The histomorphologic features, immunohistochemical reactivity, and DNA content of four cases of a rare tubular variant of seminoma are presented. These neoplasms were characterized by a predominantly ...tubular architectural pattern that resembled yolk sac tumor, embryonal carcinoma, and sex cord-stromal tumors. The patients' ages were 15, 24, 27, and 44 years. On initial examination, three patients had painless testicular enlargement, and one had a large retroperitoneal mass and a clinically occult primary testicular tumor. The size of the tumors ranged from 1.7 to 6.0 (mean, 4.0) cm. Microscopically, the tumor cells had a tubular or tubulopapillary pattern that consisted of a single layer of cells, often in a back-to-back arrangement with intervening fibrovascular septa. Areas of classic seminoma were present in all cases. Scattered syncytiotrophoblastic giant cells were seen in two tumors. The tumor cells of both the classic and the tubular components of the seminomas were diffusely positive for placental alkaline phosphatase but were negative for cytokeratin and alpha-fetoprotein. DNA flow-cytometric analysis demonstrated abnormal stemlines with hypotetraploid DNA and a mean DNA index of 1.7 in both the classic and the tubular components. The presence of concurrent areas of classic seminoma, similar cytologic features in the tubular and classic seminoma areas, and the identical immunohistochemical and DNA flow-cytometric findings indicate that tubular seminoma is a histologic variant of seminoma. Although the behavior of the tubular variant appeared not to differ from that of classic seminoma in our small series, its recognition is important in the differential diagnosis and management of testicular masses.
Angiomyolipoma has a unique immunophenotype with co-expression of muscle-specific actin and melanocytic markers such as HMB-45 and Melan-A. The most recently developed melanocytic markers, ...microphthalmia transcription factor and tyrosinase, have not been studied in the diagnosis of angiomyolipoma. We tested 29 renal angiomyolipomas (21 classic histology, 4 epithelioid variants, 2 lipomatous variants, and 2 leiomyomatous variants) with an immunohistochemical panel, including microphthalmia transcription factor, tyrosinase, HMB-45, Melan-A, and muscle-specific actin. Results were compared with 15 renal cell carcinomas (9 conventional types, 6 with sarcomatoid change), 2 leiomyosarcomas, 5 liposarcomas, and 1 unclassified high-grade sarcoma. Microphthalmia transcription factor expression was seen in 22 of 29 angiomyolipomas, one renal cell carcinoma, and one well-differentiated liposarcoma (that is, 2 of 23 non-angiomyolipomas; sensitivity 75%, specificity 91%). Tyrosinase expression was seen in 4 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 14%, specificity 100%). HMB-45 was positive in 24 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 83%, specificity 100%). Melan-A was expressed by 25 of 29 angiomyolipomas and 0 of 23 non-angiomyolipomas (sensitivity 86%, specificity 100%). Muscle-specific actin was expressed by 29 of 29 angiomyolipomas and 2 of 23 non-angiomyolipomas (both leiomyosarcomas; sensitivity 100%, specificity 91% 100% excluding leiomyosarcomas). Microphthalmia transcription factor showed the most widespread staining in angiomyolipoma (50% of cases staining more than half of the tumor cells) followed by Melan-A (24% of cases staining more than 50%). Only three cases showed positivity for all four melanocytic markers, while in one case each only microphthalmia transcription factor and Melan-A were positive. We conclude that microphthalmia transcription factor, but not tyrosinase immunostaining, has a sensitivity and specificity that rivals those of the established markers, HMB-45 and Melan-A, in the diagnosis of angiomyolipoma. Our data supports the use of a panel in difficult cases that includes antibodies to microphthalmia transcription factor, either Melan-A or HMB-45, and muscle-specific actin to provide the best mix of high sensitivity, high specificity, nuclear and cytoplasmic immunolocalization, and widespread staining of cells within a given tumor.
The First New Science gives a clear account of Vico's mature philosophy: the belief that certain functions which are necessary for the maintenance of human society and culture, including philosophy, ...also condition them historically. This challenges the traditional view that philosophy can lay claim to an historically independent viewpoint, thus bringing into question the legitimacy of the claims of universal prescriptive political theories as against the de facto political beliefs of particular historical societies. This is the first of Vico's later major books in which he wrote in Italian in order not merely to expound but to demonstrate in practice, his conception of the philosophical importance of etymology. This 2002 Cambridge Texts edition is the first complete English translation of the 1725 text. Accompanied by a glossary, bibliography, chronology of Vico's life and expository introduction, it makes this important work accessible to students for the first time.
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