A clinicopathological study of inflammatory pseudotumors of the liver with special reference to vessels.
OBJECTIVE
Inflammatory pseudotumor of the liver is rare, and patients with inflammatory pseudotumor frequently undergo unnecessary surgical resection as a result of misdiagnosis of malignancy. In this study, we therefore investigated inflammatory pseudotumor clinicopathologically to clarify its characteristics.


METHODS
Twenty patients including 3 with inflammatory pseudotumor and 17 with various malignant liver tumors were studied. We further investigated tumor vessels by means of immunohistochemistry using monoclonal antibodies against CD34, factor VIII-related antigen and alpha-smooth muscle actin.


RESULTS
Although serum levels of alkaline phosphatase were significantly higher in inflammatory pseudotumor patients than in other patients, the laboratory data alone could not precisely distinguish inflammatory pseudotumor from other hepatic tumors. On imaging studies such as ultrasonography and computed tomography, significant changes in tumor size, especially size reduction, during relatively short follow-up periods were often observed in inflammatory pseudotumor but not in other liver tumors. An enhancement of the peripheral regions of inflammatory pseudotumor was frequently observed in the early phase of contrast-medium dynamic computed tomography. This might be due to abnormal vessels located in the peripheral regions of inflammatory pseudotumor which might result from obliteration of some pre-existing vessels in portal tracts within inflammatory pseudotumor. Immunohistochemical analysis further revealed that abnormal vessels in the peripheral regions of inflammatory pseudotumor were positively stained with CD34, factor VIII-related antigen and alpha-smooth muscle actin as were tumor sinusoids within hepatocellular carcinoma and tumor capillaries in other malignant liver tumors.


CONCLUSIONS
Although inflammatory pseudotumor seems to have some features in imaging studies, a biopsy is needed for a correct diagnosis of inflammatory pseudotumor.
Seki
Shuichi
S
Third Department of Internal Medicine, Osaka City University Medical School, Osaka, Japan. s.seki@med.osaka-cu.ac.jp
Kitada
Takuya
T
Sakaguchi
Hiroki
H
Iwai
Shuji
S
Hirohashi
Kazuhiro
K
Higaki
Ikko
I
Nakamura
Kenji
K
Wakasa
Kenichi
K
Kinoshita
Hiroaki
H
D000199:Actins / Q000032:analysis; D000368:Aged; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000032:analysis; D001706:Biopsy; D001808:Blood Vessels / Q000737:chemistry / Q000276:immunology / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006104:Granuloma, Plasma Cell / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008102:Liver Circulation; D008107:Liver Diseases / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism; D014057:Tomography, X-Ray Computed; D014841:von Willebrand Factor / Q000032:analysis
D000199:Actins; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D003287:Contrast Media; D014841:von Willebrand Factor