Splenic pathologies: A pictorial review of common, wandering, twisting and rare presentations.

Liposarcoma is a relatively common soft tissue malignancy with a wide spectrum of clinical presentations and imaging appearances. Several subtypes are described, ranging from lesions nearly entirely composed of mature adipose tissue, to tumors with very sparse adipose elements. The imaging appearance of these fatty masses is frequently sufficiently characteristic to allow a specific diagnosis, while in other cases, although a specific diagnosis is not achievable, a meaningful limited differential diagnosis can be established. The purpose of this paper is to review the spectrum of malignant fatty tumors, highlighting the current classification system, clinical presentation and behavior, treatment and spectrum of imaging appearances. The imaging review will emphasize CT scanning and MR imaging, and will stress differentiating radiologic features.

Lipoma is the most common soft-tissue tumor, with a wide spectrum of clinical presentations and imaging appearances. Several subtypes are described, ranging from lesions entirely composed of mature adipose tissue to tumors intimately associated with nonadipose tissue, to those composed of brown fat. The imaging appearance of these fatty masses is frequently sufficiently characteristic to allow a specific diagnosis. However, in other cases, although a specific diagnosis is not achievable, a meaningful limited differential diagnosis can be established. The purpose of this manuscript is to review the spectrum of benign fatty tumors highlighting the current classification system, clinical presentation and behavior, spectrum of imaging appearances, and treatment. The imaging review emphasizes computed tomography (CT) scanning and magnetic resonance (MR) imaging, differentiating radiologic features.

Pheochromocytomas are relatively rare neuroendocrine tumors of the adrenal medulla. Their variable clinical presentation and biologic behavior often make accurate diagnosis challenging. A variable spectrum of imaging appearances--some of which may also mimic other diseases--has been recognized. This article reviews the epidemiology; associations; and clinical, biochemical, pathologic, and multimodality imaging features of pheochromocytomas including diagnostic pearls and pitfalls. Pheochromocytomas are often considered the great mimicker of other adrenal tumors. Because of their varied clinical, imaging, and pathologic appearances, accurate diagnosis can be challenging. The various imaging appearances on ultrasound, CT, MRI, and functional imaging can be complementary and have features that are useful for differentiating pheochromocytoma from other lesions of the adrenal.

Atypical presentations of parathyroid gland pathology: A pictorial review

The reported prevalence of invasive lobular carcinoma (ILC) is variable, with more recent studies indicating that ILC accounts for 10%-15% of all invasive breast carcinomas. However, the radiologic diagnosis and management of ILC can be uniquely challenging. Current imaging modalities are not very specific for differentiating ILC from other invasive breast cancers, and ILC has a tendency to have appearances at mammography that are atypical for invasive ductal carcinomas, resulting in higher false-negative rates. The clinical detection of ILC can also be difficult, since ILC frequently fails to form a palpable lesion. This tendency of ILC to have atypical imaging and clinical appearances is related to its histopathologic features and its failure to elicit a desmoplastic response. Despite these diagnostic challenges, however, imaging remains crucial in the detection and management of ILC. Mammography, ultrasonography (US), and magnetic resonance (MR) imaging all play important roles, with each modality having its own advantages and limitations. The use of US and MR imaging as adjuncts to mammography increases sensitivity in the detection of ILC and provides useful information for further management and presurgical planning. Familiarity with the spectrum of imaging appearances of ILC is essential.

To assess and compare the multiphasic computed tomography (CT) features of neuroendocrine tumor (NET) liver metastases and to investigate the possibility to predict the histologic subtype of the primary tumor. Between January 2013 and December 2017 patients with biopsy proven NET with at least one liver metastasis who underwent multiphasic CT were enrolled in this study. All cases were acquired using a standardized multiphasic liver CT protocol, arterial, portal, and hepatic venous phases were obtained. Images were retrospectively analyzed in consensus by two abdominal radiologists blinded to clinical data and histologic subtype. The size, number, and location of lesions were noted. Enhancement patterns of each lesion on arterial, portal, and hepatic venous phases were assessed. For quantitative analysis, CT attenuation of tumors, liver parenchyma, and aorta were measured using a circular region of interest (ROI) on arterial, portal, and hepatic venous phases for reflecting the blood supply of the tumor. Tumor-to-aorta and tumor-to-liver ratio were calculated in all three phases. Differences between subtypes of NET liver metastases were studied using ROC analysis of clustered data. A total of 255 neuroendocrine tumor liver metastases divided into 101 (39.6%) pancreatic, 60 (23.5%) gastroenteric and 94 (36.8%) lung NET liver metastases were analyzed. Contrast enhancement of lesions was homogeneous in 78% of patients (n = 199), which was significantly more frequent in patients with pancreatic group than in those with gastroenteric origin (n = 90, 89.1% vs. n = 28, 46.7%; p < 0.001). Gastroenteric NET metastases frequently showed heterogeneous enhancement, which was significantly higher than in the other two groups (50% vs. 3% and 2%). With respect to the location of the primary tumor, the difference in enhancement patterns of the liver lesions was statistically significant (p < 0.001). Pancreatic NET metastases were mostly hyperdense on arterial images and isodense on portal and hepatic venous phase images (79.2%, n = 80). Gastroenteric NET metastases were mostly hyperdense on arterial phase images and hypodense on portal and hepatic venous phase images (n = 28, 46.7%). The most frequent pattern for lung NET metastases was hypoattenuation on all three phase images (n = 44, 46.8%). ROC analysis of clustered data revealed statistically significant differences between pancreatic NET liver metastases, gastroenteric NET liver metastases, and lung NET liver metastases in terms of tumor-to-aorta (T-A) ratio and tumor-to-liver (T-L) ratio (p < 0.001). We observed statistically significant differences in multiphasic CT features (enhancement pattern, T-A ratio, and T-L ratio) between histologic subtypes of NET liver metastases. As the difference in histological subtypes of NET liver metastases results in a different prognosis and different management strategy, these CT features might help to identify the primary tumor when it is not known to ensure accurate tumor staging and to provide optimal treatment.

The characterization of focal splenic lesions by ultrasound can be quitechallenging. The recent introduction of contrast-enhanced ultrasound (CEUS) hascome to play a valuable role in the field of imaging splenic pathologies,offering the possibility of an ionizing radiation-free investigation. BecauseCEUS has been incorporated into everyday clinical practice, malignant diseasessuch as focal lymphomatous infiltration, metastatic deposits, benign cysts,traumatic fractures, and hemangiomas can now be accurately depicted andcharacterized without the need for further imaging. More specifically, splenictraumatic fractures do not require additional imaging by computed tomography(with ionizing radiation exposure) for follow-up, because splenic fractures andtheir complications are safely imaged with CEUS. In the new era of CEUS, morepatients benefit from radiation-free investigation of splenic pathologies withhigh diagnostic accuracy.

The purpose of this study was to determine the spectrum of imaging appearances of pheochromocytoma and the associated clinical and biochemical features. In this retrospective study, a citywide pathology database (2000-2011) was searched to identify the records of patients with pheochromocytoma. The search yielded the cases of 53 patients (28 men, 25 women; mean age, 50 years). The institutional PACS and radiology information system records, hospital charts, and the provincial electronic health records of these patients were reviewed. Imaging appearances and clinical and biochemical features related to pheochromocytomas were recorded. One chart was not available for review. In the 52 cases analyzed, 40 of the patients had symptoms: 31 patients had hypertension; 10 had the triad of palpitations, diaphoresis, and headaches; and all had elevated urinary metanephrine concentrations. Seven patients had a familial syndrome, and five had bilateral pheochromocytomas. One patient had an extraadrenal pheochromocytoma, and five had malignant tumors. The mean size of pheochromocytomas was 4.0 cm. Most pheochromocytomas were heterogeneous (CT, 56%; MRI, 65%; ultrasound, 45%) and were MIBG positive (90%). Eleven of 34 (32%) pheochromocytomas had T2 signal intensity greater than that of the spleen. Most pheochromocytomas were less enhancing than the spleen (CT, 85%; MRI, 71%). Contrast-enhanced CT was performed on 33 tumors, of which 20 enhanced less than the spleen and 8 showed similar enhancement to the spleen; contrast-enhanced MRI was performed on 24 tumors, of which 12 enhanced less than the spleen and 5 showed similar enhancement to the spleen. Predominant cystic change was found in 4 of 20 (20%) ultrasound, 9 of 41 (22%) CT, and 11 of 34 (32%) MRI examinations. Eight of 34 (24%) pheochromocytomas were hemorrhagic, two (5%) had calcifications, and three of six were PET positive. Two cystic pheochromocytomas and one lipid-containing pheochromocytoma were misdiagnosed as adrenal adenomas. Most pheochromocytomas were heterogeneous at imaging, were MIBG positive, accompanied elevated urinary metanephrine concentrations, and were symptomatic. High T2 signal intensity was found in approximately one third of solid tumors. Atypical imaging features included homogeneity, cystic change, hemorrhage, intense enhancement, calcifications, intracellular lipid, bilaterality, and malignancy.

This article reviews the optimal cardiac MRI sequences for and the spectrum of imaging appearances of cardiac tumors. Recent technologic advances in cardiac MRI have resulted in the rapid acquisition of images of the heart with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MRI provides optimal assessment of the location, functional characteristics, and soft-tissue features of cardiac tumors, allowing accurate differentiation of benign and malignant lesions.

Teaching PointsMetabolic and storage diseases constitute a heterogeneous group of disorders that occur in the setting of altered biochemical homeostasis. Many of these disorders affect the lungs, either exclusively or as part of a systemic syndrome. For example, amyloidosis can be limited to the tracheobronchial tree or involve the kidneys, lungs and heart. The indolent course of some of these disorders and the non-specific clinical symptoms often result in a diagnostic challenge. Imaging, particularly high-resolution computed tomography (HRCT), is an invaluable asset in the diagnosis of these clinical conditions. Some metabolic and storage diseases have characteristic HRCT appearances, helping narrow the differential diagnosis. Correlation of the radiological and histopathological findings of this group of diseases has also helped improve understanding of these disorders. In addition, CT can offer guidance when tissue sampling is warranted and aid in histopathological diagnosis. This article describes the pertinent clinical features of the more common metabolic and storage diseases affecting the lungs, illustrates their respective HRCT findings and provides the relevant differential diagnosis. • To recognise the various metabolic and storage lung diseases • To identify the characteristic imaging findings in various metabolic and storage lung diseases • To discuss the relevant differential diagnoses of each of these diseases

Pheochromocytomas are rare catecholamine-secreting tumors with many clinical and imaging manifestations. They may produce overwhelming cardiovascular crises if the diagnosis is not made or if appropriate treatment is delayed. It is thus important to recognize both their characteristic and atypical imaging appearances. Pheochromocytomas are encountered, sometimes unexpectedly, across a range of imaging modalities. They are characteristically solid, hypervascular masses with high signal intensity on T2-weighted magnetic resonance (MR) images. A wide spectrum of imaging appearances is seen, however, and pheochromocytomas may mimic other adrenal lesions, both benign and malignant. They may be dark on T2-weighted MR images, in contrast to their more classic bright T2-weighted appearance. Other atypical features include fatty, hemorrhagic, cystic, and calcific changes. Pheochromocytomas may contain sufficient fat to be mistaken for an adenoma at computed tomography (CT) or MR imaging. They may also demonstrate rapid contrast material washout and be mistaken for an adenoma owing to their deenhancement profile; however, their washout pattern can be inconsistent. The appearance of pheochromocytomas at radionuclide imaging is also unpredictable. These characteristics at CT, MR imaging, and scintigraphy pose diagnostic challenges, since they allow pheochromocytomas to mimic many other adrenal masses. Pheochromocytoma is an important, often clinically occult neoplasm with devastating consequences if overlooked. Radiologists must be aware of the various forms that pheochromocytomas can assume at imaging.

Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) enhancement patterns for differentiating solid pancreatic lesions and compare them with conventional ultrasound (US) and enhanced computed tomography (CT). A total of 210 patients with solid pancreatic lesions who had definite pathological or clinical diagnoses were enrolled. Six CEUS enhancement patterns were proposed for solid pancreatic lesions. Two US doctors blindly observed the CEUS patterns of solid pancreatic lesions and the interrater agreement was analyzed. The diagnostic value of CEUS enhancement patterns for differentiating solid pancreatic lesions was evaluated, and the diagnostic accuracy was compared with that of US and enhanced CT. There was good concordance for six CEUS enhancement patterns of solid pancreatic lesions between the two doctors, with a kappa value of 0.767. Hypo-enhancement (Hypo-E) or centripetal enhancement (Centri-E) as the diagnostic criteria for pancreatic carcinoma had an accuracy of 87.62%; hyper-enhancement (Hyper-E) for neuroendocrine tumors had an accuracy of 92.89%; capsular enhancement with low or uneven enhancement inside the tumor (Capsular-E) for solid pseudopapillary tumors had an accuracy of 97.63%; and iso-enhancement (Iso-E) or iso-enhancement with focal hypo-enhancement (Iso-fhypo-E) for focal pancreatitis had an accuracy of 89.10%. The diagnostic accuracy of CEUS was significantly different from that of US for 210 cases of solid pancreatic lesions (p < 0.05) and was not significantly different from that of enhanced CT for 146 cases of solid pancreatic lesions (p > 0.05). The different enhancement patterns of solid pancreatic lesions on CEUS were clinically valuable for differentiation. • Six CEUS enhancement (E) patterns, including Hyper-E, Iso-E, Iso-fhypo-E, Hypo-E, Centri-E, and Capsular-E, are proposed for the characterization of solid pancreatic lesions. • Using Hypo-E or Centri-E as the diagnostic criteria for pancreatic carcinoma, Hyper-E for neuroendocrine tumors, Capsular-E for solid pseudopapillary tumors, and Iso-E or Iso-fhypo-E for focal pancreatitis on CEUS had relatively high diagnostic accuracy. • The diagnostic accuracy of CEUS was greatly increased over that of US and was not different from that of enhanced CT.

Posterior reversible encephalopathy syndrome (PRES) refers to a clinical and radiologic entity with diverse clinical causes. Patients present with a variety of symptoms ranging from headache, altered mental status, seizures and vision abnormalities to loss of consciousness. In cases with severe clinical manifestations, such as coma and/or status epilepticus, admission to the intensive care unit may be required. PRES is usually characterized by altered signal intensity in subcortical white matter of posterior cerebral hemispheres in magnetic resonance imaging (MRI) studies and resolve in weeks with appropriate treatment. Diagnosis depends on combination of suggestive clinical findings and radiological features. With increasing experience on PRES, atypical imaging features are described in case series. In this pictorial review, wide imaging feature spectrum of PRES is illustrated including unusual locations and atypical manifestations. Since MRI contributes to an essential part of the diagnosis, atypical imaging features of this syndrome should be well known by physicians and radiologists in order to recognize and treat it immediately. In suitable cases with atypical radiological features in the absence of classical findings, diagnosis of PRES should be kept in mind to avoid delay in diagnosis and hence, permanent neurological sequela. Keywords: Posterior reversible encephalopathy syndrome, magnetic resonance imaging, atypical feature, unusual location.

Inferior vena cava (IVC) leiomyosarcoma is a rare and aggressive malignancy arising from smooth muscle cells of the IVC wall, accounting for less than 1 in 100,000 adult malignancies. It carries a poor prognosis, with high recurrence rates and 5-year disease-free survival reported as low as 6%. Clinical presentation is often vague, including abdominal or back pain, lower extremity edema, and weight loss, making imaging pivotal for diagnosis. Contrast-enhanced CT (CECT) is the modality of choice, but diagnosis remains challenging due to overlap with more common pathologies such as renal cell carcinoma, hepatocellular carcinoma, adrenal tumors, and retroperitoneal lymphadenopathy. This pictorial review presents a curated series of cases highlighting the spectrum of imaging appearances of IVC leiomyosarcoma. By showcasing both typical and atypical imaging patterns, this review aims to broaden radiologists' diagnostic awareness and improve confidence in identifying this elusive tumor. Special emphasis is placed on 3D CT imaging techniques, including optimal acquisition protocols and post-processing methods, to enhance lesion visualization and vascular mapping. Early and accurate recognition is crucial, as aggressive surgical resection remains the mainstay of treatment. Understanding key imaging clues can facilitate timely diagnosis and intervention, ultimately impacting patient outcomes in this rare but life-threatening disease.