Hepatoid yolk sac tumor of the ovary (endodermal sinus tumor with hepatoid differentiation): a light microscopic, ultrastructural and immunohistochemical study of seven cases

Hepatoid variant of yolk sac tumor of the testis

A case of testicular yolk sac tumor (endodermal sinus tumor) consisting predominantly of hepatoid cells is documented. A mass measuring approximately 4 x 3 cm was noted in the left testis of a 64-year-old man. Preoperative examination revealed an elevated serum level of alpha-fetoprotein (5479 ng/mL). Histologically, the lesion was composed predominantly of sheet-like or trabecular proliferation of hepatocyte-like cells with eosinophilic or clear cytoplasm. The tumor cells were immunoreactive for alpha-fetoprotein, antimitochondrial antibody, cytokeratin (AE1/AE3), alpha-1-antichymotrypsin, alpha-1-antitrypsin, albumin, carcinoembryonic antigen and epithelial membrane antigen. It was necessary to distinguish this variant lesion from metastatic hepatocellular carcinoma, embryonal carcinoma and hepatoid carcinoma.

Ovarian yolk sac tumor with virilization during pregnancy: immunohistochemical demonstration of Leydig cells as functioning stroma

A case is reported of yolk sac tumor occurring in the left ovary and complicated by pregnancy. The 22-year-old patient presented at 28 weeks gestation with virilization and elevated serum levels of testosterone and alpha-fetoprotein. The tumor showed the typical features of yolk sac tumor with a mixture of islands of Leydig cells. The accumulations of Leydig cells were well demarcated from the cellular components of the yolk sac tumor and were distributed throughout the tumor, although with predominant localization at the periphery. By immunohistochemistry the Leydig cells were intensely positive for vimentin and negative for cytokeratins, allowing clear distinction from the cell components of the yolk sac tumor, which were positive for cytokeratins and negative for vimentin. Testosterone was also identified in the cytoplasm of the Leydig cells. After tumor resection the testosterone and alpha-fetoprotein levels declined simultaneously; this, together with the immunohistochemical demonstration of testosterone, indicates that the Leydig cells were responsible for the endocrine manifestations. Furthermore, antibodies against inhibin alpha-subunit and calretinin could be used to detect the Leydig cells. The present case, a combination of yolk sac tumor and Leydig cells acting as a functioning stroma and causing virilization during pregnancy, is very rare.

Adenocarcinoma of the uterine cervix with choriocarcinomatous and hepatoid differentiation: report of a case

A case of adenocarcinoma of the uterine cervix that showed choriocarcinomatous and hepatoid differentiation was encountered in a 65-year-old woman. She presented with genital bleeding and had multiple metastatic nodules in the lungs. At operation, a large, hemorrhagic, and necrotic tumor was found in the uterine cervix. The major portion of the tumor consisted of typical choriocarcinoma admixed with minor areas of hepatoid carcinoma and endocervical adenocarcinoma. Human chorionic gonadotropin and alpha-fetoprotein were detected in tumor cells in the choriocarcinomatous and hepatoid areas, respectively. The patient died of pulmonary metastasis 4 months after the operation. The coexistence of choriocarcinomatous and hepatoid carcinoma in an endocervical adenocarcinoma has not been reported previously. Both heterotopic components were probably derived from aberrant differentiation (or neometaplasia) of the somatic epithelial cells of the endocervical adenocarcinoma.

The role of electron microscopy in gynecological pathology

Electron microscopy, as a diagnostic method, has been available to pathologists for about half a century. Its use in studying normal and abnormal gynecological tissues has been applied during the second half of that period, and many works on specific female genital topics have been published. Several of those subjects are worthy of citing in a review of the present type. Clear cell carcinoma has been revealed to be a mullerian, rather than a wolffian, derivative. Small cell carcinoma of the ovary with hypercalcemia is comprised of cells shown ultrastructurally to be epithelial, but unlike surface epithelial cells, germ cells, sex-cord cells, or neuroendocrine cells. Further electron microscopic studies provided evidence that these small cell tumors are not adult diffuse granulosa cell tumors, endometrioid stromal tumors, primitive neuroectodermal tumors, or numerous other primary and metastatic small cell tumors. Electron microscopy has also been useful in determining that not all signet-ring cell tumors of the ovary are stromal, and that there are multiple types of signet-ring (vacuolated) cells in ovarian tumors. Smooth muscle tumors are well known to have multiple light microscopic phenotypes, and electron microscopy has proven to be diagnostic in many of these cases, especially in epithelioid smooth muscle tumors. A number of other gynecological neoplasms that have been better defined by electron microscopic studies are described. Embryology and histogenesis are other areas of study in which electron microscopy has been a major contributor of new information at the subcellular level. Electron microscopy, solely or in harmony with clinical information, light microscopy, and immunohistochemistry, has been and is a valuable tool for the pathologist in the study of histogenesis and accurate diagnosis of gynecological lesions.

Adult granulosa cell tumor of the ovary with foci of hepatic cell differentiation: a report of four cases and comparison with two cases of granulosa cell tumor with Leydig cells

We report four ovarian granulosa cell tumors of the adult type containing small foci of hepatic cell differentiation. The patients ranged in age from 35 to 54 years and had unilateral adnexal masses. The smallest tumor was 4.0 cm in diameter and the largest, 11.0 cm in diameter. Three tumors were solid and cystic, and one was cystic. Microscopic examination showed typical patterns of adult granulosa cell tumor, with the additional finding of scattered islands of large cells with abundant eosinophilic, slightly granular cytoplasm and central round nuclei containing single prominent nucleoli. Bile pigment was detected in canaliculi between some of the large cells in three tumors. The hepatic cells were positive immunohistochemically for cytokeratin (CAM 5.2) and epithelial membrane antigen in two cases and alpha-fetoprotein in one of two cases. Carcinoembryonic antigen was stained in a canalicular pattern in two cases. Staining for vimentin and alpha-inhibin was negative. Liver cells in granulosa cell tumors must be differentiated from Leydig cells, which are found very rarely in granulosa cell tumors, and luteinized stromal and granulosa cells, which are present more commonly in these tumors; all three of the latter cell types are positive for alpha-inhibin.

alpha-Fetoprotein-producing adenocarcinoma of the pancreas presenting focal hepatoid differentiation

We report a rare case of pancreatic carcinoma producing alpha-fetoprotein (AFP), showing focal hepatoid differentiation in metastatic lymph nodes. A 65-yr-old female was admitted because of abdominal pain. The serum AFP was measured at 16,170 ng/mL. Radiological examinations revealed a mass measuring 6 cm in diameter in the body and tail of the pancreas. A right supraclavicular lymphadenopathy was found and biopsied. Light microscopy showed a tumor consisting of a portion of a hepatoid area and well-differentiated adenocarcinoma, which was suggestive of a hepatoid adenocarcinoma. Immunohistochemical analysis showed that the tumor cells expressed AFP, alpha 1-antitrypsin (AT) and albumin. Although the pathological diagnosis of the primary pancreatic tumor was not obtained, this appears to be the first case of hepatoid adenocarcinoma of the pancreas.

Hepatocytic differentiation in retiform Sertoli-Leydig cell tumors: distinguishing a heterologous element from Leydig cells

Sertoli-Leydig cell tumors (SLCT) of the ovary are rare sex cord-stromal neoplasms. A minority of SLCT are characterized by a pattern resembling that of the rete ovarii and frequently have a range of homologous and heterologous tissues. Approximately 20 cases of SLCT have been reported to have elevation of serum alpha-fetoprotein (AFP) levels, or tissue immunoreactivity for AFP, a protein usually associated with germ cell neoplasms, especially yolk sac tumor. We identified hepatocytic differentiation in five cases of retiform SLCT (RSLCT), and confirmed immunohistochemically that these cells are hepatocytes rather than Leydig cells. Hepatocytes are positive for keratins (AE1/3 and Cam 5.2), AFP, and ferritin, negative for vimentin, and show weak to moderate staining for inhibin. Leydig cells are negative for keratins, positive for vimentin, and intensely positive for inhibin. Immunohistochemistry is needed to distinguish hepatocytic differentiation from Leydig cells with certainty. Including the cases in this report, hepatocytic differentiation has been associated with a retiform pattern in SLCT in 14 of 25 cases (56%). The association of these two patterns appears to be characteristic of a relatively primitive sex cord-stromal neoplasm.

Ovarian hepatoid yolk sac tumours: morphological, immunohistochemical and ultrastructural features

AIM

The clinicopathological, immunohistochemical and ultrastructural features of two ovarian hepatoid yolk sac tumours (H-YST) from our files are reviewed.

METHODS AND RESULTS

Using avidin-biotin-peroxidase complex technique, the immunoprofile of these tumours was compared to that of a classic yolk sac tumour and to that previously reported for hepatocellular carcinomas. The clinicopathological and morphological features of our cases are similar to the seven previously reported ovarian cases. This rare germ cell tumour occurs in young females (mean age = 17.6 years) and presents most commonly with abdominal pain and a large ovarian mass (average size = 140 mm). Histologically, the tumours display a striking resemblance to hepatocellular carcinoma. The absence of an associated typical pattern of yolk sac tumour or other germ cell neoplasm may make it difficult to recognize the germ cell origin of this lesion. Our cases demonstrated positive staining for alpha-fetoprotein and alpha-1-antitrypsin. In addition, there was immunoreactivity with polyclonal carcinoembryonic antigen (CEA) antiserum in a canalicular pattern, focal staining for inhibin, oestrogen and progesterone receptors and absence of immunoreactivity for CK7 that contrasts with the immunophenotype of a usual yolk sac tumour.

CONCLUSIONS

Ovarian H-YST and hepatocellular carcinoma share a similar immunoprofile. Ovarian H-YST is a highly aggressive tumour, most patients exhibit recurrence or die of disease within 2 years of diagnosis.

Intracardiac yolk sac tumor in an infant girl

We report about a two and a half year old girl with a primary yolk sac tumor (YST) of the heart, located in the interventricular septum. The girl was admitted to the hospital with a systolic cardiac murmur. Echocardiography revealed a smoothly surfaced tumor which based on the interventricular septum below the aortic valve and filled out more than half of the left ventricular cavity. Diagnosis of a yolk sac tumor was established on a frozen section of a biopsy taken at surgery and confirmed by the examination of the resected material. Excessively elevated serum alpha-fetoprotein (AFP) levels contributed to this diagnosis. Follow up examinations of the patient including computed tomography (CT) of head, thorax and abdomen, did not indicate an extracardiac tumor manifestation. We found no previous report of a primary intracardial yolk sac tumor in the literature.

An autopsy case of hepatoid carcinoma of the ovary with PIVKA-II production: immunohistochemical study and literature review

A case of hepatoid carcinoma of the ovary in a 61-year-old Japanese woman, who showed high serum levels of alpha-fetoprotein and CA125, is reported. Grossly, the left ovarian tumor, which measured 12 x 9 cm, was solid and multinodular. Histologically, the tumor resembled hepatocellular carcinoma by its architectural and cytological features. Liver cell differentiation was indicated functionally by the immunohistochemical detection of alpha-fetoprotein and protein induced by vitamin K absence or antagonist II (PIVKA-II) and by positive bile production, and the hepatocellular differentiation was structurally in accord with keratin 7, 8 and 18 expression. CA125 expression, commonly present in ovarian surface epithelial carcinomas, suggested that this neoplasm originated from ovarian common epithelial cells. There are only nine such cases in the literature. A review of these cases reveals that hepatoid carcinoma of the ovary occurs exclusively in postmenopausal women (mean age, 62.7 years) and that the prognosis is poor.

Yolk sac tumor with a unique uniform hepatoid pattern histology

BACKGROUND

Yolk sac tumors (YST) exhibit several different histological subtypes and the mechanisms of cellular differentiation and prognosis of each subtype remain unknown.

RESULTS

We report two infants with sacrococcygeal YST; one represented a typical histological subtype and the other showed a hepatoid subtype with uniform histology. The isoform of alpha-fetoprotein (AFP) in the patient with the hepatoid pattern was examined by lectin-affinity immunoelectrophoresis and represented as a YST, but not hepatocellular, subtype. The patient with typical YST responded well to VAB-6 combination chemotherapy. However, this regimen was only partially effective to the patient with the pure hepatoid histological subtype, and an etoposide with ifosfamide and cisplatin (VIP) regimen as a salvage chemotherapy combined with complete tumor resection was useful to achieve complete remission (CR). Both of the patients have been in CR for more than four years.

Immature teratomas in children: pathologic considerations: a report from the combined Pediatric Oncology Group/Children's Cancer Group

Pediatric germ cell tumors (n = 135) with a major component of immature teratoma (IT) registered on Pediatric Oncology Group/Children's Cancer Group treatment protocols from 1990 to 1995 were reviewed. Sixty cases were pure IT with no malignant component and 75 were mixed tumors with a major component of IT. Foci of yolk sac tumor (YST) were present in all 75 mixed tumors; additional malignant components were present in 15. The IT component was as follows: 47% grade 3, 29% grade 2, 24% grade 1. There were no significant correlations between tumor grade and patient age by specific subsets or overall (all p > 0.10). Significant correlations were detected between stage and the presence of foci of YST (p = 0.0145) and grade and the presence of foci of YST (p < 0.001). Serum alpha-fetoprotein concentrations were elevated at diagnosis in 96% of ovarian tumors with foci of YST and were mildly elevated (< 60 ng/dL) in only 16% of tumors without YST. Overall 2- to 6-year survival rate was 96% and was related to the presence of YST. Central pathologic review revealed aspects of morphologic diagnosis that were most frequently misinterpreted by contributing pathologists. These included the classification of differentiating tissues as immature and the failure to recognize two well-differentiated patterns of YST (the hepatoid pattern resembling fetal liver and the well-differentiated glandular pattern resembling fetal lung or intestine). Such foci were often overlooked. The authors conclude that the presence of microscopic foci of YST, rather than the grade of IT, per se, is the only valid predictor of recurrence in pediatric IT at any site.

Hepatoid yolk sac tumors of the mediastinum: a clinicopathologic and immunohistochemical study of four cases

Four cases of primary hepatoid yolk sac tumors of the anterior mediastinum are described. The patients were all men between the ages of 26 and 40 years (median 33). Clinically, they all presented with a history of shortness of breath and chest pain of several weeks' duration. None of the patients had a history of germ cell tumor elsewhere or evidence of any hepatic abnormality. Grossly, all the tumors were described as large mediastinal masses that impinged on adjacent structures. Histologically, they were characterized by sheets of medium-sized, round to polygonal neoplastic cells with moderate amounts of eosinophilic cytoplasm and round to oval nuclei with prominent nucleoli. The cellular proliferation was homogeneous and displayed moderate cellular atypia and scattered mitotic activity. All the tumors showed focally the presence of more conventional areas of yolk sac tumor, with islands of tumor cells showing a reticular pattern of growth admixed with scattered intra- and extracellular hyaline globules and occasional Schiller-Duval bodies. Immunohistochemical studies showed strong positivity of the tumor cells for alpha-fetoprotein in both components of the lesions. Follow-up information was available in three patients, all of whom developed lung metastases within a year after initial diagnosis. Two of these patients died of tumor within the same period, whereas a third patient has been lost to follow-up. The present cases illustrate an unusual histologic pattern of yolk sac tumor in the mediastinum and highlight the importance of considering this tumor in the differential diagnosis of lesions showing a hepatoid pattern of growth in the mediastinal area.

Yolk sac tumors of the mediastinum with prominent spindle cell features: a clinicopathologic study of three cases

Three cases of primary mediastinal yolk sac tumors with prominent spindle cell features are presented. The patients were three men 24-34 years of age (mean 29). Clinically, two patients presented with symptoms of chest pain and cough; no clinical information was provided for the third patient. Grossly, the tumors were described as large mediastinal masses, with a hemorrhagic and necrotic cut surface. Histologically, the tumors were characterized by a predominantly atypical spindle cell proliferation admixed with areas that showed focally the characteristic reticular growth pattern of yolk sac tumors, with the presence of Schiller-Duval bodies and intra- and extracellular hyaline globules. Immunohistochemical studies performed in one case showed positive staining for keratin and alpha-fetoprotein in both the spindle cell and reticular components of the tumor. Follow-up information was obtained in two patients; they both died of tumor with metastases to the lungs 1 year after initial diagnosis. The present cases expand the spectrum of histopathologic growth patterns that may be observed in yolk sac tumors of the mediastinum and stress the issue of careful sampling and evaluation of mediastinal neoplasms for arriving at the correct diagnosis.

Hepatoid adenocarcinoma of the lung: report of a case of an unusual alpha-fetoprotein-producing lung tumor

We report on a rare tumor of the lung characterized by its morphologic hepatoid features and alpha-fetoprotein production. This unusual neoplasm arose in the left lung of a 36-year-old man in whom clinical and radiologic examinations did not reveal any other tumor. The serum level of alpha-fetoprotein was measured at 6,090 ng/mL and was parallel to the evolution of the tumor. Despite treatment, the patient died 7 months after the diagnosis. The microscopic appearance of the tumor was the same as observed in hepatocarcinoma and hepatoid adenocarcinoma of the ovary or the stomach, with a tubular, papillary, or trabecular pattern. Periodic acid-Schiff-positive hyaline globules were numerous, and tumor cells showed immunohistologic positivity for alpha-fetoprotein and carcinoembryonic antigen. This lung adenocarcinoma was first described by Ishikura et al. in 1990 and was named hepatoid lung adenocarcinoma. Like the rare hepatoid carcinoma of the gallbladder, the pancreas, the ampulla of Vater, the renal pelvis, and the bladder, the exact histogenesis and the prognosis of this type of lung tumor are not yet known.

Combined choriocarcinoma, hepatoid adenocarcinoma, small cell carcinoma and tubular adenocarcinoma in the oesophagus

We describe an oesophageal tumour composed of choriocarcinoma, hepatoid adenocarcinoma, small cell carcinoma and tubular adenocarcinoma. The choriocarcinomatous areas and hepatoid adenocarcinomatous areas contained beta human chorionic gonadotropin-positive cells and alpha fetoprotein-positive cells, respectively. The small cell carcinomatous areas contained cells positive for serotonin or adrenocorticotrophic hormone, while the tubular adenocarcinomatous areas contained cells positive for carcinoembryonic antigen. Non-neoplastic gastric type columnar epithelium was found directly adjoing the tumour at the oral side. This tumour, with its unprecedented histology combination of tissues may have originated in Barrett's oesophagus, although we could not confirm a history of chronic gastro-oesophageal reflux.

A case of ovarian serous adenocarcinoma suggestive of transformation to an AFP-producing tumor during chemotherapy

Ovarian serous adenocarcinoma with AFP production is very rare. A case involving a 66-year-old woman with an elevated serum AFP level without detectable hepatic involvement. AFP-positive cells were seen in the tumor at the second surgery. Fifty-seven percent of serum AFP from the patient bound Con A, whereas 43% did not. Similarly, 54% of the tumor fluid also bound Con A. These suggest that the serum AFP was similar to that of gastrointestinal tumors and yolk-sac tumors.

Endometrioid-like variant of ovarian yolk sac tumor with foci of carcinoid: an ultrastructural study

The endometrioid-like variant of ovarian yolk sac tumor is a rare neoplasm composed partially or completely of glandular tissue resembling endometrioid carcinoma, but identifiable histologically and immunohistochemically as an extraembryonic endodermally differentiated germ cell tumor. Only nine examples of this neoplasm have been published previously, and none was studied by electron microscopy. One of these rare neoplasms, the first documented to have foci of carcinoid, has recently been observed and studied ultrastructurally. Electron microscopic observations showed that the main component of the neoplasm had glandular epithelial cells with nuclear and cytoplasmic features difficult to distinguish from the cells of Müllerian endometrioid and endometrial adenocarcinoma, but a minor component of mucinous adenocarcinoma was confirmed as intestinal by the epithelial cells having characteristic microvilli with filamentous cores and rootlets. In addition, neuroendocrine cells present in the glands and in nests were readily identified ultrastructurally by their dense-core granules. Electron microscopy may be useful in supplementing light microscopic and immunohistochemical examination of this variant of yolk sac tumor.

Coexistence of choriocarcinoma and hepatoid adenocarcinoma in the stomach

The case is presented of a 46 year old woman who had a gastric tumor with components of choriocarcinoma, hepatoid adenocarcinoma and common types of adenocarcinoma. Although two histologic types of tumor producing carcinoplacental or carcinofetal proteins were contained within the tumor, immunohistochemical analyses, especially of placental alkaline phosphatase, clearly showed that each component was present separately within the same tumor. It was only hepatoid adenocarcinoma cells that permeated the lymph and blood vessels. After the recurrence, the serum level of alpha-fetoprotein (AFP) markedly elevated, but that of human chorionic gonadotropic beta-subunit (hCG-beta) was always within normal range. These findings indicate that in the present case the hepatoid adenocarcinoma component was more aggressive in growth than the choriocarcinoma component.

Hepatoid adenocarcinoma in the urinary bladder. Unusual localization of a newly recognized tumor type

A tumor mass resected from the anterior bladder wall of a 68-year-old woman displayed unusual histologic features: sheets of hepatoid cells merging focally with a secondary glandular pattern of adenocarcinoma. Intracytoplasmic hyaline globules and bile production within the solid areas supported the impression of hepatocytic differentiation. Immunoreactivity for alpha-fetoprotein (AFP) and alpha-1-antitrypsin and a striking canalicular immunostaining pattern for carcinoembryonic antigen and epithelial membrane antigen all indicate hepatocellular differentiation within this bladder tumor. This represents a case of a hepatoid adenocarcinoma located in the urinary bladder. The use of the term "hepatoid" in the literature is reviewed and the reported cases are grouped into two distinct categories of tumors: (1) germ cell tumors with focal hepatoid areas and (2) true hepatoid adenocarcinomas that meet histologic and immunohistochemical criteria for hepatocellular differentiation. AFP-producing tumors without any other feature of hepatocellular differentiation should not be considered as hepatoid tumors. This classification of hepatoid tumors is likely to be important in elucidating the histogenesis and clinicopathologic features of these unusual neoplasms.

Prognostic significance of histopathological subtypes in stage I pure yolk sac tumour of the ovary

The correlation between histological subtype [endodermal sinus (ES), polyvesicular vitelline (PV), glandular (G) and hepatoid (H) subtypes] and the prognosis of pure yolk sac tumours (YSTs) of the ovary was investigated. From 1964 to 1989, 35 patients with YSTs were treated with primary surgery and adjuvant chemotherapy. The prevalence of histological subtypes was as follows: 14 patients had a single subtype, either ES (12) or G (2); 12 patients had two subtypes, ES+G (4), ES+PV (3), ES+H (4) or G+H (1); six patients had three subtypes, ES+P+H (4) or ES+G+H (2); and three patients had all four subtypes. Multivariate analysis showed that important predictors were FIGO stage, chemotherapeutic regimen and residual tumour size. However, for stage I, multivariate analysis showed that the histological subtype was a superior predictor to the subclassification of FIGO stage I, age or chemotherapeutic regimen (P = 0.03). Kaplan-Meier analysis showed that YSTs composed of an admixture of three or four subtypes was associated with a better prognosis than those composed of one or two subtypes (P < 0.01), other variables being constant.

Immature endodermal teratoma of the ovary: embryologic correlations and immunohistochemistry

Two grade 2 ovarian immature, predominantly endodermal teratomas are reported. The teratomas were in stage I and occurred in two girls, 9 and 10 years of age, who were treated with triple chemotherapy. These neoplasms differed from the usual immature ovarian teratoma as they contained no neuroectodermal components and had high alpha-fetoprotein and low human chorionic gonadotropin levels as their serum markers despite the absence of other concomitant germ cell tumors. The epithelia of the teratomas demonstrated exclusively the embryologic development of endoderm, ranging from early endoderm to tissues similar to esophagus, liver, and intestinal structures. All epithelial derivatives were positive for alpha-fetoprotein and alpha 1-antitrypsin. Liver and esophagus expressed fibrinogen, while intestine and esophagus were positive not only for carcinoembryonic antigen and chromogranins but also for thyroglobulin, thus reflecting yet another type of endodermal differentiation into thyroid. Focal human chorionic gonadotropin positivity associated with primitive intestinal and esophageal epithelia may reflect the early embryologic relationships between endoderm and trophoblast. These cases demonstrate that simultaneous alpha-fetoprotein and human chorionic gonadotropin secretion may occur in immature teratoma. The mesenchymal component also showed a wide range of differentiation, from primitive mesoblastic cells to differentiated cells, such as hemopoietic foci, smooth muscle, bone, and cartilage. Both the primitive endoderm and the mesenchyme co-expressed vimentin and keratin, reflecting their intimate developmental relationships and possibly supporting the hypothesis of mesenchyme originating from endoderm, as suggested by previous embryologic studies. Since endodermal and mesenchymal areas similar to those described here are found in association with yolk sac tumors and embryonal carcinoma, it is possible that the present cases may represent an endodermal differentiation accomplished by either of these developmentally related germ cell tumors.

Update on malignant ovarian germ cell tumors

The evolution of therapy for malignant ovarian germ cell tumors has been one of the true success stories in oncology. This article reviews the major advances in this field, with emphasis on more recent developments. During the past two decades, the nomenclature and histologic criteria for the major histologic subtypes have been standardized. Although the role of secondary debulking is uncertain, it probably has merit in selected patients. The use of second-look laparotomy should be limited as much as possible. Chemotherapeutic regimens have evolved to the current "gold standard"--the combination of bleomycin, etoposide, and cisplatin, with overall disease-free survival rates of greater than 95%. For patients with metastatic dysgerminoma, chemotherapy has replaced radiation therapy as the treatment of choice. For those few patients who do not respond to first-line therapy, the combination of vinblastine, ifosfamide, and cisplatin is the most popular regimen for the subset of platinum-sensitive tumors. For those with platinum-resistant tumors, dose intensification with autologous bone marrow rescue or Phase II drugs are being investigated. Studies on the late effects of treatment reveal that reproductive potential can be preserved in most young patients. In summary, although the progress in this field has been phenomenal, small incremental advances will continue to occur during the 1990s.

Fine-needle aspiration cytology of an endometrioid-like variant of yolk sac tumor

A 36-year-old male with a history of immature teratoma and embryonal carcinoma of the testis was admitted to the hospital for abdominal pain and fever. A CT scan revealed a large right abdominal mass. The patient's serum alpha-fetoprotein (AFP) was 46.8 ng/ml (reference < 25 ng/ml). Fine-needle aspiration (FNA) of the mass revealed malignant glandular cells. Chemotherapy was instituted, followed by resection of the large abdominal mass. The tumor was grossly encapsulated, consisting of large areas of necrotic, hemorrhagic tissue surrounded by smaller, multiloculated cysts. Microscopically, the tumor had a villoglandular pattern and variably stratified tall columnar cells. A prominent feature of the columnar cells was supranuclear and subnuclear vacuolization. Intracytoplasmic PAS-positive, diastase-resistant hyaline globules were occasionally present. AFP by immunoperoxidase was prominent within the tumor. This recurrence of the previously diagnosed testicular teratoma with embryonal carcinoma represents a yolk sac tumor with components strongly resembling endometrioid carcinoma, a variant only recently described in eight cases of ovarian origin (Clement et al.: Am J Surg Pathol 1987; 11(10):767-778). We believe this is the first reported case of an endometrioid-like variant of testicular yolk sac tumor and also the first report of the FNA cytology findings in this variant.

Hepatocellular carcinoma metastatic to the ovary: a report of three cases discovered during life with discussion of the differential diagnosis of hepatoid tumors of the ovary

Three cases of hepatocellular carcinoma with ovarian metastases discovered during the patient's life are reported. A 31-year-old woman presented with back pain, and radiographic studies disclosed massive liver enlargement and bilateral ovarian tumors. The second patient, a 38-year-old woman, had an enlarged liver at the time of laparoscopic tubal ligation, and subsequently underwent right hepatic lobectomy for hepatocellular carcinoma. Three months later a left ovarian tumor was detected and a total abdominal hysterectomy with bilateral salpingo-oophorectomy performed. The third patient, a 68-year-old woman, presented with gastrointestinal symptoms and weight loss, and had bilateral ovarian tumors and widespread tumor at laparotomy. Two patients died of their disease at 18 months and 4 years 7 months; the third patient is alive with residual tumor at 7 months. The ovarian tumors, which were bilateral and multinodular in two cases and focally cystic in one case, ranged from 4 to 11 cm in maximum dimension, and had yellow-green or yellow sectioned surfaces. On microscopic examination, they were composed of cells with moderate to abundant eosinophilic cytoplasm growing diffusely and in nodules, nests, and trabeculae; cysts or glands were conspicuous in two cases. Bile was present in one tumor. The main differential diagnostic considerations were hepatoid yolk sac tumor and hepatoid carcinoma, primary or metastatic in the ovary. A variety of features, including the age of the patient, unilaterality or bilaterality of the ovarian tumors, distribution of disease, and microscopic features of the neoplasm, including the identification of bile, established the diagnosis. Metastatic hepatocellular carcinoma must be included in the differential diagnosis of oxyphil cell tumors of the ovary.

Pediatric malignant ovarian tumors: a 43-year review

Thirty-eight girls with malignant ovarian tumors were reviewed and studied during a 43-year period, 1945 to 1988 inclusive. The age range was 3 to 16 years. Eighteen girls were prepubertal and 16 were pubertal at diagnosis. Precocious puberty was noted in 4 children. The most common presenting symptoms and signs were pain, abdominal swelling, and pelvic mass. Emergency surgery for acute pain (? appendicitis) was needed in only 7 patients. Tumor size and cysts did not relate to histology or outcome. Tumors were classified histologically (germ cell, sex cord/stromal, epithelial tumors). Twenty-one (54%) of the patients survived 1 to 27 years (median, 8 years). Sixteen were left with ovarian tissue, 11 functioning. Diagnosis and treatment have been aided by better noninvasive radiological methods, tumor markers, newer and better chemotherapy, and pathological review and reclassification of these tumors as pediatric experience slowly increases. We can make at least four statements that differ from our past experience: (1) pure endodermal sinus tumor was previously confused histologically with embryonal carcinoma; (2) gonadoblastoma is associated with 45,X/46,Y, 45,X, or 46,Y karyotype and is known to be premalignant; (3) sex cord/stromal tumors are not necessarily malignant and metastatic behavior cannot be predicted from the histology; and (4) currently, epithelial tumors are classified as cystadenomas and are considered to be borderline malignancy. Current management should aim at both cure and preservation of fertility with conservative surgery whenever possible. The future must lie in chemotherapy.

Combined hepatoblastoma and yolk sac tumor of the liver

The authors report a liver tumor that occurred in a 6-month-old boy in which areas of yolk sac and hepatoblastoma were identified. To the best knowledge of the authors, this morphologic pattern has not been reported previously. Theories of histogenesis are discussed.

Plasma protein and apolipoprotein synthesis by human yolk sac carcinoma cells in vitro

Three human yolk sac carcinoma cell lines were characterized for the expression of several markers. Each of the cell lines expressed alpha-fetoprotein, without detectable levels of chorionic gonadotropin, and the level of alpha-fetoprotein expression increased dramatically when the cultures were held without passage for extended periods. The secretion of a number of plasma proteins was documented by metabolic labeling, immunoprecipitation, and gel analysis. The major plasma proteins detected were alpha-1-antitrypsin, alpha-fetoprotein, transthyretin, beta-2 microglobulin, and plasminogen, with lower levels of transferrin and complement C4 released. Apolipoproteins B, E, and A1 were secreted in high levels as well and were found in the form of lipoprotein particles. Time course experiments on the synthesis of apolipoproteins E and A1 indicated that, as with alpha-fetoprotein, the level of synthesis increased substantially when the cultures were held without passage. The results indicate that these yolk sac carcinoma cells display a protein expression profile similar to that observed for the human yolk sac, and the possibility that the cells may have the potential to differentiate is discussed.

Hepatocytes in the mouse stomach

Hepatocytes occurred in the stomach as incidental findings in 4 110-112-week-old mice (3 B6C3F1 and 1 Crl:COBS-CD1) sacrificed at termination of 2-yr toxicity/carcinogenicity bioassays of unrelated chemicals. Both sexes, and control and treated animals, were affected. Grossly, 2 mice only had 1.0-5.0 mm, smooth, cream-colored nodules protruding from the glandular stomach mucosa. Histologically, the glandular stomach submucosa and lamina propria adjacent to the limiting ridge, and in one case, the forestomach submucosa had circumscribed accumulations of well-differentiated hepatocytes with abundant eosinophilic cytoplasm and round central nuclei. Adjacent gastric glands sometimes exhibited dilation, epithelial hyperplasia, mineralization and/or microherniation into the submucosa. Ultrastructurally, the hepatocytes were polygonal cells with abundant mitochondria and rough endoplasmic reticulum; intercellular bile canaliculus-like structures exhibiting intraluminal microvilli and bounded by desmosomes were also present. No evidence of hepatocellular carcinoma or primary gastric neoplasms was found. No definitive conclusions concerning cell of origin or pathogenesis of these hepatocytes could be made, but hypotheses include congenital anomaly or post-natal transdifferentiation (metaplasia).

Alpha-fetoprotein (AFP)-producing gastric carcinoma. Is it hepatoid differentiation?

Biochemical and immunohistochemical analyses were done on five cases of gastric carcinoma with excessive production of alpha-fetoprotein (AFP). Histologic and ultrastructural examination of these cases showed conventional poorly differentiated adenocarcinoma of cuboidal or polygonal tumor cells in the medullary area with scattered AFP-positive cancer cells. Comparative studies on serum AFP between these cases and in hepatocellular carcinoma (HCC) or in testicular yolk sac tumor cases using concanavalin A (ConA)-affinity and lens culinalis agglutinin A (LCA)-affinity sepharose columns revealed that the AFP derived from four cases had a high ConA nonadsorping rate and high LCA-reactive fraction similar to that of yolk sac tumor. The AFP from one case had a small LCA-reactive fraction similar to that of HCC. Further immunohistochemical study using several markers for liver cells or germ cell tumor did not show additional evidence of these tumor cells to differentiate into liver cells or yolk sac tumor cells. Thus, this study indicates that AFP-producing gastric carcinomas are not always derived from hepatoid differentiation of the foregut. These gastric carcinomas might be categorized into medullary tumor with gastrointestinal tract-specific AFP.

Hepatoid adenocarcinoma: a distinctive histological subtype of alpha-fetoprotein-producing lung carcinoma

Seven cases of alpha-fetoprotein (AFP)-producing lung carcinoma were studied histologically to determine whether they fell into any previously described category. The patients were all males from 40 to 73 years of age and their serum AFP levels ranged from 1039 to 320,000 ng/ml. Five cases of hepatoid adenocarcinoma, one case of endodermal sinus tumour, and one case of papillary adenocarcinoma were found. The possible origins of the tumours and their differential diagnosis are discussed. Hepatoid adenocarcinoma is a major histological category among AFP-producing lung carcinoma; other types are less frequent. The occurrence of hepatoid adenocarcinoma in both the stomach and the lung suggests that this neoplasm may also be seen in other organs of endodermal origin. It may be a major histological subtype of AFP-producing endodermal neoplasms of non-germ cell origin.

Pathology of gynecologic malignancies

This review encompasses advances in the pathology of female genital tract tumors that have been deemed to have clinical significance. A number of newly described neoplasms are discussed as are the results of analyses of large series of cases of previously described tumors. Recent revision in terminology and the application of newer techniques for evaluating neoplasms, such as flow cytometry, are also briefly reviewed.

Endodermal sinus tumor of the ovary: a paradoxical response to chemotherapy

A patient with ovarian endodermal sinus tumor metastatic to the liver responded unusually to chemotherapy. She experienced histologically documented regression of all intraperitoneal disease with the exception of the liver metastases when given vinblastine, bleomycin, and cisplatin. She eventually died of liver failure. A review of patients with ovarian endodermal sinus tumor who either presented with initial liver metastases or had recurrent disease in the liver leads us to conclude that the liver is a preferential site for spread, that liver metastases carry an ominous prognosis, and that failure to see prompt liver metastatic tumor response after systemic chemotherapy should signal a need for a more aggressive therapeutic approach to the liver lesions.

Hepatoid gastric adenocarcinoma

A case of hepatoid gastric adenocarcinoma is reported. The tumor had the histological and immunohistochemical features of both liver cell carcinoma and conventional intestinal-type adenocarcinoma. We discuss the main clinical and pathological features of this uncommon variety of gastric cancer.

Intestinal variant of ovarian endodermal sinus tumor

A case of ovarian endodermal sinus tumor (EST) with exclusive intestinal differentiation in a 28-year-old black woman is reported. The tumor cells form irregular glands with focal early Paneth cell differentiation resembling intestinal Luberkuhn's crypts. Clinical and pathological features as well as immunohistochemical findings are described.

Immunohistochemical differentiation of yolk sac-type alpha-fetoprotein from hepatic-type alpha-fetoprotein

In order to differentiate yolk sac-type alpha-fetoprotein (AFP) from hepatic-type AFP, 5 yolk sac tumors (YSTs) and 6 hepatocellular carcinomas (HCCs) were examined immunohistochemically by the peroxidase-antiperoxidase (PAP) method for AFP, and paradoxical concanavalin A (P-Con A) staining, which has been reported to detect glycoprotein including AFP. In all 5 YSTs, AFP was negative for P-Con A staining. On the other hand, AFP was strongly positive for the same staining in all 6 HCCs. A similar staining pattern for AFP was observed in human yolk sac endodermal cells and embryonal hepatocytes. Thus, it was clarified that yolk sac-type AFP was unable to bind with Con A, in contrast with hepatic-type AFP, on tissue sections. It was concluded that the PAP method for AFP and P-Con A staining might facilitate the immunohistochemical differentiation of these two types of AFP, and that it would be useful for clarifying the histogenesis of various AFP-secreting tumors.

Mediastinal germ cell tumors and histiocytosis

Two cases of mediastinal germ cell tumors associated with primary hemoproliferative disorders are reported. The first case was a 23-year-old man who presented simultaneously with a mediastinal immature teratoma with focal yolk sac differentiation and a cytologically benign histiocytic proliferation associated with refractory thrombocytopenia. In the second case, an unsuspected mediastinal immature teratoma with focal yolk sac and hepatic differentiation was found postmortem in a 33-year-old man who had died of fulminant malignant histiocytosis. Although the histiocytosis in the former case failed to fulfill all the usual diagnostic criteria of malignant histiocytosis, both cases probably represent different manifestations of the same pathologic process. Review of the 19 published cases of hematologic malignancies associated with mediastinal germ cell tumors and of related experimental studies suggests a role for yolk sac differentiation in the pathogenesis of this syndrome.

Heterotransplantation of an alpha-fetoprotein-producing human gallbladder carcinoma into nude mice

An alpha-fetoprotein (AFP)-producing human gallbladder carcinoma showing direct invasion into the liver was transplanted into BALB/c-nu/nu nude mice. Although patient serum levels of AFP and carcinoembryonic antigen (CEA) were within normal limits, they were elevated to 1,040 ng/ml and 22.1 ng/ml, respectively, after cholecystectomy. Prominent liver metastasis was demonstrated by diagnostic imaging techniques shortly after the operation. Pathologically, the resected tumor consisted of papillotubular adenocarcinoma and the part which had invaded the liver showed a solid growth pattern with no papillo-tubular structure. The transplanted tumor showed both papillo-tubular and solid growth patterns, in which positive reactions for AFP, CEA, ferritin (FER), carbohydrate antigen 19-9 (CA 19-9), albumin (ALB) and fibrinogen (FIB) were confirmed by the avidin-biotin-peroxidase complex method. Serum levels of AFP, CEA, CA 19-9, beta 2-microglobulin (BMG) and FER were elevated in the nude mice bearing tumor transplants. Twenty-five percent of the serum AFP from nude mice with tumor transplants bound with concanavalin A (Con A), suggesting that the tumor was of gastrointestinal rather than hepatic origin.

Hepatoid carcinoma of the ovary. A newly described tumor

Five cases of ovarian carcinoma with hepatoid features, three of them primary and two probably primary, are described. The tumor cells were arranged predominantly in sheets and contained moderate to abundant amounts of eosinophilic cytoplasm; varying numbers of tumor cells stained immunohistochemically for alpha fetoprotein. In contrast to the much younger age range of patients with ovarian hepatoid yolk sac tumors, the ages of the five patients with hepatoid carcinomas ranged from 42 to 78 (average, 63 years), and none of them had gonadal dysgenesis or recognizable germ cell components within their tumors. All the tumors presented as adnexal masses; in four cases they were Stage III and in one case, Stage IIB; this last tumor spread to the upper abdomen within 4 years. In three cases the clinical course and pathology findings indicated that the tumor had originated in the ovary; in the remaining two cases the tumors were interpreted as only probably primary in the ovary. Hepatoid carcinomas must be distinguished from other ovarian neoplasms, especially from hepatoid yolk sac tumors.

Intrapericardial yolk sac tumor in an infant girl

This article is a report on the first known case of an intrapericardial yolk sac (endodermal sinus) tumor discovered in a 14-month-old girl. The patient presented with a systolic murmur, cardiomegaly, and manifestations of cardiac failure. At surgery a large, friable, intrapericardial mass with no evidence of extrapericardial spread was found. Histologic and immunohistochemical findings were diagnostic of yolk sac tumor. Following initial resection, chemotherapy, and a second resection 13 months after the first, the patient died 24 months after diagnosis. Tumor enlargement was associated with elevated serum alpha-fetoprotein levels.

Production of alpha-fetoprotein by human germ cell tumors in vivo and in vitro

The production of alpha-fetoprotein (AFP) by human germ cell tumors was studied in surgical specimens, cultured cells and transplanted tumors in nude mice. AFP was detected most frequently in yolk sac (endodermal sinus) tumors, and it was also detected, though only occasionally, in embryonal carcinomas and in teratomas. AFP-positive cells in teratomas presented a glandular or hepatoid appearance. Our experimental data suggest that AFP production in embryonal carcinomas is due to the functional expression of yolk sac differentiation preceding its morphologic expression. Although the transplanted tumors maintained the productivity of AFP, the cultured cells were not successful in maintaining a continuous AFP production.