Diagnosis
Leiomyosarcoma in a patient with Wilms' tumor; a secondary
primary tumor
Findings
Computed tomography of the abdomen and pelvis was performed with
oral and intravenous contrast. The study showed a 10-cm mass in the
right lower quadrant involving the small bowel (figure 1).
Double-contrast barium evaluation demonstrated medial displacement
of the hepatic flexure. Ultrasound evaluation confirmed a 9.7 * 8.9
* 6.3-cm complex, predominantly solid mass in the right pelvis
(figure 2). Ultrasound-guided needle biopsy was performed.
Discussion
The incidence of second primary tumors (SPT) among childhood
cancer survivors has been reported as six-fold greater than the
general population.1,2 The risk following radiotherapy
alone is reported as four-fold greater than the general population;
radiotherapy in combination with cyclophosphamide increases the
risk nine-fold. Second primary tumors have been reported in
patients treated for central nervous system tumors (particularly
retinoblastoma), Hodgkin's disease, and Wilms' tumor, as in this
patient.
Wilms' tumor is the most common intra-abdominal malignancy in
childhood.3 Advances in treatment strategies over the
past 30 years have increased 5-year survival from 20% to 95% in
those with the more favorable prognosis.4 Radiation
therapy, once commonly utilized, is now utilized only in patients
with metastases, lymph node involvement, or unfavorable
histology.
The national Wilms' tumor study group reviewed the incidence of
SPT following treatment of Wilms' tumor.2 The risk of
development of SPT after treatment of Wilms' tumor is 8.5 times
higher than the cancer incidence for the general
population.2 The present case is one of a
leiomyosarcoma. Abdominal irradiation, as therapy for Wilms' tumor,
is associated with 1.43 cases of new cancer per 10 Gy of radiation
dose administered during the therapy for Wilms' tumor. The relative
risk for thyroid, bone, connective tissue, gastrointestinal (GI),
and central nervous system tumors and leukemia increase in patients
treated for Wilms' tumor.2
The dose-limiting structure for radiation therapy to the abdomen
and pelvis is usually the small bowel.5 The clinical
signs and symptoms of acute small bowel toxicity secondary to
radiation therapy include nausea, vomiting, diarrhea, and
malabsorption. Late complications include stricture formation,
fistula, bowel obstruction, and secondary malignancies.
Radiological findings include bowel wall thickening, stricture, and
dilatation related to obstruction.
In the general population, small bowel neoplasms account for 3%
to 6% of all GI tumors.6,7 Malignant small bowel tumors
are more common than benign small bowel tumors. Endocrine cell
tumors (carcinoids) and lymphomas are the most common cancers of
the small bowel. Adenocarcinoma and leiomyosarcoma are the third
and fourth most common malignancies of small bowel.
Leiomyosarcoma represents 20% of all small intestine
malignancies.7,8 Patients with leiomyosarcoma usually
present in the fifth and six decades of life with a male to female
ratio of 3:1. Leiomyosarcoma occurs most commonly in the jejunum
and ileum and is the most common neoplasm of Meckel's diverticula.
The presenting symptoms for leiomyosarcoma of the large or small
bowel vary by site of origin. Patients with involvement of the
duodenum and ileum present most commonly with blood
loss.4 Patients with involvement of the colon present
most commonly with pain. Gastrointestinal leiomyosarcoma is usually
radioresistant; therefore, surgery is the primary treatment.
Complete surgical resection, including en bloc resection of
adjacent structures, improves overall survival. Leiomyosarcoma
spreads through local extension to adjacent organs, peritoneal
surfaces, and omental seeding. Hematogenous spread to the liver,
lungs, adrenal glands, spleen, brain, and bone has been
reported.
The radiological findings of GI leiomyosarcoma have been
described previously.7,9 Plain radiographs may
demonstrate a large soft-tissue mass that contains air,
representing communication of the lumen of the tumor with the lumen
of bowel. Deformity/displacement of small bowel segments,
ulcerations, and tracts and cavities that may fill with contrast
may be observed on barium studies. Computed tomography may
demonstrate a bulky, eccentrically growing, enhancing, soft-tissue
mass. Central areas of necrosis may also be detected.
1. Hawkins MM, Draper GJ , Kingston JE:
Incidence of second primary tumours among childhood cancer
survivors. Br J Cancer 56:339-347, 1987.
2. Breslow NE, Takashima JR, Whitton JA, et al:
Second malignant neoplasms following treatment for Wilms' tumor: A
report from the National Wilms' Tumor Study Group. J Clin Oncol
13:1851-1859, 1995.
3. Webber BL, Parham DM, Drake LG , Wilimas JA:
Renal tumors in childhood. Pathol Annu 27(Pt 1):191-232, 1992.
4. Johnson MA, Gibbs DH, Gouldman J, et al:
Leiomyosarcoma of the colon: A second malignant neoplasm after
treatment for a Wilms' tumor. Am Surg 65(1):6-10, 1999.
5. Hong A, Stevens G , Stephen M: Protection of
the small bowel during abdominal radiation therapy with a tissue
expander prosthesis. Aust N Z J Surg 70:690-692, 2000.
6. Miettinen M, Sarlomo-Rikala M, Lasota J:
Gastrointestinal stromal tumors: Recent advances in understanding
of their biology. Hum Pathol 30:1213-1220, 1999.
7. Ashley SW , Wells SA, Jr.: Tumors of the
small intestine. Semin Oncol 15:116-128, 1988.
8. Akwari OE, Dozois RR, Weiland LH , Beahrs
OH: Leiomyosarcoma of the small and large bowel. Cancer
42:1375-1384, 1978.
9. Maglinte DDT: Small bowel: Malignant tumors.
In: Gore RM, Levine MS, Laufer I (eds). Textbook of
Gastrointestinal Radiology.
Philadelphia, W.B. Saunders, 1994.
Prepared by Janio Szklaruk, MD, PhD, Eric Tamm, MD, and Paul
M. Silverman, MD of the Division of
Diagnostic Imaging at the University of Texas MD Anderson Cancer
Center, Houston, TX.