Gastroblastoma in a 28-year-old man with nodal metastasis: proof of the malignant potential

Gastroblastoma - a case report and literature review

OBJECTIVE

To report a new case of gastroblastoma and conduct an exhaustive review of the clinical, morphological, immunohistochemical, molecular features, diagnosis, treatment, and prognosis, to enhance understanding of this condition.

METHODS

We retrospectively analyzed the case of a 50-year-old woman diagnosed with gastroblastoma and conducted a review and summary of relevant literature.

RESULTS

To date, 27 cases have been reported, including the present case. The mean patient age at the time of presentation was 35.0 years (range, 5-74 years), and the disease showed no sex predilection. The most common location was the gastric antrum, and the average lesions size was 5.7 cm (range, 1.3-15 cm). Most patients underwent gastrectomy(n = 23), while several underwent ESD(n = 2) or EFTR(n = 1). Fusion genes were identified, including MALAT1-GLI1(n = 8), EWSR1-CTBP1(n = 1), PTCH1:GLI2(n = 1), and ACTB-GLI1(n = 1)Four patients had metastasis and one of them dead of disease. Immunohistochemical (IHC) analysis revealed that pancytokeratin was always positive in epithelioid components, while vimentin and CD10 were always positive in mesenchymal components. CD56 were often positive in both two components.

CONCLUSION

A comprehensive evaluation of clinical and pathological features is crucial for accurate diagnosis. Partial gastrectomy and EFTR could be an appropriate treatment. The risk factors that affect the prognosis need more cases to be clearly defined. We present this exhaustive literature review to increase awareness of gastroblastoma, better characterize the disease, and provide a reference point for gastroblastoma research in the future.

Gastroblastoma with a novel ACTB::GLI1 gene fusion in a 19-year-old male

Gastroblastoma is a rare gastric biphasic tumor composed of mesenchymal and epithelial elements in variable proportions. These tumors usually arise in the gastric antrum of children and young adults and are reported to harbor a recurrent MALAT1::GLI1 fusion. Herein we report a case of gastroblastoma in a 19-year-old male who presented with intermittent epigastric abdominal discomfort. Antrectomy revealed a 5.6-cm multi-lobulated, tan-pink mass with solid and focally cystic areas involving the submucosa, muscularis propria, and subserosa. All tumor cells demonstrated immunoreactivity for GLI-1, CD56, and vimentin; epithelial elements expressed pancytokeratins (AE1/AE3 and Oscar), and mesenchymal cells demonstrated focal positivity for CD10. Next generation sequencing revealed a novel ACTB::GLI1 fusion without evidence of the recurrent MALAT1::GLI1 fusion. Nine months after surgery, the patient is well without evidence of recurrence or metastases. To our knowledge, this is the first case of gastroblastoma harboring this novel ACTB::GLI1 fusion.

Blastomas of the digestive system in adults: A review

Blastomas, characterized by a mixture of mesenchymal, epithelial, and undifferentiated blastematous components, are rare malignant neoplasms originating from precursor blast cells. This review focuses on digestive system blastomas in adult patients, including gastroblastoma, hepatoblastoma, and pancreatoblastoma. Gastroblastoma is a biphasic, epitheliomesenchymal tumor, with only sixteen cases reported to date. In addition to the characteristic histology, metastasis-associated lung adenocarcinoma transcript 1 - glioma-associated oncogene homolog 1 gene fusion is typical, although recently novel ewing sarcoma breakpoint region 1 - c-terminal binding protein 1 and patched 1 - glioma-associated oncogene homolog 2 fusions have been described. Hepatoblastoma is exceptionally rare in adults and can show a variety of histologic patterns which may cause diagnostic difficulty. Pancreatoblastoma, primarily a pediatric tumor, displays acinar differentiation and squamoid nests with other lines of differentiation also present, especially neuroendocrine. Diagnostic approaches for these blastomas include a combination of imaging modalities, histopathological examination, and molecular profiling. The treatment generally involves surgical resection, which may be supplemented by chemotherapy or radiotherapy in some cases. Prognoses vary with gastroblastoma generally showing favorable outcomes post-surgery whereas hepatoblastoma and pancreatoblastoma often have poorer outcomes, particularly in the setting of metastases. This review highlights the complexity of diagnosing and managing these rare adult blastomas as well as the need for ongoing research to better understand their pathogenesis and improve treatment strategies.

Gastroblastoma: a case report and literature review

Objective

Gastroblastoma is an extremely rare gastric tumor. Its pathogenesis remains unclear and there is a lack of specific clinical symptoms. The aim of this paper is to report a case of gastroblastoma and provide references for the diagnosis, treatment, and prognosis of this disease.

Methods

The diagnosis and treatment of a 51-year-old female patient with gastroblastoma were retrospectively reported. Analyzing this case by combining the clinical data such as imaging and pathological results of patients with the relevant literature.

Results

The patient's chief complaint was the presence of melena persisted for over two weeks. Abdominal contrast-enhanced CT showed gastric antral nodules, and micro-probe endoscopic ultrasonography was considered as "gastric antral protruding lesions". The initial diagnosis of "gastric stromal tumor" was made after admission, and surgical treatment was performed on September 23, 2021. Postoperative pathology showed that gastric mixed epithelial and stromal tumor, combined with immunohistochemical staining, was suggestive of gastroblastoma. No signs of tumor recurrence or metastasis were observed during the 2-year follow-up.

Conclusion

Combined with the existing literature reports, the incidence of gastroblastoma is mainly higher in young men, and the predilection site is gastric antrum. The biological behavior of the tumor tends to be indolent, and the prognosis of most cases is favorable. However, due to the extremely small number of cases, this conclusion still needs a large number of cases and follow-up data to support. Postoperative pathological and immunohistochemical examination results are the only methods for definite diagnosis at present, and surgery is the first choice for treatment.

Unusual or Uncommon Histology of Gastric Cancer

This review comprehensively examines the diverse spectrum of gastric cancers, focusing on unusual or uncommon histology that presents significant diagnostic and therapeutic challenges. While the predominant form, tubular adenocarcinoma, is well-characterized, this review focuses on lesser-known variants, including papillary adenocarcinoma, micropapillary carcinoma, adenosquamous carcinoma, squamous cell carcinoma (SCC), hepatoid adenocarcinoma, gastric choriocarcinoma, gastric carcinoma with lymphoid stroma, carcinosarcoma, gastroblastoma, parietal cell carcinoma, oncocytic adenocarcinoma, Paneth cell carcinoma, gastric adenocarcinoma of the fundic gland type, undifferentiated carcinoma, and extremely well-differentiated adenocarcinoma. Although these diseases have different nomenclatures characterized by distinct histopathological features, these phenotypes often overlap, making it difficult to draw clear boundaries. Furthermore, the number of cases was limited, and the unique histopathological nature and potential pathogenic mechanisms were not well defined. This review highlights the importance of understanding these rare variants for accurate diagnosis, effective treatment planning, and improving patient outcomes. This review emphasizes the need for ongoing research and case studies to enhance our knowledge of these uncommon forms of gastric cancer, which will ultimately contribute to more effective treatments and better prognostic assessments. This review aimed to broaden the pathological narrative by acknowledging and addressing the intricacies of all cancer types, regardless of their rarity, to advance patient care and improve prognosis.

LncRNA MALAT1 signaling pathway and clinical applications in overcome on cancers metastasis

In spite of its high mortality rate and difficulty in finding a cure, scientific advancements have contributed to a reduction in cancer-related fatalities. Aberrant gene expression during carcinogenesis emphasizes the importance of targeting the signaling networks that control gene expression in cancer treatment. Long noncoding RNAs (lncRNAs), which are transcribed RNA molecules that play a role in gene expression regulation, are a recent innovative therapeutic approach for diagnosing and treating malignancies. MALAT1, a well-known lncRNA, functions in gene expression, RNA processing, and epigenetic control. High expression levels of MALAT1 are associated with several human disorders, including metastasis, invasion, autophagy, and proliferation of cancer cells. MALAT1 affects various signaling pathways and microRNAs (miRNAs), and this study aims to outline its functional roles in cancer metastasis and its interactions with cellular signaling pathways. Moreover, MALAT1 and its interactions with signaling pathways can be promising target for cancer treatment.

Gastroblastoma of the Pylorus: A Case Report and Review of the Literature

Gastroblastoma is an extremely rare biphasic tumor that typically occurs in the stomach in patients between the ages of 10 and 30. Only 16 cases have been reported previously. These tumors are important to diagnose and distinguish from more aggressive neoplasms; although numbers are small, prognosis appears excellent overall with complete excision, with only occasional metastasis and/or local recurrence. We report a case of gastroblastoma in a 26-year-old male arising from the pylorus and extending through the first and second portions of the duodenum. This is the first case to be reported from this specific location.

Gastroblastoma in a 5-year-old child: a case report and literature review

Background

Gastroblastoma is an extremely rare stomach tumor with a biphasic cell morphology of epithelioid and spindle cells. Due to the low incidence rate and the lack of specific clinical characteristics, it is easy to misdiagnose. Detailed imaging analysis is also unavailable. At present, we reported a case of gastroblastoma to analyze its clinical and imaging characteristics. In addition, we reviewed the imaging findings, current diagnosis, treatment, and outcome of gastroblastoma.

Case presentation

A 5-year-old girl was admitted to our hospital with upper abdominal pain and melena. Endoscopic examination showed a protuberant submucosal mass on the greater curvature of the gastric body. Abdominal ultrasonography and an abdominal enhanced computed tomography further confirmed the mass. The patient was pathologically diagnosed with gastroblastoma after radical surgery in February 2021.

Conclusion

We described a rare case of gastroblastoma and may provide a new perspective on imaging diagnosis, treatment, and outcome of this tumor. Gastroblastoma tends to occur in male patients, typically affects young people, and has low malignant potential and a low rate of recurrence and metastasis. Gastroblastoma usually arises in the gastric muscularis propria with hypoecogenic and submucosal characteristics in ultrasound examination and significant enhancement in computed tomography (CT) scan. Surgical resection and regular follow-up after surgery are the main management of the disease. Clinicians should strengthen the understanding of this rare tumor for early detection and treatment.

Gastroblastoma without GLI1 and EWSR1 gene breaks

OBJECTIVE

To report a rare gastroblastoma; discuss its clinical features, histopathological morphology, diagnosis, differential diagnosis, treatment, and prognosis; and so as to improve the understanding on this disease and provide reference for its diagnosis, treatment, and prognosis.

METHODS

The diagnosis and treatment, imaging examination, pathological, and genetic data of a 19-year-old young female patient with gastroblastoma were analyzed retrospectively, and the relevant literature was reviewed and summarized.

RESULTS

The patient was found to have a "gastrointestinal stromal tumor" for 3 days by physical examination in another hospital. Abdominal CT and MRI considered "solid pseudopapilloma of pancreas" and clinically planned to perform "radical pancreatoduodenectomy." During the operation, the tumor was observed to bulge from the posterior wall of the gastric antrum, and the root was located in the gastric antrum, so it was changed to "partial gastrectomy + Ronx-y gastrojejunal anastomosis." The postoperative pathology showed that the tumor was bi-differentiated between gastric epithelium and mesenchymal. Combined with the results of IHC and the opinions of several consultation units, the diagnosis of gastric blastoma (low-grade malignancy) was supported. However, the fracture rearrangement of GLI1 and EWSR1 genes was not detected by FISH. After 19 months of follow-up, no signs of tumor recurrence and metastasis were found.

CONCLUSION

Combined with existing literature reports, gastroblastoma occurs in young people, equally in men and women, and tends to occur in the gastric antrum. The biological behavior of the tumor tends to be inert, and the prognosis of most cases is good. Postoperative pathology and IHC are reliable methods for the diagnosis of gastric blastoma, and surgical resection of the lesion is the preferred treatment.

Gastroblastoma mimics the embryonic mesenchyme of the foregut: a case report

BACKGROUND

Gastroblastoma is a rare gastric tumor composed of epithelial and spindle cell components. The characteristic MALAT-GLI1 fusion gene has only been identified in 5 reported cases. We report the morphological characterization of gastroblastoma with the MALAT1-GLI1 fusion gene in a young Japanese woman.

CASE PRESENTATION

A 29-year-old Japanese woman visited Iwate Medical University Hospital with upper abdominal pain. Computed tomography revealed a tumor in expansive lesions involving the gastric antrum. Histologically, we observed a biphasic morphology composed of epithelial and spindle cell components. The epithelial components appeared as slit-like glandular structures with tubular or rosette-like differentiation. The spindle cell components consisted of short spindle-shaped oval cells. Immunohistochemical (IHC) analysis revealed that the spindle cell component was positive for vimentin, CD10, CD56, GLI1, and HDAC2, and focally positive for PD-L1. The epithelial component was positive for CK AE1/AE3, CAM5.2, and CK7, and negative for CK20 and EMA. Both components were negative for KIT, CD34, DOG1, SMA, desmin, S100 protein, chromogranin A, synaptophysin, CDX2, and SS18-SSX. The MALAT-GLI1 fusion gene was detected molecularly.

CONCLUSIONS

We report the following new findings with this case: (i) gastric tumors mimic the gastrointestinal mesenchyme in the embryonic period; (ii) nuclear expression of PD-L1 and HDAC2 were observed in the spindle cell component of a gastroblastoma. We speculate that histone deacetylase (HDAC) inhibitors may offer a promising treatment option for gastroblastoma.

Gastroblastoma Treated by Endoscopic Submucosal Excavation with a Novel PTCH1::GLI2 Fusion: A Rare Case Report and Literature Review

Gastroblastoma is an extremely rare stomach tumor that primarily presents in adolescent and early adulthood, with a biphasic cell morphology of epithelioid and spindle cells. In light of its similarity to other childhood blastomas, it has been named gastroblastoma. Few patients showed a potential of metastasis and recurrence, however, most of the reported cases were alive, with no evidence of the disease after surgical treatment. Commonly, MALAT1-GLI1 fusion has been considered to be the most relevant mutation. Herein, we present a case of an asymptomatic 58-year-old man who happened to find a submucosal gastric mass during a gastroscope and received endoscopic submucosal excavation (ESE). He turned out to have a gastroblastoma with a novel PTCH1::GLI2 fusion confirmed by Sanger sequencing. The patient was discharged two days after ESE without any complication and was recurrence-free during his one-year follow-up. According to the previous literature and our own experience, in cases with characteristic histopathology and immunohistochemistry patterns, a diagnosis of gastroblastoma should be considered even without a MALAT1-GLI1 fusion. Gastroblastoma pursues a favorable clinical outcome and endoscopic therapy could be an effective alternative treatment choice.

Case Report: Submucosal gastroblastoma with a novel PTCH1::GLI2 gene fusion in a 58-year-old man

Gastroblastoma is a rare biphasic tumor of the stomach that generally presents in young patients. MALAT1-GLI1 gene fusion was considered to be the characteristic molecular alteration of this tumor in previous reports. Herein, we described a 58-year-old man with a mass mainly located in the submucosa of the stomach. Microscopic examination showed a biphasic morphology with the same immunohistochemical phenotype as gastroblastoma. Interestingly, a novel PTCH1::GLI2 fusion rather than MALAT1-GLI1 fusion was detected in the tumor by RNA-based next generation sequencing (NGS). This was the first report that demonstrated a novel PTCH1::GLI2 gene fusion in gastroblastoma, and thus expanded the molecular spectrum of this tumor. The underlying pathogenesis merits further investigation.

Gastroblastoma with a novel EWSR1-CTBP1 fusion presenting in adolescence

Gastroblastomas are rare tumors with a biphasic epithelioid/spindle cell morphology that typically present in early adulthood and have recurrent MALAT1-GLI1 fusions. We describe an adolescent patient with Wiskott-Aldrich syndrome who presented with a large submucosal gastric tumor with biphasic morphology. Despite histologic features consistent with gastroblastoma, a MALAT1-GLI1 fusion was not found in this patient's tumor; instead, comprehensive molecular profiling identified a novel EWSR1-CTBP1 fusion and no other significant genetic alterations. The tumor also overexpressed NOTCH and FGFR by RNA profiling. The novel fusion and expression profile suggest a role for epithelial-mesenchymal transition in this tumor, with potential implications for the pathogenesis of biphasic gastric tumors such as gastroblastoma.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Recent developments in gastroesophageal mesenchymal tumours

The pathologist's approach to gastroesophageal mesenchymal tumours has changed dramatically during the last 25 years. In particular, gastrointestinal stromal tumour (GIST) has evolved from a wastebasket mesenchymal tumour category to a precisely defined entity with an increasingly detailed genetic subclassification. This subclassification has brought gastrointestinal mesenchymal neoplasia into the realm of precision medicine, with specific treatments optimised for particular genetic subtypes. Molecular genetic data have also greatly improved our understanding of oesophageal mesenchymal tumours, including the discovery that so-called 'giant fibrovascular polyps' in fact represent a clinically distinctive presentation of well-differentiated liposarcoma. Here, we will focus on gastroesophageal mesenchymal tumours for which there have been recent developments in classification, molecular genetics or tumour biology: granular cell tumour, 'giant fibrovascular polyp'/well-differentiated liposarcoma, plexiform fibromyxoma, gastroblastoma and, of course, GIST.

Gene of the month: GLI-1

The Glioma-associated homologue-1 (GLI-1) gene was first discovered to be amplified in glioblastoma multiforme. It encodes for a zinc-finger transcription factor in the Kruppel family of proteins and is important in the sonic hedgehog signalling pathway. GLI-1 also plays a role in several other pathways and is important for proliferation, migration, invasion, growth and angioinvasion, and cancer stem cell self-renewal in a variety of malignancies. GLI-1 is amplified in several malignancies, including an epithelioid, pericytomatous soft tissue neoplasm that can exhibit malignant behaviour. More recently, GLI-1 fusions with other partner genes have been found in three rare tumours: a pericytomatous tumour with a t(7;12) translocation, where it partners with Actin beta 1, and gastroblastoma and plexiform fibromyxoma, where the partner gene is metastasis-associated lung adenocarcinoma transcript 1, respectively.

A Malignant Neoplasm From the Jejunum With a MALAT1-GLI1 Fusion and 26-Year Survival History

The transcription factor GLI1 is a critical effector of the sonic hedgehog pathway. Gene fusions that activate GLI1 have recently been reported in several tumor types including gastroblastoma, plexiform fibromyxoma, a subset of pericytomas, and other soft tissue tumors. These tumors arise in a wide variety of anatomical origins and have variable malignant potentials, morphologies, and immunohistochemistry profiles. In this case report, we describe a malignant tumor from the jejunum with a MALAT1-GLI1 gene fusion that expressed a truncated constitutively active GLI1 protein and GLI1 targets that were detectable by immunohistochemistry. The tumor showed high-grade epithelioid and spindle cell morphology, strongly expressed CD56, and focally expressed other neuroendocrine markers and cytokeratins, but not S100 protein or SMA. The tumor recurred multiple times in liver, soft tissue, and lung over the course of 26 years, the longest reported follow-up for a GLI1 fusion-associated tumor. These metastatic tumors were also composed of epithelioid and spindle cells, but showed lower morphological grade than the primary tumor. The metastatic tumors resembled the recently reported "malignant epithelioid neoplasms with GLI1 rearrangements." The tumor also had a relatively high tumor mutation burden for a sarcoma. This case report expands the sites of origin for GLI1 rearranged neoplasms and shows that despite being associated with high-grade morphology, these malignancies can be associated with very long-term survival.

Gastroblastoma in Adulthood-A Rarity among Rare Cancers-A Case Report and Review of the Literature

Gastroblastoma (GB) is a rare gastric epithelial-mesenchymal neoplasm, first described by Miettinen et al. So far, all reported cases described the tumor in children or young adults, and similarities with other childhood blastomas have been postulated. We report a case of GB in a 43-year-old patient with long follow up and no recurrence up to 100 months after surgery. So far, this is the second case of GB occurring in the adult age >40-year-old. Hence, GB should be considered in the differential diagnosis of microscopically comparable conditions in adults carrying a worse prognosis and different clinical approach.

Gastroblastoma harbors a recurrent somatic MALAT1-GLI1 fusion gene

Gastroblastoma is a rare distinctive biphasic tumor of the stomach. The molecular biology of gastroblastoma has not been studied, and no affirmative diagnostic markers have been developed. We retrieved two gastroblastomas from the consultation practices of the authors and performed transcriptome sequencing on formalin-fixed paraffin-embedded tissue. Recurrent predicted fusion genes were validated at genomic and RNA levels. The presence of the fusion gene was confirmed on two additional paraffin-embedded cases of gastroblastoma. Control cases of histologic mimics (biphasic synovial sarcoma, leiomyoma, leiomyosarcoma, desmoid-type fibromatosis, EWSR1-FLI1-positive Ewing sarcoma, Wilms' tumor, gastrointestinal stromal tumor, plexiform fibromyxoma, Sonic hedgehog-type medulloblastomas, and normal gastric mucosa and muscularis propria were also analyzed. The gastroblastomas affected two males and two females aged 9-56 years. Transcriptome sequencing identified recurrent somatic MALAT1-GLI1 fusion genes, which were predicted to retain the key domains of GLI1. The MALAT1-GLI1 fusion gene was validated by break-apart and dual-fusion FISH and RT-PCR. The additional two gastroblastomas were also positive for the MALAT1-GLI1 fusion gene. None of the other control cases harbored MALAT1-GLI1. Overexpression of GLI1 in the cases of gastroblastomas was confirmed at RNA and protein levels. Pathway analysis revealed activation of the Sonic hedgehog pathway in gastroblastoma and gene expression profiling showed that gastroblastomas grouped together and were most similar to Sonic hedgehog-type medulloblastomas. In summary, we have identified an oncogenic MALAT1-GLI1 fusion gene in all cases of gastroblastoma that may serve as a diagnostic biomarker. The fusion gene is predicted to encode a protein that includes the zinc finger domains of GLI1 and results in overexpression of GLI1 protein and activation of the Sonic hedgehog pathway.

Gastroblastoma, a biphasic neoplasm of stomach: A case report

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Gastroblastoma is a rare gastric biphasic tumor with both epithelial and mesenchymal components.

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To the best of our knowledge only eight cases have been reported in the English literature till date.

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Surgical excision remains the mainstay of treatment.

Introduction

Gastroblastoma is a rare gastric biphasic tumor with both epithelial and mesenchymal components. To the best of our knowledge only eight cases have been reported in the English literature till date.

Presentation of case

We report a case of a 29-year-old female, hospitalized for epigastric pain with poor general condition. An upper gastrointestinal endoscopy showed a polypoid mass in the stomach near the gastric cardia suspicious of gastrointestinal stromal tumor. The patient underwent atypical proximal gastrectomy with splenectomy. Detailed histopathological examination of the resected specimen revealed the diagnosis of gastroblastoma. After six months, the patient developed loco-regional recurrence for which surgical debulking was performed.

Discussion

Gastroblastoma is predominantly seen in young adults with non-specific complaints. They appear as submucosal lesion in the stomach mimicking gastrointestinal stromal tumor. Preoperative diagnosis is often difficult. Surgical resection remains the mainstay of treatment. On histology, they consist of mesenchymal component which stain positively for vimentin and CD10 and epithelial component which is positive for cytokeratin on immunohistochemistry.

Conclusion

Gastroblastoma is a malignant tumor with risk of local recurrence after curative resection.

Gastric hepatoid adenocarcinoma resulting in a spontaneous gastric perforation: a case report and review of the literature

Background

Gastric hepatoid adenocarcinoma (GHAC) is an atypical form of gastric cancer (GC) that has similar tissue morphology to hepatocellular carcinoma and frequently produces alpha-fetoprotein. We present an exceedingly rare case of GHAC resulting in a spontaneous gastric perforation.

Case presentation

A 61-year-old man presented at our institution complaining of abdominal and back pain. A computed tomography scan revealed a spontaneous gastric perforation with a solitary liver tumor and lymph node swelling. Following a diagnosis of advanced-stage GC with a gastric perforation, perforative peritonitis, multiple lymph node metastases, and a solitary metastasis of the lateral segment of the liver, the patient underwent distal gastrectomy. Histopathology of the resected specimen revealed that the tumor cells were arranged in a hepatoid pattern. On immunohistochemical staining, the tumor cells were positive for alpha-fetoprotein and Sal-like protein 4. Thus, the patient was diagnosed with GHAC. Hepatic resection of the solitary liver metastasis was performed. However, recurrence occurred and the patient achieved complete response following tegafur/gimeracil/oteracil-based chemotherapy.

Conclusions

GHAC is a highly malignant histological subtype of GC. We reported on an extremely rare case of GHAC resulting in a spontaneous gastric perforation and reviewed the literature, including epidemiological data, treatment regimens, and the association between GHAC and alpha-fetoprotein-producing GC.

A peculiar case report of extraovarian Brenner tumor arising in the omentum

Background

Brenner tumors almost always develop in the ovary. Exceptionally, extraovarian Brenner tumors have been reported in the lower abdomen or pelvic organs. Here, we introduce a peculiar case of an extraovarian Brenner tumor arising in the omentum.

Case presentation

A 43-year-old woman presented with a palpable abdominal mass. Computed tomography (CT) scan revealed a 9.0-cm solid mass in the omentum. The tumor was not associated with pelvic structures, including the ovaries. It was excised under the clinical impression of an extragastrointestinal stromal tumor or neurogenic tumor. Grossly, the mass was a well-circumscribed solid tumor, with yellow-tan cut surface and minute cystic spaces. Microscopically, the tumor showed well-defined epithelial nests with variable cystic changes embedded in an abundant fibrous stroma. The cells within the nests were reminiscent of benign urothelial cells in that they had oval, frequently grooved nuclei. The epithelial cells focally showed a gradual transition into the surrounding stromal cells with short spindled features. The urothelium-like cells were positive for pancytokeratin, WT-1, p63, CK7, uroplakin-III, and GATA-3 but were negative for CD34, CD10, CK20, c-KIT, DOG-1, PAX-8, and calretinin. Morphological and immunohistochemical features of the tumor were the same as an ovarian Brenner tumor, and so it was diagnosed as an extraovarian Brenner tumor.

Conclusions

Although the location of the tumor was very unusual, we could diagnose the tumor as an extraovarian Brenner tumor on the basis of the histologic and immunohistochemical findings. This is the first case of extraovarian Brenner tumor arising in the omentum near the stomach ever reported in the English literature.

Myoepithelial carcinoma of the stomach: A diagnostic pitfall

Myoepithelioma/myoepithelial carcinomas are not commonly found in soft tissues and are especially rare at visceral sites. This report describes a case of a rare low-grade myoepithelial carcinoma of the stomach. A 61-year-old female patient presented with postprandial abdominal discomfort. Endoscopy revealed a 1.1 cm submucosal lesion. Local excision was performed after malignancy was confirmed by biopsy. The resection margin is free of tumor and she received no adjuvant therapy. The tumor was characterized by multinodular growth with biphasic epithelioid and spindle components. Infiltrative margin and nuclear pleomorphism are seen. Tumor cells were positive for both epithelial and myoepithelial markers. Evidence of epithelial differentiation was confirmed by electron microscopy. No EWSR1 rearrangement was detected. The final diagnosis was low-grade myoepithelial gastric carcinoma. The patient is currently well, and no evidence of recurrence or metastasis was found after ten-month of follow-up. Myoepithelial carcinoma should be considered in the differential diagnosis of a biphasic gastric tumor.

Mesenchymal Tumors of the Gastrointestinal Tract Other than GIST

Mesenchymal tumors involve the gastrointestinal (GI) tract more frequently than other visceral organs. Many such tumors are small, and are benign and increasingly being detected incidentally during colonoscopic screening. Some tumors show distinctive features at this site, such as schwannoma and clear cell sarcoma-like tumor of the GI tract. Without knowledge of these features, recognition of these tumor types can be difficult. This reviews addresses recent developments and diagnostic features of mesenchymal tumors of the GI tract other than gastrointestinal stromal tumor (GIST).