AJR 2004; 183:1608-1610
© American Roentgen Ray Society
Metastatic Cerebellar Medulloblastoma in the Liver Mimicking a Complicated Cyst: Sonographic and MDCT Findings
Banu Cakir1,
Nefise Cagla Tarhan1,
Mehmet Coskun1,
Binnaz Handan Ozdemir2,
Alper Bozkurt1 and
Ozgur Ozyilkan3
1 Department of Radiology, Baskent University Faculty of Medicine, Fevzi Cakmak
Cad. 10.sok., No: 45, Bahcelievler, Ankara 06490, Turkey.
2 Department of Pathology, Baskent University Faculty of Medicine, Ankara 06490,
Turkey.
3 Department of Internal Medicine, Baskent University Faculty of Medicine,
Ankara 06490, Turkey.
Received January 2, 2004;
accepted after revision March 9, 2004.
Address correspondence to B. Cakir
(banuc{at}baskent-ank.edu.tr).
Introduction
Medulloblastoma is the most common childhood intracranial tumor. It is
rarely found in adults; approximately 20% of medulloblastomas occur in adults
[1,
2]. Medulloblastomas often
spread through the cerebrospinal fluid but rarely disseminate to systemic
sites [3]. Although rare cases
of liver metastasis of this tumor have been reported previously in the
literature, we know of no reports of the imaging features of this metastasis.
We report the sonographic and MDCT findings of a unique case of a young adult
with a posterior fossa medulloblastoma that metastasized to the liver
mimicking a complicated cyst.
Case Report
A 20-year-old man was admitted to our emergency department with gait
ataxia, nausea, and headache. Results of the neurologic examination were
otherwise unremarkable. Cranial CT showed a lobulated, heterogeneously
enhanced midline posterior fossa mass arising within the cerebellar vermis
measuring 3 x 3 cm with surrounding white matter edema. Obstructive
hydrocephalus was diagnosed. Cranial MRI and proton MR spectroscopy were
performed. The findings were consistent with a primary brain tumor, probably a
medulloblastoma. Spinal MR images obtained for evaluation of spinal seeding
were unremarkable. Ventriculoperitoneal shunting was not performed, and the
vermian mass was totally excised immediately. Pathologic examination confirmed
that the tumor was a medulloblastoma. After the excision of the primary mass,
the patient received radiotherapy combined with steroid therapy. Findings of
the initial cranial MDCT follow-up examinations were unremarkable.
Ten months after the surgery, the patient was admitted to the oncology
department with persistent fever (
39°C), weakness, anorexia, and pain
in his legs. WBC was unremarkable, but the results of liver function tests
were elevated. Abdominal sonography revealed two rounded, well-circumscribed,
hypoechoic lesions in the right lobe of the liver. The lesions had thickened
walls, and one lesion had septations (Fig.
1A). Color Doppler sonography performed with a 7.5-MHz probe
showed minimal vascularization around the masses. Unenhanced abdominal MDCT
also revealed the two well-circumscribed hypodense lesions in the right lobe
of the liver (Fig. 1B). After
contrast administration, no enhancement was seen within the lesions, but
minimal wall enhancement was noted (Figs.
1C and
1D). The density of the lesions
(40–50 H) was higher than that of serous fluid. These findings, combined
with the patient's clinical presentation, were most suggestive of an
infectious process. Infected liver cysts or liver abscesses were the primary
differential diagnoses. Gelatinous material was aspirated by sonographically
guided fine-needle aspiration biopsy. Histopathologic evaluation revealed
cells with a high nuclear–cytoplasmic ratio, and the nuclei were
hyperchromatic with frequent mitoses. The findings were identical to those in
the vermian medulloblastoma (Fig.
1E) and supported the diagnosis of metastatic medulloblastomas to
the liver. A bone scan showed radiopharmaceutical accumulation in various
bones that also was consistent with skeletal metastases.
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Fig. 1A. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Transverse sonogram shows lesion 1 as
hypoechoic, rounded cystic mass (arrows) with thickened wall and
septations.
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Fig. 1B. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Unenhanced abdominal MDCT scan reveals lesion
1 as well-circumscribed hypodense mass (arrows). Density of lesion
(40–50 H) was higher than that of serous fluid.
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Fig. 1C. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Enhanced abdominal MDCT scans show lesion 1
(C) and lesion 2 (D). In both cases, no enhancement is seen
within lesion itself (arrows), but minimal wall enhancement is
visible.
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Fig. 1D. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Enhanced abdominal MDCT scans show lesion 1
(C) and lesion 2 (D). In both cases, no enhancement is seen
within lesion itself (arrows), but minimal wall enhancement is
visible.
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Fig. 1E. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Photomicrograph of histopathologic specimen
shows cells with high nuclear–cytoplasmic ratio. Nuclei (arrow)
are hyperchromatic with frequent mitoses. (H and E)
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At follow-up, cranial MDCT showed a vermian mass consistent with recurrent
tumor. Chemotherapy was started, and 1 month after the treatment, repeat
abdominal MDCT showed a reduction in the size of the lesions and a solid
component within the cystic lesions that enhanced after contrast
administration (Fig. 1F).
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Fig. 1F. —20-year-old man with cerebellar medulloblastoma and two
lesions in right lobe of liver. Enhanced abdominal MDCT scan obtained after 1
month of treatment shows that lesion 1 has decreased in size and that solid
component (arrows) within cystic lesion enhanced after contrast
administration.
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Discussion
Medulloblastoma is an infratentorial primitive neuroectodermal tumor that
accounts for approximately 1.5% of all intracranial tumors. The incidence of
medulloblastoma varies between 20% and 35% of pediatric intracranial tumors,
but it is rare in the adult population
[4]. Kadin and Rubenstein
[5] suggested that
medulloblastomas arise from germinal cells (or their remnants) anywhere along
their migratory path. The primary symptoms are headache, vomiting, and an
unsteady gait [4]. Bilateral
papilledema and signs of cerebellar vermis dysfunction are revealed at
neurologic examination. The clinical use of contrast-enhanced CT and MRI for
evaluation of medulloblastoma is common.
Extraneural metastases of medulloblastoma are rare. Previous reports
describing extracranial metastases have suggested that ventriculoperitoneal
shunting facilitates distant dissemination
[6–8].
There have been a few reported cases of distant metastasis without
ventriculoperitoneal shunting
[6]. Eberhart et al.
[3] reported the predominant
sites of systemic metastasis without shunting to be the bones or the bone
marrow (91% of the cases). Metastases to soft tissues, lymph nodes, or lungs
were found in 13% of the cases. Eberhart et al. revealed that anaplasia is
more common in medulloblastomas with involvement outside the central nervous
system. In our patient, moderate anaplasia has been noted. Berger et al.
[7] retrospectively analyzed
extraneural metastases of central nervous system tumors, and none of the
patients with medulloblastoma had liver metastases. Hyun et al.
[1] described an orbital
primitive neuroectodermal tumor that had metastasized to the liver and that
showed abdominal CT findings mimicking liver abscesses. They reported the case
of a 37-year-old woman who developed a persistent fever after vaginal delivery
in whom contrast-enhanced abdominal CT revealed six rounded,
well-circumscribed areas of decreased attenuation that mimicked liver
abscesses. The patient's history included surgery for orbital primitive
neuroectodermal tumor, and the pathology of the aspirate from the hepatic
lesions was identical to that of the orbital primitive neuroectodermal tumor.
To our knowledge, a medulloblastoma of the brain with systemic liver
metastasis has not been previously described with its detailed imaging
features.
In our patient, abdominal sonography showed hypoechoic lesions in the
liver, and abdominal MDCT also revealed hypodense lesions with minimal wall
enhancement. In evaluating these findings combined with the patient's clinical
presentation for the differential diagnosis, we first thought these lesions to
be indications of an infected liver cyst or liver abscesses with minimal
inflammatory reaction. After treatment, the solid components of the lesions
became more prominent, with their decreased sizes suggesting metastasis.
This rare case shows cystic liver metastasis of a cerebellar
medulloblastoma in an adult. In evaluating cystic liver lesions of children
and young adults who have had a known primary primitive neuroectodermal tumor,
the possibility of metastasis should always be kept in mind even if no solid
component has been visualized. Although metastasis is a differential diagnosis
in these lesions, one must still perform an aspiration biopsy in a febrile
patient with a cystic lesion to exclude the possibility of a liver
abscess.
References
- Hyun CB, Lee YR, Bemiller TA. Metastatic peripheral primitive
neuroectodermal tumor (PNET) masquerading as liver abscess: a case report of
liver metastasis in orbital PNET. J Clin Gastroenterol2002; 35:93
–97[Medline]
- Tomlinson FH, Scheithauer BW, Meyer FB, et al. Medulloblastoma. I.
Clinical, diagnostic, and therapeutic overview. J Child
Neurol 1992;7:142
–155[Abstract/Free Full Text]
- Eberhart CG, Cohen KJ, Tihan T, Goldthwaite PT, Burger PC.
Medulloblastomas with systemic metastases: evaluation of tumor histopathology
and clinical behavior in 23 patients. J Pediatr Hematol
Oncol 2003;25:198
–203[Medline]
- Zhang R, Zhou L. Medulloblastoma. Chin Med
J 1999;112:297
–301[Medline]
- Kadin ME, Rubenstein LJ. Neonatal cerebellar medulloblastoma
originating from the fetal external granular layer. J Neuropathol
Exp Neurol 1970; 29:583
–589[Medline]
- Roebuck DJ, Villablanca JG, Maher K, Nelson MD Jr. Surveillance
imaging in children with medulloblastoma (posterior fossa PNET).
Pediatr Radiol2000; 30:447
–450[Medline]
- Berger MS, Baumeister B, Geyer JR, Milstein J, Kanev PM, Leroux PD.
The risks of metastases from shunting in children with primary central nervous
system tumors. J Neurosurg1991; 74:872
–877[Medline]
- Jamjoom ZA, Jamjoom AB, Sulaiman AH, Naim-Ur-Rahman, al-Rabiaa A.
Systemic metastasis of medulloblastoma through ventriculoperitoneal shunt:
report of a case and critical analysis of the literature. Surg
Neurol 1993;40:403
–410[Medline]
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Introduction
Case Report
