Abstract: 13-year-old girl presented to the emergency room with a
history of recurrent headaches in the occipital area after
urination for thepast 2 years. The headaches were becoming constant
after each episode of urination in the past few months prior to
presentation and the headaches started approximately 1 minute after
urination, and lingered for approximately 3 minutes. She reported
pain of "10" on a 10-point rating scale, but indciated that the
pain usually subsided or lingered at "2" out of 10.
Her medical, surgical, and family histories were significant
only for a cousin with migraines and a positive history of diabetes
and hypertension. Physical examination was remarkable for
hypertension with a bood pressure of 132/89. The patient was
started on alpha-and beta-blockers for the headache, hypertension
and palpitations she experienced after voiding. During her
admission, she was noticed to have systolic blood pressures of
>200 mmHg right after urination and normal systolic blood
pressure before urination. Ultrasound, computed tomography (CT) and
magnetic resonance imaging (MRI) studies were performed (Figures 1
to 3 depict ultrasound and MRI results).
The differential diagnosis included neurofibroma,
rhabdomyosarcoma, transitional cell carcinoma, leiomyosarcoma and
neuroblastoma.
The urinalysis had a trace of blood and 1+ bacteria but was
otherwise negative. Other findings included:
- white count 8.58 with 63% segs, 28% lymphs, 5% monos, 3% eos
and 1% basophil;
- Hg 14.2, platelets 401;
- sodium 140, potassium 3.9, chloride 106, bicarb 26, bun 10,
creatinine 0.6, glucose 124;
- plasma metanephrine was normal at 0.20 nmol/L (normal
0.00-0.49); and,
- plasma normetanephrine was elevated at 5.36 nmol/L (normal
0.00-0.89 nmol/L).
Diagnosis
Urinary bladder pheochromocytoma
Findings
The renal ultrasound (Figure 1) revealed a vascular solid mass
in the anterior wall of the urinary bladder, slightly to the left
of the midline, measuring 3.4 cm transverse by 2.8 cm
anteroposterior by 3.9 cm craniocaudal. The abdomen and pelvis were
otherwise normal(Figure 2). MRI (Figure 3) showed an abnormal soft
tissue mass, measuring 3.4 x 2.8 x 3.9 cm, located anterior to the
urinary bladder,just to the left of the midline, which indented the
urinary bladder.
CASE FOLLOW-UP
Based on the imaging findings, the patient was started on an
alpha-blocker and surgery was performed after alpha blockage was
obtained. A partial cystectomy was performed and the histologic
diagnosis was extra-adrenal paraganglioma (pheochromocytoma).
Discussion
Pheochromocytoma of the urinary bladder is a rare entity.
Patients with this lesion usually present with the triad of
sustained hypertension, hematuria and postmicturition syncope.
Urinary bladder pheochromocytoma has no sex predilection, but there
is a slight female preponderance.1,2 Childhood
pheochromocytomas are more commonly multicentric and extra adrenal
and only 2% of these pheochromocytomas are
malignant.2
Pheochromocytomas of the urinary bladder probably arise in the
paraganglia of the visceral (autonomic) nervous system, located
submucosally either in the dome or in the posterior wall, close to
the trigone. These lesions can be seen in the context of familial
syndromes or diseases, including neurofibromatosis, von
Hippel-Lindau, Sturge-Weber, tuberous sclerosis and multiple
endocrine neoplasia type II.
If pheochromocytoma is suspected on clinical and laboratory
grounds, imaging studies are useful in localizing the tumor as well
as determining multiple sites or metastases. Sonographically,
pheochromocytoma appears as a sharply demarcated soft tissue mass.
It may be purely solid or may contain foci of hemorrhage and
necrosis that appear cystic. The Doppler study characteristically
shows low resistance flow.3 CT has a high sensitivity
for detecting adrenal (94%) and extra-adrenal (82%)
pheochromocytomas.1
MR is more sensitive than all other imaging modalities.
Pheochromocytomas typically display intermediate signal intensity
on T1-weighted images and high signal intensity on T2-weighted
images, likely because of the high intracellular water content and
rich vascularity.4
In our study however, the T2-weighted images did not appear as
profoundly bright as in adrenal pheochromocytomas. This may be
attributed to differences in the cytologic and vascular
patterns.5
Lifelong yearly follow-up with monitoring of blood pressure and
signs and symptoms, as well as catecholamine assays, is
recommended. Clinicians can use 131I-methyliodobenzylguanidine
(MIBG) imaging when recurrence or incomplete resection is
suspected. Imaging with 131I-MIBG is regarded to be 67% to 70%
specific. Imaging with 18F-fluorodeoxyglucose (FDG) is regarded as
being 80% to 90%sensitive.
CONCLUSION
Pheochromocytoma of the urinary bladder is a rare entity that
usually presents with the triad of sustained hypertension,
hematuriaand postmicturition syncope. The surgical management of
urinary bladder pheochromocytoma is usually partial cystectomy.
Total cystectomy with lymph node dissection is reserved for
malignant lesions.
- Whalen RK, Althausen AF, Daniels GH. Extra-adrenal
pheochromocytoma. J.Urol. 1992;147:1-10.
- Sweetser PM, Ohl DA, Thompson NW. Pheochromocytoma of the
urinary bladder. Surgery. 1991;109:677-681.
- Cronan JJ, Do HM, Monchik JM, Stein BS. Bladder
pheochromocytoma: Color Doppler sonographic correlation. J
Ultrasound Med. 1992;11:493-495.
- Warshawsky R, Bow SN, Waldbaum RS, Cintron J.Bladder
pheochromocytoma with MR correlation. J Compt Assist
Tomogr. 1989;13:714-716.
- Kier R, McCarthy S. MR characterization of adrenal masses:
Field strength and pulse sequence considerations.
Radiology. 1989;171:671-674.