Immunohistochemistry as a fundamental tool for the differential diagnosis of polymorphous low-grade adenocarcinoma

Polymorphous low-grade adenocarcinoma (PLGA) is a subtype of salivary gland carcinoma with a marked predilection for the minor salivary glands. The diagnosis of this lesion can be a challenge in incisional biopsies because of its similarity to other salivary neoplasms and the difficulty of analyzing its infiltrative nature and neurotropism. Diagnosis can be facilitated, however, by immunohistochemistry, a technique that has become a fundamental tool to the pathologist. The purpose of this study was analyze the immunohistochemical aspects of 4 cases that were examined in the São José dos Campos School of Dentistry. The patients included 4 women, ages 32 to 57 years (mean, 50 years), who reported an intraoral painless lesion, ranging in size from 1 to 3 cm (mean, 1.75 cm) with a variable evolution period. Histologically, the lesions showed similar aspects, characterized by polymorphous growth pattern, including solid, cribriform, trabecular, papillary, and single-file arrays. The tumors showed positivity to cytokeratins (Cks) 7 and 8 and vimentin, variable expression for Ck 14, and a negative reaction to Cks 13 and 19 and muscle-specific actin. PLGA is a tumor of the salivary gland that must be distinguished from other neoplasms for therapeutic and prognostic considerations, and the panel of antibodies employed in this study was effective for its diagnosis.

Human papillomavirus and Epstein-Barr virus infection, p53 expression, and cellular proliferation in laryngeal carcinoma

Laryngeal carcinomas are aggressive neoplasms with controversial association with the human papillomavirus (HPV) and Epstein-Barr virus (EBV). So far, the impairment of p53 protein function and its impact on cellular proliferation has not been studied adequately in these tumors. In this work, molecular biologic techniques were used to assess the frequency of HPV and EBV in 110 squamous cell carcinomas of the larynx. In addition, accumulation of p53 and Ki-67 cell proliferation antigen expression in malignant cells was assessed by immunohistochemical analysis. High-grade HPV was found in 37.3% of cases, and none had demonstrable EBV infection. Accumulation of p53 was found in 78.2% of the cases, and it was related to a high Ki-67 labeling index and higher histologic grade. The results demonstrate association of HPV with more than one third of laryngeal carcinomas studied, mainly glottic tumors. Tumors with increased cell proliferation were more frequently high grade, with p53 accumulation and lymph node metastasis. © American Society for Clinical Pathology.

Myxopapillary ependymoma of the posterior mediastinum

A left paravertebral mass discovered incidentally on routine examination in a 39-year-old woman is described. Computerized tomography studies revealed a 7 × 6 cm, well circumscribed, noncalcified soft tissue mass with lobular borders abutting the left inferior pulmonary vein and descending aorta. It was not possible to determine the exact anatomic location of the mass based on the imaging studies as both peripheral lung tumors and posterior mediastinal lesions may exhibit the imaging findings described here. At thoracotomy, the mass was seen to be well circumscribed, focally attached to the pleura but without involvement of lung parenchyma, and situated in the left posterior mediastinum. On histological examination, the lesion showed the classical features of myxopapillary ependymoma. Immunohistochemical studies confirmed this impression by demonstrating strong positivity of the tumor cells for S-100 protein, glial fibrillary acidic protein, and CD99 and negative staining with other differentiation markers. A review of the literature with a discussion of the histologic and radiologic differential diagnosis of these lesions is presented. © 2006 Elsevier Inc. All rights reserved.

In situ expression of mononuclear cell markers and interleukin-2 receptor in renal allograft biopsies of acute rejection and borderline cases

The correct diagnosis of renal allograft rejection may be difficult using only clinical and/or histopathological criteria. Immunological assays should be considered in order to evaluate the phenotype of inflammatory infiltrate in renal allograft biopsies. Immunohistochemical studies were performed to detect mononuclear cells, CD4 and CD8 T lymphocytes, B lymphocytes, macrophages, null cells, and positive cells for interleukin-2 receptors. A total of 41 allograft biopsies classified into three groups were studied: acute cellular rejection (28 biopsies/22 patients), borderline (7 biopsies/5 patients) and control (6 biopsies/6 patients). In the rejection group (RG), increased cellularity was found mainly at the tubulo-interstitial level. Expression of CD8 positive cells was higher in RG when compared to borderline (BG) and control (CG) groups, respectively (0.9 vs. 0.0 vs. 0.35 cells/mm2; p < 0.001). Expression of macrophages was not statistically significant among the three groups (RG = 0.6 vs. BG = 0.2 vs. CG = 0.0 cells/mm2; p < 0.02). In the BG, CD4 + cells predominated (BG = 0.2 vs. RG = 0.05 vs. CG = 0.0 cells/mm2; p < 0.05). Clinically these patients were treated as cases of acute rejection. The numbers and different types of infiltrating cells did not correlate with patient's clinical outcome. Copyright © Informa Healthcare.

Intraosseous schwannoma mimicking a periapical lesion on the adjacent tooth: Case report

Aim: To present an additional case of intraosseous schawannoma involving the apical area in the mandibular alveolar bone mimicking an inflammatory periapical lesion. Summary: This article describes a case of schwannoma periapically located mimicking an inflammatory periapical lesion in the mandible of a 34-year-old female. Diagnostic and therapeutic problems can occur when this lesion is misinterpreted as being endodontic in origin. The diagnosis, radiograph, immunohistochemical aspects and treatment are also discussed. Key learning points: • Intraosseous schwannoma is a rare unilocular radiolucency that when located periapically could be misdiagnosed as an endodontic lesion and result in unnecessary root canal treatment. • The vitality of the pulp is an important test to exclude lesions of inflammatory origin. • Histological examination is important to establish the diagnosis of lesions in the periradicular region. © 2007 International Endodontic Journal.

Tissue inhibitor of metalloproteinase-2 (TIMP-2) location in the ventral, lateral, dorsal and anterior lobes of rat prostate by immunohistochemistry

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a major role in extracellular matrix component degradation in several normal and abnormal tissue situations; they are also found in human seminal plasma. MMPs have been found in rat prostate secretions and are nearly lobe specific in expression pattern. The aim of this study was to evaluate whether TIMP-2, like other semen components, is expressed differently from different rat prostatic lobes. Immunohistochemical staining was performed in both young and adult rat ventral (VP), lateral (LP), dorsal (DP), and anterior (AP) prostatic lobes and confirmed by western blotting. TIMP-2 expression was found in the epithelial cells in the following sequence: LP > AP > DP > VP, in both young and adult rats. In this study, 100% of adult LP presented histological signs of prostatitis, where TIMP-2 immunostaining was positive in normal epithelium even with intraluminal neutrophils, but was reduced or absent in the epithelium with intraepithelial leukocytes or with periductal stroma disorganization associated with mononuclear cell infiltration. However, TIMP-2 expression in LP was not induced by prostatitis, since younger rat LPs were also strongly TIMP-2 positive. The distal and intermediate VP regions were TIMP-2 negative, but the proximal regions were strongly stained. Western blotting results confirmed the high TIMP-2 expression in the LP lobe. Thus, TIMP-2 is expressed differently between the prostatic lobes and is another nearly lobe-specific protein, which plays a role in the regulation of MMP activity in seminal plasma and glandular homeostasis. TIMP-2 is also another regional ductal variation of VP. Further studies should address whether TIMP-2 expression is related to the highest incidence of rat LP prostatitis and adenocarcinoma. © 2006 International Federation for Cell Biology.

Toxoplasma gondii in semen of experimentally infected swine

Eight reproductive boars were divided into three groups and inoculated with Toxoplasma gondii [GI (n=3) 1.5×104 oocysts strain P; GII (n=3) 1.0×106 tachyzoites strain RH; and GIII (n=2) non-inoculated control]. Clinical, hematological, parasitemia and serological tests and studies of the parasite in the semen through bioassay and PCR, and in reproductive organs (Bioassay and immunohistochemical analyses) were conducted to evaluate the toxoplasmic infection. Blood and semen were collected on day -2, -1, 1, 3, 5, 7, 9, 11, 14 and weekly up to 84 days post-inoculation (DPI). No clinical or hematimetric alteration was observed in the boars. Parasitemia was detected in one boar inoculated with oocysts at the 7th DPI and in another boar infected with tachyzoites (GII) at the 3rd and 49 th DPI. Serological tests revealed antibodies against T. gondii in animals inoculated with oocysts or tachyzoites at the 7th DPI with dilutions of 1:256 and 1:64, which reached peaks of 1:4096 at day 11 and 9, respectively. The bioassays revealed the presence of the parasite in semen samples of a boar inoculated with oocysts (GI) at 3, 49 and 56 DPI and from two boars infected with tachyzoites (GII), one animal at 5 and two animals at 49 days DPI. Mice inoculated with semen from the control group (GIII) remained serologically negative. PCR analysis showed T. gondii DNA in the semen of Boar 1 and Boar 3 inoculated with tachyzoites and oocysts, respectively. The immunohistochemical tests showed T. gondii in the reproductive organs of Boar 1 and Boar 2, inoculated with tachyzoites and oocysts, respectively. These findings suggest the possible occurrence of venereal transmission of T. gondii in swine.

Apoptosis in different gastric lesions and gastric cancer: Relationship with Helicobacter pylori, overexpression of p53 and aneuploidy

Apoptosis has an essential function in maintaining the integrity of the gastrointestinal mucosa. Its deregulation is associated with the occurrence of lesions such as in atrophic gastritis, peptic ulcers, intestinal metaplasia, and stomach tumorigenesis. Thus, the aim of the present study was to investigate the frequency of apoptotic cells (apoptotic index, AI) by using two different immunohistochemical techniques, TUNEL and anti-activated caspase-3 antibody (CPP32), in gastric dyspepsia [chronic gastritis (CG, N = 34), chronic atrophic gastritis (CAG, N = 11), gastric ulcer (GU, N = 17), and intestinal metaplasia (IM, N = 15)], normal gastric mucosae (NM, N = 8), and gastric adenocarcinoma (GC, N = 12). The relationship was investigated between the AI and Helicobacter pylori infection, diagnosed by PCR, overexpression of p53 protein determined by immunohistochemistry, and aneuploidy by fluorescence in situ hybridization, as performed by our laboratory in previous studies. No significant differences were observed in AI between the different groups, whether by the TUNEL technique (F = 1.60; P = 0.1670) or by CPP32 antibody (F = 1.70; P = 0.1420). Nonetheless, CAG and CG groups had AI statistically higher than those of normal mucosae. These two groups (CAG and CG) also showed a higher frequency of apoptosis-positive cases (TUNEL+ or CPP32+). Generally, there was no correlation between the AI detected by the TUNEL and CPP32 techniques in the groups studied, except in the GC group (r = 0.70). Moreover, there was no significant association between apoptosis and H. pylori infection, overexpression of p53 protein and aneuploidy, but the H. pylori-positive cases only of GU (P = 0.0233) and IM (P = 0.0253) groups displayed a statistically higher AI compared to H. pylori-negative NM, when the CPP32 antibody technique was used. Thus, CG and CAG have increased apoptosis, which may occur independent of an association with H. pylori infection, aneuploidy and overexpression of p53 protein. ©FUNPEC-RP.

Immunohistochemistry assay to detect Turkey coronavirus (TCoV) from experimentally infected poults

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Descripción inmunohistoquímica de la encefalitis en bovinos brasileños naturalmente infectados con el herpesvirus bovino tipo 5 (HVB-5)

Twelve cases of viral meningoencephalitis in Brazilian cattle were submitted to immunohistochemical analysis for inflammatory response description. All the cases showed severe neurological signs followed by death. Mild to moderate histological inflammatory changes in the brain and cerebellum characterized the neurological infection showing meningitis, mononuclear perivascular cuffing, gliosis, haemorrhage, and macrophages (gitter cells) accompanying great areas of malacia. None of the cases showed intranuclear inclusion bodies. However, in five of them it was possible to isolate the BoHV-5. In order to collect data to allow the description of the inflammatory response in these cases, brain samples from all of the cases were analyzed by immunohistochemistry using polyclonal antibodies against CD3 to detect T cells, and against GFAP to detect astrocytes. On the other hand, monoclonal antibodies were used against BLA to detect B cells and, against MAC 387 to detect macrophages. The results indicate different degrees of prominent astrocytic response, and at the same time, T lymphocytes constituted a high percentage of the mononuclear cells which characterized the inflammatory response.

Localization of myosin-Va in subpopulations of cells in rat endocrine organs

Myosin-Va is a Ca 2+/calmodulin-regulated unconventional myosin involved in the transport of vesicles, membranous organelles, and macromolecular complexes composed of proteins and mRNA. The cellular localization of myosin-Va has been described in great detail in several vertebrate cell types, including neurons, melanocytes, lymphocytes, auditory tissues, and a number of cultured cells. Here, we provide an immunohistochemical view of the tissue distribution of myosin-Va in the major endocrine organs. Myosin-Va is highly expressed in the pineal and pituitary glands and in specific cell populations of other endocrine glands, especially the parafollicular cells of the thyroid, the principal cells of the parathyroid, the islets of Langerhans of the pancreas, the chromaffin cells of the adrenal medulla, and a subpopulation of interstitial testicular cells. Weak to moderate staining has been detected in steroidogenic cells of the adrenal cortex, ovary, and Leydig cells. Myosin-Va has also been localized to non-endocrine cells, such as the germ cells of the seminiferous epithelium and maturing oocytes and in the intercalated ducts of the exocrine pancreas. These data provide the first systematic description of myosin-Va localization in the major endocrine organs of rat. © 2008 Springer-Verlag.

Desmoplastic small round cell tumor of the kidney mimicking wilms tumor: A case report and review of the literature

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive, malignant neoplasm usually present with the widespread abdominal serosal involvement and affects mainly adolescents and young adults. When presenting within visceral organs, as kidney, the diagnosis of DSRCT imposes significant difficulties. We present a case of primary DSRCT of the kidney in a 10-year-old boy mimicking clinically and pathologically Wilms tumor. The tumor showed morphologic and immunohistochemical features of DSRCT and the presence of the Ewing sarcoma and Wilm tumor 1 fusion transcripts resulting from the t(11;22) (p13;q12) reciprocal translocation. DSRCT should be considered in the differential diagnosis of Wilm tumor and other small blue-round cell tumors of the kidney. © 2009 by Lippincott Williams & Wilkins.

Prostatic stromal cells of old gerbils respond to steroidal blockades creating a microenvironment similar to reactive stroma

The present study examined the changes in prostatic stroma of old gerbils (18 months) submitted to orchiectomy associated or not with steroidal blockades. Animals were divided into six groups, all surgically castrated except the control group composed of intact animals. The other two controls were formed by castrated animals, one that received and one that did not receive the drug vehicle. In the experimental groups, doses of flutamide (10 mg/kg/day) and/or tamoxifen (1 mg/kg/48 h) were applied for 1, 3, 7 and 30 days post-castration. The methodologies involved were: morphological (HE, Gömöri reticulin, Picrosirius-hematoxylin), immunohistochemical (tenascin, type IV collagen) and ultrastructural analyses. Gradually, the epithelial compartment was significantly exceeded in volume by the stromal compartment, characterizing regression but not atrophy of the gland. The smooth muscle cell frequency increased significantly after 30 days and participated effectively in the stromal increase. Large collagen I and tenascin deposits in the subepithelial region were a hallmark of prostatic acini in the experimental groups up to 7 days, while in the 30-day group these elements practically disappear. Fibroblasts with reactive aspect, changes in basement membrane structure and maintenance and/or increase of blood vessels were also associated with treatments. These results showed, in part, the sensitivity of stromal components to suppressed hormones and favored the creation of a differentiated glandular microenvironment. Therefore, the data suggest the importance of considering aging when analyzing aspects of prostatic regression between rodents and humans after hormonal ablation. © 2011 Elsevier Masson SAS. All rights reserved.

Renal cell carcinoma with cutaneous metastasis in a dog

The present report describes the occurrence of skin metastasis in a dog with primary renal carcinoma. The clinical findings included progressive weight loss, inappetence, palpable abdominal mass and cutaneous nodules. The histopathological examination was carried out after unilateral nephrectomy and was confirmed by immunohistochemistry. The immunohistochemical and histopathological findings characterized this case as renal cell carcinoma with skin metastasis.

MMP-2 and MMP-9 localization and activity in the female prostate during estrous cycle

The gerbil female prostate undergoes morphological and physiological changes resulting from hormonal fluctuations that occur during the reproductive cycle. These repetitive cycles of glandular growth and regression are followed by an extensive reconstruction and remodeling of prostate stroma throughout the reproductive life of the female gerbil. The objective of this study was to evaluate the effect that the hormonal fluctuations of the reproductive cycle have on the stromal remodeling and the expression and activity of matrix metalloproteinases MMP-2 and -9 in the adult female gerbil prostate. For this, serological, ultrastructural, immunohistochemical and biochemical methods were employed. The results showed that the major stromal alteration coincide with the peak of estradiol, which occurs in estrus, and with the peak of progesterone, occurring during diestrus II. MMP-2 and -9 presented a similar pattern of expression and activity during estrous cycle. The estrus was the phase of greater expression and activity of MMP-2 and -9. On the other hand, in DI and DII, the tissue expression and activity of MMP-2 and -9 was very weak. These results are important since they suggest the involvement of estradiol and progesterone in regulating the expression and activity of MMP-2 and -9 in adult gerbil female prostate. © 2011 Elsevier Inc.