Structural changes induced by antineoplastic therapies: keys to evaluate tumor response to treatment.

The criteria to define therapeutic response in oncology are those proposed by Miller, characterized by four response categories (complete response, partial response, no change, progression of disease), and based upon both measurable and non-measurable (and otherwise assessable) morphological parameters in comparison with baseline and subsequently modified following the Response Evaluation Criteria In Solid Tumors. In addition to these classical morphological criteria, we review the predictive value of structural changes in the evaluation of response to antineoplastic therapies. The goal of the present review is to evaluate in detail structural variations (calcification, fibrosis, differentiation, necrosis, cavitation, vascularization, edema, and pseudocapsule formation) induced by therapy, and to ascertain their significance in terms of biological evolution of the neoplastic process.

Focal Castleman disease of the lung: MRI findings.

Castleman disease is an uncommon benign disorder mainly affecting mediastinal lymph nodes and rarely visceral organs. The most typical structural finding is hypervascularity which can be well demonstrated both by CT and MRI. We report MR findings of an unusual case of solitary parenchymal lung involvement.

Enlarging tongue masses in neurofibromatosis type 1: MR findings of two cases.

Plexiform neurofibromas usually occur in the neck, pelvis, and extremities. Jaws and oral cavity plexiform neurofibromas have also been described. Magnetic resonance (MR) patterns for neurofibromas are typical. They include low-to-intermediate signal intensity on T1-weighted images, enhancement of the solid component of the tumor after contrast medium administration, heterogeneity on T2-weighted images, and in some cases, multiple target signs due to a collagen central area. We report MR findings of two neurofibromatosis type 1 (NF1) patients with enlarging tongue plexiform neurofibromas.

Duodenal hemangiopericytoma: CT and MRI findings.

Hemangiopericytoma (HPC) is a rare mesenchymal tumor generally occurring in adults and originating from the pericytes. The tumor more commonly affects the soft tissues of the extremities, the pelvis, and the retroperitoneum. We describe the computed tomographic and magnetic resonance appearance of a patient affected by HPC of the duodenum.

Hemangiosarcoma of the adrenal glands: CT findings in two cases.

Hemangiosarcomas of the adrenal gland, both benign and malignant, are exceedingly rare; only a dozen of them have been reported in literature to our knowledge. We describe herein the findings at CT of 2 primary hemangiosarcomas of the adrenal glands. We also discuss their etiology, incidence, and differential diagnosis, particularly in relation to more frequent primary adrenal lesions, such as adrenal adenomas and carcinomas. CT will generally show a heterogeneous mass with frequent necrosis, contrast-enhancement, and occasional calcifications. A prospective diagnosis cannot be made by imaging alone, and pathology represents the discriminating method for a correct diagnosis.

Primary effusion lymphomas in AIDS: CT findings in two cases.

Primary effusion lymphomas represent an unusual subset of AIDS-related non-Hodgkin's lymphomas. They are associated with herpes virus 8 and Epstein-Barr virus and characterized by predominant involvement of the serous body cavities (pleura, pericardium, peritoneum) as lymphomatous effusion without any identifiable tumour mass. We report herein CT findings in two patients with primary effusion lymphoma emphasizing the possible neoplastic nature of a pleural effusion in a patient with AIDS.

Peliosis hepatis with pseudotumoral and hemorrhagic evolution: CT and MR findings.

Peliosis hepatis is an uncommon benign disorder characterized by blood-filled cavities within the liver. We describe the sonographic, computed tomographic, and magnetic resonance appearance of a patient affected by peliosis hepatis with pseudotumoral and hemorrhagic evolution and direct demonstration of the ectatic vascular components.

Lipomatous tumors of the stomach: CT findings and differential diagnosis.

This article reviews the computed tomography imaging features of a variety of gastric tumors containing fatty tissue. Lipoma, angiolipoma, liposarcoma, and teratoma are described. Differential diagnosis includes primary and reactive lipomatosis, carcinoma engulfing the perivisceral fat thus mimicking differentiated liposarcoma, and mesenchymal gastric and peritoneal neoplasms.

[Calcified renal metastases: their etiology, pathogenesis, computed tomographic aspects and differential diagnosis]. / Metastasi renali calcificate: eziologia, patogenesi, aspetti con Tomografia Computerizzata e diagnostica differenziale.

PURPOSE: To describe CT findings of calcified renal metastases focusing on differential diagnosis problems. MATERIAL AND METHODS: We retrospectively reviewed abdominal CT scans of 8000 patients with tumor, performed from 1984 to 1998. Among the 58 renal metastases, 9 showed a calcific component. We evaluated the location, morphostructural pattern, histology of the primary lesion, the synchronous or metachronous character and the type of treatment. All the lesions were pathologically proved. RESULTS: The primary histotype of the 9 metastases was as follows: 4 mucin-producing adenocarcinomas of the large bowel, 1 gastric mucinous adenocarcinoma, 1 chondrosarcoma, 1 osteosarcoma, 1 melanoma, 1 papillary thyroid carcinoma. In all the cases the renal metastasis was unilateral and unifocal. Granular multiple calcifications were demonstrated within the metastases of mucin-producing adenocarcinoma of the large bowel (3), within the metastasis of chondrosarcoma (1) and of melanoma (1). Diffuse "star-like" calcifications were demonstrated in renal metastases of mucin-producing adenocarcinoma of the large bowel and of gastric mucinous adenocarcinoma (1). Peripheral "egg-shell" calcifications were demonstrated in renal metastasis from papillary thyroid carcinoma (1). Completely calcified monofocal calcification was demonstrated in renal metastasis from osteosarcoma (1). DISCUSSION AND CONCLUSIONS: Calcified renal metastases are rare lesions related to specific oncotypes. The differential diagnosis (carcinoma with calcifications, osteosarcoma, chondrosarcoma, nephrocalcinosis, granulomatosis, hydatidosis etc.) is particularly difficult because of the aspecificity of the morphostructural pattern. Diagnosis is based on a history of specific oncotypes (papillary and mucin-secreting carcinomas, osteosarcoma and chondrosarcoma), but in most cases it requires pathologic confirmation.

Non-Hodgkin lymphomas of the ovaries: MR findings.

PURPOSE: The goal of this work was to describe MR findings (morphology, structure, signal intensity) of ovarian non-Hodgkin lymphoma (NHL). METHOD: We reviewed the MR images of five female patients aged 13-70 years (mean 46 years) with histologically proven NHL of the ovaries. We evaluated morphological and signal intensity findings of the lesions. MR features were correlated with pathologic parameters. RESULTS: All the patients were affected by B-cell NHL; one patient showed a primary involvement of the ovaries; in one patient, ovarian disease was diagnosed 30 months after surgical resection of a primary uterine lymphoma; the remaining three had a systemic lymphoma. In three cases, the ovarian involvement was bilateral. The mean size of the lesions was 7.9 cm. All the lesions showed homogeneous low signal intensity on T1-weighted images and intermediate to high intensity on T2-weighted images. The postgadolinium images showed mild to moderate heterogeneous enhancement. The peripheral enhancement was better demonstrated in fat-suppressed images. CONCLUSION: The diagnosis of primary ovarian lymphoma should be considered in the presence of large bilateral solid ovarian masses with homogeneous appearance (low signal on T1 and mildly high on T2) without infiltrative pattern of growth or regressive changes (necrosis, hemorrhage, calcifications) and with little contrast enhancement.

[Gastric stromal tumors. Findings with computerized tomography]. / Tumori stromali gastrici. Aspetti con Tomografia Computerizzata.

PURPOSE: Gastric stromal tumors are an ill-defined group of lesions arising from muscle wall cells and characterized by extremely variable biological patterns. Thanks to modern immunohistochemical and ultrastructural techniques, four main classes of these lesions have been identified, namely: 1) tumors with differentiation toward smooth muscle cells; 2) tumors with differentiation toward neural elements; 3) tumors with dual differentiation toward both cell types; 4) tumors lacking differentiation toward either cell type. We investigated the yield of CT in diagnosing and characterizing gastric stromal tumors. MATERIAL AND METHODS: We retrospectively reviewed the CT findings of 38 patients (15 men and 23 women; mean age 51 years) with pathologically proven gastric stromal tumors, namely 31 of myoid origin, 4 of neural origin, 2 with both muscle and neural differentiation, 1 lacking differentiation with either cell type. Morphological (size, margins, growth pattern, enlarged lymph nodes, metastases) and structural (density, calcifications, necrosis, cystic changes, enhancement patterns) parameters were evaluated and compared with histopathologic diagnosis. RESULTS: The myoid tumors involved gastric fundus in 9/13 and 5/7 benign lesions and lesions with variable biological patterns, respectively, while the malignant tumors exhibited diffuse involvement in 7/11 of cases. Eleven of 13 benign lesions had regular shape and a diameter +/- 5 cm, while 5/7 intermediate tumors and 7/11 malignant ones were 6-10 cm and over 10 cm (1/7 and 3/11, respectively). Tumor growth was intramural (6/13) or mixed (5/13) in the benign lesions, mainly exophytic in the malignant ones, and finally variable (2/7 intramural, 3/7 exophytic and 2/7 mixed) in the tumors with intermediate patterns. Calcifications were identified only in 3 benign lesions. Structure was homogeneous in 11/13 of the benign lesions with regular contrast enhancement (10/12), heterogeneous due to necrotic areas in nearly all (10/11) or most (5/7) malignant and intermediate forms, respectively. Enlarged lymph nodes (4/11) or synchronous metastases (7/11) were found in the malignant lesions. Our two schwannomas had a pseudocystic structure with regular peripheral contrast enhancement; the neurofibroma was characterized by multiple, markedly hypodense and hypovascular lesions. Both the malignant neurogen form and the two tumors with dual differentiation showed a diffuse, aspecific and infiltrating pattern. The lesion without differentiation had a "benign" shape and structure even though it developed metastases two years after radical surgery. CONCLUSIONS: Despite the lack of specificity of CT patterns of gastric stromal tumors, these parameters are useful in differentiating benign from overtly malignant forms. The definition "gastric stromal tumor with benign, variable, or malignant macroscopic appearance" should be used in the radiologic report.

[Gastric tumors with fatty components. CT findings and differential diagnosis]. / Tumori gastrici con componente adiposa. Aspetti con Tomografia Computerizzata e diagnostica differenziale.

PURPOSE: To assess the role of CT in diagnosing and characterizing gastric fatty tumors. MATERIAL AND METHODS: We reviewed the CT scans of 16 patients (8 men, 8 women, mean age 52 years) with gastric fatty tumors (11 lipomas, 3 liposarcomas, 1 angiolipoma, 1 teratoma) examined from 1990 to 1999. The differential diagnosis considered primary and secondary lipomatosis, carcinoma engulfing the perivisceral fat and thus mimicking a liposarcoma, mesenchymal gastric and primary peritoneal tumors. RESULTS: Lipomas involved the fundus (7/11), the body (3/11), the antrum (1/11). Multifocality was found in one case. Lesions size ranged 25 to 65 mm (mean 35 mm). All the lipomas showed homogeneous structure with negative (-30 -100) HU values. A pseudocapsule was demonstrated in 7/11 cases. No infiltrative growth was demonstrated. The angiolipoma located in the fundus showed a vascular component with strong contrast enhancement. All the liposarcomas were bigger than 10 cm and there was a strong correlation between pathologic specimen and CT findings. The differentiated liposarcomas showed the classic heterogeneous fatty density; on the contrary the myxoid and the pleomorphic types showed an aspecific structure with necrotic/cystic changes, mostly demonstrated in the myxoid type. The teratoma was a solid mass with fatty, solid, necrotic and calcified components. CONCLUSION: CT allows the diagnosis and characterization of gastric fatty tumors. The preoperative diagnosis of lipomas plays a major clinical role because it often makes surgery unnecessary.

Pseudotumoral bilateral involvement of the breast in Erdheim-Chester disease: CT appearance.

We report a case of pseudotumoral involvement of the breast in Erdheim-Chester disease. CT shows an enlargement of both breasts with inhomogeneous structure, microcalcifications, and foci of fatty density.

[Mesenchymal tumors of the pancreas: computed tomography patterns]. / Tumori mesenchimali del pancreas. Aspetti con Tomografia Computerizzata.

PURPOSE: To report the CT patterns of pancreatic mesenchymal lesions and to investigate the capabilities and limitations of this technique in terms of characterization. MATERIAL AND METHODS: We selected the CT examinations of 23 patients from all CT examinations of the pancreas performed from 1986 to 1998. The patients were 10 to 85 years old and all lesions but two (1 lipoma and 1 lymphoma) had pathologic confirmation. Two lymphangiomas, 2 lipomas, 4 Schwannomas (SCH), 1 plexiform neurofibroma, 1 cystic teratoma, 1 pancreatoblastoma, 9 non-Hodgkin's lymphomas (NHL), 1 undifferentiated sarcoma and 2 leiomyosarcomas were diagnosed. RESULTS: Lipomas had typically homogeneous negative HU values, and NHL a homogeneous hypodense pattern with mild contrast enhancement, with no necrosis or calcifications in both diffuse and nodular forms; SCH had variable appearance, with water/slightly negative HU numbers or highly enhanced patterns with a central necrotic core depending on the main Antoni A or B histology. Lymphangiomas appeared as complex cysts, with thin and regular or calcified walls and intracystic septa, while the plexiform neurofibroma had near-water homogeneous density with mild contrast enhancement and an infiltrating growth pattern. Our teratoma had multiple calcifications, mucinous and lipid components. The pancreatoblastoma, sarcomas, and leiomyosarcomas exhibited no specific findings. CONCLUSIONS: In selected cases, CT can provide virtually diagnostic information (lipoma and teratoma), or at least highly suggestive findings (NHL, plexiform neurofibroma, lymphangioma). Moreover, knowledge of the variable morphostructural patterns of mesenchymal histotypes (SCH, sarcoma etc.) permits to include them in the differential diagnosis of pancreatic masses.