DOI:10.2214/AJR.04.1788
AJR 2006; 186:507-509
© American Roentgen Ray Society
Diffuse Mesenteric Extramedullary Hematopoiesis with Ascites: Sonography, CT, and MRI Findings
Christopher Holden1,
Oliver Hennessy1 and
Wai-Kit Lee1
1 All authors: Department of Medical Imaging, St. Vincent's Hospital, University
of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia.
Received November 18, 2004;
accepted after revision January 24, 2005.
Address correspondence to W.-K. Lee.
Keywords: abdominal imaging • CT • MRI • small bowel • sonography
Introduction
Extramedullary hematopoiesis is ectopic hematopoiesis that occurs as a
compensatory response to insufficient bone marrow hematopoiesis. Clinically
apparent extramedullary hematopoiesis in the gastrointestinal tract is rare
[1]. It may cause bowel
obstruction, simulate a carcinoma, or present with ascites
[2,
3]. There are several case
reports that diagnosed mesenteric infiltration by extramedullary hematopoiesis
at surgery or biopsy [3,
4], but there is a paucity in
the literature of the imaging findings of diffuse mesenteric extramedullary
hematopoiesis. We present the sonographic, CT, and MRI findings in a
histologically confirmed case of diffuse peritoneal extramedullary
hematopoiesis with ascites.
Case Report
A 64-year-old man presented with a 4-month history of progressive abdominal
distention, loss of weight, loss of appetite, and night sweats. He had a
12-year history of biopsy-proven idiopathic myelofibrosis, which had been
managed with myelosuppressive agents (corticosteroids and hydroxyurea), and in
recent years he was transfusion-dependent. Splenectomy performed 8 years
earlier for symptomatic splenomegaly and thrombocytopenia showed diffuse
splenic extramedullary hematopoiesis.
Imaging evaluation included abdominal CT, MRI, sonography, and
sonographically guided biopsy. A contrast-enhanced CT showed hepatomegaly,
periportal infiltration, ascites, and diffuse infiltration of the small bowel
mesentery with mildly enhancing soft tissue
(Fig. 1A). There was no small
bowel obstruction.
View larger version (130K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Contrast-enhanced axial CT image shows diffuse infiltration of
small bowel mesentery and encasement of small bowel.
|
|
MRI showed homogeneous soft tissue diffusely infiltrating the small bowel
mesentery and encasing the small bowel loops. This tissue was of intermediate
T1 signal intensity and intermediate-to-high T2 signal intensity compared with
muscle (Figs. 1B and
1C). Gadolinium-enhanced
coronal T1-weighted images demonstrated mild early and late enhancement (Figs.
1D and
1E). Sonography showed that the
mesenteric soft tissue was iso- to hypoechoic and without significant
vascularity (Fig. 1F). At the
time of imaging, the differential diagnoses included peritoneal
carcinomatosis, leukemic transformation of myelofibrosis, or peritoneal
tuberculosis. Peritoneal extramedullary hematopoiesis was not considered
because such extensive peritoneal involvement had not been previously
described.
View larger version (102K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1B —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Axial T1-weighted image with fat saturation at a similar level
to A shows mesenteric infiltrate to be isointense to muscle.
Hyperintense fluid within small bowel lumen is iodinated contrast from
fluoroscopic study performed on same day.
|
|
View larger version (118K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1C —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Corresponding axial T2-weighted image demonstrates mesenteric
infiltrate to be iso- to mildly hyperintense to muscle. Liver (L) is markedly
hypointense due to transfusion-related secondary hemosiderosis.
|
|
View larger version (162K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1D —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Gadolinium-enhanced coronal T1-weighted image with fat
saturation shows early mild enhancement of mesenteric infiltrate.
|
|
View larger version (161K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1E —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Gadolinium-enhanced coronal T1-weighted image with fat
saturation shows late mild enhancement of mesenteric infiltrate.
|
|
View larger version (167K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1F —64-year-old man with diffuse mesenteric extramedullary hematopoiesis
with ascites. Longitudinal sonogram of mesentery shows hypoechoic soft tissue
interposed between two bowel loops (B).
|
|
Hemoserous fluid was obtained at a diagnostic paracentesis. Pale tan fatty
cores of soft tissue were obtained at sonography-guided mesenteric biopsy.
Both the mesenteric histopathology and ascitic cytology showed large abnormal
megakaryocytes, which stained positively for factor VIII-related antigen, and
were diagnostic of extramedullary hematopoiesis. Both tissue specimens were
negative for malignancy and infectious causes, including Mycobacterium
tuberculosis. The patient was started on oral thalidomide. He suffered
repeat episodes of severe duodenal variceal bleeding, which was refractory to
endoscopic and medical treatment, and he died from an episode of massive
hematemesis 4 weeks after the hospital admission. The family declined an
autopsy.
Discussion
Extramedullary hematopoiesis occurs in hemoglobinopathies,
myeloproliferative disorders, or bone marrow infiltration. Idiopathic
myelofibrosis is an uncommon chronic myeloproliferative disorder of unknown
cause, which is characterized by leukoerythroblastosis, bone marrow fibrosis,
extramedullary hematopoiesis, and hepatosplenomegaly. Ninety-four percent of
patients with idiopathic myelofibrosis have splenomegaly, and extramedullary
hematopoiesis is almost always found in the spleen in these patients
[1].
Extramedullary hematopoiesis can occur in any tissue of mesenchymal origin
and has been described in a wide variety of organs, including in the chest,
abdomen, and neural axis, but it typically involves the liver and spleen.
Elsewhere, extramedullary hematopoiesis is usually subclinical and
microscopic. Extramedullary hematopoiesis may diffusely infiltrate the organ
(such as in the liver and spleen) or form pseudotumors (such as in the
paravertebral region of the chest). Peritoneal and small bowel involvement
with extramedullary hematopoiesis is rare; often takes the form pseudotumor
masses; and may occur as mural deposits, serosal implants, or within abdominal
nodes at histology [2,
4,
5].
The imaging findings of extramedullary hematopoiesis are variable and have
been described almost entirely for focal deposits of extramedullary
hematopoiesis. It is anticipated that the imaging characteristics in diffuse
extramedullary hematopoiesis will parallel that of focal extramedullary
hematopoiesis. The variability of the imaging appearance of extramedullary
hematopoiesis has been hypothesized to be dependent on the relative amounts of
the normal marrow constituents—fat, hematopoietic cells, and
fibrosis—within the extramedullary hematopoiesis deposit
[6]. In a sonogram, focal
extramedullary hematopoiesis can appear as echogenic, hypoechoic, or
heterogeneous masses [6]. In a
CT scan, focal extramedullary hematopoiesis is often a heterogeneous hypodense
mass with absent, minimal, or heterogeneous enhancement
[5,
6]. Burnt out extramedullary
hematopoiesis has been described as predominantly of fat density with little
or no contrast enhancement or as showing iron deposition
[5]. In an MR image, focal
extramedullary hematopoiesis is iso- to mildly hyperintense to muscle in both
T1- and T2-weighted scans, with variable contrast enhancement in a similar
manner to CT [7]. Because the
imaging appearances of focal and diffuse peritoneal extramedullary
hematopoiesis are nonspecific, histologic diagnosis is required.
Ascites in our patient may have been due to portal hypertension related to
underlying myelofibrosis. Ascites in association with peritoneal
extramedullary hematopoiesis is uncommon
[3]. Ascites occurs in 5-10% of
patients with idiopathic myelofibrosis and is usually due to portal
hypertension [1]. The
pathogenesis of ascites with extramedullary hematopoiesis is controversial,
but is thought to be due to a number of possible causes, including rupture of
hepatosplenic nodules of extramedullary hematopoiesis into the peritoneal
cavity, peritoneal implants of extramedullary hematopoiesis, and portal
hypertension [3]. Causes of
portal hypertension in idiopathic myelofibrosis include presinusoidal or
sinusoidal extramedullary hematopoiesis infiltration and postsinusoidal causes
(Budd-Chiari) or may be related to splenomegaly
[3]. Portal hypertension with
severe refractory variceal bleeding was the terminal event in our patient,
which is a common complication in patients with idiopathic myelofibrosis.
When serosal extramedullary hematopoiesis implants are extensive enough to
cause an exudative ascites, they are refractory to conventional drug therapy.
Because few cases of clinically apparent extramedullary hematopoiesis are
reported, there is controversy as to the most effective and appropriate
treatment. Treatments that have been used to control peritoneal extramedullary
hematopoiesis or refractory ascites from extramedullary hematopoiesis include
low-dose abdominal radiation therapy, which can be associated with transient
but severe bone marrow aplasia
[3]; direct intraperitoneal
chemotherapy [8]; and oral
thalidomide [9]. Thalidomide,
an antiangiogenic agent, was chosen in our patient. It has been reported to
provide beneficial results, but the clinical response only becomes apparent
after a number of weeks of therapy with a reported median duration of therapy
of 16 weeks in one series [9].
Our patient was only on thalidomide for 2 weeks before he died and there was
no significant documented clinical response.
Conclusion
In conclusion, we present an unusual case of diffuse mesenteric
extramedullary hematopoiesis with ascites in a 64-year-old man with idiopathic
myelofibrosis. The differential diagnosis of diffuse peritoneal thickening in
patients with idiopathic myelofibrosis, which is often accompanied secondarily
by immunosuppression, not only includes peritoneal carcinomatosis, leukemic
transformation of myelosclerosis, and peritoneal tuberculosis, but also
extramedullary hematopoiesis. While the imaging findings are not diagnostic of
extramedullary hematopoiesis, imaging is invaluable in guiding tissue sampling
and in monitoring morphologic response to therapy. Histologic diagnosis is
required to triage appropriate therapy in this difficult-to-manage group of
patients.
References
- Guermazi A, de Kerviler E, Cazals-Hatem D, Zagdanski AM, Frija J.
Imaging findings in patients with myelofibrosis. Eur
Radiol 1999; 9:1366
-1375[CrossRef][Medline]
- Sunderland K, Barratt J, Pidcock M. Extramedullary hemopoiesis
arising in the gut mimicking carcinoma of the cecum.
Pathology 1994;26
: 62-64[CrossRef][Medline]
- Liote F, Yeni P, Teillet-Thiebaud F, et al. Ascites revealing
peritoneal and hepatic extramedullary hematopoiesis with peliosis in agnogenic
myeloid metaplasia: case report and review of the literature. Am J
Med 1991; 90:111
-117[Medline]
- Tzankov A, Krugmann J, Steurer M, Dirnhofer S. Idiopathic
myelofibrosis with nodal, serosal and parenchymatous infiltration.
Acta Haematol 2002;107
: 173-176[Medline]
- Georgiades CS, Neyman EG, Francis IR, Sneider MB, Fishman EK.
Typical and atypical presentations of extramedullary hemopoiesis.
AJR 2002; 179:1239
-1243[Free Full Text]
- Gupta P, Naran A, Auh YH, Chung JS. Focal intrahepatic
extramedullary hematopoiesis presenting as fatty lesions.
AJR 2004; 182:1031
-1032[Free Full Text]
- Chourmouzi D, Pistevou-Gompaki K, Plataniotis G, Skaragas G,
Papadopoulos L, Drevelegas A. MRI findings of extramedullary haemopoiesis.
Eur Radiol 2001;11
: 1803-1806[Medline]
- Stahl RL, Hoppstein L, Davidson TG. Intraperitoneal chemotherapy
with cytosine arabinoside in agnogenic myelofibrosis with myeloid metaplasia
and ascites due to peritoneal extramedullary hematopoiesis. Am J
Hematol 1993; 43:156
-157[Medline]
- Elliott MA, Mesa RA, Li CY, et al. Thalidomide treatment in
myelofibrosis with myeloid metaplasia. Br J Haematol2002; 117:288
-296[CrossRef][Medline]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
Top
Introduction
Case Report
