Observation versus excision of lobular neoplasia on core needle biopsy of the breast.

PURPOSE: Controversy surrounds management of lobular neoplasia (LN), [atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS)], diagnosed on core needle biopsy (CNB). Retrospective series of pure ALH and LCIS reported "upgrade" rate to DCIS or invasive cancer in 0-40%. Few reports document radiologic/pathologic correlation to exclude cases of discordance that are the likely source of most upgrades, and there is minimal data on outcomes with follow-up imaging and clinical surveillance.

METHODS: Cases of LN alone on CNB (2001-2014) were reviewed. CNB yielding LN with other pathologic findings for which surgery was indicated were excluded. All patients had either surgical excision or clinical follow-up with breast imaging. All cases included were subject to radiologic-pathologic correlation after biopsy.

RESULTS: 178 cases were identified out of 62213 (0.3%). 115 (65%) patients underwent surgery, and 54 (30%) patients had surveillance for > 12 months (mean = 55 months). Of the patients who underwent surgical excision, 13/115 (11%) were malignant. Eight of these 13 found malignancy at excision when CNB results were considered discordant (5 DCIS, and 3 invasive lobular carcinoma), with the remainder, 5/115 (4%), having a true pathologic upgrade: 3 DCIS, and 2 microinvasive lobular carcinoma. Among 54 patients not having excision, 12/54 (22%) underwent subsequent CNB with only 1 carcinoma found at the initial biopsy site.

CONCLUSIONS: Surgical excision of LN yields a low upgrade rate when careful consideration is given to radiologic/pathologic correlation to exclude cases of discordance. Observation with interval breast imaging is a reasonable alternative for most cases.