Most small, incidentally discovered, well-marginated renal parenchymal neoplasms grow slowly and are not an immediate threat to a patient's life. Watchful waiting might be appropriate instead of surgical removal, especially in patients who are elderly or may not survive surgery.

A multicentre study was undertaken to provide fundamentals for improved standardization and optimized interpretation guidelines of dynamic contrast-enhanced MRI. Only patients scheduled for biopsy of a clinical or imaging abnormality were included. They underwent standardized dynamic MRI on Siemens 1.0 (163 valid lesions > or = 5 mm) or 1.5 T (395 valid lesions > or = 5 mm) using 3D fast low-angle shot (FLASH; 87 s) before and five times after standardized bolus of 0.2 mmol Gd-DTPA/kg. One-Tesla and 1.5 T data were analysed separately using a discriminant analysis. Only histologically correlated lesions entered the statistical evaluation. Histopathology and imaging were correlated in retrospect and in open. The best results were achieved by combining up to five wash-in or wash-out parameters. Different weighting of false-negative vs false-positive calls allowed formulation of a statistically based interpretation scheme yielding optimized rules for the highest possible sensitivity (specificity 30%), for moderate (50%) or high (64-71%) specificity. The sensitivities obtained at the above specificity levels were better at 1.0 T (98, 97, or 96%) than at 1.5 T (96, 93, 86%). Using a widely available standardized MR technique definition of statistically founded interpretation rules is possible. Choice of an optimum interpretation rule may vary with the clinical question. Prospective testing remains necessary. Differences of 1.0 and 1.5 T are not statistically significant but may be due to pulse sequences.

Nephrogenic adenoma is a rare lesion of the urinary tract. The diagnosis usually is straightforward when characteristic microscopic and clinical findings are present, and the entity is familiar. However, misdiagnosis, in particular of adenocarcinoma of the prostate gland, may occur. Immunohistochemical stains often are needed to make such a distinction, but currently available markers offered only partial help. It recently was demonstrated that nephrogenic adenoma in renal transplant patients originated from the renal tubular epithelium. This newly proved, but long sought information may be helpful in the differential diagnosis of nephrogenic adenoma. In this study, we investigated the expression of a renal transcription factor, PAX2, in 39 nonrenal transplant-related nephrogenic adenomas, 100 adenocarcinomas of the prostate gland, and 47 urothelial carcinomas of the urinary tract. A strong and distinct nuclear staining of PAX2 was found in all 39 cases of nephrogenic adenoma (100%), but not in normal prostate tissue, normal urothelium, adenocarcinomas of the prostate gland, and invasive urothelial carcinomas. Focal CD10 was detected in six of 13 nephrogenic adenomas in the superficial papillary component and in normal prostate epithelium, normal urothelium, lymphocytes, adenocarcinoma of the prostate gland, and urothelial carcinoma. There was no uroplakins detected in nephrogenic adenoma. Therefore, these findings are suggesting that nephrogenic adenoma in nonrenal transplant patients may also arise from the renal epithelium, as did the comparable lesions after transplantation. PAX2 is a specific and sensitive immunohistochemical marker in identification and differential diagnosis of nephrogenic adenoma.

One of the first applications of Simulated Moving Bed (SMB) technology was in p‐xylene recovery from mixed xylenes. The three main industrial processes for p‐xylene separation from mixed xylenes based on SMB technology are: UOP's Parex, IFP's Eluxyl, and Toray's Aromax. These units operate in liquid phase (T = 180°C and P = 9 bar), achieving high recovery of almost pure p‐xylene with high on‐stream efficiency and extended adsorbent life. In this work, the industrial scale SMB process is investigated from modeling, simulation, and optimization points of view, using experimentally measured xylene adsorption equilibrium and kinetics data on ion exchanged faujasite zeolite. The aim is to develop tools for training of SMB unit operators and choice of the best operating conditions. Useful studies for better understanding of the influence of the operating parameters, adsorbent packing, and separation requirements on unit productivity are presented. SMB unit revamping strategies and operative actions are proposed. The practical application of “separation volume” methodology in the selection of optimum operating conditions that lead to maximum p‐xylene productivity with minimal desorbent consumption is described. © 2006 American Institute of Chemical Engineers AIChE J, 2007

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Metastases or secondary deposits account for 16% of the malignant neoplasms involving the major salivary glands. A correct diagnosis of a secondary neoplasm is important to avoid unnecessary radical surgery and to guide further therapy. Fine-needle aspiration biopsy (FNAB) is an excellent noninvasive diagnostic tool for evaluating salivary gland lesions. We reviewed 36 secondary malignant salivary gland neoplasms evaluated by FNAB. Ancillary studies were performed in selected cases. Follow-up included clinical correlation and review of histologic material. For 4 adenocarcinomas, 4 squamous cell carcinomas, 1 undifferentiated carcinoma, 1 cutaneous basal cell carcinoma, 10 cutaneous melanomas including 1 desmoplastic variant, 3 osteosarcomas, 11 non-Hodgkin lymphomas, and 2 multiple myelomas, there was 1 false-negative FNAB result. The desmoplastic melanoma was interpreted as reactive lymphoid hyperplasia. A malignant diagnosis was given in all remaining cases except the secondary basal cell carcinoma, which was diagnosed as a neoplasm with basal cell features. FNAB is a reliable tool to differentiate hematologic malignant neoplasms and melanomas from other salivary gland neoplasms. A complete knowledge of the clinical history, review of previous pathologic materials, and, in some instances, the use of ancillary studies are crucial for recognizing solid malignant neoplasms secondarily involving the salivary glands.

BACKGROUND Fine‐needle aspiration biopsy (FNA) has been successful in diagnosing epithelial lesions of the breast. Its role in the evaluation of spindle cell and mesenchymal lesions of the breast, which include a variety of benign and malignant conditions, is less clear. This article discusses the cytologic features and differential diagnosis of these lesions, as well as the potential diagnostic pitfalls associated with them. METHODS FNAs of the breast, in which a spindle cell or mesenchymal component was a key or dominant feature, were retrieved. Fibroadenomas without cellular stroma and typical lipomas were excluded. RESULTS Forty‐six aspirates (0.87%) in a series of 5306 breast FNAs contained a significant spindle cell or mesenchymal component. The aspirates were classified into 4 categories: 1) reactive conditions, including 2 diabetic mastopathies, 3 granulation tissue specimens, and 7 granulomatous lesions; 2) benign neoplastic conditions, including 1 mammary hamartoma, 1 dermatofibroma, 1 fibromatosis, 2 granular cell tumors, 2 angiolipomas, and 7 cellular fibroadenomas; 3) low grade malignant neoplastic lesions, including 10 low grade phyllodes tumors; and 4) high grade malignant neoplastic lesions, including 1 metaplastic carcinoma with chondroid stroma, 1 pleomorphic liposarcoma, 2 malignant fibrous histiocytomas, 2 osteosarcomas, and 4 metastatic melanomas. A specific diagnosis was rendered in 38 cases (82.6%). The mammary hamartoma was diagnosed as fibrocystic changes; the dermatofibroma as benign spindle cell lesion, not otherwise specified (NOS); and the primary osteosarcoma as an atypical spindle cell proliferation, NOS. The reactive ductal epithelial cells in one of the granulomatous mastitis specimens, as well as the hyperplastic ductal epithelial cells in one of the phyllodes tumors, were interpreted as atypical ductal proliferation. The marked cytologic atypia displayed by one granular cell tumor was interpreted as low grade adenocarcinoma and the primary liposarcoma as poorly differentiated carcinoma. CONCLUSIONS Breast lesions with a significant spindle cell or mesenchymal component are rarely encountered in FNA and constitute a heterogeneous group that may pose a diagnostic dilemma. FNA should be the initial diagnostic procedure for investigating these lesions, as a specific diagnosis was rendered in the majority of cases. Cancer (Cancer Cytopathol) 1999;87:359–71. © 1999 American Cancer Society.

In a twist: [28]Hexaphyrin phosphonium adducts formed from the reaction with phosphines have been identified as Möbius aromatic species. On the other hand, the Hückel aromatic [26]hexaphyrin PdII complex underwent regioselective nucleophilic reactions with phosphines to provide Möbius aromatic [28]hexaphyrin phosphonium adducts. The phosphonium ylide contribution is more dominant and hence more aromatic in the latter phosphonium PdII complexes.