Fine needle aspiration cytology of ductal adenoma of the breast with intracellular mucin: a report of three cases.
BACKGROUND
Ductal adenoma of the breast is a benign lesion that can mimic both the clinical and cytopathologic features of carcinoma. Benign breast lesions with intracellular mucin are extremely rare, and ductal adenoma with intracellular mucin has not previously been reported. Here we present three cases of ductal adenoma of the breast with foci of intracellular mucin.


METHODS
Three patients were admitted to Tokai University School of Medicine Hospital and underwent fine needle aspiration cytology and histologic examination by excisional biopsy or partial resection. Fine needle aspiration cytology was performed using a 23-gauge needle, and smears were immediately fixed in ethanol and stained as Papanicolaou preparations. Epithelial cells formed cohesive clusters, consisting of biphasic luminal and myoepithelial cells accompanied by apocrine metaplasia with occasional high nuclear atypia. All three cases showed intracellular mucin, in varying amounts, which led to their being overdiagnosed as malignant lesions.


CONCLUSIONS
To avoid overdiagnosis of ductal adenomas as malignant lesions, it is important to recognize that both intracytoplasmic mucin and atypical apocrine features can be usual cytologic findings of this disease.
Division of Diagnostic Pathology, Tokai University Hospital, Shimokasuya 143, Isehara City, Kanagawa 259-1193, Japan. itoh-cyt@is.icc.u-tokai.ac.jp
Hitoshi
H
Itoh
Yoko
Y
Miyajima
Nobuaki
N
Kato
Akihiko
A
Serizawa
Tomohisa
T
Machida
Shinobu
S
Umemura
Robert Y
RY
Osamura
D000236:Adenoma / Q000473:pathology*; D000368:Aged; D044963:Biopsy, Fine-Needle; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism*
D009077:Mucins