Lobular Carcinoma in situ with stromal microinvasion

 Microinvasion with LCIS seems unusual and ill-defined.  So I don't think they have good data on it.   Microinvasion, of course, would be smaller than macroinvasion, if that's a proper term.

In this 1998 abstract Lobular carcinoma in situ is not known to progress to microinvasive disease. Although this feature is rare, the current understanding that lobular carcinoma in situ is a marker needs to be revised. http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1096-9098(199801)67:1<41::AID-JSO9>3.0.CO;2-M/abstract

MICB was ductal in 18 patients, including one tubular carcinoma, and was lobular in three patients. ... Eleven patients underwent mastectomy, nine received radiation therapy, one received chemotherapy, and two underwent lumpectomy only. Median follow up was 28 months (range, 18–63 months). One patient had a chest wall recurrence of infiltrating duct carcinoma and another recurred with duct carcinoma in situ.

“Microinvasion” has been a contentious term ever since it was coined. In squamous cell carcinoma of the uterine cervix, for which the term is well established for more than a half century, the microinvasive foci vary from 3 to 5 mm depending on the definition used. 26 The size controversy is worse in the breast, for which the term was introduced relatively recently. 8 The definition of microinvasive carcinoma of the breast (MICB) has varied from as vague as “DCIS [ductal carcinoma in situ] with evidence of stromal invasion,”18 “focal microinvasion . . . in one or several ducts,”12 “microscopic focus of malignant cells invading beyond the basement membrane,”25 “not invading more than 10% of the surface of surface of histologic section,”15,24 to as specific as focus of invasion measuring ≤1 mm 2,4,8,21 and 2 mm, 10,20 as summarized in an excellent commentary by Schnitt. 16 Thus, the extent of invasion in MICB has varied from one to several millimeters in the literature, making comparison of clinical data, and treatment recommendations, difficult. To still this nosologic mayhem, the Union Internationale Contra Cancer (UICC) introduced a new TNM stage, T1 mic, in 1996 and defined it as “microinvasion 0.1 cm or less in greatest dimension.”5 Since then, this is the first attempt to study the clinicopathologic profile of T1 mic tumors that adhere strictly to the most recent TNM guidelines by using an ocular micrometer to measure and a sensitive double immunoenzyme-labeling technique to evaluate equivocal foci of invasion. 13 http://journals.lww.com/ajsp/Abstract/2000/03000/Microinvasive_Carcinoma__T1mic__of_the_Breast_.12.aspx

You may want to get 2nd opinions on both your pathology report and 2nd opinions on your medical care, if you have any doubts.