Mucin-producing Cystic Hepatobiliary Neoplasms: Updated Nomenclature and Clinical, Pathologic, and Imaging Features.

Cystic hepatobiliary neoplasms with mucin-producing epithelium-mucinous cystic neoplasm of the liver (MCN) and intraductal papillary neoplasm of the bile duct (IPNB)-are rare and distinct entities that have unique clinical, pathologic, and imaging features. They are differentiated pathologically by the presence of subepithelial ovarian-like hypercellular stroma (OLS), which is the defining histopathologic feature of MCN. MCN is commonly a benign, large, solitary, symptomatic, multiloculated cystic mass without biliary communication that occurs in middle-aged women. On the other hand, IPNBs are a heterogeneous spectrum of tumors, which are commonly associated with invasive carcinoma, occur in older patients, and can be differentiated from MCN by communication with the biliary tree, intraductal masses, associated biliary ductal dilatation, and absent OLS. Understanding of these rare neoplasms has grown and evolved over time and continues to today, but uncertainty and controversy persist, related to the rarity of these tumors, relatively recent designation as separate entities, inherent clinicopathologic heterogeneity, overlapping imaging features, and the fact that many prior studies likely included MCN and cystic IPNB together as a single entity. Confusion regarding these neoplasms is evident by historical inconsistencies and nonstandardized nomenclature through the years. Awareness of these entities is important for the interpreting radiologist to suggest a particular diagnosis or generate a meaningful differential diagnosis in the appropriate setting, and is of particular significance as MCN and cystic IPNB have overlapping imaging features with other more common hepatobiliary cystic masses but have different management and prognosis. Online supplemental material is available for this article. Work of the U.S. Government published under an exclusive license with the RSNA.

Propagation Imaging in the Demonstration of Common Shear Wave Artifacts.

In this article, we describe our experience with shear wave propagation imaging (SWPI) as an adjunct to 2-dimensional (2D) shear wave elastography (SWE) in a cohort of patients being evaluated for diffuse liver disease. Two-dimensional SWE has been extensively studied in previous publications; however, 2D SWE using propagation images has not been widely described in the literature to date. We observed that when certain artifacts occurred on the color elastograms, highly characteristic changes to shear wave propagation contours were seen, which can help clarify the cause of the artifacts. To our knowledge, the use of SWPI to explain the etiology of artifacts has never been published before. The artifacts described in this article include the capsule reverberation artifact, penetration limitation or dropout artifact, artifact due to blood vessels, shadowing artifact, tissue motion artifact, and near-field distortion/precompression artifact. Hence, the purpose of this article is to show examples of common artifacts seen on 2D SWE as depicted on corresponding SWPI to demonstrate that both types of image displays are complementary to each other.

Aberrant Vascular Anatomy Associated With Artifactual Focal Avidity in the Liver on PSMA PET.

ABSTRACT: 68 Ga-prostate-specific membrane antigen (PSMA) PET/CT is a valuable tool for staging and restaging of prostate cancer. Prostate-specific membrane antigen expression is not specific to prostate cancer, as it is expressed in normal tissues as well as in neoplastic and nonneoplastic processes. Awareness of the broad possibility of lesions with PSMA avidity is necessary to recognize normal variants and avoid potential pitfalls in image interpretation. We present a series of cases showing physiologic focal PSMA avidity in hepatic segment IVb. We correlate this uptake with aberrant hepatic vasculature. The awareness of this variant is important for accurate image interpretation to prevent additional invasive procedures, undue treatment escalation, and denial of curative treatment to patients.

Multimodality imaging spectrum of complications of horseshoe kidney.

Horseshoe kidney is the most common congenital renal fusion anomaly with an incidence of 1 in 400-600 individuals. The most common type is fusion at the lower poles seen in greater than 90% of the cases, with the rest depicting fusion at the upper poles, resulting in an inverted horseshoe kidney. Embryologically, there are two theories hypothesizing the genesis of horseshoe kidney - mechanical fusion theory and teratogenic event theory. As an entity, horseshoe kidney is an association of two anatomic anomalies, namely, ectopia and malrotation. It is also associated with other anomalies including vascular, calyceal, and ureteral anomalies. Horseshoe kidney is prone to a number of complications due to its abnormal position as well as due to associated vascular and ureteral anomalies. Complications associated with horseshoe kidney include pelviureteric junction obstruction, renal stones, infection, tumors, and trauma. It can also be associated with abnormalities of cardiovascular, central nervous, musculoskeletal and genitourinary systems, as well as chromosomal abnormalities. Conventional imaging modalities (plain films, intravenous urogram) as well as advanced cross-sectional imaging modalities (ultrasound, computed tomography, and magnetic resonance imaging) play an important role in the evaluation of horseshoe kidney. This article briefly describes the embryology and anatomy of the horseshoe kidney, enumerates appropriate imaging modalities used for its evaluation, and reviews cross-sectional imaging features of associated complications.

Bilateral Epstein-Barr virus-associated adrenal leiomyomas in a child without an established immunodeficiency.

Adrenal leiomyomas are rare, bilateral ones being rarer. Literature available on these rare tumors documents only 4 cases in children less than 12 years of age. Each case has been associated with acquired immune deficiency syndrome or some other immunodeficiency state. Here we present a rare case of large, bilateral, adrenal leiomyomas in a child with no known immunodeficiency. An 11-year-old girl with a past history of herpes zoster (1 year before the present complaints) was admitted with abdominal pain of 2 months' duration. Radiology revealed bilateral adrenal neoplasms, probably bilateral pheochromocytoma. Histology showed bilateral adrenal leiomyomas that were Epstein-Barr virus associated. We report this case to draw attention to the occurrence of a common pathologic entity at an uncommon site in a setting of no definite known immunodeficiency.