Multinucleation is an objective feature useful in the diagnosis of pleomorphic lobular carcinoma in situ.
OBJECTIVE
Bi- and multinucleated (B/M) cells are present in a variety of tumors. We evaluated lobular carcinoma in situ (classic and pleomorphic types) and ductal carcinoma in situ (DCIS) to determine if this objective morphologic feature aids the differential diagnosis.


METHODS
The number of B/M cells was recorded in pleomorphic lobular carcinoma in situ (PLCIS) (n = 20), classic lobular carcinoma in situ (CLCIS) (n = 26), and DCIS (n = 37).


RESULTS
Binucleated cells were significantly more frequent in PLCIS (100%) vs DCIS (43%; P < .0001) and CLCIS (54%; P = .0004). Multinucleated cells were present in 25% of PLCIS cases and 8% of DCIS cases, and they were absent in CLCIS. The quantity of B/M per high-power field (hpf) was less in DCIS (mean, 1.1) and CLCIS (mean, 2.5) compared with PLCIS (mean, 5.8). Thirty-five percent of PLCIS cases had more than five B/M per hpf.


CONCLUSIONS
Binucleated cells are significantly more frequent in PLCIS vs CLCIS and DCIS. Multinucleated cells were never identified in CLCIS. PLCIS should be considered as a diagnosis when B/M is noted.
From the Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL;
Luis Z
LZ
Blanco
From the Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL;
Tiffany A
TA
Thurow
From the Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL;
Aparna
A
Mahajan
Department of Pathology, Abbott-Northwestern Hospital, Minneapolis, MN and.
Barbara
B
Susnik
Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL.
Irene
I
Helenowski
Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL.
Joan S
JS
Chmiel
From the Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL; megan-sullivan@northwestern.edu.
Megan E
ME
Sullivan
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D018275:Carcinoma, Lobular / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology*; D005260:Female; D006801:Humans; D008875:Middle Aged
D014408:Biomarkers, Tumor; D015820:Cadherins
Binucleation; Ductal carcinoma in situ; Lobular carcinoma in situ; Multinucleation; Pleomorphic