Primary invasive micropapillary carcinoma of the colon.
OBJECTIVE
Invasive micropapillary carcinoma (IMPC) is associated with frequent lymph node metastasis and adverse clinical outcome. IMPC has been reported in breast, urinary bladder, ureter, lung and parotid gland but not in colon. We present the clinicopathological features of three cases of primary IMPC of the colon with a review of the literature.


RESULTS
The patients (one man and two women) were 53, 67 and 68 years old, respectively. The size of the tumour ranged from 20 to 100 mm in diameter. Histologically, all cases were composed predominantly of papillary tumour cell clusters with spaces in a background of fine fibrocollagenous stroma. One of the tumours (case 1) was nearly completely composed of IMPC, but the other two were associated with foci of adenocarcinoma and concurrent mucinous carcinoma, respectively. MUC1 was positive in all cases, suggestive of reverse cell orientation which is responsible for its unique histological features.


CONCLUSIONS
We report three cases of primary IMPC of the colon. Its clinical significance remains undetermined but the presence of this component may represent a poor prognostic factor.
Sakamoto
K
K
Department of Pathology, Tohoku University Hospital, Sendai, Japan. ksakamoto@patholo2.med.tohoku.ac.jp
Watanabe
M
M
De La Cruz
C
C
Honda
H
H
Ise
H
H
Mitsui
K
K
Namiki
K
K
Mikami
Y
Y
Moriya
T
T
Sasano
H
H
D000368:Aged; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000473:pathology*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018396:Mucin-1 / Q000096:biosynthesis; D009361:Neoplasm Invasiveness
D018396:Mucin-1