Hepatic Inflammatory Myofibroblastic Tumor Research Articles

A Surgical Case of Inflammatory Myofibroblastic Tumor of the Liver: Potentially Characteristic Gross Features

We herein reported a very rare surgical case of inflammatory myofibroblastic tumor (IMT) of the liver, showing potentially unique and specific gross findings on its cut surface: our IMT demonstrated a relatively well-demarcated and partly infiltrative and likely extrahepatic (ie serosal) but not intrahepatic mass, appearing firm and hemorrhagic, and yellow-whitish in color. The patient, who was a woman in her early 70s with 2-year follow-up for lung cryptococcosis and traffic accident, incidentally presented with unenhanced and low-density, heterogeneous mass on abdominal dynamic CT in the peripheral right lobe of the liver. We could conclusively diagnose the current lesion as the hepatic IMT after thorough analyses including a wide panel of immunohistochemical antibodies. Despite that, all clinicians and pathologists should be aware that the potentially characteristic, extrahepatic gross feature of IMT of the liver might also be one of the powerful supplementary tools for reaching its correct diagnosis. One of our aims in the presented case report is to emphasize that the hepatic IMT should be considered clinicopathologically in the differential diagnosis of mass lesions on the liver.

Medical imaging findings and pathological characteristics of hepatic inflammatory myofibroblastic tumor

Objective To study the medical imaging findings and the pathological features of hepa-tic inflammatory myofibroblastic tumor (HIMT) using CT, MRI and histopathology. Methods The CT and MRI findings of 31 patients with HIMT which were confirmed by histopathology on surgically resected specimen were analyzed retrospectively. The location, size, shape, edge, density or signal, and contrast enhancement of these tumors were analyzed. Results The tumors were located in the right liver in 26 patients, in the left liver in 5 patients, and under the hepatic capsule in 27 patients. The tumors were solitary in 28 patients and multiple in 3 patients. The maximum diameter of the tumor ranged from 2.1 cm to 12.5 cm. The average diameter was (3.6±1.2) cm. The tumors were round or oval in 21 patients and irregular in 10 patients. 19 patients underwent CT examination and all tumors showed low density, with a CT value which ranged from 5 to 35HU. The average value was (27.6±5.3) HU. The density of tumors was homogeneous in 6 patients and inhomogeneous in 13 patients, and among these 13 patients, 3 were alveolate. Twenty-one patients underwent MRI scan and all showed a low signal on T1WI, 12 patients showed an equal signal and 9 patients showed a slightly higher signal on T2WI. In 6 patients the signals were homogeneous and in 15 patients they were inhomogeneous. On CT and MRI enhanced scans the whole tumor was enhanced in 12 patients, the edge was enhanced in 9 patients, the septum was enhanced in 8 patients and no enhancement was observed in 2 patients. Pathological examination under microscopy observed the presence of proliferation of spindle cells, chronic inflammatory cells which included the proliferation of lymphocytes, plasma cells and collagen fiber formation. The spindle cells had the characteristics of fibroblasts and myofibroblast cells. Immunohistochemical examination showed the wave type protein (Vimentin) was positive in 23 patients, the smooth muscle actin (SMA) was positive in 18 patients, the muscle actin (MSA) and the specificity of junction protein (Desmin) were positive in 12 patients, CD68 was positive in 4 patients, and the ALK, S-100 protein, CDll7 and CD35 were all negative. Conclusions The radiological features of CT and MRI plain scan varied. The patterns of contrast enhancement included full tumor filling, marginal enhancement, compartment enhancement, and no enhancement. The enhanced features varied from mild to moderate enhancement in the arterial phase, further enhancement in the portal phase and mild enhancement in the delayed phase. Key words: Hepatic tumor; Inflammatory myofibroblastic tumor; Magnetic resonance imaging (MRI); Computed Tomography (CT)

Diffusion-weighted magnetic resonance imaging for non-neoplastic conditions in the hepatobiliary and pancreatic regions: pearls and potential pitfalls in imaging interpretation.

Potentially, diffusion-weighted magnetic resonance imaging (DWI) can assess the functional information on concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion. DWI in the hepatobiliary and pancreatic regions has demonstrated the usefulness to detect malignant lesions and differentiate them from benign lesions. However, it has been shown more recently that there is some overlap in ADC values for benign and malignant neoplasms. Moreover, some non-neoplastic lesions in the hepatobiliary and pancreatic regions exhibit restricted diffusion on DWI, because of pus, inflammation, or high cellularity. Focal eosinophilic liver disease, hepatic inflammatory myofibroblastic tumor, granulomatous liver disease, acute cholecystitis, xanthogranulomatous cholecystitis, focal pancreatitis, or autoimmune pancreatitis frequently exhibit restricted diffusion on DWI, which may be confused with malignancy in the hepatobiliary and pancreatic regions. Thus, DWI should not be interpreted in isolation, but in conjunction with other conventional images, to avoid the diagnostic pitfalls of DWI. Nevertheless, the presence of diffusion restriction in the non-neoplastic lesions sometimes provides additional information regarding the diagnosis, in problematic patients where conventional images have yielded equivocal findings. DWI may help differentiate hepatic abscess from malignant necrotic tumors, gallbladder empyema from dense bile or sludge in the gallbladder, and pylephlebitis from bland thrombosis in the portal vein. Therefore, knowledge of DWI findings to conventional imaging findings of diffusion-restricted non-neoplastic conditions in the hepatobiliary and pancreatic regions helps establishing a correct diagnosis.

Inflammatory Myofibroblastic Tumor of the Liver: A Diagnostic Challenge.

Inflammatory myofibroblastic tumor (IMT) is an uncommon myofibroblastic neoplasm that was formerly included within the broad category of inflammatory pseudotumor (IPT). IMT is rarely encountered in the liver. Similar to IMT of other organs, the interchangeable use of the terms IMT and IPT in liver has made the analysis of these lesions difficult. In this review, clinical and pathological features of IMT of the liver are reviewed and the differential diagnosis of IMT is discussed, with emphasis on IPT and the other entities included in this large category. IMT can mimic malignant tumors. There are no known unique diagnostic clinical, laboratory, or radiological features. The definitive diagnosis of IMT depends on careful pathological examination. The histopathological evaluation of hepatic IMT reveals that, the myxoid/vascular pattern is the most frequently observed, followed by, in decreasing frequency, fibrous histiocytoma-like pattern and hypocellular fibrous pattern. In IMT of the liver, anaplastic lymphoma kinase (ALK) expression reliably predicts the presence of an ALK gene rearrangement. The diagnosis of hepatic IMT depends on the dominant histopathological pattern, and the management of the disease is still controversial. IMT of the liver is a distinctive neoplasm of intermediate biological potential, and should be distinguished from the variety of lesions that are included under the broad category of IPT. Therefore, to avoid confusion regarding the true incidence and behavior of hepatic IMT, the term IPT should not be used interchangeably with IMT. The rarity of IMT in liver should not minimize its consideration in the differential diagnosis of liver tumors, especially in patients with tumor markers in normal range.

An inflammatory myofibroblastic tumor in liver with ALK and RANBP2 gene rearrangement: combination of distinct morphologic, immunohistochemical, and genetic features

Inflammatory myofibroblastic tumor is an intermediate-grade neoplasm with potential for recurrence and rare metastasis. Rearrangement of the anaplastic lymphoma kinase gene with variable fusion partners and anaplastic lymphoma kinase expression using immunohistochemistry are noted in about half of the tumors. We present a hepatic inflammatory myofibroblastic tumor from a 34-year-old man with an unusual rearrangement between the Ran binding protein 2 and anaplastic lymphoma kinase genes, as well as a peculiar round cell transformation of tumor cells and a unique nuclear membrane expression of anaplastic lymphoma kinase protein. As the fourth reported inflammatory myofibroblastic tumor with this fusion so far, we find that these genetic and morphologic features may be related to a poor clinical outcome. The diagnostic difficulty and other prognostic factors of inflammatory myofibroblastic tumor are also discussed.

Imaging appearance of hepatic inflammatory myofibroblastic tumor

Objective To describe the CT and MR imaging features of hepatic inflammatory myofibroblastic tumor(IMT).Methods The CT(n=12)and MRI(n=2)findings of pathologically proved hepatic IMT in 12 patients were retrospectively analyzed.Results All the tumors of the 12 patients were solitary and located in right hepatic lobe.Six tumors were solid and 4 tumors were solid-cystic.The other 2 tumors were periportal soft-tissue infiltration.The tumors appeared as solid or solid-cystic hypodense mass on CT images.The lesions were dark in T1-weighted sequences and slightly bright on T2-weighted sequences.There was homogeneous or inhomogeneous moderate to significant enhancement in solid portion of the tumors.Honeycomb-like enhancement was demontrated both in the peripheral part and at the intratumoral septa of the solid-cystic mass.Conclusion CT and MRI can provide helpful information for the clinical diagnosis and differential diagnosis of hepatic IMT. Key words: Neoplasms,muscle tissue; Liver neoplasms; Tomography,X-ray computed; Magnetic resonance imaging

Inflammatory Myofibroblastic Tumor of the Liver

We report a case of hepatic inflammatory myofibroblastic tumor in a 26-year-old African American man who presented with right upper quadrant pain, weight loss, and fatigue during the previous year. Hepatomegaly was found on physical examination. Laboratory findings were significant for mild normocytic, normochromic anemia and elevated erythrocyte sedimentation rate. Imaging studies showed 2 contiguous masses suspicious for malignancy. A left partial hepatectomy was performed; the preoperative differential diagnosis was for angiosarcoma and hepatocellular carcinoma. The resected liver specimen showed 2 contiguous, firm, tan-white nodules that microscopically represented a proliferation of spindled myofibroblast cells set in an inflammatory and collagenized background. The spindle cells were strongly reactive for smooth muscle actin but negative for ALK-1. The morphologic and immunophenotypic findings, coupled with the clinical presentation, were consistent with an inflammatory myofibroblastic tumor of the liver.

Inflammatory myofibroblastic tumor in children: clinical review with anaplastic lymphoma kinase, Epstein-Barr virus, and human herpesvirus 8 detection analysis

Background/Purpose Inflammatory myofibroblastic tumor (IMT) is considered as an intermediate neoplasm that may present malignant features. Differential diagnosis with other tumor processes is sometimes difficult. Similar anaplastic lymphoma kinase (ALK) gene abnormalities as in anaplastic large cell lymphoma have been reported. Human herpesvirus 8 (HHV-8) DNA sequences have been described in adult pulmonary IMTs and Epstein-Barr virus (EBV) has been reported in splenic and hepatic IMTs, suggesting the importance of both viruses in IMT development. This article aims to evaluate ALK, EBV, and HHV-8 expression in children with IMT and to correlate our findings with clinical features. Methods Sixteen children (range, 1-15 years) who had surgery for IMT between 1978 and 2003 were evaluated retrospectively. Formalin-fixed, paraffin-embedded archival tissues were stained for HHV-8 and ALK with immunohistochemistry. Epstein-Barr virus was detected by in situ hybridization (EBER probes). Results Tumors were located in the pulmonary lobe (n = 4), urinary tract (n = 4), mesentery or bowel (n = 4), hepatic lobe (n = 1), vena cava (n = 1), spinal cord (n = 1), and soft tissue (n = 1). Five children were treated with steroids and/or antibiotics before surgery, with no substantial result. IMT was excised totally in all but 2 cases. Four patients presented aggressive IMT with recurrence or metastasis requiring new surgery. ALK was positive in 3 (18.8%) cases and EBV in 1 pulmonary and 1 bladder tumor, all of them without recurrence or metastasis. None of the cases were positive for HHV-8. All patients are now disease-free with a mean follow-up of 4.2 years. Conclusions Considering the present lack of efficient medical treatment, surgery should still be considered as the mainstay therapy in IMT, even in cases of recurrence or metastases. Larger multicentric studies would be necessary to understand the prognostic significance of ALK, EBV, and HHV-8 and their relationships with the origins of the tumor.

Inflammatory myofibroblastic tumor of the hepatobiliary system: report of MR imaging appearance in four patients.

The purpose of this report is to describe the magnetic resonance (MR) imaging features of hepatic inflammatory myofibroblastic tumor (IMT). Two observers retrospectively analyzed images from six MR imaging examinations in four consecutive patients. Tumor location, size, extent, morphology, and number; signal intensity on nonenhanced images; enhancement pattern on serial gadolinium-enhanced images; duct wall thickness; and presence of biliary dilatation, vascular invasion, and lymphadenopathy were assessed. MR imaging findings were compared with histologic findings. On MR images, hepatic IMT manifested as a mass-like lesion in two patients and an area of periportal soft-tissue infiltration in three; one patient had both patterns. Because periportal infiltration is a common feature in both IMT and other malignant tumors of the porta hepatis, histologic examination should be considered before diagnosis and treatment.