title: Spontaneous breast cancer remission: A case report.
abstract: BACKGROUND
  Spontaneous breast cancer remission is a rare phenomenon. We report the disappearance from the remaining breast of a new primary carcinoma that had been confirmed through cytology of a pathological specimen, in a case that is strongly suspected to be spontaneous remission.
  
  
  METHODS
  A 44-year-old woman underwent breast-conserving surgery for a tumor located on the border between the upper-outer and lower-outer quadrants of the left breast (T2, N1, M0; Stage IIB). Eleven years after surgery, computed tomography indicated a mass in the upper-inner quadrant of the left breast. Excisional biopsy was initially planned for treatment following the definitive diagnosis because cytology revealed malignancy. The patient had noticed tumor regression one month after fine-needle aspiration and repeat ultrasonography performed the day before excisional biopsy confirmed the tumor reduction. On pathological examination, no tumor cells were observed in the mass.
  
  
  CONCLUSIONS
  There was a discrepancy between FNA cytology and pathological diagnosis in our patient. The cytological findings indicated malignancy, but the pathological findings did not. When a tumor's pathological diagnosis is not malignant even though its FNA cytology diagnosis was malignant, sampling error, cytological over-diagnosis or some other error may have occurred. In this case, however, these were not detected. Because fibrosis was visible on pathological examination, we believe that these events corresponded to spontaneous remission.
  
  
  CONCLUSIONS
  We report a rare case of spontaneous remission in which the cancer disappeared on pathological examination although the cytological diagnosis had been malignant.
authors.affiliation: Department of Surgery, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: i_eisaku_ukasie@yahoo.co.jp.
authors.forename: Eisaku
authors.initials: E
authors.lastname: Ito
authors.affiliation: Department of Surgery, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: satokon@m2.gyao.ne.jp.
authors.forename: Satoko
authors.initials: S
authors.lastname: Nakano
authors.affiliation: Department of Surgery, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: masa-2398@nifty.com.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Otsuka
authors.affiliation: Department of Laboratory, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: a_ke3421@mrc.biglobe.ne.jp.
authors.forename: Akemi
authors.initials: A
authors.lastname: Mibu
authors.affiliation: Department of Radiology, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: m-kariko@zd5.so-net.ne.jp.
authors.forename: Masahito
authors.initials: M
authors.lastname: Karikomi
authors.affiliation: Department of Pathology, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Oinuma
authors.affiliation: Department of Pathology, Kawaguchi Municipal Medical Center, 180 Nishi-Araijyuku, Kawaguchi City, Saitama, 333-0833, Japan. Electronic address: yama-m@kf6.so-net.ne.jp.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yamamoto
keywords: Breast cancer; Healing carcinoma; Spontaneous cancer remission