Phillip A. Isotalo

Surgical pathology of noninfectious ascending aortitis : A study of 45 cases with emphasis on an isolated variant

BackgroundAortitis is emerging as an important cause of ascending aortic aneurysm in the elderly. Its features have not been described in a surgical population. DesignRetrospective clinicopathologic review of 45 cases of active noninfectious aortitis among 513 consecutive ascending aortic resections (1985 to 1999). MethodsClinical data were collected from medical records. Histopathologic features were recorded during review of slides stained with hematoxylin-eosin and Verhoeff-van Gieson. Cases were categorized by predefined clinical criteria. Clinicopathologic features were compared among groups, with emphasis on unsuspected aortitis without systemic arteritis. ResultsThe 2 largest groups were isolated aortitis (47%) and giant cell arteritis (31%). Other aortitis groups included Takayasu (14%), rheumatoid (4%), and unclassified (4%). Patients with isolated aortitis and giant cell arteritis were generally women (80%; mean age 73 y). All 6 with Takayasu arteritis were women (mean age 26). Although giant cell arteritis and isolated aortitis were histologically indistinguishable, their clinical courses differed substantially. Among 21 patients with isolated aortitis (2 treated with corticosteroids), only 10% later developed aortic aneurysms. In contrast, of 14 patients with giant cell arteritis (11 treated with corticosteroids), 21% subsequently developed aneurysms (P=0.09). ConclusionsAortitis primarily affected women. Patients with isolated aortitis and giant cell arteritis were generally older than 50 years and, by definition, those with Takayasu arteritis were younger. In patients with isolated aortitis, outcomes were generally good, despite the absence of anti-inflammatory therapy. Accordingly, a conservative approach may be warranted for managing this subset of patients with aortitis.

Adenomatoid tumor of the adrenal gland: A clinicopathologic study of five cases and review of the literature

We report the clinicopathologic, immunophenotypic, DNA ploidy, and MIB-1 proliferative findings of five adenomatoid tumors of the adrenal gland. All patients were male, and tumors were incidental radiologic, surgical, or autopsy findings. Mean patient age at diagnosis was 41 years (range 31–64 years). The tumors ranged from 1.2 to 3.5 cm (mean 2.8 cm; median 3.2 cm) in greatest dimension, and all originated within the adrenal gland. The tumors were composed of anastomosing variably sized tubules lined by epithelioid as well as flattened cells. Signet-ring-like cells were present in all cases. The previously described histologic patterns of adenomatoid tumor, adenoid, angiomatoid, cystic, and solid, were observed, and each tumor contained multiple histologic patterns. In three of five cases, there was extra-adrenal extension of tumor into periadrenal adipose tissue. All adenomatoid tumors infiltrated the adrenal cortex, and in four cases the adrenal medulla was involved. All tumors exhibited strong immunoreactivity for calretinin, cytokeratins AE1/AE3, and CAM 5.2, cytokeratin 7, and vimentin. Tumors showed weak and focal immunoreactivity for cytokeratin 5/cytokeratin 6 and were negative for CD15, CD31, CD34, cytokeratin 20, MOC31, and polyclonal carcinoembryonic antigen. Ploidy analysis using Feulgen-stained sections and image analysis showed that three tumors were diploid and two were tetraploid. Tumors exhibited low MIB-1 proliferative activity, ranging from 0.2% to 2.7% (mean 1.6%). In three cases with clinical follow-up, no recurrence or metastases occurred. Adrenal gland adenomatoid tumors are morphologically and immunophenotypically identical to adenomatoid tumors of the genital tract and appear benign.

Primary cardiac diffuse large B cell lymphoma presenting with superior vena cava syndrome

Primary cardiac lymphomas are rare extranodal lymphomas that should be distinguished from secondary cardiac involvement by disseminated non-Hodgkins lymphoma. Cardiac lymphomas often mimic other cardiac neoplasms, including myxomas and angiosarcomas, and often require multimodality cardiac imaging, in combination with endomyocardial biopsy, excisional biopsy or pericardial fluid cytology, to establish a definitive diagnosis. A 60-year-old immunocompetent man who presented with superior vena cava syndrome secondary to a right atrial, primary cardiac diffuse large B cell lymphoma (non-Hodgkins lymphoma) is described in the present article. The patient had no clinical evidence of disseminated lymphoma and was successfully treated with prompt surgical excision of his atrial mass, followed by anthracycline-based chemotherapy. The patient required multi-modality cardiac imaging to accurately identify and plan surgical excision of his cardiac lymphoma. The therapeutic management and clinical and radio-logical features of primary cardiac lymphoma are reviewed.

Detection of Prostate Cancer from RF Ultrasound Echo Signals Using Fractal Analysis

In this paper we propose a new feature, average Higuchi dimension of RF time series (AHDRFT), for detection of prostate cancer using ultrasound data. The proposed feature is extracted from RF echo signals acquired from prostate tissue in an in vitro setting and is used in combination with texture features extracted from the corresponding B-scan images. In a novel approach towards RF data collection, we continuously recorded backscattered echoes from the prostate tissue to acquire time series of the RF signals. We also collected B-scan images and performed a detailed histopathologic analysis on the tissue. To compute AHDRFT, the Higuchi fractal dimensions of the RF time series were averaged over a region of interest. AHDRFT and texture features extracted from corresponding B-scan images were used to classify regions of interest, as small as 0.028 cm of the prostate tissue in cancerous and normal classes. We validated the results based on our histopathologic maps. A combination of image statistical moments and features extracted from co-occurrence matrices of the B-scan images resulted in classification accuracy of around 87%. When AHDRFT was added to the feature vectors, the classification accuracy was consistently over 95% with best results of over 99% accuracy. Our results show that the RF time series backscattered from prostate tissues contain information that can be used for detection of prostate cancer

Aspergillus fumigatus pacemaker lead endocarditis: A case report and review of the literature

The diagnosis of fungal endocarditis requires a high index of clinical suspicion. Rarely, pacemaker implantation may be a risk factor for the development of fungal endocarditis. A 71-year-old man with a history of multiple transvenous pacemaker manipulations and fever of an uncertain source is described. A diagnosis of culture-negative pacemaker endocarditis was established only after repeat transthoracic echocardiography. Amphotericin B was instituted; however, the patient developed a cerebral infarct and died. Postmortem examination demonstrated Aspergillus fumigatus within a large pacemaker lead thrombus, tricuspid and aortic valve vegetations, and septic pulmonary and renal emboli. The present report describes the clinical and pathological features of a rare case of Aspergillus fumigatus pacemaker lead endocarditis and suggests that serial echocardiograms may be effective in the early detection of pacemaker lead vegetations. The diagnostic features and therapeutic management of pacemaker lead endocarditis are reviewed.

Discrete Fourier Analysis of Ultrasound RF Time Series for Detection of Prostate Cancer

In this paper, we demonstrate that a set of six features extracted from the discrete Fourier transform of ultrasound radio-frequency (RF) time series can be used to detect prostate cancer with high sensitivity and specificity. Ultrasound RF time series refer to a series of echoes received from one spatial location of tissue while the imaging probe and the tissue are fixed in position. Our previous investigations have shown that at least one feature, fractal dimension, of these signals demonstrates strong correlation with the tissue microstructure. In the current paper, six new features that represent the frequency spectrum of the RF time series have been used, in conjunction with a neural network classification approach, to detect prostate cancer in regions of tissue as small as 0.03 cm2. Based on pathology results used as gold standard, we have acquired mean accuracy of 91%, mean sensitivity of 92% and mean specificity of 90% on seven human prostates.

Mediastinal thymolipoma : A rare occurrence with striated myoid cells

We describe a 49-year-old man who presented to hospital with unstable angina and who underwent emergency coronary artery bypass grafting. During the surgical procedure, an incidental anterior mediastinal mass was discovered. Histological examination of this mediastinal mass revealed a thymolipoma containing numerous polygonal, striated myoid cells that were immunoreactive for desmin, muscle-specific actin and myoglobin. Electron microscopy demonstrated numerous Z band structures confirming myoid differentiation. Even though the appearance of myoid cells in thymolipoma may be alarming, this tumor should be recognized as a benign entity. Thymolipomas containing striated myoid cells should be differentiated from more ominous thymic neoplasms, including teratomas and thymic liposarcomas. To our knowledge, this is only the third reported case of thymolipoma containing striated myoid cells.

In situ hybridization for the differentiation of Actinomyces and Nocardia in tissue sections.

The specific identification of filamentous bacteria in tissue sections can be difficult. The filamentous bacteria Actinomyces and Nocardia often produce similar host responses and single bacterial organisms seem morphologically similar; however, their differentiation may be clinically significant. In situ hybridization (ISH) may assist in the rapid and accurate identification of these microorganisms. In this study, DNA probes were directed against the variable regions of 16S ribosomal RNA genes of multiple Actinomyces and Nocardia spp. Probes were tested on 26 formalin-fixed, paraffin-embedded tissue specimens, each of which contained diagnostic foci of filamentous bacteria confirmed by both Gram and Grocott methenamine silver stains. On the basis of histology and clinical features, cases were classified as Actinomyces-related, n=13 with 6 culture-proven cases and Nocardia-related, n=13 with 11 culture-proven cases. Using this classification, all cases were assessed for cross-reactivity using other species-specific probes and probe specificity was determined. Overall, Gram and Grocott methenamine silver histochemical stains (100% sensitivity) were more sensitive than ISH (77% sensitivity for both Actinomyces and Nocardia probes). The slender caliber of filamentous bacteria was a limitation for ISH interpretation and necessitated careful examination of some slides. Probes demonstrated 100% specificity for identifying both species, 100% positive predictive value and 81% negative predictive value. No mixed infections were observed. This study demonstrates that ISH is highly specific for distinguishing between Actinomyces and Nocardia spp. in tissue sections. Although histochemical stains demonstrate greater sensitivity for organism detection, ISH is a rapid and specific technique that is especially useful for evaluating culture-negative or clinically unsuspected cases of filamentous bacterial infection.

A new approach to analysis of RF ultrasound echo signals for tissue characterization: animal studies

We present the results of an animal tissue characterization study to demonstrate the effectiveness of a novel approach in collecting and analyzing ultrasound echo signals. In this approach, we continuously record RF echo signals backscattered from a tissue sample, while the imaging probe and the tissue are fixed in position. The continuously recorded RF data generates a time series of RF signal samples. The Higuchi fractal dimension of the resulting time series at each spatial coordinate of the RF frame, averaged over a region of interest, serves as our tissue characterizing feature. The proposed feature is used along with Bayesian classifiers and feed-forward neural networks to distinguish different types of animal tissue. Pairwise classification of four different types of animal tissue are performed. Accuracies are in the range of 68%-96% and are significantly higher than the natural split of the data. The promising results of this study show that analysis of RF time series as proposed here, can potentially give rise to effective measures for ultrasound-based tissue characterization.