From the radiologic pathology archives: gastrointestinal lymphoma: radiologic and pathologic findings.

Gastrointestinal (GI) lymphoma encompasses a heterogeneous group of neoplasms that have a common lymphoid origin but variable pathologic and imaging features. Extranodal marginal zone B-cell lymphoma (ENMZL) and diffuse large B-cell lymphoma (DLBCL) are the most common. ENMZL usually occurs in the stomach, where it is associated with chronic infection by Helicobacter pylori, and is typically a superficial spreading lesion that causes mucosal nodularity or ulceration and mild wall thickening. DLBCL may arise de novo or from transformation of ENMZL or other low-grade lymphomas. This form of lymphoma produces extensive wall thickening or a bulky mass, but obstruction is uncommon. Mantle cell lymphoma is the classic cause of lymphomatous polyposis, but multiple polyps or nodules can also be seen with ENMZL and follicular lymphoma. Burkitt lymphoma is usually characterized by an ileocecal mass or wall thickening in the terminal ileum in young children, often in the setting of widespread disease. Primary GI Hodgkin lymphoma, which is rare, may be manifested by a variety of findings, though stenosis is more common than with non-Hodgkin lymphoma. Enteropathy-associated T-cell lymphoma is frequently associated with celiac disease and is characterized by wall thickening, ulceration, and even perforation of the jejunum. Accurate radiologic diagnosis of GI lymphoma requires a multifactorial approach based on the clinical findings, site of involvement, imaging findings, and associated complications.

From the radiologic pathology archives: esophageal neoplasms: radiologic-pathologic correlation.

Esophageal neoplasms have a wide spectrum of clinical features, pathologic findings, and imaging manifestations. Leiomyomas are the most common benign esophageal neoplasm, typically appearing as smoothly marginated intramural masses. Fibrovascular polyps arise in the cervical esophagus, gradually elongating as they are pulled inferiorly by esophageal peristalsis. Granular cell tumors are generally incidental small intramural masses with an appearance similar to that of leiomyomas. Malignant esophageal neoplasms are a common cause of cancer mortality, particularly squamous cell carcinoma (SCC) and adenocarcinoma. Both of these tumors occur in older men, most often appearing as irregular infiltrative lesions at barium examination, with evidence of tumor spread beyond the esophagus at cross-sectional imaging. Adenocarcinoma arises from Barrett esophagus and is much more likely than SCC to involve the gastroesophageal junction. Esophageal involvement by lymphoma is usually secondary to tumor spread from the stomach or mediastinum. Spindle cell carcinoma is a biphasic malignancy with carcinomatous and sarcomatous elements that forms a bulky polypoid intraluminal mass. Neuroendocrine carcinoma is an aggressive neoplasm that may be hypervascular and is usually associated with metastatic disease at presentation. Understanding the imaging appearances and pathologic bases of esophageal neoplasms is essential for their detection, differential diagnosis, staging, and treatment planning.

Sclerosing angiomatoid nodular transformation of the spleen: CT and MRI features with pathologic correlation.

OBJECTIVE: The objective of this study was to describe the CT and MRI features of sclerosing angiomatoid nodular transformation of the spleen with pathologic correlation. MATERIALS AND METHODS: Nine patients with surgically resected and pathologically confirmed sclerosing angiomatoid nodular transformation were included in the study. Clinical history was reviewed to determine patient demographics and symptoms at presentation. Gross pathologic, histologic, and immunohistochemical findings were recorded. CT (n = 9) and MRI (n = 4) examinations were evaluated for lesion shape and margins, intrinsic characteristics, and enhancement pattern. RESULTS: Patients included were six women and three men, with a mean age of 41.2 years. Pathologic features of sclerosing angiomatoid nodular transformation included multiple angiomatous nodules in a radiating pattern with a central stellate fibrous scar and evidence of hemosiderin deposition. On imaging, the lesions were solitary and round, 78% having a lobulated margin. They were heterogeneously hypoenhancing during the arterial and portal venous phases of contrast-enhanced CT or MRI, with peripheral enhancing radiating lines in 88% of lesions. They showed progressive enhancement and were isoenhancing or hyperenhancing in the delayed phase. A hypoenhancing central scar was shown on imaging in 22% of lesions. All lesions were hypointense on T2-weighted images. CONCLUSION: Sclerosing angiomatoid nodular transformation shows characteristic CT and MRI findings reflecting the underlying pathology. Typical features are a solitary, round, lobulated mass with early peripheral enhancing radiating lines and progressive enhancement of the angiomatous nodules; delayed enhancement of the fibrous tissue; and hypo-intense T2 signal intensity from hemosiderin deposition.

Abdominal twists and turns: part I, gastrointestinal tract torsions with pathologic correlation.

OBJECTIVE: The gastrointestinal tract is secured in place by various suspensory ligaments. Laxity or incomplete development of these anchoring ligaments can lead to hypermobility and predispose the patient to torsion-related ischemic pathology. A prompt diagnosis is necessary to avoid life-threatening consequences of prolonged visceral ischemia. Abdominal torsions are rarely diagnosed clinically, and it is often the responsibility of the radiologist to recognize and make the diagnosis through radiography, fluoroscopy, or cross-sectional imaging. This article reviews the imaging spectrum (with radiologic-pathologic correlations) and therapeutic implications of gastrointestinal tract torsions. CONCLUSION: Torsion-related ischemic pathology may involve any portion of the gastrointestinal tract from the stomach to the colon. The clinical presentation of gastrointestinal tract torsion is nonspecific, and radiologists are relied on to make this diagnosis. Recognition of the predisposing factors and imaging spectrum of gastrointestinal tract torsions is essential to help direct timely intervention in these potentially life-threatening entities.

Abdominal twists and turns: part 2, solid visceral torsions with pathologic correlation.

OBJECTIVE: The solid abdominal viscera are secured in place by various suspensory ligaments. Laxity or incomplete development of these anchoring ligaments can lead to hypermobility and predispose the patient to torsion-related ischemic pathology. The clinical symptoms of solid visceral intraabdominal torsions are nonspecific. A prompt diagnosis is critical to avoid life-threatening consequences of prolonged visceral ischemia. Abdominal torsions are rarely diagnosed clinically, and it is often the responsibility of the radiologist to recognize and make the diagnosis through cross-sectional imaging. This article reviews the imaging spectrum, radiologic-pathologic correlations, and therapeutic implications of solid visceral intraabdominal torsions, including some unusual solid organ and abdominal fat torsions. CONCLUSION: The clinical presentation of solid visceral intraabdominal torsion is nonspecific and radiologists are relied on to make this diagnosis on cross-sectional imaging studies. Recognition of the predisposing factors and imaging spectrum of intraabdominal torsions is essential to help direct timely intervention in these potentially life-threatening entities.

From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation. Part 2. Malignant tumors.

Malignant primary hepatic tumors in children include lesions unique to the pediatric age group and others that are more common in adults. Important considerations when evaluating a child with a liver tumor are the age of the patient, laboratory findings, and specific imaging features. The most common primary malignant hepatic tumor in the pediatric population, hepatoblastoma occurs almost exclusively in patients younger than 5 years with no history of liver disease. Hepatoblastoma is associated with elevated serum α-fetoprotein (AFP) level and appears predominantly solid. Hepatocellular carcinoma (HCC) is the most common malignant liver tumor in older children, often with a history of liver disease. HCC is associated with elevated serum AFP level and also appears as a solid mass. Fibrolamellar carcinoma occurs in adolescents without elevated AFP level and contains a T2-hypointense fibrous scar that usually does not enhance. Undifferentiated (embryonal) sarcoma occurs in young children, contains cystic and mucoid components, and mimics a cyst at magnetic resonance imaging and computed tomography but appears solid at ultrasonography. Epithelioid hemangioendothelioma is a multifocal vascular tumor in older children with a distinctive imaging appearance of confluent peripheral nodules with adjacent capsular retraction. Angiosarcoma rarely occurs in young children and frequently shows evidence of hemorrhage. Embryonal rhabdomyosarcoma of the biliary tree is unique to children, usually under 5 years of age, and frequently demonstrates an intraductal growth pattern. Knowledge of the pathologic features of these tumors and their imaging appearances can help radiologists offer an appropriate differential diagnosis and management plan.

Pancreatic endocrine tumors: radiologic-clinicopathologic correlation.

Pancreatic endocrine tumors (PETs) are primarily well-differentiated tumors composed of cells that resemble normal islet cells but that arise from pancreatic ductal cells. They are classified as functioning or nonfunctioning according to their associated clinical symptoms; insulinoma, gastrinoma, and glucagonoma are the most common functioning PETs. They also are classified according to their biologic behavior, although all PETs have malignant potential. Most are sporadic, but some are associated with familial syndromes such as multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, and neurofibromatosis type 1. At imaging, PETs typically appear as well-defined hypervascular masses, a finding indicative of their rich capillary network. Cystic change, calcification, and necrosis are common in large tumors, which are associated with a poorer prognosis and a higher prevalence of local and vascular invasion and metastases than are smaller tumors. Even when metastases are present, many well-differentiated PETs have an indolent course. Poorly differentiated PETs are rare and have an infiltrative appearance; patients with such tumors have a poor prognosis. Knowledge of the characteristic clinical, pathologic, and radiologic features of PETs is important in the evaluation and management of patients with a suspected clinical syndrome or a pancreatic mass.

Tumors of the liver and intrahepatic bile ducts: radiologic-pathologic correlation.

Primary tumors of the liver can be classified pathologically based on their cell of origin into epithelial tumors, arising from hepatocytes or biliary epithelium, and nonepithelial tumors, including mesenchymal tumors and lymphoma. Characteristic findings on MR imaging can be seen in many cases. This article reviews the MR imaging appearance of these tumors with pathologic correlation.

From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation part 1. Benign tumors.

Benign hepatic tumors in children include lesions that are unique to the pediatric age group and others that are more common in adults. Infantile hemangioendothelioma, or infantile hepatic hemangioma, is a benign vascular tumor that may cause serious clinical complications. It is composed of vascular channels lined by endothelial cells. At imaging, large feeding arteries and draining veins and early, intense, peripheral nodular enhancement with centripetal filling on delayed images are characteristic features. Mesenchymal hamartoma of the liver occurs in young children and is characterized pathologically by mesenchymal proliferation with fluid-containing cysts of varying size and number. The mesenchymal component or cystic component may predominate; this predominance determines the imaging appearance of the tumor. Benign epithelial tumors that are common in adults may infrequently occur in childhood. These include focal nodular hyperplasia (FNH), hepatocellular adenoma, and nodular regenerative hyperplasia. All are composed of hyperplastic hepatocytes similar to surrounding liver parenchyma and may be difficult to discern at imaging. Preferential hepatic arterial phase enhancement helps distinguish FNH and hepatic adenoma from uninvolved liver. Hepatic adenoma often has intracellular fat and a propensity for intratumoral hemorrhage, neither of which are seen in FNH. Unlike adenoma, FNH often contains enough Kupffer cells to show uptake at sulfur colloid scintigraphy. Nodular regenerative hyperplasia is often associated with portal hypertension, which may be evident at imaging. Knowledge of how the pathologic features of these tumors affect their imaging appearances helps radiologists offer an appropriate differential diagnosis and management plan.

Pigmented villonodular synovitis: radiologic-pathologic correlation.

Pigmented villonodular synovitis (PVNS) represents an uncommon benign neoplastic process that may involve the synovium of the joint diffusely or focally (PVNS) or that may occur extraarticularly in a bursa (pigmented villonodular bursitis [PVNB]) or tendon sheath (pigmented villonodular tenosynovitis [PVNTS]). Pathologic specimens of the hypertrophic synovium may appear villous, nodular, or villonodular, and hemosiderin deposition, often prominent, is seen in most cases. The knee, followed by the hip, is the most common location for PVNS or PVNB, whereas PVNTS occurs most often in the hand and foot. PVNTS is also referred to as giant cell tumor of the tendon sheath (GCTTS). PVNTS is the most common form of this disease by a ratio of approximately 3:1. Radiographs reveal nonspecific features of a joint effusion in PVNS, a focal soft-tissue mass in PVNB or PVNTS, or a normal appearance. Extrinsic erosion of bone (on both sides of the joint) may also be seen and is most frequent with intraarticular involvement of the hip (>90% of cases). Cross-sectional imaging reveals diffuse involvement of the synovium (PVNS), an intimate relationship to the tendon (PVTNS), or a typical bursal location (PVNB), findings that suggest the diagnosis. However, the magnetic resonance (MR) imaging findings of prominent low signal intensity (seen with T2-weighting) and "blooming" artifact from the hemosiderin (seen with gradient-echo sequences) are nearly pathognomonic of this diagnosis. In addition, MR imaging is optimal for evaluating lesion extent. This information is crucial to guide treatment and to achieve complete surgical resection. Recurrence is more common with diffuse intraarticular disease and is difficult to distinguish, both pathologically and radiologically, from the rare complication of malignant PVNS. Recognizing the appearances of the various types of PVNS, which reflect their pathologic characteristics, improves radiologic assessment and is important for optimal patient management.

Primary osseous tumors of the foot and ankle.

Primary bone tumors involving the foot or ankle may be imaged, because they are symptomatic or may be found incidentally on imaging studies investigating other causes of pain or swelling. As an uncommon location for malignant bone tumors, lesions within the foot and ankle are subject to misdiagnosis. This article reviews the most commonly encountered primary benign and malignant osseous neoplasms that affect the foot and ankle, emphasizing their characteristic radiologic and MR imaging features to aid in appropriate patient management.