In 1985, a 63-year-old woman underwent left modified radical mastectomy and prophylactic
right mastectomy for infiltrating lobular carcinoma, stage T3N1M0, and received adjuvant
chemotherapy. At a screening colonoscopy in 2002, she was found to have diverticulosis.
In 2005, the patient developed left lower quadrant abdominal pain, which responded
to antibiotics; she was presumed to have diverticulitis and was referred to a surgical
clinic. Three weeks later, she underwent elective laparoscopic resection of the left
colon.
Intraoperatively, a mass was found at the rectosigmoid junction, and a frozen section
initially demonstrated malignant cells. A left hemicolectomy was performed. During
laparotomy, a firmness 2 × 3 cm in size was noted in the right colon. The proximal
abnormality was left in place pending final pathology. Once the patient had recovered
from surgery, a colonoscopy was carried out in order to visualize the ascending colon.
A circumferential friable mass lesion was seen just above the ileocecal fold, and
biopsies were obtained (Figure [1]).
Biopsies of both masses revealed carcinoma, with tumor cells diffusely infiltrating
the submucosa, muscularis propria, and subserosa, many forming single files. Immunohistochemically,
the tumor was positive for estrogen receptor (> 95 %, 2 - 3+) and pankeratin, features
which are both consistent with metastatic lobular breast cancer (Figure [2]).
Figure 1 A circumferential friable mass lesion in the ascending colon.
Figure 2 Positive estrogen-receptor staining in the pathology specimen from the endoscopic
biopsy of the right colon mass. There are small, round, relatively uniform tumor cells
(stained brown) scattered in the lamina propria (estrogen-receptor stain, original
magnification 40 ×).
Metastases from breast cancer to the gastrointestinal tract, and particularly the
colon, are extremely rare [1]
[2]. The clinical presentation may vary from an asymptomatic abdominal mass to a stenotic
lesion causing obstruction, or the symptoms may mimic ulcerative colitis or diverticulitis,
as in this case [1]
[3]
[4]. Although certain features may suggest metastasis rather than primary cancer, radiographic
differentiation between the two is particularly difficult during the later stages
of disease [5]. If possible, histopathological and immunohistochemical comparison with the original
breast cancer specimen should facilitate a correct diagnosis and dictate the appropriate
management.
Endoscopy_UCTN_Code_CCL_1AD_2AC
