Capsular retraction: an uncommon imaging finding in hepatic inflammatory pseudotumour

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.

Causes of hepatic capsular retraction: a pictorial essay

Abstract

Hepatic capsular retraction refers to the loss of the normal convex hepatic contour, with the formation of an area of flattening or concavity. This can result from myriad causes, including intrinsic hepatic conditions such as cirrhosis, biliary obstruction, benign tumours, malignancy and infections, as well as extrahepatic causes such as trauma. This article aims to provide familiarity with this wide spectrum of conditions, including mimics of hepatic capsular retraction, by highlighting the anatomic, pathologic and imaging features that help distinguish these entities from one another.

Teaching Points

• Hepatic capsular retraction can occur due to various intrinsic or extrinsic hepatic causes.

• Hepatic capsular retraction is observed in both benign and malignant conditions.

• Recognising associated imaging features can help elicit causes of hepatic capsular retraction.

MRI characteristics for the differential diagnosis of benign and malignant small solitary hypovascular hepatic nodules

PURPOSE

To compare the MRI findings of benign and malignant solitary hypovascular hepatic nodules and identify the differentiating features.

MATERIALS AND METHODS

A total of 135 patients with solitary hypovascular hepatic lesions up to 3 cm (mass forming intrahepatic cholangiocarcinoma, n=29; metastases, n=26; inflammatory pseudotumors and solitary necrotic nodule, n=48; and hemangioma, n=32) were assessed. MRI findings were analyzed, and lesions were scored for peripheral and intratumoral appearance and enhancement patterns.

RESULTS

Univariate and multivariate analyses showed that the most common findings for benign lesions were subcapsular, sharp margin, homogeneous, marked high signal on T2WI, mild hyperintensity on T2WI, increasing intensity of peripheral globular enhancement, and persistent central septum-like linear enhancement on delayed phase (P<0.05). An area under the curve of 0.955 was obtained for differentiating malignant from benign nodules using the combined imaging features of ill-defined margins, heterogeneity, decreasing intensity of peripheral rim-like enhancement, and central increasing intensity of patchy enhancement. Interobserver agreement was good, ranging from 0.72 to 1.00.

CONCLUSION

MRI may be a useful noninvasive method for determining whether hypovascular hepatic nodules are malignant or benign.

A case of hepatic inflammatory pseudotumor protruding from the liver surface

We report a case of a resected hepatic inflammatory pseudotumor (IPT) protruding from the liver surface. A 69-year-old male with diabetes mellitus was admitted to hospital for investigation of an hepatic mass. An irregularly shaped, low-echoic mass measuring 21 × 18 mm was identified by ultrasound in S6. On computed tomography, the tumor appeared to be growing extrahepatically. After contrast enhancement, the lesion showed persistent peripheral enhancement, while the central part was hypoenhanced. On T2-weighted magnetic resonance imaging (MRI), the central portion of the lesion was hyperintense compared with the periphery. EOB-enhanced MRI revealed the mass to be being hypointense in contrast to the surrounding liver parenchyma in the hepatobiliary phase. On diffusion-weighted images, the lesion was hyperintense. Percutaneous biopsy was not attempted to avoid tumor cell dissemination. The patient underwent partial hepatectomy because of suspected malignancy. Histopathological examination of the resected specimen revealed fibrotic tissue and abundant vessels in the periphery, while a massive infiltration of inflammatory cells and fewer vessels were observed in the center. The patient was finally diagnosed with hepatic IPT of the fibrohistiocytic type.

The analysis of enhancement pattern of hepatic inflammatory pseudotumor on contrast-enhanced ultrasound

OBJECTIVE

The aim of this study was to assess the role of contrast-enhanced ultrasound (CEUS) in the characterization of hepatic inflammatory pseudotumor (IPT).

METHODS

We retrospectively reviewed 36 cases of histopathologically diagnosed IPT. Nodule enhancement appearances during the arterial, portal, and delayed phases were defined as hyperenhancement, isoenhancement, hypoenhancement, and non-enhancement compared with the surrounding liver parenchyma. Statistical analysis was performed by the one-way ANOVA and χ (2) tests.

RESULTS

Among total 36 cases, 7 nodules were absent of contrast enhancement during all three phrases on CEUS. Twenty-nine nodules appeared different forms of enhancement in arterial phase. Diffuse homogeneous hyperenhancement, diffuse heterogeneous hyperenhancement, peripheral rim-like enhancement, and diffuse iso-enhancement were found in 10, 12, 5, and 2 of the nodules, respectively. Twenty-five nodules showed hypoenhancement in portal and delayed phases. Four nodules showed contrast washed out synchronously with normal liver parenchyma. The median time to enhancement, median time to peak, and median time to wash out of the nodules were 17 s (range 11-28 s), 23 s (range 14-42 s), and 45 s (range 23-100 s), respectively. No statistical significant differences were found in the above parameters of nodule enhancement and proportion of enhancement patterns when dividing the nodules into subgroups by nodule size.

CONCLUSION

IPT displays a variety of enhancement patterns due to pathological changes in the course of disease progression. Some characteristics on CEUS may be helpful in the differential diagnosis of IPT.

Hepatic capsular retraction: spectrum of diagnosis at MRI

Hepatic capsular retraction is an imaging feature that deserves the attention of the radiologist. Hepatic capsular retraction is associated with a number of hepatic lesions, benign or malignant, treated or untreated. The purpose of this pictorial review is to discuss the most common benign and malignant hepatic lesions associated with this feature with an emphasis on magnetic resonance imaging (MRI).

Splenic sarcoidosis mimicking neoplastic disease

Sarcoidosis is a multisystem granulomatous disease of unknown cause that commonly involves the spleen. Sarcoid can produce either homogeneous splenomegaly or multiple splenic nodules. Although other organ system involvement usually occurs, this is not invariable. Herein, we report on the clinical, histological, and radiological features-including sonography and MRI-of an isolated splenic sarcoidosis that mimicked neoplastic disease in a 37-year-old female. Knowledge of this atypical sonographic presentation may prevent unnecessary splenectomy.

Computed Tomography and Magnetic Resonance Imaging Findings of a Malignant Hepatic Epithelioid Hemangioendothelioma: A Rare Case of Solitary Small Nodular Form

We report the case of a rare solitary small nodular form of malignant hepatic epithelioid hemangioendothelioma in a patient followed by computed tomography and gadoxetic acid (Gd-EOB-DTPA)–enhanced magnetic resonance imaging with histological analysis. This case showed early peripheral septal and nodular enhancement and delayed centripetal enhancing pattern with capsular retraction, mimicking peripheral cholangiocarcinoma, inflammatory pseudotumor, or metastases. The histological and immunohistochemical findings were diagnostic of a malignant hepatic epithelioid hemangioendothelioma.

Recurring multicystic inflammatory pseudotumor of the liver: a case report

Inflammatory pseudotumor (IPT) of the liver is a rare benign lesion for which imaging diagnosis remains a challenge. We report the case of a 39-year-old Algerian woman, who presented epigastric pains combined with fever and jaundice. Ultrasound, CT scan and MRI showed the presence of a 10 cm-long multi-septated cystic mass of the left lobe, with peripheral enhancement. A left-hepatectomy was performed and histopathology revealed an IPT of the liver. During the 4 following years, the patient had three other recurrences of liver IPT at various locations distinct from the original, revealed by the same clinical symptoms. During these relapses, the lesions did regress thanks to a medical treatment. This observation underlines the difficulty of the diagnosis and treatment of liver IPT.

Imaging findings of calcifying fibrous tumour of the liver

Calcifying fibrous tumour (CFT) is a recently recognised rare benign lesion characterised by dense hyalinised collagenous tissue, psammomatous or dystrophic calcifications and a lymphoplasmacytic infiltrate. The usual locations of the lesion are the soft tissues of the extremities, but rarely it occurs in the abdomen. Recently, we experienced a case of CFT found in the liver of a 29-year-old woman. Here, we describe the characteristic radiological and histopathological findings, along with a review of the relevant literature.