AJR 2000; 174:574-575
© American Roentgen Ray Society
MR Imaging of Hepatic Myelolipoma
C. Savoye-Collet,
O. Goria,
M. Scotté and
J. Hemet
Rouen University Hospital Charles Nicolle 76031 Rouen,
France
A 25-year-old man who underwent followup examination for type IV
Ehlers-Danlos syndrome was referred for abdominal sonography because of
elevated level of serum alkaline phosphatase. We found a hyperechogenic
heterogeneous nodule with calcifications in segment IV of the liver
(Fig. 3A). Serum
-fetoprotein level was normal. No CT scan was obtained because of
previous Harrington dorsal distraction rods. Abdominal MR imaging was
performed on a 1-T scanner (Gyroscan; Philips Medical Systems, Eindhoven, the
Netherlands) using an axial spin-echo T1- and T2-weighted sequence. No fat
suppression was used because of artifacts linked to magnetic field
inhomogeneity and metallic prosthesis. A 17 x 8 cm well-encapsulated
mass of segment IV was visualized as showing heterogeneous hyperintensity and
containing necrosis (Fig. 3B)
on T2-weighted images and as showing heterogeneous low signal intensity on
T1-weighted images. The mass was initially hypointense after administration of
a gadolinium bolus, and on the delayed-phase images, peripheral enhancement
was observed (Fig. 3C).
Laparotomy was proposed and a left hepatectomy was performed. The histologic
examination macroscopically confirmed an 18 x 9 cm well-defined, solid,
encapsulated tumor (880 g). The central portion of the tumor contained fat
separated by strands with hematopoietic cells. The mixture of hematopoietic
and adipose tissues was characteristic of myelolipoma (myeloid metaplasia).
Focal nodular hyperplasia surrounded the tumor. Postoperative course was
uneventful and the patient was discharged on the eighth postoperative day.
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Fig. 3A. —25-year-old man with type IV Ehlers-Danlos syndrome who was referred
for abdominal sonography because of elevated level of serum alkaline
phosphatase. Longitudinal sonogram shows hyperechoic mass with hypoechoic
areas and calcifications.
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Fig. 3B. —25-year-old man with type IV Ehlers-Danlos syndrome who was referred
for abdominal sonography because of elevated level of serum alkaline
phosphatase. Axial spin-echo T2-weighted MR image (TR/TE, 1250/130) shows
large (17 x 8 cm) well-defined hepatic mass with heterogeneous signal
intensity.
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Fig. 3C. —25-year-old man with type IV Ehlers-Danlos syndrome who was referred
for abdominal sonography because of elevated level of serum alkaline
phosphatase. Axial spin-echo T1-weighted MR image (520/15) after
administration of gadolinium shows peripheral enhancement and well-defined
central necrosis.
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We report a case of myelolipoma in an unusual location; myelolipoma is most
often a lesion of the adrenal gland, occurring as an incidental finding in
approximately 0.4% of autopsies
[1]. Extraadrenal myelolipoma
has been noted in the retroperitoneum, parietal pleura, mediastinum, gastric
antrum, and thoracic spine [2,
3]. Grosdidier et al.
[4] reported a case of hepatic
myelolipoma and, to our knowledge, fewer than 10 of these cases have been
reported to date [1,
2,
3,
4]. Our case is of particular
interest because of the location of the myelolipoma, the young age of the
patient, and the association with Ehlers-Danlos syndrome.
Abdominal sonography revealed a heterogeneous lesion with calcification. MR
imaging showed a well-marginated mass with pseudocapsule showing delayed
heterogeneous enhancement on administration of gadolinium. Despite the fatty
areas in the tumor, we did not observe increased signal intensity on
T1-weighted MR images. This was probably explained by the presence of admixed
marrowlike elements, which have medium signal intensity
[3]. The calcifications were
partly responsible for hypointense areas, contributing to the global
heterogeneous appearance, on T1- and T2-weighted MR images. Our imaging
findings correlated with the macroscopic findings at surgery. The histologic
results confirmed the diagnosis. The tumor was composed of fat cells and
hematopoietic cells, including mature and developing myeloid, erythroid, and
megakaryocytic cells. Marrowlike areas could be clearly seen.
On MR imaging, a well-defined hepatic mass with a pseudocapsule,
heterogeneous fatty architecture, and contents with an elevated attenuation is
suggestive of myelolipoma. The presence of fat and myeloid cells in a
percutaneous biopsy sample confirmed a definitive diagnosis of an asymptomatic
benign lesion.
References
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Rubin E, Russinovitch NA, Luna RF, Tishler JM, Wilkerson JA.
Myelolipoma of the liver. Cancer
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Rao P, Kenney PJ, Wagner BJ, Davidson AJ. Imaging and pathologic
features of myelolipoma. RadioGraphics
1997;17:1373-1385[Abstract]
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Kenney PJ, Wagner BJ, Rao P, Heffess CS. Myelolipoma: CT and
pathologic features. Radiology
1998;208:87-95[Abstract/Free Full Text]
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Grosdidier J, Boissel P, Macinot C, Drouin P. Hepatic myelolipoma:
apropos of a case [in French]. Nouve Press Med
1973;2:1777-1779
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