Hepatoid adenocarcinoma of the papilla of Vater

Enteroblastic adenocarcinoma of the ampulla of Vater

Adenocarcinoma with enteroblastic differentiation is a rare histologic subtype of adenocarcinoma of the gastrointestinal tract that shows unique histologic and immunohistochemical features that resemble fetal intestinal epithelium. This histological subtype has been widely described in the stomach, where it most frequently appears, but, in other locations, it is misdiagnosed because of the poor experience in routine diagnostic setting. Here we present a case of an 87-year-old male with an adenocarcinoma of the ampulla of Vater with enteroblastic differentiation with a literature review of the cases described of this subtype in this location to date. The anatomical peculiarity of the ampulla, joined with the infrequent nature of this histological subtype, makes this case of great interest to aid to better characterize the biological behavior of these tumors.

An autopsy case of alpha-fetoprotein-producing large duodenal adenocarcinoma

We report an autopsy case of a large duodenal adenocarcinoma that produced alpha-fetoprotein (AFP). The patient was a man in his 70s with diabetes mellitus. He presented with epigastralgia and was referred to our hospital. Upper gastrointestinal endoscopy and abdominal computed tomography revealed a large tumor of 11 cm in diameter in the descending limb of the duodenum. A tumor biopsy showed poorly differentiated adenocarcinoma. Although his carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels were within the normal range, his AFP levels were significantly elevated (42,078.4 ng/mL). Due to vascular invasion, curative resection was not feasible, and chemotherapy was chosen as the treatment option. After gastrojejunostomy was performed to enable oral intake, one cycle of modified leucovorin/5-fluorouracil/oxaliplatin (mFOLFOX6) therapy was administered. However, it proved ineffective, and the patient's anorexia gradually worsened. Ultimately, he succumbed to the progression of cancer cachexia. Autopsy findings revealed a 14-cm-long duodenal carcinoma primarily located in the duodenal bulb, with direct invasion into the stomach, pancreas, and liver. A pathological examination confirmed a diagnosis of poorly differentiated adenocarcinoma with AFP production. Duodenal cancer is rare, and AFP-producing duodenal cancer is even rarer, with only 21 reported cases, including our own. We present this autopsy case of AFP-producing duodenal adenocarcinoma and review the cases reported in the relevant literature.

Whole-exome sequencing and bioinformatics analysis of a case of non-alpha-fetoprotein-elevated lung hepatoid adenocarcinoma

Hepatoid adenocarcinoma of the lung (HAL) is an exceptionally rare malignant tumor with prominent hepatocellular carcinoma (HCC)-like characteristics in organs or tissues outside the liver, while there is no tumor in the liver. Most HAL cases have various degrees of serum alpha-fetoprotein (AFP) levels and exhibit a similar origin and clonal evolution process to HCC. We studied a case of HAL without elevating the AFP level by performing whole-exome sequencing (WES) and bioinformatics analyses after surgical resection. Our results showed mutations in two driver genes, NLRP3 and PBX1, and we identified HNRNPR, TP73, CFAP57, COL11A1, RUSC1, SLC6A9, DISC1, NBPF26, and OR10K1 as potential driver mutation genes in HAL. In addition, 76 significantly mutated genes (SMG) were identified after the statistical test of each mutation type on genes.

Hepatoid carcinoma and related entities of the extrahepatic bile duct: A clinicopathological study of four cases

Hepatoid carcinoma or related entities (HPC/RTs) are extremely rare, especially in the extrahepatic bile duct (EHBD). Only a few case reports have been published. We analyzed the clinicopathological features of HPCs/RTs in EHBD. HPC/RT of extrahepatic cholangiocarcinoma (eCCA) cases were selected based on the histological characteristics and immunohistochemical detection of spalt-like transcription factor 4 (SALL4) and/or alpha-fetoprotein (AFP). Four HPC/RT cases arose in the distal but not in the perihilar EHBD. The four patients with HPC/RT included one female and three males with a median age of 77 years. There are various macroscopic types of HPC/RT. The predominant histological features were two solid-type carcinomas that mimicked hepatocellular carcinoma and two well-differentiated tubular adenocarcinomas. Immunohistochemically, SALL4 and glypican-3 were expressed in all cases, and AFP was expressed in one case. Cancer cell phenotypes included intestinal, pancreatobiliary, and mixed pancreatobiliary and intestinal types. Focal neuroendocrine differentiation and severe perineural and lymphovascular invasions were also observed. HPC/RT recurred in two patients within 2 years, and one patient died 13 months postoperatively. It is suggested that the HPC/RT of EHBD shares common characteristics with HPC/RT arising in various organs, and has some unique characteristics. HPC/RT of EHBD might be more aggressive than conventional eCCA.

Carcinosarcoma of the stomach with alpha-fetoprotein-producing hepatoid adenocarcinoma: an unexpected combination of two rare subtypes of gastric cancer in one tumor

Carcinosarcoma is a rare malignant neoplasm comprising both epithelial and mesenchymal components. Hepatoid adenocarcinoma (HAC) is another rare type of cancer. To date, there are only four reported cases of concurrent carcinosarcomas with HAC across all tumor types, all of which were observed in uterine tumors. Here, we report an unusual case of gastric carcinosarcoma associated with alpha-fetoprotein (AFP)-producing HAC in a 76-year-old woman. Upon admission, the patient had an elevated serum AFP concentration (448 µg/L), a necrotic polypoid tumor of the central gastric cardia revealed by endoscopy, and no evidence of distant metastasis indicated by computed tomography (CT). Owing to malignancy indicated by biopsy, the patient underwent proximal subtotal gastrectomy. The resected tumor was composed of both an HAC component and a sarcoma component, microscopically. The sample was positive for AFP, hepatocyte paraffin (Hep-Par) 1, glypican-3, SALL4, CDX2, cytokeratin (CK) (pan), CK18, desmin, and vimentin staining immunohistochemically. In summary, the tumor was diagnosed as carcinosarcoma of the stomach with AFP-producing HAC. To our knowledge, this is the first report of gastric carcinosarcoma with AFP-producing HAC in the English literature describing gastric tumors.

Hepatoid Adenocarcinoma of the Stomach: Current Perspectives and New Developments

Hepatoid adenocarcinoma of the stomach (HAS) is a rare malignant tumor, accounting for only 0.17-15% of gastric cancers. Patients are often diagnosed at an advanced disease stage, and their symptoms are similar to conventional gastric cancer (CGC) without specific clinical manifestation. Morphologically, HAC has identical morphology and immunophenotype compared to hepatocellular carcinoma (HCC). This is considered to be an underestimation in diagnosis due to its rare incidence, and no consensus is reached regarding therapy. HAS generally presents with more aggressive behavior and worse prognosis than CGC. The present review summarizes the current literature and relevant knowledge to elaborate on the epidemic, potential mechanisms, clinical manifestations, diagnosis, management, and prognosis to help clinicians accurately diagnose and treat this malignant tumor.

Alpha-Fetoprotein-Producing Early Gastric Cancer with Intramucosal Hepatoid and Fetal Enteric Differentiation

Alpha-fetoprotein (AFP)-producing gastric carcinomas (AFPGCs) are relatively rare tumors known to have a poor prognosis and commonly found as advanced lesions. Histologically, AFPGCs have been described as having hepatoid and fetal enteric (enteroblastic) morphology and are associated with conventional adenocarcinomas. Prior studies reported a hepatoid component present only in invasive areas and hypothesized that AFPGCs may develop hepatoid features during the process of tumor invasion. We report three cases of AFP-producing early gastric cancer which had an intramucosal hepatoid component. Immunohistochemistry showed that the hepatoid component was diffusely immunoreactive for SALL4, AFP, arginase-1, and HepPar1, and focally for CDX2 and PDX1. An intramucosal transition between the hepatoid component and conventional intramucosal adenocarcinoma was identified. Two patients also had a coexistent fetal enteric component, which was admixed with a hepatoid component. Although at an early stage one patient subsequently developed liver metastasis and a second patient was suspected of having liver metastasis, these were not biopsy-proven. The latter patient had a previous history of hepatocellular carcinoma (HCC) and SALL4 was used on the HCC to distinguish metastatic/further HCC from a gastric metastatic primary with hepatoid differentiation.

Hepatoid carcinoma of the pancreas: A case report and review of the literature

BACKGROUND

Hepatoid carcinoma (HC) is an extremely rare neoplasm that is morphologically similar to hepatocellular carcinoma. HC has been described in various organs; however, HC of the pancreas is extremely rare. To our knowledge, only 38 cases have been reported. We present a case of HC of the pancreas in a 36-year-old male patient.

CASE SUMMARY

A 36-year-old cachexic man with no significant past medical history was transferred to our hospital with a history of painless jaundice, elevated blood glucose and significant weight loss. Lab tests showed elevated serum transaminases, bilirubin and alpha-fetoprotein levels. Magnetic resonance imaging of the upper abdomen showed a diffusely enlarged pancreas, appearing “sausage-shaped”. Magnetic resonance cholangiopancreatography showed upstream ductal dilation secondary to stricture of the main pancreatic duct and the common bile duct, which were not visible. Immunohistochemistry of biopsied tissue from a percutaneous pancreatic biopsy showed tumor cell positivity for HepPar1, polyclonal carcinoembryonic antigen and CK19, suggestive of HC of the pancreas. The characteristics of 39 patients with HC of the pancreas were reviewed.

CONCLUSION

HC of the pancreas is more prevalent in males, and patients have a median age of 57 years. It is most commonly asymptomatic or presents as abdominal back pain, and the pancreatic tail is the most common location. At the time of diagnosis, liver metastasis is often present.

Primary pulmonary hepatoid adenocarcinoma: A case report and review of the literature

RATIONALE

Hepatoid adenocarcinoma of lung (HAL) is a rare malignant tumor, which can be defined as a primary alpha-fetoprotein (AFP)-producing lung carcinoma. The majority of hepatoid adenocarcinoma (HAC) expressed AFP in tumor cells, but AFP expression is not required for its diagnosis according to the modified diagnostic criteria. Despite that HAC exhibits a poor prognosis and ineffective treatment options, early diagnosis and aggressive treatment can result in long-term survival.

PATIENT CONCERNS

We report a 70-year-old Chinese male patient with alcoholic intake over 30 years and smoking history of 60 cigarettes per day for 40 years. He sought medical consultation for productive cough and hemoptysis sputum.

DIAGNOSES AND INTERVENTIONS

Chest CT scan revealed a mass (6.4 × 5.5 cm) in the left lower lobe of the lung. The patient underwent curative surgical resection, and subsequently diagnosed as HAL.

OUTCOMES

Eighteen months after primary diagnosis, the patient died of multiple organ failure caused by distant metastases.

LESSONS

Familiarizing with the clinical features and modified diagnostic criteria of this rare tumor may increase awareness of the disease among clinicians and pathologists, thereby avoiding misdiagnosis and mistreatment.

Clinicopathological features and prognosis of intestinal hepatoid adenocarcinoma: evaluation of a pooled case series

BACKGROUD

Intestinal hepatoid adenocarcinoma (IHA) is a very rare and unique intestinal malignancy. Due to the lack of case series specifically pertaining to IHA, the clinicopathological features and prognosis of it remain unclear.

RESULTS

Of the 42 patients enrolled in this study, 30 (71.4%) were male. Twenty-one cases (50.0%) were located in the colon. Eight cases (19.0%) had accompanying inflammatory bowel disease (IBD). Elevated serum alpha-fetoprotein (AFP) was detected for most patients (25/33, 84.8%). Twenty-five (59.5%) patients received complete resections. Vascular invasion (22/36, 61.1%), lymph node metastasis (28/36, 77.8%) and distant metastasis (21/42, 50.0%) were common. The 1-year progression-free survival (PFS) and disease-specific survival (DSS) of IHA were 26.9% and 30.6%, respectively. Multivariate analysis showed that only pTNM stage was an independent risk factor for PFS and DSS. PFS and DSS in patients with IHA were significantly lower than those with colorectal adenocarcinoma (CA) and hepatoid adenocarcinoma of the stomach (HAS).

CONCLUSIONS

IHA most commonly occurred in the colon and accompanied by IBD in several cases. pTNM stage was an independent factor for prognosis. The prognosis of IHA was significantly worse than that of CA and HAS.

PATIENTS AND METHODS

Clinical data of IHA from four patients managed at our institution between January 2010 and December 2016, and 38 cases from research databases prior to 2017 were retrospectively studied.

Hepatoid Adenocarcinoma of the Extrahepatic Bile Duct in a Patient with Polysplenia Syndrome

Hepatoid adenocarcinoma (HAC) is a rare subtype of extrahepatic adenocarcinoma that is characterized by its morphological and functional similarities to hepatocellular carcinoma. We herein present a novel case of HAC arising from the extrahepatic bile duct in a 75-year-old Japanese woman with polysplenia syndrome. This is the second reported case of HAC arising from this site. The tumor induced jaundice and hemobilia. A total of four isolated intraductal polypoid masses of HAC were found. No recurrence was seen five months after surgery. Further reports of similar cases will be needed to clarify the clinical characteristics and the prognosis of this malignancy.

Pancreatic Hepatoid Carcinoma Mimicking a Solid Pseudopapillary Neoplasm: A Challenging Case on Endoscopic Ultrasound-guided Fine-needle Aspiration

A 59-year-old man was admitted to our hospital for treatment of a 45 mm pancreatic mass found during a medical examination. Endoscopic ultrasound-guided fine-needle aspiration cytology showed polygonal cells with pseudopapillary structures. The tumor cells were positive for nuclear/cytoplasmic β-catenin and CD10, and negative for chromogranin A. After a tentative diagnosis of a solid pseudopapillary neoplasm, middle pancreatectomy was performed. Histologically, polygonal cells with abundant eosinophilic cytoplasm formed in the trabeculae and were immunohistochemically positive for HepPar1 and protein induced by vitamin K absence or antagonist-II. The tumor was finally diagnosed to be pancreatic hepatoid carcinoma. No recurrence occurred for 12 months, even without adjuvant chemotherapy.

A hepatoid carcinoma of the pancreatic head

Hepatoid carcinoma (HC) is an extremely rare form of neoplasm. Its cellular structure resembles that of a hepatocellular carcinoma (HCC). To date, only 26 cases of hepatoid carcinoma of the pancreas have been reported in the literature. We report the diagnosis of a hepatoid carcinoma of the pancreatic head in a 78-year-old male patient. The tumor was detected incidentally during routine abdominal ultrasound scanning. Laboratory tests did not show any abnormalities except for a monoclonal gammopathy of undetermined significance. After CT, MRI, and laparoscopic biopsy that failed to obtain the diagnosis, the patient underwent a Whipple procedure. The final pathology report described a hepatoid carcinoma of the pancreatic head (pathological T3, N0 (0/10), L0, V0, R0, M0). After the patient recovered, no further therapy was recommended by the tumor board and he was discharged. Regular follow-up was suggested; however, the patient suddenly died of acute coronary artery disease 2 months after surgery.

A case of adenocarcinoma with enteroblastic differentiation of the ampulla of Vater

Cancer of the ampulla of Vater is rare, though it has various histological types and its histogenesis is fascinating in view of the anatomically complex nature of the ampulla. Fetal gut-like adenocarcinoma, usually found in the stomach, can also develop in the ampullary region in extremely rare cases. Here we present a case of ampullary adenocarcinoma with enteroblastic and neuroendocrine differentiation. A 55-year-old woman presented with an epigastric pain. Endoscopic examination revealed a 2-cm submucosal tumor-like lesion in the ampulla. The surgical specimen showed that an exposed protruding type of tumor appeared as a well-demarcated whitish-yellow solid mass. Microscopically, the tumor had proliferated in the common channel and invaded the duodenal submucosa with mucosal lesion of intestinal-type adenocarcinoma. The main tumor consisted of three different histological types showing transitional areas: adenocarcinoma with enteroblastic differentiation (ENT), neuroendocrine carcinoma (NEC), and well differentiated adenocarcinoma (WEL). Morphologically the ENT resembled fetal gut and immunohistochemically expressed SALL4 and glypican 3. The WEL was positive for CK20 and CDX2, revealing an intestinal-type phenotype. AFP and HepPar1 were not evident in any part of the lesion. We speculated this tumor had arisen from intestinal-type adenocarcinoma of the common channel and acquired enteroblastic and neuroendocrine differentiation during growth.

Hepatoid carcinoma of the pancreas combined with serous cystadenoma: a case report and review of the literature

Pancreatic hepatoid carcinoma (HC) is an extremely uncommon neoplasm of pancreas that resembles hepatocellular carcinoma (HCC). We report a case of incidentally detected pancreatic HC combined with a serous microcystic cystadenoma, in a 47-year-old man, while he was being evaluated for renal calculi. Contrast enhanced computed tomography (CECT) of abdomen revealed a lesion with mild heterogeneous enhancement in the tail of pancreas and another proximal lesion having moderate enhancement, and a calculus in the neck of gallbladder. Serum chromogranin, carcinoembryonic antigen (CEA) and CA 19-9 levels were within normal limits. He underwent laparoscopic distal pancreatectomy with splenectomy and cholecystectomy. Pathologically the distal tumor was encapsulated and characterized by eosinophilic cytoplasm, vesicular nucleus with prominent nucleolus and intranuclear eosinophilic inclusions. The cells were arranged in trabecular pattern separated by sinusoids. Canalicular and intercellular bile plugs were seen. On immunohistochemistry tumor cells were positive for hepatocyte specific antigen and weakly positive for alpha fetoprotein (AFP). The proximal tumor showed features of serous microcystic adenoma. Based on these findings, the case was diagnosed as hepatoid tumor of pancreas combined with serous microcystic cystadenoma. Post operative AFP was 1.75 IU/mL. The patient is on follow up for the last eight months and there is no evidence of recurrence.

Hepatoid adenocarcinoma of the stomach: A case report and literature review

Hepatoid adenocarcinoma (HAC) is a rare form of gastric cancer that has unique clinicopathological features and an extremely poor prognosis. The present case report describes a patient who was referred to the No. 461 Hospital of PLA (Changchun, China) due to nausea and occasional vomiting of acid/water. The patient was diagnosed with gastric signet-ring cell carcinoma and surgery was recommended. A total gastrectomy was performed on the operable lesion. Histopathological analysis revealed that the tumors exhibited two pathological changes: HAC and signet-ring cell carcinoma differentiation. Furthermore, the tumor cells were immunohistochemically positive for α-fetoprotein, cytokeratin low/high molecular weight, Cam5.2, cytokeratin 7, p53, epithelial membrane antigen and carcinoembryonic antigen. Previous studies and our experience have suggested that HAC is an aggressive type of adenocarcinoma; however, radical surgery and chemotherapy may positively impact clinical outcomes.

Pancreatic hepatoid carcinoma: a rare form of pancreatic neoplasm

Primary pancreatic hepatoid carcinoma (PHC) is extremely rare, resembling hepatocellular carcinoma (HCC) in terms of morphology and immunohistochemical features. Hepatoid carcinoma can present in other organs, most noticeably in the stomach. PHC is present in two forms either a pure form like HCC or admixed with other histologic tumor components characteristic of the underlying primary site (endocrine tumors, ductal, or acinar adenocarcinomas). Here, we report a 69-year-old male patient with distal pancreatic mass incidentally found during a CT scan workup for a pulmonary nodule suspicious for metastatic prostate adenocarcinoma. We described the clinical, cytological, and histological finding and conducted a literature review.

Establishment and biological characterization of a novel cell line derived from hepatoid adenocarcinoma originated at the ampulla of Vater

Hepatoid adenocarcinoma is a rare gastrointestinal tumor and mostly reported in the stomach. Effective chemotherapy has yet to be developed to improve poor prognosis. The present study was undertaken to establish a useful cell line derived from a hepatoid adenocarcinoma, possibly leading to a new therapeutic strategy. The new human cell line VAT-39 was established from a metastatic lymph node of a 69-year-old Japanese male patient with hepatoid adenocarcinoma of the ampulla of Vater. The primary tumor and metastatic lymph node were composed of hepatoid adenocarcinoma cells exhibiting immunohistochemical reactivity for alpha-fetoprotein (AFP) and glypican-3 (GPC3). In the metastatic lymph node, Periodic acid-Schiff (PAS) staining clarified diffuse deposition of glycogen in the cytoplasm, indicating analogous characteristics to the primary hepatoid adenocarcinoma. Moreover, VAT-39 cells produced high levels of AFP in the cultured medium, and reverse-transcriptase polymerase chain reaction (RT-PCR) verified increased expression of GPC3 mRNA in this cell line. Further, we evaluated the sensitivity to major chemotherapeutic drugs against the bile duct cancer. Neither 5-fluorouracil nor gemcitabine showed particular sensitivity to this cell line. The tumorigenicity of the cultured cells was confirmed in athymic nude mice and the histological features of the explanted tumor were similar to the VAT-39 cell line. The present VAT-39 is the first hepatoid adenocarcinoma cell line that originates from the ampulla of Vater and it will be applicable for basic biological studies searching for new strategies of molecular targeted chemotherapy to this disease.

Hepatoid adenocarcinoma of the extrahepatic duct

Hepatoid carcinoma is a unique type of extrahepatic tumor associated with hepatic differentiation and displays the morphological and functional features of hepatocellular carcinoma. Hepatoid carcinoma of the extrahepatic duct has rarely been reported in the literature. We report a 62-year-old man who presented with epigastric discomfort, xanthochromia, dull pain of the right shoulder, nausea and pruitus. Microscopic examination of the extrahepatic duct indicated that the tumor was primarily composed of “hepatoid cells”, which were characterized by an eosinophilic cytoplasm, enlarged nucleus and prominent nucleoli. The cells were arranged in nests or proliferated in a trabecular pattern. Immunohistochemistry indicated that the tumor cells were positive for hepatocyte paraffin 1 and cytokeratins 8 and 18. Based on these findings, this case was diagnosed as hepatoid carcinoma of the extrahepatic duct.

Hepatoid pancoast tumor. A case report and review of the literature

A 48-year-old male patient presented with a Pancoast tumor of the right lung and a serum alpha-fetoprotein (αFP) at 39,000 ng/ml. Alpha-fetoprotein is a tumor marker found elevated in patients with hepatocellular carcinoma (HCC), germ cell or stromal tumors of the ovary and nonseminomatous testicular cancer. Occasionally, this tumor marker may rise in non-neoplastic conditions such as cirrhosis and hepatitis and only exceptionally in rare cancers with hepatoid differentiation. We present our case report and review the English literature for αFP-producing lung carcinomas. To the best of our knowledge this is the first report in the literature of an αFP producing Pancoast tumor.

Clinicopathologic characteristics and treatment outcomes of hepatoid adenocarcinoma of the stomach, a rare but unique subtype of gastric cancer

BACKGROUND

Gastric hepatoid adenocarcinoma (HAC) is a special type of gastric cancer that morphologically mimics hepatocellular carcinoma. In this study, we performed an evaluation of clinicopathologic characteristics, treatment outcome, and prognosis in patients with gastric HAC.

METHODS

We consecutively enrolled patients with pathologically proven gastric HAC at Seoul National University Hospital between January 1996 and December 2008 and conducted a retrospective review. Among 15,253 patients with gastric cancer, 26 patients (0.17%) were diagnosed as gastric HAC.

RESULTS

Among 26 patients, 22 were male and the median age was 63. Stage at diagnosis was stage IB in 3 patients, stage II in 6 patients, stage III in 7 patients, and stage IV in 10 patients. Eight patients out of 18 patients with stage IB, II, III, and IV relapsed after curative surgery. Relapse-free survival for these patients was 16.67 months. The most common metastatic site was intraabdominal lymph nodes (n = 9), followed by the liver (n = 8). Thirteen patients received palliative chemotherapy. The most commonly used regimen was a combination of fluoropyrimidine and platinum. Partial response was observed in one patient and stable disease in 5 patients. Median overall survival and progression free survival of these patients were 8.03 (95% CI: 6.59-9.47) and 3.47 months (95% CI: 0.65-6.29), respectively.

CONCLUSIONS

Gastric HAC is a very rare but unique type of stomach cancer. Early detection of this type of cancer is of critical importance to patient prognosis. Additional studies to reveal the biology of this tumor are warranted.

Alpha-fetoprotein-producing adenocarcinoma in which the metastatic route was determined from calcified lesions

Alpha-fetoprotein (AFP)-producing adenocarcinoma is known for its rapid progression and poor prognosis, and chemotherapy regimens are yet to be standardized. Here we describe the first report of AFP-producing adenocarcinoma with calcification. The metastatic route was visualized from the calcification, and combination chemotherapy was performed. A 77-year-old Japanese man was transferred to our hospital for treatment of liver tumors. Computed tomography (CT) revealed multiple liver tumors with portal vein tumor thrombosis. The tumors were highly attenuated before enhancement, suggesting various degrees of calcification. Serum levels of carcinoembryonic antigen (CEA), AFP, and the proportion of fucosylated AFP were considerably elevated. Gastroduodenoscopy revealed an elevated tumor occupying the duodenal bulb with an ulcerative lesion in the vicinity of the gastroduodenal junction, and biopsy specimens from the duodenum and liver revealed medullary adenocarcinoma with calcification. Three-dimensional reconstruction of CT images clearly showed that the calcified lesions had spread from the gastroduodenal junction to the liver via a route comprising the corresponding local vein, the superior mesenteric vein, and portal vein. The patient was accordingly diagnosed with calcified AFP-producing adenocarcinoma with multiple liver metastases. Combination chemotherapy using TS-1 and cisplatin (CDDP) resulted in a striking response for the initial 4 months in terms of tumor markers and CT findings. This is the first report of AFP-producing adenocarcinoma with calcification. A metastatic route from the primary tumor to the liver was clearly visualized by tracing the calcified lesions. Combination chemotherapy based on 5-fluorouracil and CDDP may have the potential to prolong survival.

Analysis of clinicopathologic features and prognostic factors in hepatoid adenocarcinoma of the stomach

OBJECTIVE

To investigate the different nature between hepatoid adenocarcinoma of the stomach (HAS) and common stomach cancer without the hepatoid differentiation areas (non-HAS).

METHODS

From January 1996 to December 2007, 45 patients were diagnosed as HAS on the basis of the characteristic histologic features resembling hepatocellular carcinoma in Fudan University Shanghai Cancer Center. The clinicopathologic features and the relevant prognosis of these patients were evaluated. In addition, 225 stage-matched common stomach cancer patients were selected as controls.

RESULTS

Histologically, the polygonal tumor cells were arranged in trabecular fashion or solid nests separated by narrow fibrous stroma composed of sinusoid-like capillaries. Immunohistochemically, the tumor cells were positive for α-fetoprotein. Under transmission electron microscope, numerous circular granules of dense electron were found in the cytoplasm. HAS showed a higher rate of vascular invasion, lymph node metastasis, and liver metastasis than non-HAS. The 5-years survival rates of HAS and non-HAS were 9% and 44%, respectively. The prognosis of HAS was poorer than that of non-HAS (P<0.05).

CONCLUSION

HAS had different clinicopathologic features and prognosis from non-HAS.

Cerebral metastasis from hepatoid adenocarcinoma of the stomach

We first report a rare case of metastasis from gastric hepatoid adenocarcinoma (HAC) to cerebral parenchyma, in a 50-year-old Chinese patient. He complained of a one-month history of a paroxysm of headache in the left temple and pars parietalis accompanied with binocular caligation caligo, insensible feeling of limbs and transient anepia. Magnetic resonance (MR) imaging revealed a spherical occupying lesion in the left posterior-temple lobe which was clinically diagnosed as a metastatic tumor. Three years ago, the patient accepted total gastrectomy as he was pathologically diagnosed at gastroscopy having an adenocarcinoma. Eight months after gastrectomy, the occupying lesion in liver was detected by ultrasound and CT, and he accepted transcatheter arterial embolization. Before operation of the brain metastasis, no obvious abnormality was found in liver by ultrasound. Histopathological characteristics of the brain tumor were identical to those of stomach tumor. The growth pattern of both tumors showed solid cell nests. The tumor cells were polygonal, and had abundant eosinophilic cytoplasm and round nuclei with obvious nucleoli. Sinusoid-like blood spaces were located between nodular tumor cells. Immunohistochemistry-stained tumor cells were positive for AFP and negative for Hep-Par-1. According to these histopathological findings, both tumors were diagnosed as HAC and metastatic HAC. The patient remained alive 16 mo after tumorectomy of the cerebral metastasis. The differential diagnosis of brain metastasis from metastatic tumors should use a panel of antibodies to avoid confusing with the brain metastasis of hepatocellular carcinoma (HCC). This paper describes this rare case of metastasis from gastric hepatoid adenocarcinoma to cerebral parenchyma, and provides a review of the literature concerning its histopathological and immunohistochemical characteristics.

A case of an alpha-fetoprotein-producing intrahepatic cholangiocarcinoma suggests probable cancer stem cell origin

Recent evidence suggests that some cancers may originate from cancer stem cells, which may derive from carcinogenesis of normal stem cells. A hepatic progenitor cell population, which gives rise to hepatocytes and cholangiocytes, has been suggested in humans, though whether these cells can give rise to malignant tumors has not been confirmed. We report here a case of an alpha-fetoprotein (AFP)-producing intrahepatic cholangiocarcinoma (ICC) in an 81-year-old woman with chronic hepatitis C viral infection, suggesting malignant transformation of hepatic stem cells as a mechanism for hepatic neoplasia. Abdominal computed tomography revealed a low-density mass with surrounding enhancement measuring 5 cm x 5 cm in segments IV and VIII of the liver. The preoperative serum levels of tumor markers were 1.7 ng/ml of carcinoembryonic antigen, 22 mAU/ml of protein induced by vitamin K absence or antagonist II, 43.4 U/ml of carbohydrate antigen 19-9, and 1,560 ng/ml of AFP. Following central bisegmentectomy of the liver, serum AFP levels decreased dramatically. Histologically, the tumor cells showed indistinct glandular structures with abundant fibrous stroma. Immunohistochemical analysis demonstrated that the neoplastic cells reacted strongly to antibodies against AFP and cytokeratin (CK) 7. In addition, cancer cells showed partially positive reaction to anti-CK14, a liver stem cell marker, and to anticluster designation (CD) 133, a hematopoietic stem cell marker, and negative reaction to antihepatocyte paraffin (HepPar) 1. These data may indicate that the tumor was derived from a normal liver stem cell that underwent oncogenic transformation.

Hepatoid carcinoma of the pancreas: a case report and literature review of a heterogeneous group of tumors

Hepatoid carcinomas are tumors that display, at least focally, cytologic and/or architectural features of hepatocellular carcinoma. They have been described in several organs, most notably in the stomach and ovary. We report a case of hepatoid carcinoma of the pancreas that developed in a 41-year-old woman in association with a pancreatic endocrine carcinoma. The fine needle aspiration material was characterized by the presence of monotonous, small-to-medium sized tumor cells with round nuclei and finely granular chromatin, intermixed with more atypical tumor cells displaying larger nuclei with coarse clumped chromatin, prominent nucleoli, and moderate amounts of foamy cytoplasm. The excised specimen displayed a poorly differentiated pancreatic endocrine carcinoma associated with well-defined islands of larger tumor cells growing in a perisinusoidal pattern which, based on their immunohistochemical profile and the demonstration of bile, proved to represent a hepatoid component. This case and prior examples in the literature suggest that hepatoid carcinomas of the pancreas appear to be a heterogeneous group of tumors (pure or associated with another histologic component) that are often associated with early liver metastasis and a short survival, although those arising as a component of endocrine tumors seem to fare slightly better. Hepatoid carcinoma of the pancreas should be included in the differential diagnosis of pancreatic tumors composed of large eosinophilic cells.

Hepatoid carcinoma of the pancreas

Background

Hepatoid carcinoma of the pancreas is extremely rare. This article tries to summarize the clinical features and outcomes of pancreatic hepatoid carcinoma.

Methods

The data pool for analysis includes the case we encountered with hepatoid carcinoma of the pancreas and the reported cases in the literature.

Results

Twenty-three cases of hepatoid carcinoma of the pancreas were analyzed. This tumor occurred more frequently in male than in female patients (69.6 vs. 30.4 %). Tumor sizes range from 0.5 to 11.0 cm with median of 6.0 cm. The most common symptom was epigastric pain (36.4 %). When the tumor locates at pancreatic head, nausea/vomiting (62.5 %) is more common, followed by jaundice and epigastric pain (50.0 %). For those at pancreatic body-tail, 42.9 % of the patients presented no symptom. Alpha-fetoprotein (AFP) was abnormally elevated in 60 % of the cases. Hepatoid carcinoma in the pancreas could be either pure form or mixed form with other malignancy (40.9 %), with the most common coexisted pathology of malignant neuroendocrine tumor (22.7 %). Metastasis occurred in 36.4 % of the cases at the diagnosis of this tumor, including liver metastasis in 31.8 % and lymph node metastasis in 21.1 %. The overall 1-year survival rate was 71.1 % and 5-year 40.4 %, with a median of 13.0 months. Unresectability, hepatic, and lymph node metastases are associated with negative impact on survival outcome.

Conclusions

Elevation of serum AFP may be a clue leading to the diagnosis of pancreatic hepatoid carcinoma. This tumor could be mixed form with other malignancy. Surgical resection should be the treatment of choice whenever possible.

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.

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.

Malignant mixed Mullerian tumor of the uterine corpus with alpha-fetoprotein-producing hepatoid adenocarcinoma component

OBJECTIVES

Hepatoid adenocarcinoma is a rare tumor and has the histological coexistence of well-differentiated adenocarcinoma and nests of hepatoid cells with immunoreactivity for alpha-fetoprotein (AFP). A case of hepatoid adenocarcinoma in malignant mixed Mullerian tumor of the uterus is presented with a review of the literature.

CASE

The patient is a 63-year-old woman who complained of abnormal genital bleeding. Serum AFP concentration was 5060 ng/ml. Histologically, the tumor was composed of endometrioid adenocarcinoma, neoplastic hepatoid cells, and sarcoma component including leiomyosarcoma and rhabdomyosarcoma. After operation followed by six courses of platinum-based chemotherapy, serum levels of AFP dropped into normal range.

CONCLUSIONS

This is, to our knowledge, the first report of malignant mixed Mullerian tumor of the uterus with an AFP-producing hepatoid adenocarcinoma component.

Malignant mediastinal germ cell tumor with pure hepatoid differentiation

We describe a germ cell tumor of anterior mediastinal origin, with pure hepatoid differentiation and elevated serum AFP in a 41-year-old man. This is the first report of such a neoplasm analyzed by conventional stains and immunohistochemistry. Hepatocellular differentiation was proved by immunoreactivity with HepPar-1 and alpha-fetoproein (AFP), membranous expression of carcinoembryonic antigen (CEA-poly) in a canalicuar pattern, and focal expression of cytokeratin 19 in abortive ductular structures. Our investigation shows that mediastinal germ cell tumors with hepatoid components typically arise in middle-aged men; they are of pure hepatoid differentiation, as demonstrated here, or exclusively associated with yolk sac structures.

Hepatoid carcinoma of the uterus that collided with carcinosarcoma

The case of a 68-year-old woman who was seen at Tokyo Kousei Nenkin Hospital because of abnormal genital bleeding is described. A malignant uterine tumor was suspected based on biopsy results. Hysterectomy and bilateral salpingo-oophorectomy were performed. Grossly, a solid whitish tumor occupied the area from the endocervix to the uterine body. On the consecutive fundal side, a whitish tumor protruded into the uterine cavity. Histologically, the tumor occupying the endocervical side showed a trabecular growth pattern. Many periodic acid-Schiff (PAS)-positive hyaline globules were observed. The cytoplasm of the tumor cells and the hyaline globules were immunohistochemically positive for alpha-fetoprotein (AFP). The tumor occupying the fundal side was identified as having endometrioid adenocarcinoma and spindle cell sarcoma components. The two tumors collided at a clear boundary. The present case was pathologically diagnosed as a collision cancer involving a hepatoid carcinoma and a carcinosarcoma. To our knowledge, this is the fourth reported case of a hepatoid carcinoma of the uterus. When no lesion is detected in the liver and stomach of a patient whose serum AFP level is abnormally high, the female reproductive system, such as the ovaries and uterus, should be examined as a possible site of AFP-producing cancer.

Hepatoid adenocarcinoma of the urinary bladder

Hepatoid adenocarcinoma is rare in the urinary bladder with only three well-illustrated previously reported cases. Pathological diagnosis is based on a combination of histological features resembling hepatocellular carcinoma and the positive immunostaining for alpha-fetoprotein. We present the clinicopathological features of four additional cases. The patients were males 66, 85, 61 and 68 years old. Hematuria was the initial symptom in all four patients. Two cases were treated by cystoprostatectomy and the remaining two by transurethral resection of the bladder. On histology, the cases showed a mixture of cells growing in a solid fashion and sheets or anastomosing trabeculae of hepatoid cells merging focally with a secondary glandular pattern of adenocarcinoma. Intracytoplasmic hyaline globules in all and bile production in three of the cases also supported the impression of hepatocytic differentiation. Immunoreactivity for alpha-fetoprotein, low molecular weight cytokeratin, alpha-1-antitrypsin, albumin, epithelial membrane antigen and a striking canalicular pattern when stained against polyclonal carcinoembryonic antigen (CEA), all indicate hepatocellular differentiation. The hepatic nature of the cells was further assessed by detecting the recently incorporated marker hepatocyte paraffin 1, by means of immunohistochemistry and albumin gene mRNA non-isotopic in situ hybridization, both of which had positive signals in all four cases. Three patients died 12, 14 and 19 months after diagnosis. The fourth patient was alive with disease at 26 months of follow-up. In conclusion, hepatoid adenocarcinoma seems to be an aggressive malignant neoplasm that is rare in the bladder whose correct diagnosis may need appropriate immunohistochemical and in situ hybridization means in addition to a complete patient clinical and pathological evaluation. The exact histogenesis and classification of these tumors remains to be established.

An alpha-fetoprotein-producing hepatoid adenocarcinoma of the endometrium

BACKGROUND

Hepatoid adenocarcinomas are tumors that arise outside the liver but resemble hepatic tissue and produce alpha-fetoprotein. These neoplasms have been described in many locations, including the lung, gastrointestinal tract, and urogenital tract, and have been associated with a poor prognosis. Two previously reported cases of hepatoid adenocarcinoma of the endometrium described aggressive tumors that were unresponsive to multiple forms of therapy.

CASE

We report a case of an alpha-fetoprotein-producing hepatoid adenocarcinoma of the endometrium that was successfully treated with surgery and adjuvant chemotherapy.

CONCLUSION

Eight years after therapy, the patient is alive with no evidence of disease, suggesting that cytoxan, adriamycin, and cis-platinum are active agents in this unusual entity.

Alpha-fetoprotein producing uterine corpus carcinoma: A hepatoid adenocarcinoma of the endometrium

A case of alpha-fetoprotein (AFP) producing endometrial carcinoma in a 60-year-old Japanese woman is presented. The patient complained of abnormal vaginal bleeding of 10 days' duration. On admission a uterine corpus mass and high serum AFP concentration (31950 ng/mL) was noted. There was no tumorous lesion in any other organ radiographically and endoscopically. Histologically, the biopsy specimen taken from the uterine mass showed a poorly differentiated endometrial carcinoma and a radical hysterectomy was subsequently performed. The postoperative serum AFP value transiently decreased with chemotherapy, however, lung metastases were found and the patient died 12 months following surgery. The resected uterus had a necrotic tumor, 6 x 5 x 4 cm in size, filling the endometrial cavity, characterized by exophytic growth with infiltration in the myometrium. Histologically, the tumor was composed of the main medullary carcinoma area with microcysts and admixed small areas of well-differentiated endometrioid adenocarcinoma, accompanied by a smooth transition with one another. In both the areas, the tumor cells had immunoreactive AFP, alpha-1-antitripsin, albumin, transferrin, carcinoembryonic antigen, CA19-9, and epithelial membrane antigen. There was no histologic evidence for a germ cell tumor. Based on these findings, this uterine corpus tumor was regarded as hepatoid variant of endometrial carcinoma. Although the histogenesis remains controversial, we assume the hypothesis that the tumor may arise in the endometrium per se in association with abnormal differentiation of muellerian duct elements.

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.

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.

Carcinoma of the stomach with hepatocyte differentiation (hepatoid adenocarcinoma)

A case of hepatoid adenocarcinoma of the stomach is reported, and the literature is reviewed. The stomach is one of the most common sites in which hepatoid adenocarcinomas have been detected. Of the 59 cases reviewed from the literature (including the current case), a 2:1 male predominance was noted, and the serum alpha-fetoprotein level was almost always increased. All patients were adults, and most had evidence of metastases at the time of resection. Prognosis seems less favorable than that associated with the more common intestinal type of adenocarcinoma of the stomach. Hepatoid adenocarcinomas typically show periodic acid-Schiff-positive, diastase-resistant intracytoplasmic globules, which are demonstrated to be positive with antibodies to alpha-fetoprotein. The tumor cells resemble liver cells, and rare cases, including our own, have evidence of bile production. In our case, messenger RNA for albumin, unique to liver cells, was demonstrated by in situ hybridization of the tumor cells.

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.

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.

Alpha-fetoprotein-producing adenocarcinoma of the sigmoid colon with possible hepatoid differentiation

A patient with adenocarcinoma of the sigmoid colon producing alpha-fetoprotein (AFP) is described. Hepatoid differentiation is suggested by the morphological appearance and production of hepatic-type AFP. The possible histogenesis of such a tumor is discussed.

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.