Enrico Orvieto

Utility of the immunohistochemical detection of FLI-1 expression in round cell and vascular neoplasm using a monoclonal antibody

FLI-1 nuclear transcription factor has been proposed as a useful tool in the differential diagnosis of small round cell sarcomas. Recently, FLI-1 has been reported as the first nuclear marker of endothelial differentiation. However, its clinical use has been hampered by major interpretation problems, due to the presence of background staining as well as staining variation between different lots of the same antiserum. In this study, a novel monoclonal antibody raised against the carboxyl terminal of the FLI-1 protein (clone GI146-222, BD Pharmingen) was tested in a series of small round cell and vascular neoplasms. Furthermore, in order to assess FLI-1 specificity, we analyzed its expression in a series of common epithelial and nonepithelial malignancies. In total, 15 Ewings sarcomas, 10 rhabdomyosarcomas, 5 desmoplastic small round cell tumors, 10 synovial sarcomas, 10 high-grade pleomorphic sarcomas, 10 malignant melanomas, 5 Merkels carcinomas, 10 colonic adenocarcinomas, 10 breast carcinomas, 10 lung adenocarcinomas, 20 angiosarcomas, 5 epithelioid hemangioendotheliomas, 10 Kaposis sarcomas and 10 benign hemangiomas, were stained. A strong FLI-1 immunoreactivity was detected in all Ewings sarcomas and vascular neoplasms, highlighting the high sensitivity of FLI-1 monoclonal antibody. However, 2/5 Merkels carcinomas and 1/10 malignant melanomas showed a strong nuclear immunostaining, suggesting that FLI-1 may not be so helpful in the differential diagnosis of cutaneous Ewings sarcoma. In addition, a weak immunoreactivity was found in 3/5 Merkel cell carcinomas, 3/10 synovial sarcomas, 5/10 malignant melanomas, 6/10 lung adenocarcinomas and in 1/10 breast carcinomas. In contrast, all the rhabdomyosarcomas, desmoplastic small round cell tumors, high-grade pleomorphic sarcomas and colonic adenocarcinomas tested were negative. Importantly, in contrast with previous studies, no background staining was observed. Our results indicate that FLI-1 monoclonal antibody can be reliably applied to the differential diagnosis of small round cell neoplasms of soft tissue, and confirm its important role as nuclear marker of endothelial differentiation, mainly helpful in those cases in which technical artifacts are seen by using the traditional membranous and cytoplasmic endothelial markers.

Rabbit Monoclonal Antibodies A Comparative Study Between a Novel Category of Immunoreagents and the Corresponding Mouse Monoclonal Antibodies

Rabbit monoclonal antibodies (RabMAbs) represent a novel category of immunoreagents that may combine the best properties of both mouse monoclonal antibodies (MMAs) and of rabbit antisera. In the attempt to verify the performance of this new class of antibodies on paraffin-embedded tissue, RabMAbs against estrogen receptor, progesterone receptor, Ki-67, cyclin D1, CD3, CD5, CD23, and synaptophysin were tested on several tumor types as well as normal tissues. The results were compared with those obtained with classic MMAs against the same antigens. RabMAbs appear to offer increased sensitivity with no apparent loss of specificity. On routine use they permit higher working dilutions (5 to 10 times on average), allowing significant improvement in terms of laboratory efficiency. The robustness of RabMAbs is further proved by the fact that in some instances optimal staining can be obtained even without antigen retrieval. In consideration of the high performance observed, routine use of RabMAbs may contribute significantly to standardize diagnostic immunohistochemical procedures.

Clinicopathologic characteristics of invasive lobular carcinoma of the breast: results of an analysis of 530 cases from a single institution.

Although invasive lobular carcinoma (ILC) is the second most common histotype of breast cancer, the prognostic implications of its clinicopathologic characteristics remain controversial.

Ectopic breast tissue as a possible cause of false-positive axillary sentinel lymph node biopsies.

Epithelial inclusions representing ectopic breast tissue are uncommonly seen in axillary lymph nodes. The extensive histopathologic examination of axillary sentinel lymph nodes of patients with breast carcinoma may increase the chances to encounter tiny foci of ectopic breast tissue, which may be misinterpreted as (micro)metastatic disease and lead to unwarranted completion of axillary dissection and to inaccurate staging and improper adjuvant treatments for the patients. Here we report on seven cases of ectopic breast tissue in axillary sentinel lymph nodes. In three cases there were coexistent micrometastases, and in the remaining cases the ectopic tissue was not associated with metastatic disease. The ectopic breast tissue showed remarkably varied morphologic features, including apocrine metaplasia and proliferative changes indistinguishable from those occurring in sclerosing adenosis and florid epithelial hyperplasia of the breast. A peripheral layer of myoepithelial cells was consistently detected in the ectopic glands and ducts. Besides awareness and purely morphologic criteria, a false-positive identification of these inclusions as metastatic carcinoma may be avoided by the use of immunohistochemical reactions for the localization of specific markers of the myoepithelial cell component, which is associated with the ectopic breast tissue.

Rabbit Monoclonal Antibodies

Rabbit monoclonal antibodies (RabMAbs) represent a novel category of immunoreagents that may combine the best properties of both mouse monoclonal antibodies (MMAs) and rabbit antisera. In the attempt to verify the performance of this new class of antibodies on paraffin-embedded tissue, RabMAbs against estrogen receptor, progesterone receptor, Ki-67, cyclin D1, CD3, CD5, CD23, and synaptophysin were tested on several tumor types as well as normal tissues. The results were compared with those obtained with classic MMAs against the same antigens. RabMAbs appear to offer increased sensitivity with no apparent loss of specificity. On routine use they permit higher working dilutions (5 to 10 times on average), allowing significant improvement in terms of laboratory efficiency. The robustness of RabMAbs is further proved by the fact that in some instances optimal staining can be obtained even without antigen retrieval. In consideration of the high performance observed, routine use of RabMAbs may contribute significantly to standardize diagnostic immunohistochemical procedures.

Malignant progression in pleomorphic xanthoastrocytoma: Personal experience and review of the literature

Pleomorphic xanthoastrocytoma (PXA) is a rare primary low-grade astrocytic tumor, recently classified as a neuroglial tumor. It generally occurs in children and young adults and shows benign behaviour (WHO II), although an anaplastic variant and malignant potential have been described. Pleomorphic xanthoastrocytomas with malignant transformation have been reported in three out of eight patients operated on for this type of tumor in our department in the last 15 years. The three patients were two adult women and a child, the primary tumors were located in the cortex of the right temporal lobe, and treatment consisted of complete surgical resection. Histological examination revealed simple PXA in two patients and a PXA with anaplastic foci in the other. Mean recurrence time was 5.7 years, with the original xanthoastrocytoma evolving to glioblastoma in two cases and anaplastic astrocytoma in the third. All three patients underwent a second operation, followed by adjuvant therapies. Two died from tumor progression and one from brain edema after intracerebral haemorrhage. A review of the available PXA literature dating back to 1979 revealed 16 cases of primary anaplastic astrocytoma and 21 cases of PXA with malignant transformation. Our experience adds three more cases of malignant transformations, outlining once again the potential malignancy of pleomorphic xanthoastrocytomas and the fact that prognosis in these cases is the same as for primary anaplastic astrocytoma and glioblastoma. Analysis of glioneuronal markers, Ki67 and p53 in all pleomorphic xanthoastrocytomas did not prove to be a discriminating factor to identify a subgroup of xanthoastrocytomas prone to malignancy. Accordingly, these tumors demand close long-term clinical and radiological follow-up.

Immunoreactivity for c-kit and p63 as an adjunct in the diagnosis of adenoid cystic carcinoma of the breast

Adenoid cystic carcinoma of the breast represents a unique clinicopathologic entity with a variable histological appearance and a relatively indolent clinical course in most of the cases. Adenoid cystic carcinoma may be difficult to differentiate from infiltrating duct carcinomas, and in particular from tubular and cribriform carcinomas, especially in core or vacuum-assisted biopsies. We evaluated the prevalence of c-kit, p63, and e-cadherin immunoreactivity in a series of 20 adenoid cystic carcinomas, comparing the results with those obtained in a series of infiltrating tubular carcinomas and infiltrating cribriform carcinomas. The hormone receptor status, proliferation labeling index, and HER/2 immunoreactivity had been previously investigated in all the cases. Three (15%) adenoid cystic carcinomas and all infiltrating tubular and cribriform carcinomas showed estrogen receptor and/or progesterone receptor immunoreactivity (P<0.00001 for estrogen and P=0.00002 for progesterone receptors). Adenoid cystic carcinomas consistently lacked any immunoreactivity for HER/2, whereas three (15%) infiltrating and cribriform carcinomas showed weak and incomplete membrane staining (P=0.23077). Membranous immunoreactivity for c-kit was found in all except one (predominantly basaloid) adenoid cystic carcinomas (95%), and in none of the infiltrating tubular and cribriform carcinomas (P<0.00001). Nuclear immunoreactivity for p63 was found in all except three (predominantly basaloid) adenoid cystic carcinomas (85%) and in none of the infiltrating tubular and cribriform carcinomas (P<0.00001). All infiltrating tubular and cribriform carcinomas and 18/20 (90%) adenoid cystic carcinomas showed immunoreactivity for e-cadherin (P=0.48718). In summary, adenoid cystic carcinomas showed the following phenotype: estrogen receptor−/progesterone receptor−/c-kit+/p63+ (13 cases, 65%), estrogen receptor−/progesterone receptor/c-kit+/p63− (three cases, 15%), estrogen receptor−/progesterone receptor−/c-kit−/p63+ (one case, 5%), estrogen receptor+/progesterone receptor+/c-kit+/p63+ (two cases, 10%), and estrogen receptor+/progesterone receptor−/c-kit+/p63+ (one case). By contrast, all the infiltrating tubular and cribriform carcinomas showed the estrogen receptor+/progesterone receptor+/c-kit−/p63− phenotype. Our data provide evidence that immunoreactivity for c-kit and/or p63 may be useful in differentiating adenoid cystic carcinomas from other types of breast cancer.

Aquaporin(s) expression in choroid plexus tumours

Objective: It was the aim of this study to investigate the pattern of aquaporin 1 (AQP1) expression in normal and neoplastic choroid plexus, with specific reference to the association with communicating hydrocephalus or liquoral cysts. Second, to infer a new view on the cerebrospinal fluid plexus production and on the etiology of the cysts and communicating hydrocephalus occasionally associated with choroid plexus papillomas. Materials and Methods: Nineteen paraffin-embedded specimens, 10 of normal choroid plexus and 9 of choroid plexus tumours, were immunostained with a monoclonal antibody raised against the intracellular C-terminal AQP1 epitope. Results were analysed in terms of intensity and intracellular distribution of immunostaining and in terms of number of stained cells; they were considered in light of the clinical association with hydrocephalus or liquoral cysts. Results: AQP1 was heavily expressed in the apical side of the choroid epithelium in normal plexus specimens. Choroid plexus papillomas showed a very heterogeneous pattern of AQP1 expression. Immunostaining was absent in the case of choroid plexus carcinoma. Very strong to strong and diffuse AQP1 expression in large to very large papillomas was associated with liquoral cysts or communicating hydrocephalus. Conclusions: AQP1 expression characterizes normal choroid plexus and plexus papillomas. Intensity and diffusion of AQP1 expression together with the size of the tumour mass are somewhat predictive of communicating hydrocephalus or liquoral cyst, lesions possibly caused by a disturbance of cerebrospinal fluid homeostasis.

Symptomatic Rathke's Cleft Cysts: A Radiological, Surgical and Pathological Review

Rathkes cleft cyst is a non neoplastic lesion remnant of the Rathkes poutch. Symptomatic cysts must be surgically treated. There are no specific neuroradiological features for this lesion. We present a series of 14 symptomatic Rathkes cleft cysts treated with transphenoidal endoscopic technique, and we correlate the MRI intensity images with the intraoperative findings, the pathological analysis, the growth pattern and the recurrence tendency, to understand wether there is a better way to recognize these lesions, especially the asyntomatic ones, that, despite other neoplastic cysts, colud only be observed with a MRI follow up.

Lack of prognostic significance of “classic” lobular breast carcinoma: a matched, single institution series

Whether invasive lobular carcinoma of the breast per se constitutes a prognostically favorable type has been debated. The present series comprises 301 consecutive “classic” lobular breast carcinomas seen at one institution between 1994 and 2001, compared to an equal number of invasive ductal carcinomas at the same institution during the same period, matched for year of surgery, age, menopausal status, primary tumor size, nodal involvement, hormone receptor status and where possible histological grade. Despite matching, the lobular carcinomas were more frequently multifocal, had more involved nodes, lower grade and lower proliferative fraction. There was no significant difference in disease-free or overall survival, locoregional relapse or time to distant metastasis between the lobular and ductal groups overall or within any examined subset, though the lobular group showed a trend to earlier appearance of contralateral breast cancer. Classical lobular histology is not an independent factor in the prognosis of early breast cancer.