Perivascular epithelioid cell tumor of the uterus: immunohistochemical, ultrastructural and molecular study

A case of perivascular epithelioid cell tumor of the uterus is reported, occurring in a 32-year-old woman. The tumor (8.0 cm in dimension) showed exophytic growth from the outer half of the myometrium. Histopathologically, the tumor was composed of thick blood vessels and perivascular epithelioid cells. The neoplastic cells were strongly immunoreactive for HMB45 antigen, CD117 (c-kit), vimentin and the progesterone receptor, but completely negative for S-100 protein, smooth muscle actin, desmin, CD34, the estrogen receptor and p16. The Ki-67 labeling index was low (1.25%). Ultrastructurally, the neoplastic cells had numerous premelanosomes with some glycogen deposits. Single-stranded DNA conformational polymorphism of p53 and methylation-specific polymerase chain reaction of p16 revealed negative results. Definite melanosomes on electron microscopic analysis and coexpression of HMB45 antigen and stem cell factor receptor (CD117) may provide the clue to understanding perivascular epithelioid cell tumor because angiomyolipoma also coexpresses HMB45 antigen and CD117.     

Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: A morphologic and immunocytochemical study of 15 cases

Sarcomatoid renal cell carcinoma (SRCC), which accounts for 5% of all renal cell carcinomas (RCC), has a worse prognosis than conventional nonsarcomatoid RCC. making accurate diagnosis important. This study reports on the morphologic and immunocytochemical features of 15 cases of SRCC (9 primary tumors and 6 metastases) diagnosed by fine-needle aspiration (FNA) biopsy. All but three cases showed a dimorphic cell population consisting of varying proportions of a high-grade epithelial component, either clear or granular-cell type and a spindle cell (sarcomatoid) component, of either fibrosarcomatous, malignant fibrous histiocytoma (MFH), or unclassified types. The sarcomatoid component in the biphasic and monophasic tumors stained positively for cytokeratin in 12 of 14 (85%) cases, for vimentin in 10 of 11 (91 %) cases, and for muscle-specific action in 4 of 11 (36%) cases. Of note, the three cases that demonstrated a purely sarcomatoid morphology stained positively for cytokeratin. Unlike in studies performed on surgically resected specimens, neither the proportion of the sarcomatoid component nor the presence of necrosis had prognostic significance, the discrepancy most likely being related to the sampling. We conclude that SRCC, both primary and metastatic, can be accurately diagnosed by FNA when cytologic features are evaluated in conjunction with immunocytochemical findings.     

Identification of Vibrio parahaemolyticus pandemic group-specific DNA sequence by genomic subtraction

A genomic subtraction between a pandemic Vibrio parahaemolyticus and a nonpandemic strain that seemed to be clonally related was performed. A subtractive DNA fragment was identified to be a part of a 16-kbp insertion sequence which was present in almost all pandemic strains but not in nonpandemic strains tested.     

Contribution of peripheral N-methyl-D-aspartate receptors to c-fos expression in the trigeminal spinal nucleus following acute masseteric inflammation

In this study, we examined the contribution of N-methyl-D-aspartate (NMDA) receptors on c-fos expression in the trigeminal brainstem nuclei following acute muscle inflammation. Mustard oil (MO; 20%, 30 microL) injected into the masseter muscle induced extensive peripheral edema and Fos-like immunoreactivity (Fos-LI) in several trigeminal brainstem areas including the subnucleus caudalis of the trigeminal spinal nucleus (Vc), the ventral and dorsal regions of the Vc/subnucleus interpolaris transition zone, and the paratrigeminal nucleus. In order to assess the effect of antagonizing NMDA receptors on MO-induced Fos-LI, rats were pre-treated with two different doses of i.v. MK-801 (0.3 mg/kg, 3 mg/kg), a non-competitive NMDA receptor antagonist, 30 min prior to MO injection. Additional groups of rats received MK-801 (0.3 mg/kg) directly in the masseter muscle or in the biceps muscle 5 min prior to MO injection. A higher dose of i.v. MK-801 (3 mg/kg) and MK-801 given locally into the masseter muscle (0.3 mg/kg) produced a significant reduction in total number of MO-induced Fos-LI. Further analyses revealed that pre-treatment with MK-801 (3 mg/kg i.v.) significantly reduced the Fos-LI all throughout the Vc. Only at the caudal Vc, there was a dose-dependent reduction of MO induced Fos-LI. Pre-treatment with masseteric MK-801 also significantly reduced the Fos-LI in the caudal Vc, with the effect greater than that produced by the same dose of MK-801 given intravenously. These results suggest that peripheral NMDA receptors contribute to nociceptive processing from craniofacial muscles.     

Development of a diagnostic PCR assay targeting the Mn-dependent superoxide dismutase gene (sodA) for identification of Streptococcus gallolyticus

A PCR-based assay to identify Streptococcus gallolyticus has been developed. The assay uses an oligonucleotide primer pair targeting a partial sequence of the manganese-dependent superoxide dismutase gene (sodA). The assay distinguished members of the S. gallolyticus group from other, closely related taxa successfully by yielding a 408-bp specific amplicon.     

Benign tumors and tumor-like lesions of the adult kidney. Part I: Benign renal epithelial neoplasms

The spectrum of renal neoplasms has expanded in recent years. Although most of the work taking place in this field has concerned malignant neoplasms of the kidney, there have been significant improvements in our knowledge of benign renal tumors and tumor-like lesions, especially in renal cell adenoma, renal oncocytoma, and renal angiomyolipoma. Awareness and knowledge of these benign lesions is important because they are often included in the differential diagnoses of malignant tumors, with which they may be confused both clinically and pathologically. The authors review the topic of benign renal neoplasms and tumor-like lesions that occur in adults, emphasizing some of the newly described aspects of these lesions.     

Immunohistochemical analysis of p53 protein expression in benign and malignant skin tumors using a panel of anti-p53 antibodies.

The expression of p53 in a variety of benign and malignant skin lesions has been first assessed in frozen sections and then compared with the results obtained in corresponding paraffin-embedded sections using various immunohistochemical staining methods with a panel of anti-p53 antibodies. Of the 48 benign and malignant skin lesions studied, 46(96%) had corresponding paraffin sections and immunohistochemical results obtained with DO7 on frozen and paraffin sections were concordant in 97%, qualitatively. Using streptavidin-biotin complex method, p53 was identified in 33% of dysplastic squamous lesions, 50% of squamous cell carcinomas (SCCs) and 36% of basal cell carcinomas (BCCs) on frozen section, whereas 25% of dysplastic squamous lesions, 40% of SCCs, and 32% of BCCs showed p53 positivity on paraffin-embedded sections. In frozen sections, the same regions of each specimen exhibited similar topographic patterns of positive immunoreactivity with both monoclonal antibodies, PAb 1801 and DO7. In contrast, immunohistochemical staining with polyclonal antibody, CM-1, gave poor morphologic resolution, although effective in paraffin-embedded sections.     

Ribosome-lamella complexes in a case of transitional cell carcinoma involving the prostate

We report ribosome-lamella complexes (RLC) in cancer cells of transitional cell carcinoma (TCC) of the prostate in a 52-year-old Caucasian man. Histopathologically, cancer cells were proliferated in various-sized nests, mostly associated with central necrosis. Some invaded into the surrounding normal glandular space and the stroma, with occasional lymphatic invasion. Fine structural study of cancer cells revealed that cross-sectioned RLC as well as densely aggregated ribosomes were detected in their cytoplasm, situated close to, but not directly connected with, dilated rough endoplasmic reticulum. These were composed of a concentric alternative arrangement of both lamellae and ribosomes. In the central and surrounding parts of the RLC, ribosomes were observed, revealing a smooth transition to the ribosomal component of RLC in size and shape. The presence of both RLC and dense aggregation of ribosomes close to the rough endoplasmic reticulum suggests that their functions might be related to specific or aberrant protein synthesis under unknown conditions. Although RLC have been often reported in hematopoietic malignancies, their occurrence in the malignant epithelial component has been only reported in a case of pulmonary adenocarcinoma. This is the first report of RLC in TCC in the literature.     

Effects of repeated subculturing and prolonged storage at room temperature of enterohemorrhagic Escherichia coli O157:H7 on pulsed-field gel electrophoresis profiles

Three clinical strains of enterohemorrhagic Escherichia coli O157:H7 which were subcultured repeatedly or stored at room temperature over a 25-week period showed appreciable variations in their pulsed-field gel electrophoresis fragment patterns. The variations could be explained by a couple of spontaneous genetic events at most and thus did not invalidate the genetic lineage of the strains.