0022-5347/00/1633-0903/0
®
THE JOURNAL OF UROLOGY
Vol. 163, 903–904, March 2000
Copyright © 2000 by AMERICAN UROLOGICAL ASSOCIATION, INC.®
Printed in U.S.A.
SQUAMOUS CELL CARCINOMA OF THE URACHUS
YUNG-CHIONG CHOW, WEN-CHOU LIN, CHI-YUAN TZEN, YUNG-KANG CHOW* AND KING-YIK LO
From the Departments of Urology and Pathology, MacKay Memorial Hospital, Taipei, Taiwan, and Department of Pathology and
Laboratory Medicine, UCLA Medical Center, Los Angeles, California
KEY WORDS: urachus; carcinoma, squamous cell; cystoscopy; bladder
Urachal tumors account for only 0.01% of all malignancies bladder mucosa and submucosa (fig. 2, B). After discharge
and 0.3% of all bladder tumors. Of the urachal tumors de- from the hospital on postoperative day 9 the patient re-
scribed previously most were adenocarcinoma. To our knowl- mained symptom-free for 18 months. Followup abdominal CT
edge only 7 cases of squamous cell carcinoma of the urachus at 7 months showed no tumor recurrences (fig. 1, B).
have been reported in the literature with no tumor-free sur-
vival after the first year. We report a case of urachal squa-
mous cell carcinoma discovered on cystoscopic examination
DISCUSSION
with the longest postoperative tumor-free survival to date of
Located in the space of Retzius the urachus is a vestigial
remnant of the allantois that develops into a fibromuscular
band, plugged with desquamated epithelial cells by adult-
hood. Urachal carcinomas are rare malignant epithelial tu-
mors involving the suprapubic and intravesical regions of the
bladder dome and anterior wall, are mostly intramural with
deep ramifications in the bladder wall and are not second-
ary.1 This rare entity accounts for only 0.01% of all malig-
nancies and 0.3% of all bladder tumors.
Most cases described previously were adenocarcinoma. Ac-
cording to the totipotential cell theory of Mostofi et al, the
transitional cell urachal lining epithelium can undergo squa-
mous metaplasia, giving rise to squamous cell carcinoma.1
Begg categorized urachal tumors into 7 classes with intramu-
cosal (class 1), intramural (class 2) and supravesical (class 3)
being the most important.2 On cystoscopy most cases of ura-
chal carcinoma are stage B2 due to the invariable deep mus-
cle involvement, and stages C and D1 represent perivesical
fat involvement and local metastasis, respectively.3
To our knowledge only 7 cases of squamous cell carcinoma
of the urachus have been reported in the literature from 1870
to 1986.4 Patient age ranged from 27 to 77 years (median 60)
and the male-to-female ratio was 6:2. Of the cases juxtavesi-
cal location was reported in 5 and intracystic location in 2.
Urachal cysts were observed in 6 cases. Ulcers were also
detected in 3 cases by cystoscopy. Local growth patterns were
divided into intramural type (4 cases) with bladder cancer
related symptoms, and supravesical type (3 cases) with he-
maturia and palpable suprapubic mass. Treatment included
excision in 7 cases, and radiation and chemotherapy in 1.
Metastasis was not observed but disease recurred in 2
cases. Urachal tumors are well known for a poor prognosis
longer than 18 months at last followup.
CASE REPORT
A 70-year-old man presented with dysuria, frequency and
painless hematuria 3 months in duration. Urinalysis demon-
strated 3 to 7 red blood cells per high power field, while
urinary cytology and excretory urography were negative.
Cystoscopy detected a calcified 1 ϫ 1 cm. mass at the bladder
dome and simultaneous bimanual examination revealed an-
other 3 ϫ 3 cm. palpable suprapubic mass, which were sus-
picious of urachal tumor. Transurethral biopsy and resection
of the bladder dome tumor extracted 2 tan tissue fragments,
eventually diagnosed as transitional cell papilloma. The
larger, tubular soft tissue mass was 3 ϫ 3 ϫ 12 cm. on
computerized tomography (CT) and extended from the supe-
rior part of the bladder to the umbilicus (fig. 1, A). Partial
cystectomy was performed with urachal tumor, umbilicus,
adjacent peritoneum and omentum, and lateral umbilical
ligaments removed en bloc. (fig. 2, A).
Grossly, the suprapubic mass was 8 ϫ 6 ϫ 6 cm. and tan
yellowish with focal necrosis. Multiple sections were sampled
with a section taken for each cm. of greatest dimension of
tumor. Microscopically, a pure well differentiated squamous
cell carcinoma of the urachus was seen with partial invasion
to the muscle layer of the bladder but no involvement of the
Accepted for publication October 22, 1999.
* Recipient of a grant from the Lymphoma Research Foundation of
America.
FIG. 1. Abdominal CT. A, urachal tumor. B, at 7-month followup no tumor recurrence is evident
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