Gluteal region rhabdomyosarcoma with contiguous intra-abdominal
Radiography of the abdomen revealed a large, lobulated, soft tissue
mass in the left gluteal region and a soft tissue haze in the left
side of the abdomen. The bowel loops were displaced to right side.
There was no evidence of bone destruction or any calcification
Ultrasound examination revealed a heterogeneous, solid mass with
few cystic areas in the left gluteal region. A mass with similar
imaging appearance was also seen in the left side of the abdomen
that extended from the midpole of the left kidney to the pelvis,
displacing the bowel loops and urinary bladder to the right side
(Figure 2). There was no ascites, and the other intra-abdominal
organs were normal.
CT of the abdomen and pelvis showed a lobulated, hypodense,
noncalcified mass in the left gluteal region (Figure 3). Following
contrast administration, heterogenous enhancement was seen. The
mass also showed invasion of the omentum and the mesentery and loss
of planes with the aorta, inferior vena cava, adjacent bowel, left
kidney, ureter, and urinary bladder.
On MRI, the mass appeared hypointense to muscle on T1-weighted
images and hyperintense on T2-weighted images. Following the
administration of gadolinium contrast, T1-weighted fat-saturated
scans showed intense enhancement with interspersed nonenhancing
areas (Figure 4).
SURGICAL AND PATHOLOGIC FINDINGS
Following excision of the gluteal region mass, laparotomy was
performed. Complete resection of the intra-abdominal mass was not
possible, and debulking surgery was attempted. Subsequently,
multiple chemotherapy was initiated. A gelatinous septate mass was
removed; the dorsal mesentery, anterior retroperitoneal fascia,
left lateroconal fascia, sigmoid colon mesentry, and the left
ureter were adherent to the mass. Histopathologic analysis revealed
embryonal-type rhabdomyosarcoma--a less frequently noted tumor
subtype in extremities.
Rhabdomyosarcoma represents approximately 5% to 15% of all solid
malignant tumors in children.1
Two major types have been
described: adult-pleomorphic and juvenile, which consists of
elements of alveolar, embryonal, and botryoid with 1 element
usually predominating. A mixed group has also been suggested to
describe a mixture of these cell types.2
The head and
neck region is most often involved (40%), while other commonly
reported sites are the genitourinary organs, the retroperitoneum,
and the extremities.3
Although alveolar histology has more often been reported in
extremity tumors,4 in this case, histopathologic
examination revealed embryonal rhabdomyosarcoma in the present
Metastatic spread of rhabdomyosarcoma is known to be diverse and
is more often seen in primary tumors of the extremities and in
those with alveolar histology. It usually occurs via the
hematogenous or lymphatic route. Diffuse intraperitoneal
involvement is rare in both primary and metastatic
forms.1 However, secondary extension into the abdomen
from retroperitoneal or pelvic rhabdomyosarcoma is relatively
frequent.5 Commonly reported findings in intraperitoneal
rhabdomyosarcoma include ascites, intraperitoneal nodules or
masses, omental caking, or a pseudomyxoma peritonei
appearance.1 However, no ascites was noted in the
MRI of rhabdomyosarcoma shows a heterogenous mass, which
indicates the presence of blood or necrosis. The mass appears
isointense to muscle on T1-weighted imaging and shows intensity
equal to or greater than fat on T2-weighted imaging.4
The MRI features in the present case are consistent with previously
reported findings, as the mass appeared slightly hypointense to
muscles on T1-weighted imaging and hyperintense to fat on
The first choice of treatment for rhabdomyosarcoma is complete
surgical excision; although chemotherapy also plays an important
role because of its high chemosensitivity. Intensive multiagent
chemotherapy, as was used in our patient, has been suggested for
patients with gross residual or metastatic disease.6
Our case documents an uncommon presentation of extremity
rhabdomyosarcoma with contiguous intra-abdominal spread involving
the subcutaneous tissue, adjacent anterolateral abdominal wall,
omentum, dorsal mesentry, and anterior retroperitoneal fascia.
- Chung CJ, Fordham L, Little S, et al. Intraperitoneal
rhabdomyosarcoma in children: Incidence and imaging characteristics
on CT. AJR Am J Roentgenol. 1998;170:1385-1387.
- Feldman BA. Rhabdomyosarcoma of the head and neck.
- Kaplan AM, Creager AJ, Livasy CA, et al. Intra-abdominal
embryonal rhabdomyosarcoma in an adult. Gynecol Oncol.
- Siegel MJ. Magnetic resonance imaging of musculoskeletal soft
tissue masses.Radiol Clin North Am. 2001;39:701-720.
- Bove KE. Pathology of selected abdominal masses in children.
- Kunieda K, Saji S, Kuwabara I, et al. Rapid growth of a
retroperitoneal rhabdomyosarcoma following right hemicolectomy for
ascending colon cancer: Report of a case. Surg Today.