Radiological Category: Gastrointestinal Principal Modality (1): Ultrasound
Principal Modality (2): Computer Tomography
Case Report # 807
Submitted by: Modupe Adeyefa, M.D.
Faculty reviewer: Varaha Tammisetti, M.D., The University of Texas Medical School
Date accepted: 11 April, 2011
• 20 year old male with a three month history of back pain relieved by Aleve but
the pain has progressively worsened. He went to his primary care physician
where a right lower quadrant mass was palpated. An abdominal ultrasound was
performed which showed two large retroperitoneal masses. He presented
about a week later to Memorial Herman Hospital because of worsening
abdominal pain and syncope.
Findings and Differentials
Ultrasound: Two large heterogeneous echogenic retroperitoneal masses.
CT: Large intraperitoneal hemoperitoneum and large “sentinel clot” adjacent to the
necrotic, hypervascular nodal masses in lower abdomen. There are 3 large, centrally
necrotic, peripherally enhancing masses in the retroperitoneum, the largest in the
pelvis and measures 9.58x8.8 cm. Smaller similar masses are noted further superiorly .
• Retroperitoneal Metastases with tumor associated hemorrhage/
• Retroperitoneal Hemangiopericytoma
Accounts for the 10%-15% of all childhood cancer which arises from constituent
cells of the immune system or from precursors. Nodal and splenic involvement are
more common in Hodgkin disease whereas extranodal involvement is more
common in Non Hodgkin lymphoma. Both can involve the retroperitoneum. It
appears as a mantle of soft tissue adenopathy surrounding the aorta, inferior vena
cava, involving the para-aortic, aortocaval and retrocaval nodal groups. CT
findings are enlarged nodes greater that 1.5 cm in the short axis involving bilateral
retroperitoneal nodal chains. Encasement of the root of the mesentery and the
superior mesenteric artery by a lymphomatous mass originating from multiple
enlarged and confluent lymph nodes may produce the so called “sandwich sign.”
They may displace aorta from the spine. The attenuation of nodes on CT is similar
Hemoperitoneum from pathologic splenic rupture is rarely associated with
lymphoma in which case the sentinel clot would be seen in the perisplenic region.
In this patient the sentinel clot is seen surrounding the lymph nodes and the lymph
nodes are necrotic with hypervascularity, both of which are not common features
associated with lymphoma.
Retroperitoneal Metastasis with tumor associated hemorrhage:
Spontaneous hemoperitoneum rarely occurs in the absence of trauma, a surgical
or interventional procedure, or anticoagulation therapy. In such cases, the
possibility of the rupture of an un-identified neoplasm must be excluded. Although
the occurrence is uncommon, any primary or metastatic tumor can rupture and
bleed into the peritoneal cavity. The most common causes in this setting would be
ruptured hepatocellular carcinoma or hepatocellular adenoma. However, no
hepatic lesions are identified and sentinel clot is seen away from the liver.
Pathologic splenic rupture may occur as a complication of a viral infection,
including infection by cytomegalovirus, malaria, or Epstein-Barr virus; a
congenital disease; a metabolic abnormality such as Gaucher disease or
amyloidosis; and, rarely, a neoplastic process such as hemangiomatosis,
angiosarcoma, leukemia, or lymphoma. However, the sentinel clot is not in the
perisplenic region and there is no splenomegaly.
The spontaneous rupture of a metastatic lesion in a solid organ or lymph node is
rare but usually results in massive hemoperitoneum. Lung carcinoma, renal cell
carcinoma, and melanoma are the metastatic lesions that can cause
Sarcoma: Malignant primary retroperitoneal tumor arising from various elements
of primitive mesenchyme, urogenital ridge or embryonic remnants. The best
diagnostic clue on imaging is a large heterogenous mass of fat and soft tissue
attenuation displacing the retroperitoneal structures or viscera. The location is
usually in the peri/paranephric region. They are classified into four types,
liposarcoma, leiomyosarcoma, fibrosarcoma or rhabdomyosarcoma.
Liposarcoma is composed of adipose tissue with attenuation values greater than
20 hounsfied unit. They are poorly marginated encapsulated masses with/without
calcification. On CT they have hetero/homogenous enhancement with a lack of
Leiomyosarcoma is the second most common and are composed mostly of
smooth muscle. They are hypervascular and contain feeding vessels. They may
appear as large solid masses with hypoechoic cystic and necrotic remnants.
Fibrosarcoma and malignant histiocytoma are the most common soft tissue
sarcomas in adults.
Rhabdomysarcoma are striated muscle tumors . They are isodence to muscle with
ill defined margins on non enhanced CT and are heterogenously enhancing on
contrast enhanced CT.
Retroperitoneal Hemangiopericytoma are hypervascular neoplasm arising form
pericytes. In a study by Goldman et al, these tumors were typically large and less
frequently in pelvic retroperitoneal space than in abdominal retroperitoneal. The
most distinctive radiologic finding is hypervascularity, Other findings includes
well defined margins and necrosis with nondistinctive amorphous calcifications.
Multiple pulmonary nodules with halo of ground
glass haziness “halo sign”
The halo sign, refers to a zone of ground glass attenuation surrounding a
pulmonary nodule or mass on CT images and they are associated with
hemorrhagic nodules, examples include:
• Angio-invasive aspergillosis: is a form of tissue invasion either
angioinvasive or airway invasive typically in patients with neutropenia or
impaired neutrophil function. Imaging findings include single or multiple
nodules, a central hypodensity due to infarction also known as hypodense
sign. The halo sign is also present which shows a large bull’s eye
surrounded by smaller rim ground glass opacification. An air cresent sign is
a late sign and follows recovery of neutrophils.
• Hemorrhagic/ hypervascular metastases such as from choriocarcinoma,
renal cell carcinoma, angiosarcoma or melanoma. The nodules may be
sharply defined. These findings mirrors chest x-ray findings with metastases
predominate in the outer 1/3 of the mid and lower lung zones. Hematogenous
nodules may have visible feeding artery or the halo sign.
• Wegener granulomatosis: A form of vasculitis that affects the lungs, kidneys
and other organs. The best diagnostic clue are multiple cavitary lung nodules
and large airwary narrowing. CT findings are similar to metastases as the
nodules can have feeding vessels. Peripheral wedge shaped consolidation from
infarct may be present. Some nodules have the CT halo sign from surrounding
hemorrhage. The trachea and bronchi are concentrically thickened, either focal
or long segments.
• Post transplant lymphoproliferative disorder (PTLD): it is a relatively uncommon
complication of both solid organs and allogeneic bone marrow transplantation.
In most cases, PTLD is associated with Epstein Barr virus infection of B cells,
either as a consequence of a reactivation of the virus posttransplantation or
from primary EBV infection acquired from the donor. CT findings include
airspace consolidation and nodular opacities with hazy margins.
• Pulmonary Kaposi sarcoma: Acquired immune deficiency syndrome related
multicentric neoplasm with propensity to involve skin, lymph nodes, GI tract
and lungs. Thoracic manifestations include bronchovascular bundle thickening
progressing to coalescent, flame shaped perihilar consolidation, poorly defined
nodules, reticular and nodular opacities with basilar predominance. There is
also marked enhancement following intravenous contrast.
Heterogeneous right testicular mass with
cystic focus, few tiny calcifications,
vascularity and irregular margins.
Based on the findings from the retroperitoneal masses, positive
halo sign on CT and a testicular mass, the diagnosis is more
likely an hemorrhagic or hypervascular metastases from a non-
seminomatous germ cell tumor such as from choriocarcinoma or
mixed germ cell tumor.
METASTATIC MIXED OR NONSEMINOMATOUS GERM CELL
TUMOR (NSGCT) SUCH AS CHORIOCARCINOMA
Pathology report from biopsied retroperitoneal masses.
- Immunohistochemical stains for Pancytokeratin, Vimentin,
Beta-HCG, Alpha Feto-Protein, CD30, Placental Alkaline
Phosphatase, and Desmin were applied to the cell block. The
positive stains are Beta HCG with the rest being negative. This
supports the diagnosis of a choriocarcinoma.
- Morphologically and immunohistochemically, the tumor was a
choriocarcinoma. However the retroperitoneal mass is large,
therefore a mixed germ cell tumor cannot be excluded.
Testicular Cancer is relatively uncommon in the United States with
approximately 5500 cases per year. These tumors arises in males of nearly any
age and may be of germ cell or non germ cell origin. There are three main types,
germ cell tumors, non germ cell tumor and extragonadal tumors.
Choriocarinoma is a rare germ cell tumor and in its pure form , it is seen in less
than 1% of patients, but it occurs in mixed cell tumors in 8% of cases. It
typically affects younger men and unlike other cancers, choriocarcinoma
metastasizes hematogenously, with the testicular primary tumor often small or
even “burnt out.” It metastasizes early via hematogenous routes to the lung,
liver, and brain, among others. This tumor represents the most common
malignancy in men between the ages of 15-35 years of age. The tumor responds
poorly to radiation and chemotherapy and carries high mortality rate. Patients
with mixed germ cell tumors with choriocarinoma fair better than those with
pure choriocarcinoma tumors, but a high human chorionic gonadotropin
(>50,000 IU/L) portends a poor prognosis with at 5 year survical rate of 48%.
Surgery is usually limited to radical orchiectomy.
After four rounds of chemotherapy, the patient had a right radical
orchiectomy which showed a mixed germ cell tumor consisting
of mature teratoma (approximately 95%) and seminoma (less than
5%). No residual choriocarcinoma was seen which indicates
excellent response to therapy.
Goldman SM, Davidson AJ, Neal j. Retroperioteneal and pelvic
hemangiopericytomas: clinical, radiologic and pathologic correlation.
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