Validation of Linear Range HER2/Estrogen Receptor/Progesterone Receptor IHControls for Daily Quality Assurance

OBJECTIVES

To evaluate a new US Food and Drug Administration (FDA)-cleared immunohistochemistry (IHC) control (IHControls [Boston Cell Standards]) comprising peptide epitopes for HER2, estrogen receptor (ER), and progesterone receptor (PR) attached to cell-sized microspheres and to compare its performance against conventional tissue controls.

METHODS

IHControls and tissue/cell line controls for HER2, ER, and PR were compared side by side daily at 5 clinical IHC laboratories for 1 to 2 months. Separately, the sensitivity of the 2 types of controls was evaluated in simulated IHC assay failure experiments by diluting the primary antibody. Additional evaluations included lot-to-lot manufacturing reproducibility of 3 independent lots and specificity against 26 antigenically irrelevant IHC stains.

RESULTS

Side-by-side testing revealed a 99.6% concordance between IHControls and tissue controls across 5 IHC laboratories and 766 individual evaluations. Three discordant quality control events were the result of operator error. Simulated assay failure data showed that both IHControls and tissue controls are similarly capable of detecting IHC staining errors. Manufacturing reproducibility of IHControls showed less than 10% variability (coefficient of variation). No cross-reactions were detected from 26 antigenically irrelevant IHC stains.

CONCLUSIONS

IHControls, the first FDA-cleared IHC controls, can sensitively and accurately detect IHC assay problems, similar to tissue controls.

Severe Graves' disease-associated orbitopathy: A rare case of frontal bone hemangioma

Graves' orbitopathy might be severe, requiring treatment with high-dose glucocorticoids. A lytic bone lesion, malignant lesions, and diseases resulting from bone remodeling processes (eg, Paget's disease) must be excluded by markers and imagery. Outcomes of high-dose glucocorticoids and thyrotoxicosis must be screened and prevented.

Impact of country of birth on genetic testing of metastatic lung adenocarcinomas in France: African women exhibit a mutational spectrum more similar to Asians than to Caucasians

Background

Limited data are available on the prevalence of oncogenic driver mutations in Caucasian populations, and especially in Europeans.

Aim

To evaluate the targetable mutational spectra in unselected patients with lung adenocarcinoma in routine clinical practice from several French hospitals, using the same molecular platform.

Patients and Methods

Samples from 2,219 consecutive patients with histologically-proven advanced lung adenocarcinoma were centrally analysed at a referenced and certified diagnostic platform in order to test for activating and resistance mutations in EGFR, KRAS, BRAF, ERBB2 and PI3KCA. Demographic and clinical features were retrieved from the medical charts. Multivariate binary logistic regression was used to determine the independent predictive factors for the occurrence of specific mutations, in the whole study population or in selected subgroups.

Findings

The overall respective incidence of EGFR, KRAS, BRAF, ERBB2 and PI3KCA mutations was 10.5%, 0.9%, 25%, 1.5%, 2.1% and 1.4%, in our study sample including 87.4% white Caucasians, 10.8% Africans and 1.8% Asians; 60.6% men, 30.7% never smoker (median age: 68.3 years). Ethnicity was an independent predictor for EGFR, KRAS and ERBB2 gene abnormalities. In all cases, a significantly higher prevalence of targetable EGFR and ERBB2, and a lower prevalence of resistance KRAS mutations were observed in African women as compared to African men or Caucasians.

Conclusions

In real life conditions of routine genetic testing, we have identified subsets of patients with specific targetable activating somatic mutations according to ethnicity, who could preferentially benefit from anti-EGFR and anti-ERBB2 targeted therapies.

Left ventricular metastasis from ocular melanoma: a new, rare, and unusual pathway?

Melanoma is a neoplasm known for its propensity for cardiac involvement. When there exists an isolated metastasis to the heart, the melanoma tends to involve the right heart. Rarely does melanoma metastasize to the left ventricle. We report the first case of choroidal melanoma that had indeed metastasized to the left ventricle and was associated with a patent foramen ovale, which may explain its initially surprising location on this side of the heart.

[Extemporaneous examination in lung pathology: the pathologist's view]

Extemporaneous examination of a thoracopulmonary lesion has an unquestionable interest when pre-surgical diagnostic workup has not allowed determining its exact nature. This examination, the sole objective of which is to guide the surgical approach, is especially important in lung pathology, due to the limited non-surgical access to thoracic lesions and the morbidity and mortality of repeated surgery. Its yield as a decision-making procedure is of utmost importance in many clinical situations, and a close collaboration between thoracic surgeons and pathologists is required to ensure its quality, in a context of mutual confidence that requires time and experience. After a presentation of the indications and practical modalities of extemporaneous examination, we will underline its limitations and insist on difficult situations for the pathologist and inadequate indications.

[Update of the GEFPICS' recommendations for HER2 status determination in breast cancers in France]

In Europe, patients who may benefit from an HER2 targeted drug are currently selected by immunohistochemistry (IHC). In situ hybridization (ISH) techniques should be used for complementary assessment of ambiguous 2+ IHC cases and for the calibration of the IHC technique. Eligibility to an HER2 target treatment is defined by an HER2 positive status being IHC test 3+ or 2+ amplified. Reliable detection of HER2 status is essential to the appropriate usage of HER2 targeted drugs because its specificity is limited to tumors overexpressing HER2. It is essential that the IHC evaluation of the HER2 status of a mammary carcinoma is optimized and reliable. This GEFPICS' guidelines look over the different steps of the IHC technique, the controls and, the rules for interpretation. Once acquired, this knowledge must be perpetuated by the observation of rules of good technical practice (internal and external controls, quality assurance programs).

[Appendiceal mucoceles, pseudomyxoma peritonei and appendiceal mucinous neoplasms: update on the contribution of imaging to choice of surgical approach]

INTRODUCTION

The treatment of pseudomyxoma peritonei (PMPs) and appendiceal mucocele (AM) has changed radically. To assess the contribution of preoperative imaging to the treatment strategy and choice of approach, a surgeon and a radiologist different from the initial radiologist examined the files of all patients treated for PMP or AM in four facilities in one district from January 1, 1996, through December 31, 2008.

PATIENTS AND METHODS

The study included 27 patients (20 men and seven women, mean age: 63+/-13 years). Eleven patients had an intact AM, seven synchronous PMP (malignant appendiceal lesion in two of seven), six metachronous PMP (five with peritoneal mucinous carcinomatosis and one with diffuse peritoneal adenomucinosis) and three a ruptured AM but not PMP. The incidence of mucin-secreting tumors observed (27 cases in 12 years in a region of 500 000 inhabitants) corresponds to a prevalence of approximately five cases per year per million inhabitants. Acute clinical pictures (7/27) were significantly more frequent for the malignant forms (5/7) (p<0,02).

RESULTS AND DISCUSSION

The overall sensitivity of computed tomography (CT) for all the criteria studied was 93%. The predictive value for AM rupture of visualization of thick calcifications was 100%. On the other hand, rupture never occurred when the CT showed an AM under pressure, with thin walls and septa. The predictive value for PMP of "scalloping" was 100%. The diagnostic accuracy of the initial reading was 25/27 for the imaging overall and 25/25 for the CT. Preoperative visualization of the exact size of the intact AM or of diagnostic information about ruptured AM and PMP helped to select an appropriate approach in 25 of 27 cases.

HER2 status determined on pre operative biopsies and in operative specimens: concordance among immunohistochemistry (IHC) fluorescence in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) techniques in the CRITHER study

Abstract #1089

Background: In breast cancer, HER2 status is generally assessed by IHC or FISH on operative tissue sample and in situ hybridization techniques are standard tools for determining equivocal IHC 2+ overexpression and deciding the correct treatment for HER2-positive breast cancer patients. For the management of their patients, oncologists or surgeons sometimes ask for assessment of HER2 status on per cutaneous core biopsy (CB).The primary objective of the CRITHER study was to investigate concordance between the results of CISH, FISH, and IHC techniques on pre-operative CB samples for HER2 status compared with HER2 status determined by FISH on surgical specimen from a population of previously untreated non-metastatic breast cancer patients in France. Methods: Analysis was performed on samples from 260 patients recruited at 24 pathology centers for the period 2003 to 2006 inclusive. Recruitment was made on the basis of IHC obtained from operative tissue samples in order to obtain around 50% HER2-positive (3+), 30% HER2-negative (0/1+), and 20% HER2-equivocal (2+) cases. CISH and IHC were performed in parallel on the pre-operative biopsy and matched surgical specimen in the participating laboratories, and FISH on both specimens in each of four reference pathology centers. IHC staining was analyzed according to different scoring systems. Results: The rate of discordance between pre-operative CISH and operative FISH was 1.8% with 1.5% false-positives and 2.2% false-negatives (k=0.963; p&lt;0.001); the corresponding rate for pre-operative IHC (excluding equivocal IHC 2+ cases) and operative FISH was 1.5% with 1.6% false-positives and 1.4% false-negatives (k=0.953; p&lt;0.001). Comparison of pre-operative and operative samples showed expected low rates of discordance for CISH (0.85%; k=0.982; p&lt;0.001) and FISH (0.45%; k=0.991; p&lt;0.001), with no false positives in either case. Results for the IHC scoring system analyses on concordance will be presented at the meeting. Discussion: As expected, concordance for both CISH and FISH between pre-operative and operative results was excellent. There was a high rate of concordance for pre-operative CISH and IHC HER2 status determination on CB (excluding equivocal IHC 2+ cases) compared with operative FISH results in patients with previously untreated non-metastatic breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1089.

[Histological modifications observed in prostate after preserving treatments for prostate cancer and their impact on Gleason score interpretation]

Total prostatectomy remains the main treatment for intermediate risk prostate cancer with a life expectancy greater than 10 years. In other cases non-surgical treatments can be proposed: external radiotherapy (exclusive or combined anti-androgen therapy), brachytherapy with permanent implants, high frequency ultrasounds (HIFU, Ablatherm), cryotherapy or exclusive hormonal treatment. For such patients in case of biological recurrence, prostate biopsies are usually performed in order to affirm the local recurrence. The histological confirmation of persistent tumor is usually required before any treatment: salvage surgery, cryotherapy, and brachytherapy or high intensity focused ultrasound (HIFU). Pathologists must be aware of the histological modifications induced by these different treatments in order to ensure an optimal interpretation of the biopsies. In this review, we describe the modifications observed in the normal prostate and in cancers after these various therapeutic methods, and also after alpha reductase inhibitors proposed as treatment of benign prostate hypertrophy and prostate cancer chemoprevention.

Prevalence of anal cytologic abnormalities in a French referral population: a prospective study with special emphasis on HIV, HPV, and smoking

PURPOSE

Studying anal cytology to detect intraepithelial neoplasia has been demonstrated to be useful in highly selected populations. This study was designed to determine the frequency of abnormal smears in a wide sample of patients consulting for anorectal symptoms.

METHODS

An anal smear was proposed during each consultation during a three-month period.

RESULTS

A total of 205 patients (112 females) were included. After the consultation, visible condylomas were detected in 12 (6 percent) of the cases. Two hundred three (99 percent) smears were able to be analyzed. No case of high-grade squamous intraepithelial lesion was found. Four cases of low-grade squamous intraepithelial lesion were found, all in HIV patients with a history of condylomatous lesions. Forty smears were interpreted as atypical squamous cells of undetermined significance and 159 were normal. The prevalence in this population of low-grade squamous intraepithelial lesion was 19 percent (4/21) in HIV seropositive males, and 15 percent (4/26) in the case of a past history of condyloma. The factors associated with an abnormal smear (low-grade squamous intraepithelial lesion or atypical squamous cells of undetermined significance) were a history of anal condylomatous lesions (odd ratio, 4.9; range, 2.1-11.5), HIV seropositivity (odd ratio, 4; range, 1.6-9.9), and smoking (odd ratio, 2.1; range, 1.1-11.5).

CONCLUSIONS

This work confirms that the frequency of low-grade squamous intraepithelial lesion is raised in HIV-seropositive males and also where there is a history of condyloma, which corroborates the necessity for regular monitoring and screening of these patients at risk. This study also suggests that the use of tobacco is associated with anal cytologic abnormalities.

Development of a Seeded Scaffold in the Great Omentum: Feasibility of an in vivo Bioreactor for Bladder Tissue Engineering

OBJECTIVES

Tissue engineering is very promising in bladder reconstruction. However, one of the main problems is to limit the development of ischaemic fibrosis during tissue maturation. We describe a model using the omentum as an in vivo bioreactor for a previously seeded scaffold.

METHODS

Bladder biopsies were taken from five female pigs, from which both urothelial and smooth muscle cells cultures were made. These cultured cells were used to seed a sphere-shaped small intestinal submucosa (SIS) matrix, which was transferred into the omentum after 3 wk of cell growth. The grafts were harvested 3 wk later and histologic, immunohistochemical, and functional studies were performed.

RESULTS

We obtained a highly vascularized tissue-engineered construct that contracted in response to acetylcholine stimulation. The wall thickness was 4mm, on average. Histologic and immunostaining analysis of the construct confirmed the presence of a multilayer urothelium on the luminal aspect and deeper fascicles organised tissue composed of differentiated smooth muscle cells and mature fibroblasts without evidence of inflammation or necrosis. Large- and small-diameter vessels were clearly identified histologically in the tissue obtained.

CONCLUSION

The omentum permitted in vivo maturation of seeded scaffolds with the development of a dense vascularisation that is anticipated to prevent fibrosis and loss of contractility. This in vivo maturation into the omentum could be the first step before in situ implantation of the construct.

[Anal metastasis from a lung cancer]

We report an anal metastasis from a lung cancer which was diagnosed on symptoms mimicking an acute anal abcess. The diagnosis was based on specific immunohistochemistry.

Alpha-methyl CoA racemase expression in renal cell carcinomas

Alpha-methyl CoA racemase (AMACR), a new molecular marker for prostate cancer, has been recently reported to be one of the most highly expressed genes in papillary renal cell carcinomas (RCCs). We tested the diagnostic usefulness of AMACR antibody in a series of 110 renal tumors: 53 papillary RCCs (33 type 1, 20 type 2); 25 conventional RCCs; 6 chromophobe RCCs; 9 oncocytomas; 5 mucinous tubular and spindle tumors; 2 urothelial carcinomas; 7 angiomyolipomas; and 2 Bellini carcinomas. Immunohistochemical staining was performed on formalin-fixed, paraffin-embedded tissue sections, with a primary prediluted rabbit monoclonal anti-AMACR antibody. Both type 1 and type 2 papillary RCCs exhibited cytoplasmic immunoreactivity for AMACR, with diffuse strong granular staining in 96.4% (53/55) of tumors, without correlation with type or nuclear grade. The 5 mucinous, tubular, and spindle cell carcinomas strongly expressed AMACR, and only 5 of 25 clear cell RCCs and 1 of 9 oncocytomas were focally reactive. The remaining 6 chromophobe RCCs, 5 urothelial carcinomas, and Bellini duct carcinomas showed no immunoreactivity for AMACR. Because high expression of AMACR is found in papillary RCCs (type 1 and 2) and in mucinous, tubular, and spindle cell carcinomas of the kidney, immunostaining for AMACR should be used in conjunction with other markers when histological typing of a renal tumor is difficult.

Steroidogenesis in aldosterone-producing adenoma revisited by transcriptome analysis

CONTEXT

Primary aldosteronism (PAL) is the most frequent cause of secondary arterial hypertension. In PAL, aldosterone production is chronic, excessive, and autonomous.

OBJECTIVE

The objective of this study was to identify the angiotensin-II independent alterations of steroidogenesis responsible for PAL.

DESIGN

Genomewide gene expression was compared in two tissues differentiated for aldosterone production, both nonstimulated by circulating angiotensin II and differing in their autonomy to produce aldosterone: aldosterone-producing adenoma (APA) and its adjacent dissected zona glomerulosa (ZG).

SETTING

The setting of this study was the Comete Network.

PATIENTS

Patients with APA were studied.

INTERVENTION

Transcriptome comparison was made of one APA and its adjacent ZG by serial analysis of gene expression; validation by in situ hybridization was performed for 19 genes in 11 samples.

OUTCOME

The study outcome was genes differentially expressed in APA and adjacent ZG.

RESULTS

Activation of steroidogenesis in PAL is restricted to the overexpression of the enzymes producing aldosterone-specific steroids, aldosterone synthase and also 21-hydroxylase, suggesting that upstream precursor production is not limiting. Increased expression of high-density lipoprotein receptor, adrenodoxin and P450 oxidoreductase suggests that these systems provide cholesterol and electrons to the mitochondrial steroidogenic enzymes. As for acute stimulation of aldosterone production, an activation of calcium signaling is suggested by concordant overexpression of calcium-binding proteins or effectors. Calcium activation may result from an abnormal activity of G(q) protein-coupled receptors. This calcium activation may be the starting point of the other gene expression changes observed in APA. Finally, other differentially expressed genes include three genes encoding unidentified proteins.

CONCLUSION

This work provides an original and integrated view of the mechanisms of aldosterone production in PAL.

[Imaging of pancreatic adenocarcinoma]

Pancreatic cancer remains the fourth most common cause of cancer death. Surgery remains the only option for cure. Accurate diagnosis and staging are essential for appropriate management of patients with pancreatic cancer. This paper reviews the state of the art for imaging modalities in the diagnosis and staging of pancreatic adenocarcinoma. The crucial role of CT has increased with the new generation of multidetector CT.

Diverticules géants du grêle et du côlon et formations pseudo kystiques sous-mésocoliques

Giant diverticula of the small intestine and colon are rare. Four cases treated at our institution in the last year are reported and compared to published cases; specific features and those which differentiate them from abdominal pseudocysts are described. They most commonly present a clinical tableau similar to commonplace diverticular disease. Awareness of this unusual condition and a good CT study are the keys to diagnosis. Giant diverticula may be acquired or congenital. The acquired type is simply a more spectacular version of commonplace diverticulosis while the congenital type, having a muscular wall and myenteric plexus, is more akin to intestinal duplications. Treatment is surgical and, in the case of sigmoid giant diverticula, usually requires a colon resection similar to that required for sigmoid diverticulitis.

[HER2 gene amplification assay: is CISH an alternative to FISH?]

The HER2 proto-oncogene encodes a transmembrane protein, which is considered to function as a growth factor receptor. Overexpression of this protein found by immunohistochemistry in about 20% of infiltrating breast carcinomas, has a predictive value of response to treatment by trastuzumab, an anti-HER2 humanized monoclonal antibody. Search for HER2 gene amplification is necessary to adapt the immunohistochemical technique quality and also in the cases of delicate analysis or weak overexpression. It is usually carried out by Fluorescence In Situ Hybridization (FISH). A more recent hybridization technique, named CISH because of its chromogenic revelation is an alternative method, which gives highly correlated results with FISH. We present details of this technique, which may be more familiar for the pathologists than FISH, because reading analysis is similar to that of immunohistochemical staining.

[2001 Standards, Options and Recommendations: practice guidelines for difficult diagnoses in surgical pathology or cytopathology in cancer patients]

CONTEXT

The Standards, Options and Recommendations (SOR) project, which started in 1993, is a collaboration between the Federation of French Cancer Centers (FNCLCC), the 20 French Regional Cancer Centers, and specialists from French public universities, general hospitals and private clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and the outcome of cancer patients.

OBJECTIVES

To elaborate practice guidelines for difficult diagnoses in surgical pathology or cytopathology in cancer patients.

METHODS

The methodology is based on a literature review and critical appraisal by a multidisciplinary group of experts who define the CPGs according to the definitions of the Standards, Options and Recommendations project. Once the guidelines has been defined, the document is submitted for review by independent reviewers.

RESULTS

The main recommendations to prevent and reduce the number of difficult diagnoses in surgical pathology or cytopathology are: The main recommendations to detect lesions associated with difficult diagnosis in surgical pathology or cytopathology are: The main recommendations to solve difficult diagnosis in surgical pathology or cytopathology are:

Primary squamous cell carcinoma of the endometrium: case history, pathologic findings, and discussion

Primary squamous cell carcinoma of the endometrium (PSCCE) is an exceedingly rare tumor. Rarely are cytological criteria discussed. We report our experience in the cytological diagnosis of a case. A postmenopausal, 64-yr-old woman suffered from pyometria. An endometrial Pap smear displayed some malignant squamous cells. Curettage of the cervix and the uterine cavity only recovered some fragments of atypical squamous epithelium whose origin could not be precisely identified. A hysterectomy with bilateral adnexectomy was decided upon. Pathological study evidenced a primary squamous cell carcinoma in the uterine cavity while the cervix was tumor-free and the lymph nodes were devoid of metastases (pT1, pN0, pM0). The patient died 46 mo PO with multiple pulmonary and renal metastases. The histological feature of PSCCE is identical to that of any tumor of a similar nature, whatever the site, especially the cervix. Confirmation of the primary endometrial nature is only possible on the hysterectomy specimen.

[Immunochemistry evaluation of HER2 status in infiltration breast cancer: technical protocol and interpretation guidelines]

In Europe, patients who may benefit from Herceptin((R)) (an HER2 targeted drug) are currently selected by immunohistochemistry (IHC). Reliable detection of HER2 status is essential to the appropriate usage of Herceptin(R), because its specificity is limited to tumours overexpressing HER2. It is essential that the IHC evaluation of the HER2 status of a mammary carcinoma be optimized and reliable. This technical paper reviews the different steps of the IHC technique, the controls and, the rules for interpretation. The sensitivity of the IHC technique must be adjusted so as not to produce false negatives or false positives. As opposed to other methods, it can be carried out whatever the fixation conditions of the tissues. The interpretation of the immunostains also requires training; it is fraught with problems for intermediate positivities. The ideal score to evaluate HER2 status has not yet been defined. It will thus be necessary to report the percentage of stained cells, the intensity of the staining, and, in respect to Herceptin((R)) treatment, the HercepTest scoring system (recommended in the package insert). Once acquired, this knowledge must be perpetuated by the observation of rules of good technical practice (internal and external controls, quality assurance programs). FISH should be used for complementary assessment of 2+ cases (on condition that they have not been fixed in Bouin's liquid) and for the calibration of the IHC technique.

[Standards, options and recommendations: practice guidelines for difficult diagnosis in surgical pathology or cytopathology in cancer patients]

CONTEXT

The "Standards, Options and Recommendations" (SOR) project, started in 1993 is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and outcome for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery.

OBJECTIVES

To develop clinical practice guidelines according to the definitions of the Standards, Options and Recommendations project for difficult diagnoses in surgical pathology or cytopathology in cancer patients.

METHODS

Data were identified by searching Medline and using the personal reference lists of members of the expert groups. Once the guidelines were defined, the document was submitted for review to 71 independent reviewers.

RESULTS

The main recommendations to prevent and reduce the number of difficult diagnoses in surgical pathology or cytopathology are: 1) The development of quality insurance programs with use of written procedures in each pathology laboratory (standard). 2) The knowledge of clinical data in order to explain surgical pathology or cytopathology results (standard). 3) The availability of complementary patient informations (radiologic data . . .) can be useful to explain surgical pathology or cytopathology results (option). The main recommendations to detect lesions associated with difficult diagnosis in surgical pathology or cytopathology are: 1) Tumor types known as potential difficult diagnosis in surgical pathology or cytopathology should be reviewed by a second pathologist. 2) The systematic second reviewing for every case is expensive but has to be done when the difficulty is know (sarcoma, lymphoma . . .) by experienced pathologists. The main recommendations to solve difficult diagnosis in surgical pathology or cytopathology are: 1) Block recuts, use of special techniques (immunocytohistochemistry and molecular biology), additional data from clinicians, second opinion by a local pathologist, or new specimen can be required for establishing the diagnosis (options). 2) Outside second opinion by expert pathologist has to be considered once the other steps did not allow to establish surgical or cytopathology diagnosis (recommendations, expert agreement).

Ivermectin in human onchocerciasis: a clinical-pathological study of skin lesions before and three days after treatment

Findings are presented from an histological study of 360 skin-snips (from iliac crests, calves, ankles) taken from 30 Ivory Coast onchocerciasis patients before and three days after an oral dose of ivermectin (200 micrograms/kg). This dose causes a nearly complete disappearance of the intralymphatic microfilariae and, surprisingly, of the "extra-vascular" ones. That shows the difficulty to localize the microfilariae on histological sections; these microfilariae are in fact inside the lymphatic pre-capillaries. There was no intensification of acute skin lesions after the treatment, thus showing that, contrary to diethylcarbamazine (DEC), ivermectin does not induce an exit of microfilariae into the extralymphatic connective tissue. Under the influence of ivermectin, paralyzed microfilariae may be carried passively towards the deep sub-cutaneous lymphatics, and then destroyed inside the regional lymph nodes, without producing major changes in the skin.

Adult-type rhabdomyoma of the palate. Cytologic presentation of two cases with histologic and immunologic study

The cytologic presentations of two adult-type rhabdomyomas of the soft palate are reported. Fine needle aspiration smears of the lesions contained globular tumor cells that had striations and intracytoplasmic rod-shaped inclusions. These inclusions, corresponding to hypertrophied Z bands, were pathognomonic of rhabdomyoma tissue. The cytologic diagnosis was confirmed by histologic and immunologic studies in both cases. The cytologic preparations fixed in alcohol or air dried did not show the "spiderweb cells" observed in the histologic sections of tissue fragments fixed in formaldehyde; this clearly illustrates that the morphology of the cells of this tumor depends primarily on the specimen preparation technique used. These cases suggest that aspiration cytology can establish the diagnosis of this benign tumor of striated muscle, for which total surgical removal is usually sufficient to effect a cure. The differential diagnosis is discussed in detail.

Primary leiomyosarcoma of the ovary: a histological and immunocytochemical study

A case of primary leiomyosarcoma of the ovary in a 35-year-old woman is presented. The tumor was investigated histologically and by histochemistry. Desmin was demonstrated in neoplastic cells. Pertinent literature is reviewed and histogenesis is discussed.

Production of monoclonal antibodies to the high fibrin-affinity, tissue-type plasminogen activator of human plasma. Demonstration of its endothelial origin by immunolocalization

Monoclonal antibodies (MAbs) to vascular plasminogen activator (vPA), the tissue-type plasminogen activator (tPA) in human plasma, were produced to be used as probes for immunochemical analysis. Human tissue sections and one of these MAbs were used to demonstrate the endothelial origin of plasma-tPA by immunohistochemistry. To produce MAbs, mice were immunized with semipurified vPA isolated from postocclusion human venous blood. Primed spleen cells were fused with the mouse myeloma cell line NS-1. Screening for MAb-producing hybridomas was performed with postocclusion euglobulins as a source of antigen by means of a solid-phase fibrin-vPA immunoassay. The selective and high-affinity binding of vPA for fibrin ensures the specificity and sensitivity of this test. Thus, eight hybridomas secreting MAbs to vPA were selected, cloned, and established as permanent hybridoma cell lines. Immunohistochemical analysis of cryostat sections of human tissues was performed with EA-delta 12D, a MAb having no inhibitory effect against vPA activity but binding to vPA with a high affinity. Thus, the only structures immunostained were endothelial cells of venules, capillaries, and arterioles. The EA-delta 12D monoclonal localization of plasma vPA in the endothelial lining of blood vessels provides evidence that tPA in plasma originates from the vascular wall and validates its designation as vascular plasminogen activator, ie, vPA. Also, our results are consistent with the fact that vPA in blood and tPA in tissues are immunologically identical and have a common endothelial origin.

Surface healing and histologic maturation of patent polytetrafluoroethylene grafts implanted in patients for up to 60 months

Histologic, transmission, and scanning electron microscopic observations were made of 26 biopsy specimens from patent polytetrafluoroethylene grafts that had been implanted as arterial bypasses for up to 60 months. The results showed the rarity of host connective tissue ingrowth, the absence of neovascularization, and the limited neointimal proliferation. The defect of staining for factor VIII-related antigen by immunohistochemistry confirmed the absence of true endothelial cells at a distance from the anastomoses. Under electron microscopy the thin neointimal layer consisted mainly of fibrin, platelets, blood cells, and cellular debris. Even in prostheses implanted for the longest periods, mature collagen and elastin were not found. Tubular microfibrils (9- to 12-nm thick) could be observed. The source of such microfibrils, probably glycoproteins, remains under investigation.