Urachal Mucinous Cystic Tumor of Low Malignant Potential with Concurrent Sigmoid Colon Adenocarcinoma
Table 1
Classification of epithelial neoplasms of urachal origin with emphasis on the cystic mucinous neoplasms, modified from Paner et al., 2016, & Amin et al., 2014 [10, 12].
Glandular neoplasms
(i) Adenoma
(ii) Cystic mucinous neoplasms:
(a) Mucinous cystadenoma (cystic tumor with a single layer of mucinous columnar epithelium, with no atypia)
(b) Mucinous cystic tumor of low malignant potential (cystic tumor with areas of epithelial proliferation, including papillary formation
and low-grade atypia/dysplasia)
(c) Mucinous cystic tumor of low malignant potential with intraepithelial carcinoma (cystic tumor with significant epithelial
stratification and unequivocal malignant cytological features and often with stroma-poor papillae and cribriform pattern)
(d) Mucinous cystadenocarcinoma with microinvasion (stromal invasion <2mm and comprising <5% of the tumor)
(e) Frankly invasive mucinous cystadenocarcinoma (stromal invasion that is more extensive than 2mm and 5%)
