[938] Non-Glandular Carcinomas of the Urachus

GP Paner, TJ Sebo, RE Jimenez. Loyola University Medical Center, Maywood, IL; Mayo Clinic, Rochester, MN

Background: The vast majority of urachal carcinomas (UCs) are adenocarcinoma (AdenoCa), to which the clinicopathological characteristics and proposed sets of diagnostic criteria for UC are largely ascribed. The 2002 WHO classification of bladder cancer recognizes rarer UC histologic types, however, these are only sporadically reported and available clinicopathological data is very limited.
Design: 8 UCs that are purely or predominantly non-glandular (i.e. non-AdenoCa) are herein described.
Results: Patients included 6 males and 2 females from 45 to 72 years old (mean 61 years). All tumors were situated in the bladder dome and mass epicenter was mainly bladder intramural (4/8), extravesical (1/8), or both (3/8). Tumor size available in 5 ranged from 2.5cm to 12cm (mean, 5.9cm). Histologically, 5/8 were urothelial carcinomas (UroCas; 2 pure, 2 predominant, 1 admixed with other histologies), 2/8 were small cell carcinomas (SCCs), and 1/8 was mixed UroCa and SCC. The 3 non-pure UroCa include: 1 with focal glandular differentiation; 1 with focal signet ring cell feature; and 1 admixed with sarcomatoid carcinoma, rhabdoid, and signet ring cell differentiations. Urachal remnants were identified in 3 cases; all with urothelium including 1 admixed with benign glandular lining. In 2 tumors, urachal in-situ and/or papillary UroCa were identified. In 3 other tumors, discrete intratumoral papillary structures were identified. Tapered invasive and/or focal in-situ UroCa were present in bladder dome surface in 3 tumors. Tumors were Sheldon stage III3A (3), IVA (3), and IVB (2) or Mayo stage II (3), III (3), and IV (2) at presentation. 6 tumors had metastasis, mostly to the lymph nodes. Follow-up in all 8 cases (range 0.5 - 60 months) showed 1-year and 2-year overall survival of 50% and 12.5%, respectively; 1 case had lumbar metastasis at 23 months. Only 1 case with stage IIIA (Mayo stage II) tumor was alive and disease free at 60 months interval.
Conclusions: 1) Non-glandular UCs vary in histology and are mainly UroCa and SCC. 2) Urachal UroCa is often admixed with other histology, including a subset which shows glandular differentiation. 3) Helpful features in diagnosis of primary non-glandular UCs include dome location, predominantly intramural and/or extravesical location with absent or minimal bladder luminal surface involvement, merging with urachal remnants, and for UroCa, identification of in-situ and/or papillary UroCa within the urachus. 4) Non-glandular UC presents with high tumor stage and suggests having a very poor prognosis, although number of cases in this study is low.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 101, Tuesday Afternoon


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