Faculty Bibliography

Focal nodular hyperplasia (FNH), hepatocellular adenoma (HCA), and hepatocellular carcinoma (HCC) compose hepatocellular neoplasms that occur in adults. These tumors demonstrate characteristic epidemiologic and histopathologic features and clinical and imaging manifestations. HCAs are monoclonal neoplasms characterized by increased predilection to hemorrhage or rupture and occasional transformation to HCC. On the other hand, FNH is a polyclonal tumorlike lesion that occurs in response to increased perfusion and has an indolent clinical course. Up to 90% of HCCs occur in the setting of cirrhosis. Chronic viral hepatitis (hepatitis B and hepatitis C) infection and metabolic syndrome are major risk factors that can induce HCCs in nonfibrotic liver. Recent advances in pathology and genetics have led to better understanding of the histogenesis, natural history, and molecular events that determine specific oncologic pathways used by these neoplasms. HCAs are now believed to result from specific genetic mutations involving TCF1 (transcription factor 1 gene), IL6ST (interleukin 6 signal transducer gene), and CTNNB1 (beta catenin-1 gene); FNHs are characterized by an "imbalance" of angiopoietin. While the beta catenin signaling pathway is associated with well- and moderately differentiated HCCs, mutations involving p53 (tumor protein 53 gene), MMP14 (matrix metalloproteinase 14 gene), and RhoC (Ras homolog gene family, member C) are associated with larger tumor size, higher tumor grade with resultant shortened tumor-free survival, and poor prognosis. Fibrolamellar carcinoma (FLC), a unique HCC subtype, exhibits genomic homogeneity that partly explains its better overall prognosis. On the basis of recent study results involving cytogenetics and oncologic pathways of HCCs, novel drugs that act against molecular targets are being developed. Indeed, sorafenib (a multikinase inhibitor) is currently being used in the successful treatment of patients with advanced HCC. Characterization of genetic abnormalities and genotype-phenotype correlations in adult hepatocellular tumors provides better understanding of tumor pathology and biology, imaging findings, prognosis, and response to molecular therapeutics.

Hepatocellular adenomas (HCAs) are uncommon, benign hepatocellular neoplasms that commonly occur in young women. Recent advances in pathology and cytogenetics have thrown fresh light on the pathogenesis of HCAs leading to classification of HCAs into 3 distinct subtypes, each with a characteristic epidemiology, histopathology, oncogenesis, and imaging findings. The aim of the article was to provide a comprehensive review of contemporary taxonomy of HCAs, with an emphasis on cross-sectional imaging findings and management.

Renal cystic diseases in adults are a heterogeneous group of disorders characterized by the presence of multiple cysts in the kidneys. These diseases may be categorized as hereditary, acquired, or developmental on the basis of their pathogenesis. Hereditary conditions include autosomal dominant polycystic kidney disease, medullary cystic kidney disease, von Hippel-Lindau disease, and tuberous sclerosis. Acquired conditions include cystic kidney disease, which develops in patients with end-stage renal disease. Developmental cystic diseases of the adult kidney include localized renal cystic disease, multicystic dysplastic kidney, and medullary sponge kidney. In recent years, many molecular and cellular mechanisms involved in the pathogenesis of renal cystic diseases have been identified. Hereditary renal cystic diseases are characterized by genetic mutations that lead to defects in the structure and function of the primary cilia of renal tubular epithelial cells, abnormal proliferation of tubular epithelium, and increased fluid secretion, all of which ultimately result in the development of renal cysts. A better understanding of these pathophysiologic mechanisms is now providing the basis for the development of more targeted therapeutic drugs for some of these disorders. Cross-sectional imaging provides useful information for diagnosis, surveillance, prognostication, and evaluation of treatment response in renal cystic diseases.

There is a heterogeneous group of noninfectious gastroenterocolitis syndromes that are characterized by immune dysregulation. Recent advances in pathologic analysis have allowed for better characterization of many of these disorders. Some entities demonstrate characteristic disease distribution, epidemiologic features, natural history, and response to specific therapy. For instance, celiac disease occurs in genetically susceptible individuals who are sensitive to gluten, eosinophilic esophagitis is an immune response to ingested allergens, and microscopic colitis predominantly occurs in older patients with chronic diarrhea and is induced or exacerbated by drugs. Eosinophilic gastroenteritis has a variety of clinical and imaging manifestations. Crohn disease and ulcerative colitis are multifactorial immune-mediated chronic inflammatory disorders and have become increasingly prevalent in recent years. Multidetector computed tomography and magnetic resonance imaging provide valuable information that may be used to diagnose these conditions, guide treatment, and assess changes after treatment, and the role of imaging in evaluating response to therapy continues to evolve and expand.

OBJECTIVE: The purpose of this review is to describe the epidemiologic, etiopathogenetic, clinical, and imaging characteristics of various nonalcoholic, nonbiliary pancreatitis syndromes. CONCLUSION: The spectrum of nonalcoholic, nonbiliary pancreatitis includes autoimmune pancreatitis, groove pancreatitis, hereditary pancreatitis, tropical pancreatitis, tuberculous pancreatitis, and metabolic pancreatitis. Advances in genetics and molecular pathology have shed new light on the etiopathogenesis and course of these syndromes. Accurate diagnosis aided by imaging findings allows optimal management.

Quantification of tumor burden and assessment of changes in tumor size after chemotherapy are commonly performed to evaluate treatment response in oncology trials. Validation and adoption of different criteria have been attempted in the past to achieve uniformity in scanning techniques and measurement metrics so that comparison of different oncological trials is feasible. Response assessment of solid tumors is usually consisted of either bidimensional (World Health Organization criteria) or unidimensional (Response Evaluation Criteria in Solid Tumors [RECIST] guidelines) measurement of tumors before and after chemotherapy. RECIST 1.1 criteria have been recently published. In this article, we try to provide a comprehensive review of the tumor response evaluation guidelines that were recently updated in attempts to overcome limitations of the previous criteria as well as incorporate recent advances in imaging techniques.

Functional ovarian neoplasms have unique clinical manifestations related to hormone overproduction and may give rise to a broad spectrum of clinical syndromes. Sex cord-stromal tumors, the most common functional ovarian neoplasms, are associated with either hyperestrogenism (as in granulosa cell tumor and thecoma) or hyperandrogenism (as in Sertoli-Leydig cell tumor and Leydig cell tumor). Other, less common ovarian neoplasms that may have endocrine or nonendocrine syndromic manifestations include germ cell tumors associated with the excessive production of human chorionic gonadotropin (eg, choriocarcinoma, dysgerminoma), monodermal teratomas (eg, carcinoid tumor, struma ovarii) associated with carcinoid syndrome and hyperthyroidism, and primary epithelial ovarian cancers associated with paraneoplastic syndromes. The application of diagnostic algorithms based on patient demographic information, clinical manifestations, laboratory findings, and cross-sectional imaging features may help identify ovarian neoplasms in complex clinical settings.

A wide variety of hepatic lesions contain fat within them in a proportion good enough to be demonstrable on imaging. With the biological behaviors quite different from each other, they form a clinico-radio-pathologic spectrum worth remembering. We present a review of common and uncommon focal hepatic lesions containing fat (micro- and macroscopic) within them and emphasize the role of imaging in their diagnosis.

OBJECTIVE: Borderline ovarian tumors comprise a unique group of noninvasive ovarian neoplasms with characteristic histology and variable tumor biology that typically manifest as low-stage disease in younger women with resultant excellent prognosis. CONCLUSION: Borderline tumors are considered to be precursors of low-grade ovarian cancers. Accurate diagnosis and staging facilitate optimal patient management particularly in patients desiring to preserve fertility.

Polyorchidism is a rare urogenital developmental anomaly defined as the presence of more than two testes. Triorchidism is the most common type of polyorchidism and presents with two testes on one side (usually the left) and one testis on the other side. We report a rare case of polyorchidism with three homolateral testes on the right side and absent testis on the left side. Magnetic resonance imaging was used in the present case to investigate the cause for infertility and to confirm this rare diagnosis without surgical exploration