A case of hepatic inflammatory pseudotumor identified by FDG-PET

Esophageal Inflammatory Pseudotumor on Al 18 F-FAPI-74 and 18 F-FDG PET/CT

ABSTRACT

A 25-year-old woman experiencing dysphagia for 2 years underwent 18 F-FDG and Al 18 F-FAPI-74 PET/CT. The scans showed local thickening of the cervical and upper thoracic esophageal wall with several calcifications, accompanied by increased and heterogeneous FDG uptake and more intense FAPI activity. Histopathological analysis following thoracoscopic esophagectomy confirmed the diagnosis of esophageal inflammatory pseudotumor.

Nonspecific inflammatory pseudotumor of the maxillary and temporal fossa: a study of seven cases

OBJECTIVE

Inflammatory pseudotumor (IPT) is a rare, locally aggressive, benign neoplasm of unknown etiology. Because of its aggressive clinical behavior and locally destructive or infiltrative features, it may be mistaken for a malignant tumor. Approximately 5%-44% of extrapulmonary IPT occur in the head and neck, primarily affecting the orbit.

STUDY DESIGN

Between 2008 and 2021, our hospital received referrals for seven patients (three men and four women, aged 42-73 years) with pain, swelling, mass, and trismus. Computed tomography, magnetic resonance imaging, and biopsy were performed on all patients to diagnose IPT.

RESULTS

Of the seven patients, four received low-dose prednisolone (PSL), one underwent surgery, and two were left untreated. The IPT disappeared in one of the two untreated cases, whereas it improved and later deteriorated in the other. The surgical patient had no recurrence. Low-dose PSL was effective in two patients; however, high-dose PSL and immunosuppressants were required in the remaining two cases owing to infiltration into each orbit or brain region.

CONCLUSIONS

Low-dose PSL treatment was applicable in IPT cases affecting the maxillary to temporal fossa region, wherein symptoms did not improve without treatment. However, when low-dose PSL was ineffective, high-dose PSL and immunosuppressants were required.

Hepatic Inflammatory Pseudotumor on 18F-FDG and 18F-FAP-42 PET/CT

ABSTRACT

Hepatic inflammatory pseudotumor is a rare benign disease. We describe the 18F-FDG and 18F-FAPI-42 PET/CT findings of hepatic inflammatory pseudotumor in a 57-year-old man. Compared with 18F-FDG, 18F-FAPI-42 PET/CT identified more lesions and showed more intense uptake within the lesions. This case illustrates that hepatic inflammatory pseudotumor should be contemplated in the differential diagnosis of liver lesions with increased 18F-FDG and 18F-FAPI-42 uptake. 18F-FAPI-42 PET/CT might be used as a helpful tool for evaluating hepatic inflammatory pseudotumor.

The Potential Utility of 18 F-FDG PET/CT in Monitoring Corticosteroid Therapy in Inflammatory Pseudotumor

ABSTRACT

A 69-year-old man with suspected gastrointestinal stromal tumor was referred to 18 F-FDG PET/CT. Images showed increased metabolism in a jejunal wall thickening, 2 liver lesions, and hepatic lymph nodes. The patient underwent wedge biopsy of the liver, which revealed inflammatory pseudotumor. The patient was treated with 20 mg/d prednisone, with a gradual dose reduction. A partial metabolic response was achieved after 2 months of therapy, and a final PET/CT showed complete metabolic response after 9 months. This clinical case shows the potential role of PET/CT in the assessment of the response of the inflammatory pseudotumor to corticosteroid therapy.

Multiple Inflammatory Pseudotumors of the Liver Demonstrating Spontaneous Regression: A Case Report

Inflammatory pseudotumor (IPT) of the liver is a rare benign disease. IPTs generally develop as solitary nodules, and cases with multiple lesions are uncommon. We herein report a case of multiple IPTs of the liver that spontaneously regressed. A 70-year-old woman with a 10-year history of primary biliary cholangitis and rheumatoid arthritis visited our hospital to receive a periodic medical examination. Abdominal ultrasonography revealed multiple hypoechoic lesions, with a maximum size of 33 mm, in the liver. Contrast-enhanced computed tomography revealed low-attenuation areas in the liver with mild peripheral enhancement at the arterial and portal phases. We first suspected metastatic liver tumors, but fluorodeoxyglucose positron emission tomography, magnetic resonance imaging and contrast-enhanced ultrasonography suggested the tumors to be inconsistent with malignant nodules. A percutaneous biopsy showed shedding of liver cells and abundant fibrosis with infiltration of inflammatory cells. Given these findings, we diagnosed the multiple tumors as IPTs. After careful observation for two months, the tumors almost vanished spontaneously. Physicians should avoid a hasty diagnosis of multiple tumors based solely on a few clinical findings, and a careful assessment with various imaging modalities should be conducted.

PET/CT Variants and Pitfalls in Liver, Biliary Tract, Gallbladder and Pancreas

A wide variety of pathological anomalies may occur in the liver, biliary system, and pancreas. It is a necessity to use many different imaging techniques in order to distinguish such varied pathologies, especially those from malignant processes. Positron Emission Tomography/Computed Tomography (PET/CT) is an imaging method that has proven its diagnostic value in oncology and can be used for different clinical purposes. Fluoro-18 fluoro-2-deoxy-D-glucose has a wide range of uses as a dominant radiopharmaceutical in routine molecular imaging, however, molecular imaging has started to play a more important role in personalized cancer treatment in recent years with new Fluoro-18 and Gallium-68 labeled tracers. Although molecular imaging has a strong diagnostic effect, the surprises and pitfalls of molecular imaging can lead us to unexpected and misleading results. Prior to PET/CT analysis and reporting, information about possible technical and physiological pitfalls, normal histological features of tissues, inflammatory pathologies, specific clinical features of the case, treatment-related complications and past treatments should be evaluated in advance to avoid misinterpretation. In this review, the physiological and pathophysiological variants as well as pitfalls encountered in PET/CT imaging of the liver, biliary tract, gallbladder, and pancreas will be examined. Other benign and malignant pathologies that have been reported to date and that have led to incorrect evaluation will be listed. It is expected that the devices, software, and artificial intelligence applications that will be developed in the near future will enable much more effective and faster imaging that will reduce the potential causes of error. However, as a result of the dynamic and evolving structure of the information obtained by molecular imaging, the inclusion of the newly developed radiopharmaceuticals in routine practice will continue to carry new potentials as well as new troubles. Although molecular imaging will be the flagship of diagnostic oncology in the 21st century, the correct analysis and interpretation by the physician will continue to form the basis of achieving optimal performance.

Huge Hepatic Fungal Inflammatory Pseudotumor Misdiagnosed as Primary Hepatocellular Carcinoma

Fungal inflammatory pseudotumor (FIPT) of the liver is a rare disease that may be mistaken for a malignant tumor. It is difficult to diagnose because of its nonspecific clinical and imaging features. We report the case of a 46-year-old Asian man who presented with a mass in the right upper quadrant of the abdomen. The patient had undergone transcatheter arterial chemoembolization therapy at another institution 6 months earlier, but the mass had continued to enlarge. He had no history of chronic hepatitis B, and the serum α-fetoprotein was negative. Contrast-enhanced ultrasonography and computed tomography images were suggestive of hepatocellular carcinoma. However, ultrasound-guided biopsy revealed features of chronic inflammation. The mass was resected and found to be an FIPT. We discuss the details of the case and review related articles.

Inflammatory Pseudotumor of Mediastinum Treated with Tomotherapy and Monitored with FDG-PET/CT: Case Report and Literature Review

Mediastinal inflammatory pseudotumor is a rare disease with reactive pseudoneoplastic features and a proven capacity for local invasion. The radiographic appearance of inflammatory pseudotumor is quite non-specific and the definitive diagnosis is based on the histological evaluation of tissue specimens. Resection of the lesion is the treatment of choice. However, nonsurgical treatments such as radiotherapy and steroids have been employed in the setting of incomplete surgical resection, tumor recurrence, and patients being unfit for surgery. The case described here is being reported because of the rare mediastinal location and atypical treatment approach including salvage irradiation and monitoring with FDG-PET/CT. Because of the irregular target volume inside the mediastinum as defined by FDG-PET/CT and the significant pulmonary comorbidity, it was deemed necessary to optimize dose delivery with intensity-modulated radiation therapy (IMRT). A possible gain by means of daily control of patient setup with image-guided radiation therapy was also hypothesized and we used tomotherapy to irradiate the lesion. The first FDG-PET/CT after treatment confirmed further reduction of the metabolic activity followed by stable disease in the mediastinum, with no new occurrence of disease 16, 24 and 30 months after tomotherapy.

Inflammatory and Ischemic Post Liver Transplant Complications Mimic Malignancy on 18F-FDG PET/CT

A 65-year-old male patient with a one year history of liver transplantation was referred for an ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to rule out post transplant lymphoproliferative disease. Multiple foci of intense abnormal ¹⁸F-FDG uptake were seen in the transplanted liver which were concerning for malignancy. Explantation of the liver approximately 1 month following the PET/CT revealed multiple inflammatory and ischemic changes including large bile duct necrosis, acute cholangitis, bile duct obstruction changes and periportal fibrosis, with no evidence of malignancy. We present the ¹⁸F-FDG PET/CT image findings of this case.

Inflammatory myofibroblastic tumor: a rare tumor of the lung

Inflammatory myofibroblastic tumor (IMT) is a rare lesion, representing 0.04–1.2% of all lung tumors. Brunn first described it in 1939, but its etiology remains uncertain. A 16-year-old patient was admitted to our hospital for further examination following abnormal radiological findings. The physical examination showed no abnormality, and routine hematological and biochemical parameters were within normal range. Chest radiograph revealed homogenous opacity of the right upper lobe with regular margins. Thoracic CT showed a nodular lesion, 30×26 mm in dimensions, with lobular contours in the right hilar. Bronchoscopic examination showed a vascular endobronchial lesion in the anterior right upper lobe, with bleeding when palpated. She underwent right thoracotomy for diagnostic and therapeutic purposes since bronchoscopic biopsy failed because of bleeding. With a pathological diagnosis of IMT, the present report discusses her case accompanied by relevant literature as it is a very rare type of lung tumor. IMT is a rare benign tumor. The diagnosis is difficult to make before surgery since its clinical and radiological features are variable and nonspecific. Although it is a benign lesion, it should be completely resected and patients should be closely monitored following the resection in order to avoid local invasion and recurrence.

Inflammatory pseudotumor of the liver: a rare case of recurrence following surgical resection

Inflammatory pseudotumor (IPT) of the liver is a rare, benign lesion that may be mistaken for malignancy. IPTs are difficult to diagnose due to non-specific clinical, laboratory and imaging features. We report the case of a 38-year old Asian male who presented with fatigue, weight loss and hepatomegaly. He was found to have a large hepatic IPT and underwent surgical resection; approximately two and a half years later, he developed acute cholangitis secondary to IPT recurrence. We present the imaging features of hepatic IPT using ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). We also review the literature on the diagnosis and management of this disease. The unique features of this case include the IPT's recurrence following surgical resection, large size and multiple modalities presented.

Inflammatory pseudotumours in the abdomen and pelvis: a pictorial essay

Inflammatory pseudotumours are uncommonly encountered lesions in the abdomen and pelvis that often present with variable and nonspecific imaging features. They may mimic other more common lesions, including malignancy. Within the appropriate clinical context, inflammatory pseudotumours merit consideration in the differential diagnosis of soft-tissue masses within the abdomen and pelvis. A preoperative diagnosis of inflammatory pseudotumour, established through biopsy, may help to differentiate this benign entity from malignancy. In this article, we reviewed the imaging features of inflammatory pseudotumours of the abdomen and pelvis, including liver, spleen, bowel, retroperitoneum, kidney, bladder, uterus, and adnexa.

A Case of Inflammatory Pseudotumor of the Liver Mimicking Hepatocellular Carcinoma on EOB-MRI and PET

A 71-year-old man was referred to us for investigation of a liver mass and adenomyomatosis of gallbladder. Findings on ethoxybenzyl diethylenetriamine-enhanced MRI (EOB-MRI) led to a presumptive diagnosis of a 1.5 cm hepatocellular carcinoma (HCC) in the right posterior lobe of the liver. Transcatheter arterial chemoembolization and radiofrequency ablation of the tumor were attempted. After 2 months, CT scan and EOB-MRI showed that the tumor had enlarged to 3 cm. Positron emission tomography (PET) confirmed abnormal metabolic activity with a high standardized uptake value of 7.3 in the lesion. These findings could indicate malignancy such as well-differentiated HCC or cholangiocarcinoma or a benign lesion such as hepatic abscess. Histopathological examination of a liver biopsy revealed a granuloma with many inflammatory cells, leading to a diagnosis of inflammatory pseudotumor of the liver. We report a rare case of hepatic inflammatory pseudotumor with enhancement on EOB-MRI and increased uptake on PET, mimicking HCC.

Diagnostic and therapeutic challenges of a large pleural inflammatory myofibroblastic tumor

We report a 48-year-old woman with a pleural pseudoneoplasm requiring different diagnostic and therapeutic strategies. After initial presentation with increasing dyspnoea, temperature, dry cough, and interscapular pain diagnostic processing showed a large mediastinal mass with marked pleural effusion and high metabolic activity in the 18F-FDG-PET/CT. Extensive CT-guided biopsy of the tumor reaching from the visceral pleura into the right upper lobe revealed no malignancy, but a marked inflammatory tissue reaction containing foam cells. Initial empiric antibiotic therapy was temporarily successful. However, in the further course the mass relapsed and was resistant to antibiotics and a corticosteroid trial. With the working hypothesis of an inflammatory myofibroblastic tumor the patient underwent surgical tumor resection, finally confirming the suspected diagnosis. Due to residual disease intravenous immunoglobulins were administered leading to sustained response. This case with a pleural localisation of a large inflammatory pseudotumor with responsiveness to immunomodulation after incomplete resection extends the reported spectrum of thoracopulmonary manifestations of this rare entity.

Inflammatory pseudotumor of the kidney mimicking malignancy on 18F-FDG PET/CT in a patient with diabetes and hepatocellular carcinoma

Inflammatory pseudotumor (IPT) is a pseudoneoplastic lesion that most commonly involves lung. We report a case of IPT of kidney associated with hepatocellular carcinoma. CT and PET/CT showed the features of renal cell carcinoma. After radical nephrectomy, histologic examination demonstrated acute pyelonephritis associated with papillary necrosis, and IPT involving renal parenchyma and capsule. Although renal IPT is a very rare tumor, awareness of its existence in the differential diagnosis of a renal mass is critical to avoid misdiagnosis. Clinician should carefully consider differential diagnosis and complications associated with acute or chronic pyelonephritis and papillary necrosis in diabetic patients, particularly.

Inflammatory pseudotumor of the liver and spleen diagnosed by percutaneous needle biopsy

An inflammatory pseudotumor (IPT) is a relatively rare lesion characterized by chronic infiltration of inflammatory cells and areas of fibrosis. IPTs are difficult to diagnose because of the absence of specific symptoms or of characteristic hematological or radiological findings. In this study, a case of a woman aged over 70 years was reported, who presented with a general malaise lasting more than two months. A computed tomography scan demonstrated a diffusely spread lesion of the liver with a portal vein occlusion and a splenic lesion surrounded by a soft density layer. Since the percutaneous liver biopsy showed findings that suggested an IPT, although the radiological findings did not exclude the possibility of a malignancy, we performed a percutaneous spleen biopsy to enable a more definitive diagnosis. The microscopic findings from the spleen specimen lead us to a diagnosis of IPT involving the liver and spleen. Subsequent steroid pulse therapy was effective, and rapid resolution of the disease was observed.

Sonazoid-enhanced ultrasonography and Ga-EOB-DTPA-enhanced MRI of hepatic inflammatory pseudotumor: a case report

A liver neoplasm was found in a 63-year-old man with alcoholic liver disease. Sonazoid-enhanced ultrasonography (US) showed that the neoplasm was isoechoic at the early vascular phase and hypoechoic at the post-vascular phase. Gadolinium ethoxybenzyl-diethylenetriamine-enhanced magnetic resonance imaging (MRI) showed that the neoplasm was hypointense at the hepatobiliary phase. We suspected that it was a malignant tumor. By needle biopsy, however, the neoplasm was diagnosed as an inflammatory pseudotumor (IPT). We encountered a rare case of hepatic IPT, the differential diagnosis of which was difficult to distinguish from malignant tumor. Here, we report new US and MRI findings of hepatic IPT.