AJR 2003; 180:493-496
© American Roentgen Ray Society
MR Features of Abdominal Splenosis
Wen-Chiung Lin1,2,
Rheun-Chuan Lee1,2,
Jen-Huey Chiang1,2,
Chao-Jung Wei1,2,
Lee-Shing Chu3,4,
Ren-Shyan Liu3,4 and
Cheng-Yen Chang1,2,5
1 Department of Radiology, Taipei Veterans General Hospital, 201, Sec. 2.
Shih-Pai Rd., Taipei, Taiwan 11217.
2 Department of Radiology, National Yang-Ming University School of Medicine,
155, Sec. 2, Li-Nong St. Taipei, Taiwan 11217.
3 Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei,
Taiwan 11217.
4 Department of Nuclear Medicine, National Yang-Ming University School of
Medicine, Taipei, Taiwan 11217.
5 Department of Radiology, National Defense Medical Center, 325, Sec. 2,
Cheng-Kung Rd., Taipei, Taiwan 11217.
Received May 17, 2002;
accepted after revision July 30, 2002.
Address correspondence to R.-C. Lee.
Introduction
The term "splenosis" was defined by Buchbinder and Lipkoff
[1] in 1939 as the heterotopic
autotransplantation of splenic tissue. Splenosis occurs after trauma or
surgical procedures of the spleen and thus differs from congenital entities
such as accessory spleen or polysplenia. Splenosis was once considered to be
uncommon because patients are usually asymptomatic. However, it has been
suggested that the occurrence of splenosis in patients after traumatic
splenectomy is from 16% to 67%
[2]. Splenosis is usually found
incidentally on imaging studies. The unexpected location, irregular shape, and
slow growth of a splenic implant may mimic a neoplasm. Lack of awareness of
the imaging findings and inadequate knowledge of patient history may lead to
misdiagnosis and unwarranted surgical intervention
[3]. Splenic scintigraphy with
technetium-99m—tagged heat-damaged RBC is frequently used to confirm the
diagnosis [4]. Nevertheless,
the imaging characteristics of splenosis have been reported to be non-specific
and are seldom reviewed in the radiology literature. We discuss the MR
features of splenosis.
Method
Review of the databases of the nuclear medicine and surgery departments at
our institution from January 1994 to December 2001 identified eight patients
who had undergone splenectomy and had intraabdominal splenic implants.
Splenosis was confirmed by excisional biopsy (n = 1) and a splenic
scan with 99mTc-tagged heat-damaged RBC (n = 7). The
location, shape, number, growth, and characteristic enhancement pattern of
splenosis in these eight patients on dynamic MR images are reviewed.
Location of Splenic Implants
Disruption of the splenic capsule with direct dissemination of splenic
tissue in splenosis may result in splenic implants in unexpected locations.
Splenic implants have been reported in the splenic fossa, peritoneal cavity,
gastrointestinal tract, liver, kidney, thorax, subcutaneous region, and even
in the head. In our eight patients with splenosis, MR imaging depicted 26
abdominal splenic implants in various locations, predominantly in the left
upper quadrant of the abdomen (Fig.
1). Four patients had multiple splenic implants, with the number
ranging from two to 10. When splenosis occurs in patients with a history of
traumatic splenic injury, the splenic implants tend to be multiple and
disseminated widely in the intraperitoneal cavity and even the extraperitoneal
cavity (Figs.
2A,2B,2C
and
3A,3B,3C,3D).
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Fig. 1. —Drawing shows seeding sites and number of splenic implants.
HP = hepatic parenchyma, SPS = subphrenic space, LSHS = left subhepatic space,
DIA = diaphragm, RSHS = right subhepatic space, SSDC = serosal surface of
descending colon, RP = renal parenchyma, PRS = perirenal space, LPG = left
paracolic gutter, DMC = descending mesocolon.
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Fig. 2A. —37-year-old man with history of car crash who underwent
splenectomy 13 years ago. Unenhanced T1-weighted MR image (TR/TE, 150/4.2)
with fat suppression shows hypointense signal in 2-cm splenic implant
(arrow) at left hepatic lobe. Note that nodule is crescent-shaped
with anterior border confined by abdominal wall (arrowhead).
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Fig. 2B. —37-year-old man with history of car crash who underwent
splenectomy 13 years ago. T2-weighted MR image (2000/86.8) obtained at same
level as A shows hypointense signal in splenic implant
(arrow).
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Fig. 2C. —37-year-old man with history of car crash who underwent
splenectomy 13 years ago. Arterial phase of contrast-enhanced dynamic MR image
(150/4.2 with fat suppression and three-dimensional spoiled gradient-echo
sequence) shows peripheral enhancement in splenic implant (arrow).
Excisional biopsy confirmed splenic implant.
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Fig. 3A. —41-year-old man with history of car crash who underwent
splenectomy 20 years ago. T1-weighted MR image (TR/TE, 150/4.2) shows
hypointense signal in sheetlike 6-cm splenic implants (large arrow)
that are invaginated into two leaves of posterior perirenal fascia
(arrowheads). Multiple smaller implants are present in perirenal
space (small arrows).
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Fig. 3B. —41-year-old man with history of car crash who underwent
splenectomy 20 years ago. Coronal delayed-phase dynamic MR image obtained 3
min after gadolinium contrast administration shows persistent lack of
enhancement in splenic implants at upper and lower poles of left kidney
(arrows). Attachment of splenic implants to renal parenchyma is
shown.
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Fig. 3C. —41-year-old man with history of car crash who underwent
splenectomy 20 years ago. Unenhanced CT scan, obtained with scanning level
approximately 2 cm cranial to A, shows crescent-shaped splenic implants
along posterior perirenal fascia. Note that edges limited by posterior
perirenal fascia are effaced (arrowheads). Note high density of
splenic implants.
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Fig. 3D. —41-year-old man with history of car crash who underwent
splenectomy 20 years ago. Splenic scan obtained with
technetium-99m—tagged heat-damaged RBC shows radionuclide uptake at
renal parenchyma and perirenal space, consistent with locations of splenic
implants on MR imaging. Note that left side of figure is left side of
patient.
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Irregular and Remodeled Shapes of Splenic Implants
The shapes of the splenic implants varied. Among the 26 splenic implants,
there were rounded (Fig.
4A,4B,4C,4D),
ovoid (Fig. 5), crescent-shaped (Figs. 2A and
3C), lobulated, conglomerate
(Fig. 6), and sheetlike
lesions (Fig. 3A). MR imaging
findings showed implants in crescent or sheetlike shapes with effaced edges
when they were limited by the abdominal wall and Gerota's fascia. We speculate
that the growth of the implants may be limited and shaped by the surrounding
anatomic structures. When seeding in an unlimited space, the splenic implants
tend to be round or ovoid (Figs.
2A,
3A, and
3C).
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Fig. 4A. —43-year-old man with pedunculated hepatic cellular carcinoma
in left hepatic lobe who underwent left lobectomy, partial resection of
diaphragm, and splenectomy because of tumor invasion. Follow-up CT scan
obtained 3 months after surgery shows that no splenic implants can be
identified.
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Fig. 4B. —43-year-old man with pedunculated hepatic cellular carcinoma
in left hepatic lobe who underwent left lobectomy, partial resection of
diaphragm, and splenectomy because of tumor invasion. Follow-up CT scan
obtained 1 year after A shows well-defined 1.5-cm nodule adhering to
left hemidiaphragm, which was confirmed to be splenic implant (arrow)
by splenic scan obtained with technetium-99m—tagged heat-damaged RBC
(not shown).
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Fig. 4C. —43-year-old man with pedunculated hepatic cellular carcinoma
in left hepatic lobe who underwent left lobectomy, partial resection of
diaphragm, and splenectomy because of tumor invasion. Axial T1-weighted MR
image obtained 5 years after A shows progressive enlargement of 2-cm
splenic implant (arrow).
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Fig. 4D. —43-year-old man with pedunculated hepatic cellular carcinoma
in left hepatic lobe who underwent left lobectomy, partial resection of
diaphragm, and splenectomy because of tumor invasion. Arterial phase of
dynamic MR image (TR/TE,150/4.2) with fat suppression and three-dimensional
spoiled gradient-echo sequence shows peripheral enhancement of splenic implant
(arrow).
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Fig. 5. —80-year-old man who underwent splenectomy 40 years ago.
Arterial phase of coronal reformatted MR image (TR/TE, 150/4.2) with fat
suppression and three-dimensional fast low-angle shot shows heterogeneous
mosaic enhancing 6-cm splenic implant (arrow) on serosal surface of
descending colon. Parasitic blood vessel (arrowheads) from inferior
mesenteric artery enters ovoid splenic implant (not shown).
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Fig. 6. —65-year-old man with traumatic disruption of spleen who
underwent splenectomy 15 years ago. Reformatted contrast-enhanced T1-weighted
MR image (TR/TE,150/4.2) with fat suppression and three-dimensional spoiled
gradient-echo sequence in arterial phase shows conglomerate 3-cm splenic
implant (arrows) in left subphrenic region.
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Progressive Enlargement of the Splenic Implants
The size of splenic implants varies from millimeters to several
centimeters. Progressive enlargement of splenic implants has been observed in
splenosis [5], probably due to
compensatory change [6]. We
observed progressive enlargement of splenic implants in two patients (Figs.
4A,4B,4C,4D).
Regeneration of splenic implants may be active after splenectomy. This
manifestation of splenosis should not be mistaken for the growth of a
neoplasm.
Signal Intensity and Enhancement Patterns on Dynamic MR Imaging
The normal adult spleen is hypointense on T1-weighted imaging and
hyperintense on T2-weighted imaging. Occasionally, the spleen may be
hypointense on T2-weighted imaging because of iron deposition
[3]. The enhancement patterns
(heterogeneous, homogeneous, and unenhanced) of the normal spleen during
dynamic MR studies have been well illustrated
[7]. The unique heterogeneous
enhancement in the spleen is attributed to different rates of blood flow in
the red and white pulp of splenic tissue
[8]. The low signal intensity
of the splenic tissue even after contrast administration may be due to iron
deposition [3]. On the basis of
our observation, the signal intensities and the enhancing patterns of the
splenic implants on T1- and T2-weighted images and on dynamic MR images appear
to be identical to those of a normal spleen (Figs.
2A,2B,2C,3A,3B,3C,3D,4A,4B,4C,4D,5).
Heterogeneous enhancement of splenic implants in seven of our patients was
shown in the arterial phase of dynamic MR imaging; these implants became
homogeneous in the delayed phase. Low signal intensity of splenic implants was
shown throughout both the arterial and the late phase in one patient.
Conclusion
Splenosis occasionally can create a confusing appearance; it may resemble
adenopathy, peritoneal carcinomatosis, or lymphoma. This confusion may lead to
unnecessary biopsy or surgical exploration. We have observed that the
characteristic signal changes and enhancement patterns of splenic implants on
MR imaging are identical to those of the normal spleen. The predominant
locations in the left upper quadrant of the abdomen and the inconsistent
remodeled shapes of splenic implants are also significant findings. Dynamic
contrast-enhanced MR studies are valuable in the differential diagnosis of
splenosis, especially for the larger implants. Knowledge of the appearance of
splenosis should be helpful to the abdominal imager.
References
- Buchbinder JH, Lipkoff CJ. Splenosis: multiple peritoneal splenic
implants following abdominal injury. Surgery
1939;6:927
-934
- Normand JP, Rioux M, Dumont M, Bouchard G, Letourneau L. Thoracic
splenosis after blunt trauma: frequency and imaging findings.
AJR
1993;161:739
-741[Abstract/Free Full Text]
- Siegelman ES, Mitchell DG, Semelka RC. Abdominal iron deposition:
metabolism, MR findings, and clinical importance.
Radiology
1996;199:13
-22[Free Full Text]
- Delamarre J, Capron JP, Drouard F, Joly JP, Deschepper B, Carton S.
Splenosis: ultrasound and CT findings in a case complicated by an
intraperitoneal implant traumatic hematoma. Gastrointest
Radiol 1988;13:275
-278[Medline]
- Artinian MA, Gilliam JI. CT of intrathoracic splenosis in the
presence of bronchogenic carcinoma. J Comput Assist
Tomogr 1993;17:827
-828[Medline]
- Brewster DC. Splenosis: report of two cases and review of the
literature. Am J Surg
1973;126:14
-19[Medline]
- Semelka RC, Shoenut JP, Lawrence PH, Greenberg HM, Madden TP,
Kroeker MA. Spleen: dynamic enhancement patterns on gradient-echo MR images
enhanced with gadopentetate dimeglumine. Radiology
1992;185:479
-482[Abstract/Free Full Text]
- Glazer GM, Axel L, Goldberg HI, Moss AA. Dynamic CT of the normal
spleen. AJR
1981;137:343
-346[Free Full Text]
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Introduction
Method
