified from diagnostic codes. Of these, 72 (58%) had a coexistent, higher-grade lesion that mandated surgery. Fifty of the remaining 53 (94%) underwent ODB. The majority of patients were asymptomatic, with 68% presenting through the breast screening programme, and in 89% of patients, the target abnormality was microcalcification. Of the 50 patients, 13 (26%) had a final diagnosis of in situ or invasive carcinoma requiring therapeutic surgery. When the cases of pleomorphic LN were excluded, 21% (10/47) were upgraded. Two of these 10 cases had discordant radiology which could have been diagnosed on repeat NCB leaving an upgrade rate of 18% (8/45). In four of the eight cases of invasive malignancy, the disease was multifocal.
Conclusions: LN is frequently asymptomatic, being identified by mammographic microcalcification alone. In 21% of classical LN cases, it is associated with an undiagnosed, higher-grade lesion requiring oncological management. In our view, patients with LN discovered on NCB should undergo open diagnostic biopsy.