Gastric choriocarcinoma and yolk sac tumor in a man: observations about its possible origin

A Rare Intersection: A Case of Gastric Adenocarcinoma With Yolk Sac Differentiation

This case report presents a rare instance of a 73-year-old male diagnosed with a yolk sac tumor (YST) coexisting with adenocarcinoma components in the stomach. YSTs are primarily gonadal and seldom occur in extragonadal sites such as the gastrointestinal tract. The patient underwent curative resection followed by chemotherapy, resulting in long-term survival without recurrence. This case contributes to the limited existing literature on gastric YSTs, emphasizing the importance of early diagnosis and effective treatment for this aggressive malignancy. It serves as a valuable addition to our understanding of the pathophysiology, diagnosis, and management of this rare condition.

Long-term survival without recurrence after surgery for gastric yolk sac tumor-like carcinoma: a case report

Background

Gastric yolk sac tumor (YST)-like carcinoma is extremely rare, and its prognosis is poor, because most patients have widespread metastases at the time of diagnosis. We report a case of gastric YST-like carcinoma with an adenocarcinoma component without metastases in which curative resection was performed.

Case presentation

A 77-year-old man complaining of melena and dizziness due to anemia was diagnosed with poorly differentiated adenocarcinoma in the gastric cardia, with a benign ulcer in the gastric body. He underwent total gastrectomy with D2 lymph node dissection for the tumor. Histological examination of the resected specimens revealed a mixture of reticular and glandular neoplastic components morphologically. In the reticular area, an endodermal sinus pattern and some Schiller–Duval bodies were confirmed. Gastric YST-like carcinoma with adenocarcinoma components, T2N0M0 Stage IB, was diagnosed. Immunohistochemical analysis showed that the YST was positive for carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP) and p53. In contrast, the adenocarcinoma was positive for p53 and negative for CEA and AFP. The patient remained healthy as of 7 years postoperatively, with no recurrence.

Conclusions

Routine medical examinations or endoscopic examinations for accidental symptom may be helpful for early diagnosis and good prognosis for gastric YST-like carcinoma, although the prognosis is generally poor.

Molecular characterization of uterine and ovarian tumors with mixed epithelial and germ cell features confirms frequent somatic derivation

Ovarian germ cell tumors, including yolk sac tumors, are most commonly diagnosed in children and young women. Most so-called yolk sac tumors reported in women >35 years old have been associated with an epithelial proliferation (endometriosis or carcinoma). Here, we describe eight cases clinically diagnosed as uterine or ovarian germ cell tumors in women >35 years old. In addition to routine morphologic examination and immunohistochemical evaluation, we present data from targeted next-generation sequencing (NGS) and isochromosome (12p) fluorescence in situ hybridization (FISH). We identified two groups of tumors with mixed germ cell and epithelial features: (1) tumors with background endometriosis and endometrioid carcinoma-like mutations (PTEN, PIK3CA, FGFR2, and CTNNB1), and (2) high-grade morphology, presumptive presence of isochromosome (12p) by FISH, and TP53 or PIK3CA mutations. These findings support the notion that the "germ cell tumor" component of these tumors is often somatically derived. Two tumors in our cohort were from premenopausal women; one showed no detectable mutations by NGS (suggestive of germ cell derivation), whereas the other showed PIK3CA, PTEN, and CTNNB1 mutations (suggestive of somatic derivation). Accurate classification of these tumors is likely important for selection of appropriate chemotherapy.

Coexistence of gastric choriocarcinoma and adenocarcinoma with reproductive hormone secretion in a man: a case report

The present study reports a rare case of a 65-year-old male patient with an exophytic ulcerative lesion in the gastric antrum. After performing a radical subtotal gastrectomy with D2 lymph node dissection and Billroth I gastrojejunostomy, histological analysis revealed a poorly differentiated adenocarcinoma combined with a biphasic pattern consisting of cytotrophoblasts and syncytiotrophoblasts. Immunohistochemical analysis showed a positive reaction with an anti-β-human chorionic gonadotropin antibody, and an abnormal increase in reproductive hormones. Furthermore, the patient succumbed to upper gastrointestinal hemorrhage in less than 3 months after the initial diagnosis, although the rupture of his liver metastasis was successfully treated by transhepatic artery embolization during the second admission.

Report of three cases of gastric choriocarcinomas-an emphasis on morphologic changes in the non-affected gastric mucosa

Primary gastric choriocarcinomas (PGC) are very rare and aggressive neoplasms with a worrisome prognosis. Most cases are reported in Asia and presented in middle-aged adults with male predominance. Most cases are associated with an intestinal adenocarcinoma; however, the pathogenesis of this tumor is uncertain. No previous reports exist of the characteristics of the non-tumoral stomach in these patients, and this data that could help to clarify their pathogenesis. We presented a series of three cases of PGC in Latin American patients, emphasizing the characteristics of non-neoplastic mucosa.

Primary Gastric Yolk Sac Tumour

Primary gastric yolk tumours are extremely rare. We report a 52-year-old male who presented to the Sultan Qaboos University Hospital, Muscat, Oman, in 2017 after having undergone a gastrectomy abroad due to a suspected poorly-differentiated adenocarcinoma. The patient subsequently returned to Oman to receive chemotherapy. However, while undergoing chemotherapy, an abdominal computed tomography scan revealed a lobulated mesenteric mass. Microscopic examination of the resected lesion confirmed a diagnosis of a yolk sac tumour. The mass was diffusely positive for α-fetoprotein (AFP) and a gastric carcinoma stain was negative. Gastrectomy slides from the patient's previous surgery were examined retrospectively. The morphology was typical for a yolk sac tumour and was negative for epithelial markers. An AFP stain showed diffuse immunoreactivity. Thus, the patient was deemed to have had a primary gastric yolk sac tumour which had later metastasised to the mesocolon. Germ cell tumour protocols were initiated and the patient responded well to treatment.

Multidisciplinary approach for treatment of primary hepatic choriocarcinoma in adult male patient

Choriocarcinoma is a rare malignant germ cell tumor and it usually occurs in the gonads (ovary or testis) and uterus. Primary hepatic choriocarcinoma (PHC) is a variant of choriocarcinoma featuring sole liver presentation without any evidence of gonodal involvements. Adult male patients with PHC carry dismal prognosis and their median survival period was less than 5 months. We herein present a first Korean case of a 54-year-old male patient with adult PHC, who was treated by surgical resection and chemotherapy through a multidisciplinary approach.

Dedifferentiated endometrioid adenocarcinoma with trophoblastic components and elevated serum alfa-fetoprotein: A case report and literature review

RATIONALE

Dedifferentiated endometrioid adenocarcinoma (DEAC) consisted of a combination of undifferentiated and differentiated carcinoma is more aggressive than other conventional endometrioid adenocarcinomas.

PATIENT CONCERNS

A 33-year-old woman with atypical vaginal bleeding was refereed to our hospital. She had an endometrial biopsy in a local clinic which showed differentiated endometrioid carcinoma with trophoblastic components. High levels of β-Human chorionic gonadotropin (β-hCG) and alfa-fetoprotein (AFP) were detected in the patient's serum.

INTERVENTIONS

The patient underwent total hysterectomy with bilateral salpingo-oophorectomy, total omentectomy and systemic pelvic lymphadenectomy in our center.

DIAGNOSIS

Pathological investigation indicated that the tumor had well differentiated and undifferentiated adenocarcinoma as well as trophoblastic components.

OUTCOMES

Serum β-hCG and AFP dropped significantly after operation. But three weeks later, the patient had developed pulmonary metastases and elevation of serum β-hCG. She died of the disease five months after surgery.

LESSONS

DEAC with trophoblastic differentiation seems to follow an aggressive course with early metastasis and poor clinical prognosis. However, due to small number of cases, further studies are necessary.

Sinonasal SMARCB1 (INI1) Deficient Carcinoma With Yolk Sac Tumor Differentiation: Report of a Case and Comparison With INI1 Expression in Gonadal Germ Cell Tumors

SMARCB1 (INI1) deficient sinonasal carcinoma is a recently recognized entity with wide histomorphologic spectrum. We present a case of this carcinoma that contained, in addition to a "common" morphology, scattered foci of yolk sac tumor differentiation. The tumor occurred in paranasal sinuses in a 44-year-old woman. Immunohistochemically, it was diffusely negative for INI1, whereas an expression of yolk sac tumor markers (α-fetoprotein, glypican-3, CDX2) was limited to the yolk sac tumor component. For comparison with the present case, we performed INI1 immunostaining on a series of 11 gonadal germ cell tumors with yolk sac tumor differentiation. All of these cases showed strong and diffuse expression of INI1, in contrast with the present sinonasal tumor. Our findings expand the morphologic spectrum of SMARCB1 (INI1) deficient sinonasal carcinoma. In addition, we show preliminarily that gonadal germ cell tumors with yolk sac tumor differentiation are not SMARCB1/INI1-deficient.

Gastric cancer with adenocarcinoma and yolk sac tumor components: A rare entity

Despite a sharp worldwide decline in the incidence and mortality due to gastric cancer during the second half of the 20th century, gastric cancer remains the world’s second leading cause of cancer-related deaths. Variants of gastric cancer account for approximately 5% of all stomach carcinomas. Herein, we report on a rare case of combined germ cell tumor and adenocarcinoma that arose in the stomach of a 68-year-old woman with a high level of alpha-fetoprotein in the serum. Clinical and pathological findings are presented.

High-level expression of divergent endodermal lineage markers in gonadal and extra-gonadal yolk sac tumors

Yolk sac tumors occur at both gonadal and extra-gonadal sites. A recent case of ovarian endometrioid-pattern yolk sac tumor with strong diffuse expression of TTF-1 illustrated the potential for misdiagnosis due to divergent expression of endodermal lineage markers. The aim of this study was to investigate the expression of four divergent endodermal lineage markers, TTF-1, CDX2, Hep Par 1, and Napsin A, in gonadal and extra-gonadal yolk sac tumors of differing age, sex, and location (excluding foci of overt hepatoid differentiation). We identified 26 cases (5 ovarian, 15 testicular, and 6 extra-gonadal) containing yolk sac tumor as identified by typical histology and confirmed by positive immunohistochemical staining for alpha-fetoprotein and glypican-3. Mixed or ambiguous foci were confirmed by immunohistochemistry (SALL4 positive and Oct-4 negative). The relative proportion of three histologic patterns: reticular/cystic, solid/myxoid, and glandular was estimated. Percent positivity for the four divergent endodermal lineage markers was compared within yolk sac tumor areas according to site, age group, and histologic pattern. High-level (>25%) staining for one or more divergent endodermal lineage markers was seen in eleven cases: Hep Par 1 in seven cases, all post-pubertal, TTF-1 in four cases, two ovarian and two extra-gonadal, and CDX2 in three cases, with no age or site predilection. No case highly expressed all three divergent endodermal lineage markers, but four co-expressed high levels of two markers: two ovarian yolk sac tumors with TTF-1 and Hep Par 1, one testicular yolk sac tumor with CDX2 and Hep Par 1, and one extra-gonadal yolk sac tumors with TTF-1 and CDX2. While no absolute correlation of high-level divergent endodermal lineage marker expression with histologic subtype was observed, TTF-1 and CDX2 expression was predominantly seen in reticular/cystic and glandular areas while Hep Par 1 was most frequent in myxoid/solid and glandular areas.

Uterine Carcinoma With Serous and Choriocarcinomatous Differentiation

Nongestational, nongonadal, and nonteratoma-related choriocarcinoma is an extremely rare entity. The tumor may be pure or associated with carcinoma. Six cases of primary endometrial carcinomas with the presence of syncytiotrophoblastlike beta-human chorionic gonadotropin (beta-HCG)-positive cells have been reported. We describe a case of endometrial carcinoma in a postmenopausal woman, that was composed almost entirely of syncytiotrophoblastic and cytotrophoblastic elements, except in the areas of lymphatic and myometrial invasion, where the neoplasm expressed a papillary serous carcinoma conformation with numerous psammoma bodies. There was not a clear transition between choriocarcinoma and serous carcinoma components. Immunohistochemically, beta-HCG was strongly positive in trophoblastic cells, whereas papillary areas expressed epithelial membrane antigen. These results suggest a double differentiation from malignant stem cells toward an extraembryonal germinal line and a papillary epithelial line. A poor prognosis is expected for this type of neoplasm with extraembryonic differentiation. In the present case, the histologic subtype of uterine papillary serous carcinoma could be an additional risk factor.

Gastric adenocarcinoma with yolk sac tumor differentiation and liver metastasis of yolk sac tumor component

Gastric adenocarcinoma with yolk sac tumor (YST) differentiation has rarely been reported. We report a case of primary gastric adenocarcinoma with yolk sac tumor differentiation and liver metastases of the YST component in a 50-years-old patient. This was suspected due to high serum level of alpha fetoprotein in the presence of a gastric fundal tumor. Gastric carcinoma with yolk sac tumor component is a rare entity with a poor prognostic outcome.

Pure choriocarcinoma of the testis presenting with jaundice: a case report and review of the literature

Introduction

Testicular cancer is the most common malignancy in men 15- to 35-years-old. The North American standard classification divides testicular cancers into germ cell tumors and non-germ cell tumors. The lymphatic spread of germ cell tumors usually involves the retroperitoneal lymph nodes. However, this spread to the retroperitoneum rarely involves the hepatic hilum. We describe an unusual case of metastatic choriocarcinoma of the testis that was clinically mimicked by a cholestatic jaundice. This is an unusual presentation of testicular cancer and, to the best of our knowledge, the first report of this kind in the literature.

Case presentation

A 28-year-old Moroccan man presented with a four-week history of progressive obstructive jaundice, and weight loss to our emergency department. Abdominal ultrasound showed a dilatation of the biliary ducts due to pathologically enlarged lymph nodes of the hepatic hilum. A complete clinical and radiologic assessment to discover the primary tumor was negative except for pulmonary metastasis. In the laboratory findings at admission there were signs of cholestasis with an abnormal increase in the rate of testicular tumor markers (serum beta-human chorionic gonadotropin level was 11,000IU/ml), which subsequently led to the suspicion of a testicular tumor. Further evaluation included testicular palpation and ultrasound which revealed a testicular nodule. The patient underwent an inguinal orchidectomy of the right testis and histopathological examination confirmed a pure choriocarcinoma. The prognosis was poor due to lymph node involvement at the hepatic hilum. He died one month later, despite general chemotherapy.

Conclusions

The clinical presentation of the disease and the rarity of this entity are two remarkable characteristics described in this case report which are rarely reported in literature.

Primary hepatic choriocarcinoma: a rare cause of spontaneous haemoperitoneum in an adult

Choricarcinoma is a beta human chorionic gonadotrophin secreting neoplasm pertinent to uterus and pregnancy mostly. It occurs primarily in gonads but rarely in extragonadal sites. Primary hepatic choriocarcinoma is an extremely rare tumor. Most of the reported cases are seen in infants representing metastasis from an occult placental choriocarcinoma. Till date, only 7 cases of primary hepatic choriocarcinoma in adults have been reported in literature. We present a case of a 40-yearold male presenting as haemoperitoneum due to ruptured hepatic tumor. He underwent emergency left lateral segmentectomy. He died on 10^th postoperative day. The surgical specimen and autopsy findings confirmed it to be primary hepatic choriocarcinoma. This is the first case report from Indian Subcontinent. A brief case report and review of literature is presented.

SALL4 represents fetal gut differentiation of gastric cancer, and is diagnostically useful in distinguishing hepatoid gastric carcinoma from hepatocellular carcinoma

The novel stem cell marker SALL4 has been identified as a diagnostic marker of germ cell tumors, especially yolk sac tumors, in gonadal organs. To clarify the significance of SALL4 as an oncofetal protein, we investigated SALL4 expression by immunohistochemistry in non-neoplastic stomach and gastric carcinoma with particular emphasis on á-fetoprotein (AFP)-producing gastric carcinoma, as AFP-producing gastric carcinoma shares expression of AFP and glypican 3 (GPC3) with yolk sac tumors and hepatic neoplasms. A total of 338 gastric carcinomas, 60 hepatocellular carcinomas, and 48 cholangiocellular carcinomas were studied by immunohistochemistry on tissue microarrays. In addition, more detailed whole tissue section immunohistochemistry was performed on non-neoplastic gastric tissue from 5 adult and 8 fetal specimens, 6 hepatoblastomas, and 31 cases of AFP-producing gastric carcinomas. SALL4 expression was observed in the neofetal stomach in gestational week 9 and disappeared thereafter. It was also identified by tissue microarray study in a fraction of gastric carcinomas (51 of 338, 15%), associated with older age (P=0.0001), male sex (P=0.0033), intestinal-type histology (P=0.0001), and synchronous liver metastasis (P=0.0047). AFP and GPC3 were closely associated with SALL4 expression in gastric carcinoma (both, P<0.0001), and a full-section study indicated that SALL4 was positive in all 31 cases of AFP-producing gastric carcinoma with diffuse staining in 24 cases (78%). Diffuse SALL4 expression was observed in the histologic patterns of hepatoid (89%), glandular (57%), and clear cell (39%) AFP-producing gastric carcinoma. In addition, SALL4 expression was completely negative in hepatoblastoma (n=6) and hepatocellular carcinoma (n=60). SALL4 is an oncofetal protein similar to AFP and GPC3, but it represents fetal gut differentiation in gastric carcinoma. SALL4 is a sensitive marker for AFP-producing gastric carcinoma and is especially useful to distinguish hepatoid gastric carcinoma from hepatocellular carcinoma.

Primary pure gastric yolk sac tumor

We describe here a case of pure gastric yolk sac tumor (YST). A 62-year-old patient underwent gastrectomy with D2 dissection. The histological report confirmed the diagnosis of YST and that two of the 14 regional lymph nodes removed were metastatic. Three courses of PEB regimen chemotherapy were delivered subsequently. Three months later the patient experienced dysphagia from stenosis of the anastomosis and a computerized tomography scan showed tumor recurrence with peritoneal nodules; the patient died one year after surgery. The origin of gastric YST is unclear but involvement of migrating germ cells during embryonic development or multipotential neoplastic protoepithelial cells of the gastric mucosa have been suggested. Generally the prognosis of gastric YST is poor and the standard therapeutic approach beyond surgery is still uncertain.

Gastric yolk sac tumor: a case report and review of the literature

Gastric yolk sac tumors are extremely rare and their prognosis is poor; most patients have widespread metastases at the time of diagnosis. The treatment of gastric yolk sac tumors consists of aggressive chemotherapy combined with radiotherapy and surgery. Here, we first report a case of gastric yolk sac tumor presenting as an early gastric cancer that was cured after a gastrectomy with lymphadenectomy.

Gastric yolk sac tumor complicated with beta-human chorionic gonadotropin-producing metastases

This report describes the case of 74-year-old man who had a gastric yolk sac tumor complicated with beta human chorionic gonadotropin (beta hCG) producing metastases. He was a heavy drinker. He was admitted to the hospital for abdominal pain and fullness. Based on computed tomography and gastric endoscopy he was diagnosed to have gastric cancer that had metastasized to the liver, lung and lymph nodes. The level of serum alpha fetoprotein (AFP) was high at 523 ng/mL. He died of multiorgan failure six days after admission. The autopsy revealed the stomach tumor to be an AFP-positive yolk sac tumor. Lymph node metastases showed the same characteristics as the stomach tumor. However, the lesions on the liver and lung were negative for AFP and positive for hCG. The yolk sac tumor seemed to have retrodifferentiated to form an hCG-producing tumor in the metastatic lesions. A gastric yolk sac tumor is extremely rare and only eight cases of gastric yolk sac tumors have been previously reported in the literature. To avoid a misdiagnosis, careful attention should be paid to the above-mentioned morphological features and immunohistochemical findings, in addition to the clinical findings.

Malignant ovarian tumor composed of endometrioid adenocarcinoma, clear cell adenocarcinoma, squamous cell carcinoma, yolk sac tumor and immature teratoma with prominent neuroectodermal and rhabdomyosarcomatous differentiation: a case study

BACKGROUND

Cases of malignant ovarian tumor composed of müllerian-type epithelial tumor and malignant germ cell tumor are extremely rare.

CASE

We herein report the case of a 34-year-old woman with an ovarian tumor which was composed of endometrioid adenocarcinoma (EAC), clear cell adenocarcinoma (CCC), squamous cell carcinoma, yolk sac tumor (YST) and immature teratoma with prominent neuroectodermal and rhabdomyosarcomatous differentiation. Even after systemic chemotherapy, this intriguing tumor recurred again and again, which is in contrast to pure germ cell tumor which is known to be sensitive to chemotherapy.

CONCLUSION

No previous cases with an identical composition have been found in the literature. Correct diagnosis of this complex and aggressive tumor is paramount.

Hepatocellular carcinoma with mesothelioma-like dissemination

Reported herein is a case of hepatocellular carcinoma (HCC) with unusual peritoneal dissemination masquerading as peritoneal mesothelioma. A 61-year-old man was clinically found to have multiple tumors in his abdominal cavity; peritonitis carcinomatosa was suspected. An autopsy revealed numerous tumors of various sizes in the abdominal serosa, omentum, and diaphragm. No signs of tumor, fibrosis, or cirrhosis were found in the liver, except for a small nodule in the hepatic triangular ligament. Histologically, the tumor cells proliferated in thick trabeculae or in sheets and formed a few canaliculi and tubules with homogenously brown contents in their lumina, which stained positively with Hall stain. Immunohistochemically, these tumors were positive for hepatocyte, alpha-fetoprotein (AFP) and low-molecular-weight cytokeratin; were focally positive for pan-cytokeratin and epithelial membrane antigen (EMA); and were negative for high-molecular-weight cytokeratin, vimentin, and calretinin. Carcinoembryonic antigen (CEA) produced a bile canalicular immunohistochemical staining pattern. Thus, the tumor was diagnosed as an HCC (Edmondson II type) of the triangular ligament with massive peritoneal dissemination. The origin of this tumor and its differential diagnosis (malignant mesothelioma, hepatoid adenocarcinoma, and hepatoid yolk sac tumor) are discussed.

Pure gastric yolk sac tumor that was diagnosed after curative resection: case report and review of literature

We recently experienced an 87-yr-old man with gastric yolk sac tumor. Preoperative diagnosis was poorly differentiated adenocarcinoma in the cardia of stomach without apparent metastasis. A total gastrectomy was performed. The precise histological examination after surgery revealed the tumor was composed of pure gastric yolk sac tumor without adenocarcinomatous components. The surgical margin and the resected lymph nodes were histologically negative for the tumor and a curative resection was performed. Five months after the operation, enlargement of the intraabdominal lymph nodes occurred with elevation of serum alpha fetoprotein (AFP), and the patient died 2 mo later. Gastric yolk sac tumors are very rare, and only six cases of gastric yolk sac tumors have been previously reported in the literature. Five out of six cases are accompanied by components of adenocarcinoma, and our present case is the second report of pure gastric yolk sac tumor to the best of our knowledge.

Hepatoid malignancy of unknown origin--a diagnostic conundrum: review of literature and case report of collision with adenocarcinoma

Hepatoid carcinomas are a group of neoplasms with features resembling hepatocellular carcinomas. Although rare, more cases have been noted to arise from various organs within the last decade. Differentiating these tumors is not only a challenge but also critical, since treatment modalities and operative strategies are dependent upon the exact nature of the hepatoid cancer. Based on a review of literature, we discuss the guidelines for differentiating these tumors and utilize these criteria to differentiate these tumors irrespective of their primary tissue of origin. We also describe an unusual case of hepatoid variant of primary peritoneal yolk sac tumor presenting with extensive carcinomatosis and as a collision with two synchronous primary colonic adenocarcinomas, neither of which has been reported to our knowledge to date, thereby falsely mimicking metastatic dedifferentiated colonic adenocarcinoma.

CASE DESCRIPTION

A septuagenarian female presented with weight loss, chronic anemia and ascites associated with bloating. Her past history was significant for COPD, hysterectomy and a bilateral oophorectomy 40 years previously. A work up which included computed tomography (CT) and contrast enema revealed significant ascites with multiple peritoneal nodules causing ascending colonic obstruction. Celiotomy revealed the entire peritoneal surface to be studded with nodules, with the largest measuring 6.0 cm. Intraoperative ultrasound, prompted by the frozen section of nodules resembling liver tissue, revealed no intrahepatic nodules. Right colectomy, omentectomy and tumor debulking were performed. The postoperative course was uneventful except for ascitic leak that spontaneously resolved.

DISCUSSION

The peritoneal nodules consisted of malignant cells arranged in cords that resembled liver tissue. In the absence of a primary identifiable liver disease, this is consistent with either hepatoid variant of primary yolk sac tumor or hepatoid carcinoma arising from the peritoneum. The right colectomy specimen revealed two mucosal ulcers consistent with colonic adenocarcinoma abutting two large tumor nodules on the serosal surface. Although grossly appearing to be contiguous, low power examination showed that the serosal nodule and the mucosal lesion were entirely different, and separated by a definite fibrous band. Immunohistochemical stains and patterns were used to differentiate the type of tumor. This article also discusses the criteria used to differentiate hepatoid yolk sac tumors (hepatoid-YSTs), hepatoid carcinomas and metastatic hepatocellular carcinomas and the phenomenon of opisthoplasia observed in certain malignancies. The difficulties encountered in identifying hepatoid carcinomas and current modalities used to differentiate these tumors are highlighted. The phenomenon of opisthoplasia and the challenges posed by this phenomenon in certain metastatic lesions are reviewed and explanations for the possible origins of hepatoid tumors are considered.

CONCLUSION

The most likely explanation in our case is that the hepatoid tumor either originated from microscopic remnant ovarian tissue left behind or primarily from the peritoneum. With no evidence of yolk sac component within the colonic tumor or in the draining lymphatics, this essentially excludes the commonly observed metastatic dedifferentiation (opisthoplasia) of adenocarcinoma to primitive forms (also known as combination tumors). Based on analysis of various factors, including tumor behavior and response to chemotherapy, we conclude that our case was a hepatoid variant of yolk sac tumor presenting in an elderly woman with carcinomatosis. This unusual presentation of two entirely different primary malignancies in close proximity is defined as "collision tumor". This is the first reported case of collision tumors involving dual colonic and primary peritoneal hepatoid-YST. Identifying the exact type still remains to be the most challenging aspect in the diagnosis of hepatoid tumors.

Breast carcinoma with choriocarcinomatous features

Although breast carcinomas have been shown to produce various ectopic substances, including human chorionic gonadotropin, it is rare to identify morphologic differentiation compatible with the hormone produced by a tumor. Presently, only eight cases of breast carcinoma with focal choriocarcinomatous differentiation have been reported in the literature. This article describes the pathologic findings, immunohistochemical profile, and clinical course in two additional cases of this unusual variant of breast carcinoma. In the first case, the tumor had morphologic features suggestive of medullary carcinoma, and the patient is doing well 12 months after presentation. In the second case, the tumor was locally advanced at presentation with histologic features consistent with metaplastic carcinoma having squamous, sarcomatoid, and choriocarcinomatous elements. The patient presented with extensive multifocal metastases 6 months after the initial presentation and is not responding well to standard or experimental treatment regimen. Immunostaining for the beta subunit of human chorionic gonadotropin was localized mostly, but not entirely, to multinucleated syncytiotrophoblast-like giant cells within both tumors.

Hepatoid adenocarcinoma with liver metastasis mimicking hepatocellular carcinoma: an immunohistochemical and molecular study of eight cases

Hepatoid adenocarcinoma (HAC) is a special type of extrahepatic adenocarcinoma, which has a striking morphologic similarity to hepatocellular carcinoma. Seven HACs arising in the stomach and one in the lung, all with liver metastasis, were studied. They shared clinical features, such as old age, high serum alpha-fetoprotein level, aggressive behavior, and hepatic tumor in absence of risk factors for hepatocellular carcinoma (HCC). Morphologically, tumors were characterized by an admixture of tubulo-and/or papillary adenocarcinoma with hepatoid foci. In six cases, liver metastases showed an exclusive hepatoid differentiation, virtually indistinguishable from HCC with solid growth pattern. As HAC and HCC cannot be differentiated on the basis of morphology alone, differences in immunohistochemical reaction patterns would be of considerable diagnostic help. Immunostaining for CK7, CK8, CK18, CK19, CK20, alpha-fetoprotein, p-CEA, and HepPar1 revealed that hepatoid areas of both primary and metastatic HAC have a specific immunoprofile, distinctive of this entity. On the one hand, positivity of virtually all HACs for alpha-fetoprotein, CK8, CK18, and the membranous, canalicular staining for polyclonal carcinoembryonic antigen underline its hepatoid nature. On the other hand, positive staining for CK19 and CK20 and frequent negativity for HepPar1 in both primary tumors and their metastases were distinctive features of HAC. Furthermore, HAC differs from combined hepatocellular cholangiocarcinoma, being negative for CK7. In addition, for comparison of immunohistochemical results, we stained with the same antibody panel a tissue microarray of 121 HCCs. Comparative genomic hybridization study of three HAC supports their hepatoid differentiation as aberrations found in HAC are common in HCC (4q-, 8p-), and hepatoblastoma (Xq+), respectively.

Germ cell tumor-like neoplasms occurring outside the anatomic midline

Most germ cell tumors occur in the gonads or in extragonadal sites in the anatomic midline; this article reviews tumors with similar or identical histologic features that arise in other topographic locations. Such lesions often represent the presence of "germ cell-like" or "germinal" components in what is otherwise recognized as a somatic neoplasm; however, they may also occur in pure form. The morphologic and immunohistochemical features of these proliferations are reviewed, according to the types of germ cell tumors that they recapitulate.

A case of ovarian endometrioid adenocarcinoma with yolk sac tumor component in a postmenopausal woman

The co-existence of an endometrioid adenocarcinoma with an ovarian yolk sac tumor is very rare. Only eight cases have been reported in the English language literature. A 54-year-old postmenopausal woman with a 6-month history of progressive abdominal distension was seen at our hospital. MR imaging revealed a large cyst with a solid intramural node. Serum alpha-fetoprotein and CA125 levels were 13143 ng/ml and 170 U/ml, respectively. At laparotomy, a large tumor approximately 20 cm in diameter was found to occupy the abdominal cavity, adhering to the swollen appendix and part of the omentum. Microscopically, foci of endometrioid adenocarcinoma together with a yolk sac tumor component were observed within a large endometriotic cyst. Since the tumor was clinically staged 1c, the patient was given 500 mg of intraperitoneal carboplatin postoperatively, followed by five courses of combination chemotherapy consisting of cisplatin, etoposide and peplomycin at 4-week intervals. The levels of both serum alpha-fetoprotein and CA 125 decreased gradually to normal ranges and remained normal at the most recent follow-up on 29 December, 2001. In contrast to a very poor prognosis of this tumor in previously reported cases, our patient showed no sign of recurrence during a 21-month follow-up period.

Primary gastric choriocarcinoma: a case report and review of the literature

Choriocarcinoma is a rapidly invasive, widely metastatic human chorionic gonadotropin (HCG)-producing neoplasm, usually intrauterine and gestational. Primary gastric choriocarcinoma is very rare, and its pathogenesis is still uncertain. We report a case of primary gastric choriocarcinoma associated with adenocarcinoma in a 36-year-old woman. The patient presented with gastrointestinal bleeding and a gastric mass clinically suspicious of gastric adenocarcinoma. Histopathologic evaluation proved the tumor to be a choriocarcinoma, with a minor component of a poorly differentiated adenocarcinoma. The patient was treated with a standard nongestational choriocarcinoma chemotherapy regimen. An impressive initial response was evidenced by clinical reduction of the tumor volume and drop of the serum beta-HCG levels after the first cycle. However, the tumor rapidly recurred in the abdomen and disseminated to the lungs, which were documented by new elevation of serum beta-HCG levels and computed tomographic scans despite continuing with 3 more cycles of chemotherapy. The patient died 6 months after diagnosis.

Co-expression of N-cadherin and alpha-fetoprotein in stomach cancer

Although N-cadherin is necessary for organ formation originating in the endoderm, the expression of N-cadherin in gastric carcinoma and its role has not yet been reported. The present study was conducted to determine the pattern of immunohistochemical expression of E-cadherin and N-cadherin, using formalin-fixed, paraffin-embedded tissues from 97 primary gastric carcinomas, including 17 which were producing alpha-fetoprotein (AFP). Samples were subdivided into 50 tubular adenocarcinomas and 47 poorly differentiated adenocarcinomas. Results showed that E-cadherin was expressed in varying degrees in areas of cell adhesion between tumor cells, in 94 out of 97 cases studied. Three cases which showed no expression of E-cadherin were diagnosed as AFP-producing tumors by immunohistochemistry. Expression of N-cadherin was observed in varying degrees in the intercellular spaces between tumor cells in 11 tubular adenocarcinomas and in six poorly differentiated adenocarcinomas, including E-cadherin-negative cases, all of which were AFP positive. The present findings suggest a possible role for N-cadherin in gastric carcinoma.

Colonic adenocarcinoma metastasizing as a germ cell neoplasm: a case report and review of the literature

Mixed tumors of the gastrointestinal tract, including both adenocarcinoma and germ cell neoplasm, have been reported infrequently. In the colon, only 9 cases, to our knowledge, have been described in the English-language literature. This is the case of a 29-year-old man with an unsuspected mixed colonic neoplasm that metastasized as the germ cell component.

Gastric adenocarcinoma with a yolk sac component: a case report and review of the literature

Gastric yolk sac tumors (YST) are very rare and are mainly reported in elderly people. We present a case of a 36-year-old man with a poorly differentiated gastric cancer showing a mixture of adenocarcinoma and yolk sac tumor that metastasized to Virchow's node. Both biopsies, Virchow's node and gastric tumor, contained areas of adenocarcinoma and yolk sac tumor that stained strongly positive for alpha fetoprotein (AFP) by the immunohistochemistry method. A high level of serum AFP (38,200 ng/mL) was also noted in this case. The response to chemotherapy in this case of mixed gastric yolk sac tumor and adenocarcinoma was not as favorable as would be expected in a pure primary germ cell tumor.

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.

Yolk sac tumor of the stomach with an adenocarcinomatous component: a case report with immunohistochemical analysis

A 56-year-old male treated for a gastric yolk sac tumor with an adenocarcinomatous component is described. A mixed area of reticular and glandular neoplastic components was morphologically identified in this tumor. Immunohistochemically, the yolk sac tumor expressed alpha-fetoprotein (AFP), placental alkaline phosphatase (PLAP), and cytokeratin, but was negative for carcinoembryonic antigen (CEA). The adenocarcinoma was positive for CEA and cytokeratin, partially positive for PLAP, and negative for AFP. In the mixed area, the tumor cells were positive for cytokeratin, weakly expressed AFP and PLAP, and sporadically stained for CEA both in the reticular and glandular components. This area was identified as a transitional area of the yolk sac tumor and adenocarcinoma. These findings demonstrate that the yolk sac and adenocarcinomatous components are closely related. It also suggests that the tumor arose from multipotential neoplastic mucosal epithelial cells with both yolk sac and gastric mucosal phenotypes.

Ovarian endometrioid adenocarcinoma with ectopic production of alpha-fetoprotein

alpha-Fetoprotein (AFP) is well known as a tumor marker of ovarian endodermal sinus tumor or embryonal carcinoma in gynecological malignancies. However, AFP production is extremely rare in ovarian epithelial cancers. Here we report a case of a 53-year-old woman with an AFP-producing ovarian endometrioid adenocarcinoma. The serum AFP level was elevated up to 2759 ng/ml preoperatively, with a subsequent decrease to the normal range after treatment. Histological examination of the tumor revealed a well-differentiated endometrioid adenocarcinoma with small foci of clear cell components. None of endodermal sinus tumor, hepatoid carcinoma, or embryonal carcinoma components were observed. Immunohistochemical analysis revealed that AFP was expressed in the cytoplasm of the endometrioid glandular lesions, but not in the clear cell components. This is probably the first case of a pure type of ovarian endometrioid adenocarcinoma with significant levels of AFP expression.

Primary coexistent adenocarcinoma and choriocarcinoma of the stomach. A case report and review of the literature

We report a case of primary gastric choriocarcinoma with liver metastasis. The mixed histologic patterns included adenocarcinoma, undifferentiated carcinoma, and choriocarcinoma. Immunohistologic staining for the beta-subunit of human chorionic gonadotrophin (beta-HCG) showed positive results in the choriocarcinoma, adenocarcinoma, and normal mucosal gland. However, positive HCG cells were present at different intensities in the choriocarcinoma, adenocarcinoma, and normal mucosal gland. The level of HCG was significantly increased in serum. This unusual tumor probably resulted from dedifferentiation of a primary adenocarcinoma or developed directly from the mucosal glands.

Ovarian endometrioid tumors with yolk sac tumor component, an unusual form of ovarian neoplasm. Analysis of six cases

The clinical, morphological, and immunohistochemical findings in six cases of ovarian endometrioid tumors (five endometrioid carcinomas and one carcinosarcoma) with a yolk sac tumor (YST) component are described. The age of the patients ranged from 31 to 73 years (average, 53), and only two patients were premenopausal. Two cases were stage Ia tumors, three stage III, and one stage IV. A substantial postoperative elevation of alpha-fetoprotein (AFP) was seen in two patients and a mild increase in another two. All six patients had surgery and postoperative cisplatin-based chemotherapy regimens, four of whom died of tumor 3 to 14 months after surgery without response to treatment. Only a stage Ia patient is alive and well 1 year after surgery. The tumors were large (average, 17 cm). Benign endometrioid lesions were found in the homolateral ovary in two cases and in the contralateral ovary in another two. All cases had endometrioid ovarian carcinomas (EOC) of various types admixed with typical YST components. Immunohistochemically, EOC areas differed from YST in their positivity for OC 125, CA 19.9, and nuclear estrogen and progesterone receptors and in their negativity for AFP, which was conspicuously positive in the YST areas. The clinicopathological profile of ovarian endometrioid tumors with YST also differs from that of YST in that it occurs in the same age range as EOC, it shows coexistence of benign endometrioid lesions, and it has a poor response to chemotherapy. The histological pattern in transitional areas may be difficult to differentiate from "endometrioid-like" (enteroblastic) YST and clear cell tumors. Ovarian endometrioid tumors with YST component should be considered a variant of endometrial carcinoma. Its recognition is necessary in view of its unusually aggressive behavior and poor prognosis.

Coexistence of choriocarcinoma and adenocarcinoma in the rectum: molecular aspects

Choriocarcinoma, a malignant tumor of usually placental origin, in divided into two groups; the gestational and non-gestational types, the latter being rare. Non-gestational choriocarcinoma occurs in the lung, mediastinum, kidney, stomach, and small intestine, but rarely appears in the large intestine. We treated a 29-year-old woman with choriocarcinoma of the rectum with adenocarcinoma. Despite the rarity of the condition and the obscurity of the histogenesis, reports of similar cases and the occurrence of the tumors in the digestive tract suggest that the condition constitutes a clinical entity of a digestive tumor.

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.

Adenocarcinoma arising from gastric immature teratoma. Report of a case in an adult and a review of the literature

BACKGROUND

Gastric teratoma is an uncommon tumor and usually occurs in infancy or childhood. To the authors' knowledge, malignant transformation in gastric teratoma has not been reported previously.

METHODS

An 83-year-old Japanese man presented with a large polypoid gastric tumor composed of teratomatous components and invasive adenocarcinoma. Numerous blocks of this tumor were analyzed histologically and immunohistochemically.

RESULTS

Histologically, the gastric tumor consisted of teratomatous components with diverse maturation, such as fibroblastic mesenchymal cells, striated muscle cells, cartilaginous islands, neuroepithelial components, glial tissues, squamous cell nests, glandular components, and foci of adenocarcinoma infiltrating the benign gastric tissues adjacent to the tumor stalk. Metastatic foci of teratomatous components in the resected lymph nodes contained adenocarcinomatous glands. An immunohistochemical study helped confirm the differentiation in the immature components and the differential diagnosis between atypical neuroepithelial cells and the adenocarcinoma.

CONCLUSION

This study indicates that the adenocarcinoma arose from immature gastric teratoma. A review of the literature suggests that this is the oldest reported patient with gastric teratoma and to the authors' knowledge is the first report describing gastric teratoma with malignant transformation.

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.