A case of hepatic inflammatory pseudotumor protruding from the liver surface

Magnetic resonance imaging of inflammatory pseudotumor of the liver: a 2021 systematic literature update and series presentation

PURPOSE

Inflammatory pseudotumors of the liver (IPTL) are not exceptional benign lesions with various etiologies, histology, and imaging appearances. The incomplete knowledge of this pathology and the wide polymorphism sometimes resembling malignancy often induce long and expensive diagnostic flow, biopsy and occasionally unnecessary surgery. We propose a systematic revision of MRI literature data (2000-2021) with some narrative inserts and 10 new complete MRI cases, with the aim of organizing the data about IPTL and identifying some typical features able to improve its diagnosis from imaging.

METHODS

We performed a systematic revision of literature from 2000 to 2021 to obtain MRI features, epidemiological, and clinical data of IPTL. The basic online search algorithm on the PubMed database was "(pseudotumor) AND (liver) AND (imaging)." Quality assessment was performed using both scales by Moola for case report studies and by Munn for cross-sectional studies reporting prevalence data. A case-based retrospective study by collecting patients diagnosed with IPTL from three different university hospitals from 2015 to 2021 was done as well. Only cases with MR examinations complete with T1/T2/contrast-enhanced T1/Diffusion-Weighted (W) images and pathology-proven IPTL were selected.

RESULTS

After screening/selection 38 articles were included for a total of 114 patients. In our experience we selected 10 cases for a total of 16 IPTLs; 8 out of 10 patients underwent at least 1 MRI follow-up. Some reproducible and rather typical imaging findings for IPTL were found. The targetoid aspect of IPTL is very frequent in our experience (75% on T1W, 44% on T2W, 81% on contrast-enhanced T1W (at least one phase), 100% on Diffusion-W images) but is also recurrent in the literature (6% on T1W, 31% on T2W, 51% on CE-T1W (at least one phase), 18% on Diffusion-W images, and 67% on hepatobiliary phase). In our experience, Apparent Diffusion Coefficient map values were always equal to or higher than those of the surrounding parenchyma, and at MRI follow-up, nodule/s disappeared at first/second control, in six patients, while in the remaining 2, lesions persisted with tendency to dehydration.

CONCLUSION

A targetoid-like aspect of a focal liver lesion must raise diagnostic suspicion, especially if IgG4-positive plasma is detected. MRI follow-up mainly shows the disappearance of the lesion or its reduction with dehydration.

Inflammatory myofibroblastic tumor of the liver: A case report and review of literature

BACKGROUND

Inflammatory myofibroblastic tumors of the liver (IMTL) are extremely rare neoplasms and very little is known about their clinical presentation, pathogenesis, and biological behavior. Due to their absolute rarity, it is almost impossible to obtain a definite diagnosis without histological examination. Because of their intermediate biological behavior with the risk for local recurrence and metastases, surgical resection is recommend whenever IMTL is suspect.

CASE SUMMARY

We herein present a case of an otherwise healthy 32-year-old woman who presented with intermittent fever, unclear anemia, malaise and right flank pain 4 mo postpartum. The liver mass in segment IVa/b was highly FDG avid in the positron emission tomography-computed tomography. Hepatic resection was performed achieving a negative resection margin and an immediate resolution of all clinical symptoms. Histological analysis diagnosed the rare finding of an inflammatory myofibroblastic tumor of the liver and revealed cytoplasmic anaplastic lymphoma kinase expression by immunohistochemistry. Twelve months follow-up magnetic resonance imaging showed no recurrence and no metastases in the fully recovered patient.

CONCLUSION

IMTLs are extremely rare and difficult to diagnose. Due to their intermediate biological behavior, surgical resection should be perform whenever feasible and patients should be followed-up in order to detect recurrence and metastasis as early as possible.

Hepatic Inflammatory Pseudotumor Protruding from the Liver Surface and Directly Penetrating the Colon

A 69-year-old man was diagnosed with a liver abscess and received antibiotics at a local hospital. He was referred to our hospital due to a persistent fever. He had hepatic masses protruding from the liver surface toward the transverse colon. We reached a diagnosis of inflammatory pseudotumor (IPT) by a percutaneous liver biopsy. Colonoscopy showed direct invasion of IPT to the colon. His condition improved by the intravenous administration of antibiotics. Hepatic IPT is often misdiagnosed as a malignant tumor. We should consider IPT when we encounter hepatic tumors, and a percutaneous liver biopsy is useful for avoiding unnecessary excessive treatments.

Morphometric analyses of small accessory liver lobes using radiological imaging

AIM

To investigate the prevalence and morphometric characteristics of small accessory liver lobes using computed tomography (CT) and magnetic resonance (MR) images.

MATERIAL AND METHODS

The study population comprised 3269 patients (1671 men and 1598 women; mean age, 67.1 ± 15.2 years) who had undergone abdominal CT examination. Small accessory liver lobes were identified after verification of their continuity with the liver parenchyma on CT images. Their imaging characteristics were analyzed and presented.

RESULTS

Thirty-five small accessory liver lobes in 33 patients (1.01%; 25 men and 8 women, 71.0 ± 11.7 years) were identified. Thirty-one patients (93.9%) had solitary lesions most frequently identified on liver segment 6 (80.0%) with the mean size 9.6 ± 4.8 mm. These showed iso (62.9%), hyper (28.6%), or hypoattenuation (8.6%) on unenhanced CT. Enhanced CT images were available for 29 lesions. Enhancement of 12 lesions (41.4%) was similar to that of the liver parenchyma, whereas 17 lesions (58.6%) showed poor enhancement. MR images were available for 10 lesions, which showed hyperintensity (50.0%) on T2-weighted images and poor enhancement (50.0%). The characteristics of other lesions were similar to those of the liver parenchyma. During observation (mean, 77.0 months; n = 29), 19 lesions remained the same size (65.5%), 5 new lesions increased size (17.2%), and 5 showed reduced size (17.2%).

CONCLUSION

Small accessory liver lobes, commonly located on segment 6, were frequently observed and did not necessarily show the same findings as the liver parenchyma. Time-dependent morphological changes were observed in approximately one-third of the lesions.

Specific imaging characteristic of solitary necrotic nodule of the liver: Marked peripheral rim-like enhancement with internal hypointensity on longer delayed MRI

OBJECTIVES

To obtain specific imaging findings of solitary necrotic nodule of the liver (SNNL) using longer delayed contrast-enhanced MRI and compare them with those of three mimic hepatic diseases.

METHODS

Sixteen patients with SNNL underwent plain and contrast-enhanced triphasic CT and multiphasic MRI with delayed time prolonged to 2 h after contrast bolus injection. Twenty-three patients with mimic lesions including seven with eight HCCs, five with five iCCs and 11 with metastatic lesions served as the control group. Those patients also received plain and multiphasic contrast-enhanced MRI. Imaging features of lesions such as peripheral wash-out time were evaluated.

RESULTS

Among the 16 SNNLs, with a prolonged delayed MRI time, the enhancement degree of tumour periphery increased gradually. When it was up to 1 h, all lesions represented moderate/marked peripheral enhancement with internal hypointensity. However, the peripheral wash-out in seven HCCs (87.5%) and all metastatic lesions except three appeared at 10 or 15 min, one iCC (20%) at 30 min and the other lesions at 1 h.

CONCLUSIONS

Longer MRI with a delayed time of 1-2 h may be useful in diagnosis SNNL, revealing the specific imaging characteristic of SNNL as pronounced peripheral enhancement with internal hypointensity.

KEY POINTS

• Longer delayed MRI plays an important role in the diagnosis of SNNL. • Characteristic imaging feature of SNNL is pronounced peripheral enhancement with internal hypointensity. • Periphery wash-out time can differentiate SNNL from mimic diseases. • Imaging findings of SNNL on routine CT and MRI are unspecific.

Immunoglobulin G4-related hepatic inflammatory pseudotumor invading the abdominal wall

A 50-year-old woman presented with epigastralgia. Computed tomography (CT) of the abdomen revealed a 6-cm well-enhanced mass extending from the left lobe of the liver to the abdominal wall, suggestive of cholangiocarcinoma. Liver and skin mass biopsies did not provide evidence of hepatic malignancy but were rich in plasma cells and sclerotic lesions. Subsequent detection of elevated serum immunoglobulin G4 (IgG4) led to a diagnosis IgG4-related inflammatory pseudotumor (IPT) of the liver. Treatment with systemic corticosteroids resulted in rapid clinical improvement. This case is the first report of an IgG4-related hepatic IPT invading the abdominal wall.