The diverse histological features in malignant peripheral nerve sheath tumours (MPNSTs) associated with NF-1 were investigated by immunohistochemical and electron microscopic analysis. Our study is focused on the differentiation of the tumour cells in the heterogeneous components.Twenty-three cases were classified as conventional type, epithelioid type, anaplastic type, and heterogeneous type, and divided into three groups by the presence of S100 protein (S100)-positive cells in each tumour; Group A was defined as having >50% S100+ cells, Group B as having <50%, and Group C as cases with no positive cells. To investigate the differentiation of the tumour cells, the morphology and immunoreactivity for neural or mesenchymal markers among the three groups were compared. For the identification of Schwannian, perineurial, and endoneurial differentiation, markers for S100, EMA and CD34 were used, respectively. In three tumours of the Group A type, there were no cases showing differentiation towards perineurial or endoneurial cells, or formation of heterogeneous components. In nine tumours of the Group B type, one tumour expressed EMA and CD34, suggesting probable perineurial and/or endoneurial differentiation. One tumour showed rhabdomyoblastic differentiation. Three tumours showed cartilaginous or osteogenic differentiation, and one of the three also showed a focal vascular differentiation. The surrounding areas of the heterogeneous components were composed of mixed S100+ cells and S100- cells. S100- cells in the areas were positive for CD34 in one case. In 11 tumours of Group C type, one tumour expressed EMA and CD34 suggesting perineurial and/or endoneurial cell differentiation. Three tumours showed rhabdomyoblastic differentiation. The tumour cells around the heterogeneous components in the three cases were negative for EMA and CD34.Our results suggest that tumour cells differentiating to Schwann cells are not the only component of MPNSTs. Furthermore, tumour cells other than Schwann cells are largely related to the formation of the heterogeneous components in MPNSTs associated with NF-1.
A case of malignant mixed mullerian tumor of the ovary in a 57 year old woman is reported along with the results of an immunohistochemical study. The tumor, measuring 16·10·9cm, was composed predominantly of adenocarcinoma with a smaller amount of anaplastic carcinoma as an epithelial component and chondrosarcoma, liposarcoma, fibrosarcoma and rhabdomyoblasts as mesenchymal elements. Immunohistochemistry using paraffin sections demonstrated cytokeratin (CK) and epithelial membrane antigen (EMA), generally regarded as epithelial markers, not only in the epithelial component but also in chondrosarcoma cells. Vimentin and desmin, generally regarded as mesenchymal markers, were exhibited partly in carcinoma cells as well as in mesenchymal elements. Positive staining for S 100 protein was obtained not only in chondrosarcoma and liposarcoma cells, but also partly in adenocarcinoma cells. This intricate immunohistochemical picture reflected the histologic findings. It is noteworthy that both carcinoma cells and chondrosarcoma cells demonstrated simultaneous expression of CK, EMA, vimentin, desmin and S 100 protein. This somewhat unusual antigen expression by tumor cells may indicate a change in the nature of tumor cells due to microenvironmental factors. Acta Pathol Jpn 40: 845 850, 1990.
A case of small cell (oat cell) carcinoma, which represents both the most dlstlnctlve and the least common type of mast carcinoma wtth neuroendocrine dlfterentiation and usually shows the most aggressive behavior, is described. Radlcal mastectomy was performed on a Wyearold female for a 10 cm tumor located in the outer part of the right breast with cutaneous ulceration Microscoplcally, the tumor predominantly consisted of a diffuse proliteration of small, round to ovoid cells with hyperchromatlc nuclei and ill‐defined, scant cytoplasm that was reminiscent of oat cell carclnoma of the lung. There were foci of invasive ductal carcinoma and ductal carcinoma in situ . Small cell carcinoma areas constituted approximately 90% of the neoplasm. The patlent had axlllary lymph node metastasis. The small tumor cells were argyrophlllc and positive for CAM5.2, carclnoembryonic antigen, neuron‐specific enolase, Leu‐7, chromogranln A and synaptophysin. Flow cytometric analysis showed an aneuplold DNA content. The patient was alive and well without disease 4 years after surgery. Small cell carcinomas of the breast may exhibkt a spectrum of malignancy that is comparable to similar tumors at better known primary sites.
Clear cell chondrosarcoma is one of the extremely rare chondrosarcomas. The pathogenesis and the molecular genetic events, which contribute to the development of clear cell chondrosarcoma, are not well elucidated, due in part to the lack of sufficient tumor tissue available. To characterize the involvement of the p53 gene abnormality in this disease, we analyzed expression and sequence alteration of p53 by immunohistochemical analysis of the protein expression and quantitative DNA/PCR and PCR-SSCP assays of the gene in 28 paraffin-embedded tissue specimens. Immunohistochemical analysis demonstrated that 7 (25%) showed patchy positive nuclear staining for p53 and 5 (18%) showed diffuse positive nuclear staining patterns. Sixteen (57%) were negative for p53 immunostaining. Quantitative DNA/PCR analysis revealed that none of the cases we studied showed significantly reduced levels of p53 amplification (<0.50), strongly suggesting an allelic deletion of the p53 gene. In contrast, however, DNA/PCR-SSCP analysis failed to detect any types of mutations resulting in amino acid substitution within exons 5-9 regions of the gene. Taken together, our data suggest that genetic alteration of p53 is a relatively rare event in clear cell chondrosarcomas but a substantial fraction of this type of tumors carries abnormal overexpression of p53, which might result from an as yet unidentified mechanism(s).
The triplex polymerase chain reaction (PCR) and high performance liquid chromatography (HPLC) techniques were used to examine the state of amplification of the c-myc gene in gastric carcinomas. Sequences from the c-myc gene and from the two control genes were coamplified by PCR. The coamplified PCR products were separated and quantified by HPLC and the copy numbers of the c-myc gene were calculated by comparing the peak areas generated by PCR products. Increased copy numbers of the c-myc gene were found in 2 of 5 patients.
The histogenesis of myofibroblastoma of the breast remains unknown.Two cases of myofibroblastoma of the female breast were analyzed using light microscopy and immunohistochemistry.The tumors were well circumscribed and predominantly composed of bland bipolar spindle cells and interspersed bands of hyalinized collagen. Additionally, one tumor contained a cartilaginous island, and the other contained a well-defined small nodule that consisted of fascicular arrangements of mitotically inactive atypical cells, simulating atypical leiomyoma. Both lesions contained a fatty element. Immunohistochemically, spindle tumor cells expressed desmin, alpha-smooth muscle actin, muscle actin, and CD34. The atypical cells were strongly and diffusely positive for all these markers. Both tumors were DNA diploid and had a moderate S-phase fraction. The patients have no evidence of disease 4 and 18 months after simple excision.Myofibroblastoma of the breast may be a benign mesenchymal neoplasm capable of diverse lines of differentiation.
