A case of osteoclastoma‐like giant cell tumor of the thyroid with 6‐year survival following radiotherapy is reported. This is believed to be the seventh case of this tumor in the literature, and the only one with known long‐term survival. This lesion differs from the usual giant and spindle cell thyroid carcinoma by the fact that its giant cells contain up to 100 or more small, uniform, benign‐appearing nuclei, and are admixed with mononuclear “stromal” cells, the overall histologic appearance resembling that of giant cell tumor of bone. This is probably an anaplastic epithelial tumor, but its histogenesis is not definitively established.

Published reports of “adenoacanthoma” of the endometrium have usually included both those cases in which the squamous elements are histologically benign and those in which they are histologically malignant. In the present report, cases with the former appearance have been classified as adenoacanthoma (or adenocarcinoma with squamous metaplasia), but tumors with malignant‐appearing squamous cells have been grouped separately as mixed adenosquamous carcinoma. Of 148 consecutive cases reviewed, 71 (48.0%) were adenocarcinomas (AC), 44 (29.7%) were adenoacanthomas (AA), 26 (17.6%) were mixed carcinomas (MC), and 7 (4.7%) were clear cell carcinomas. Clinically, there were no major differences among patients with the three predominant tumor types, but there was a tendency toward later menopause and lower gravidity among those women whose tumors contained squamous elements (AA and MC). Despite similar treatment regimens and clinical staging, actuarial 5‐year survival was 56.3% for AC, 82.9% for AA, and 35.3% for MC. Patients with MC also had a higher incidence of persistent tumor after irradiation, deeper penetration of tumor in hysterectomy specimens, and a tendency to earlier recurrences. When the MC pateints were compared with only women with poorly differentiated AC (since the glandular elements were almost always poorly differentiated in MC tumors), these two groups were quite similar in most parameters, including 5‐year survival. Similar comparisons between AA and well‐differentiated AC reveal that, despite similarities in all other respects, the 5‐year survival remains significantly higher in AA (82.9% vs. 60.6%). Thus, it appears that the poorly differentiated (i.e., histologically malignant) squamous elements in MC are a function of poorly differentiated glandular elements and may not significantly worsen an already unfavorable prognosis. The ability of a well‐differentiated carcinoma to form histologically benign squamous elements, on the other hand, seems to improve a prognosis which is already relatively favorable. Tumors formerly indiscriminately classified as adenoacanthoma should now be separated into two distinct groups, and these relationships should be investigated further.

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Four clear cell carcinomas of the vagina are reported; two (from women of 17 and 78 years of age, respectively) were studied with the electron microscope. The younger patient was a product of a pregnancy supported by administration of diethylstilbestrol. Ultrastructurally, both tumors showed glands with short, thick microvilli in the lumina, and cells attached by desmosomes and interdigitating cytoplasmic processes. The cytoplasm was packed with glycogen granules, and also featured many small, uniform mitochondria and "stacked" parallel rows of granular endoplasmic reticulum. These findings are compared with those in ovarian and cervical clear cell carcinomas previously reported, and confirm the identity of the tumors in different sites in the female genital tract. Ultrastructural and other evidence supports a miillerian origin of these tumors. All four tumors have shown an excellent response to radiation therapy.E RECENTLY REPORTED A CASE OF ENDOdermal sinus tumor of the vagina in an infant, and reviewed the world literature pertaining to so-called vaginal "mesonephromas."l I t was clear that, on both clinical and histopathologic grounds, these tumors could be separated into two distinct groups. Endoderma1 sinus tumors (also known as yolk sac carcinomas,l7 "Schiller-type" mes~nephrornas,~~ and "carcinomas of the infant vagina"p4) are predominantly tumors of infancy, are usually found in the posterior vaginal wall or in the fornices, and carry a very poor prognosis, while clear cell carcinomas usually occur in adolescents and mature women, are generally found in the anterior or lateral vaginal wall, and are associated with a relatively satisfactory prognosis. Herbst and scull^'^ have recently presented evidence that this latter tumor is of miillerian derivation, and Herbst et a1. 16 have postulated a relationship between the occurrence of this tumor in adolescents and young women and maternal stilbestrol therapy during the pregnancy at risk. Within the past 3 years, we have diagnosed four vaginal clear cell carcinomas histologically (in women of 22, 78, 17, and 22 years of age, respectively), and have studied material from two patients with the electron microscope. Our ultrastructural observations (the first reported for this tumor) are the basis of the present report. CLINICAL DATAThe pertinent clinical information for our four cases is summarized in Table 1. The mother of one of the three young women stated that she had taken diethylstilbestrol during pregnancy, while the mothers of the other young women denied any such therapy. All four women were obese, but none was diabetic or hypertensive. T w o tumors arose from the posterior vaginal wall and two were anterior. Three were described as polypoid, and three also infiltrated the underlying vaginal wall. All four women were treated by a combination of intravaginal radium and external radiation therapy, although one patient discontinued treatment before it could be completed. Complete tumor regression was noted during the course of treatment in all cases, and th...