Prognostic significance of human papillomavirus 16 viral load level in patients with oropharyngeal cancer.

Human papillomavirus (HPV) infection in patients with oropharyngeal squamous cell carcinoma (OPSCC) is a major determinant for better prognosis. However, there remain HPV-positive patients who have poor outcomes. The stratification strategy for detecting high-risk patients among those with HPV-positive OPSCC has not been well delineated, especially for Asian patients. We undertook a retrospective cohort study on the survival rate of 89 Japanese patients diagnosed with primary OPSCC. The tumors were concurrently analyzed for the presence of HPV E6 DNA/mRNA, viral DNA load, p16 expression, viral physical status, and viral variant lineage. Human papillomavirus 16 viral DNA was found in 45 (51%) OPSCCs. Human papillomavirus 16 DNA-positive OPSCCs with higher viral load (classified as HPV16 DNA-medium/high OPSCCs) showed significantly favorable overall survival and progression-free survival compared with HPV16 DNA-positive OPSCCs with lower viral load (<10 copies/cell; HPV16 DNA-low OPSCCs) and HPV16 DNA-negative OPSCCs. E6 mRNA expression was observed in all HPV16 DNA-medium/high OPSCCs but not in HPV16 DNA-low OPSCCs. Notably, p16-positive and HPV16 DNA-negative/low OPSCCs showed significantly worse survival than p16-positive and HPV16 DNA-medium/high OPSCCs and resembled HPV-unrelated OPSCCs with regard to survival and risk factor profile. Although not significant, a trend toward shorter survival was observed for HPV16-integrated OPSCCs. Phylogenetic analysis revealed two major types of HPV16 variants termed Asian (A4) and European (A1/A2/A3) variants, but no difference in survival between these variants was observed. Altogether, these findings suggest that HPV viral load is a potentially informative factor for more accurate risk stratification of patients with OPSCC.

Fumarate hydratase-deficient renal cell carcinoma: A clinicopathological study of seven cases including hereditary and sporadic forms.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) has been incorporated into the recent international histological classification of renal tumors. However, to date, there are limited studies describing the clinicopathological features of fumarate hydratase (FH)-deficient RCC, including the hereditary (HLRCC) and sporadic forms. Herein, we present a clinicopathological study of seven cases with FH-deficient RCC. The age of patients ranged from 26 to 70 years with mean and median age of 51.7 and 57 years, respectively. The follow-up data of all patients were available. One patient was alive without the disease and five patients were alive with active disease. One patient died of the disease. Family history of RCC, or skin or uterine smooth muscle tumor within second degree of kinship was present in four of seven patients. Metastasis was observed in all tumors. Metastatic sites included bone, lungs, liver, peritoneum, ovaries, tonsils, or lymph nodes. Grossly, the cut surface of the tumor usually showed light brown, brown, or whitish color. Microscopically, the cytoplasm of the tumor cells was predominantly eosinophilic and all tumors displayed various architectural patterns such as papillary, tubular, solid, or microcystic patterns. Furthermore, two tumors demonstrated a tubulocystic pattern. Sarcomatoid change and rhabdoid features were seen in five tumors and two tumors, respectively. Large cytomegaloviral (CMV) inclusion-like eosinophilic nucleoli surrounded by a clear halo were identified in all tumors. All tumors showed negative immunohistochemical reaction for FH protein. False positive results of TFE3 protein were observed in three tumors. Furthermore, a germline mutation of FH gene was identified in one patient with family history of the disease. In conclusion, FH-deficient RCC includes hereditary and sporadic forms. Grossly, this tumor is solitary and occurs unilaterally. Histologically, the tumor is characterized by various patterns such as papillary, tubular, solid, tubulocystic, or microcystic, has eosinophilic cytoplasm and CMV-like high-grade nuclei. FH-deficient RCCs frequently metastasize to other anatomic sites. TFE immunoreactivity may occur in some FH-deficient RCCs, and immunohistochemistry can accurately diagnose these tumors and mutational analysis of FH gene.

Merkel cell polyomavirus and Langerhans cell neoplasm.

BACKGROUND: The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV. METHODS: We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data. RESULTS: We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH. CONCLUSION: We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Investigation of aluminum and iron deposition on metaplastic bones in three patients with diffuse pulmonary ossification.

Diffuse pulmonary ossification (DPO) is a rare pulmonary lesion. DPO is typically detected at autopsy rather than premortem. Recently, however, several cases were diagnosed antemortem using computed tomography, high-resolution computed tomography, or video-assisted thoracic surgery. In the present study, we evaluated DPO at autopsy from two patients with post-myocardial infarction (cases 1 and 3) and one patient with duodenal cancer (case 2). Multiple metaplastic bones (nodular in case 1 and 3 or dendriform in case 2) were detected in these three cases. In an attempt to detect aluminum and iron deposition in these metaplastic bones, histochemical investigations were performed. The two nodular types of one and three cases were positive for aluminum and iron, but the dendriform type of case 2 was positive only for aluminum. The depositions occurred in a linear pattern along the calcifying front. It is of great interest that these deposition patterns were similar to those of bones from three previously reported DPO cases and from the bones of hemodialysis patients. It is suggested that these abnormal metal depositions in the calcifying front might disturb the normal mineralization processes of the metaplastic bones, although no morphological abnormality was detected, except for dense black color of calcifying front lines. Further investigations are needed in more patients with DPO to obtain more information on this topic.

Immunohistochemical analysis of invasive micropapillary carcinoma pattern in four cases of gastric cancer.

Gastric cancer with the invasive micropapillary carcinoma (IMPC) pattern has been reported to be a variant with poor prognosis and rapid progression. To the best of our knowledge, only 4 cases of gastric cancer from Japan and 11 cases from Korea have been reported to contain the IMPC pattern. In the present study, 4 cases of gastric cancer containing the IMPC pattern from 2 Japanese men and 2 Japanese women are reported. The cancer tissues, including a recurrent lesion in 1 case and lymph node metastases in 2 other cases, were examined immunohistochemically to identify suitable markers for demonstrating the peculiar "inside out" pattern of IMPC and for analyzing HER2 expression. A characteristic IMPC pattern occupied more than 10% of each cancer tissue in these 4 cases. Lymphatic invasions were very often detected; in fact, lymph node metastases were detected in 3 out of 4 cases. The unique "inside out" pattern in IMPC was clearly revealed in all cases by staining with antibodies to both epithelial membrane antigen (EMA) and KL-6, but not with an antibody to CD10. HER2 was positive in 3 of 4 cases with the IMPC pattern, including cases with a recurrent lesion or lymph node metastases. Fluorescence in situ hybridization (FISH) analyses disclosed positive results in case 1, and case 3 including lymph node metastatic foci. Highest FISH titer was 6.8 in case 1, revealing marked amplification of HER-2 gene. Four cases of gastric cancer with the IMPC pattern were reported. EMA and KL-6, but not CD10, were particularly useful markers for visualizing the characteristic "inside out" pattern of the IMPC pattern in stomach cancers, similar to the markers for breast and urinary bladder cancers.

Rapidly developing intrathoracic low-grade fibromyxoid sarcoma: A case report.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare mesenchymal tumor that primarily arises in the limbs and trunk of young adults, and rarely in the thoracic cavity. An 84-year-old Japanese woman presented with a right intrathoracic mass which was 8 cm in size. CT-guided needle biopsy did not provide a definitive diagnosis. Perioperatively, a mass was found in the right lower lobe of the lung and was suspected to have invaded the chest wall at the sixth-eighth ribs. A right lower lobectomy and combined chest wall resection were performed. Microscopic examination revealed that the tumor was a low-grade spindle cell tumor originating from the pleura demonstrating focal invasion of the lung. The tumor exhibited positivity for MUC4, and FUS gene translocation was confirmed through fluorescence in situ hybridization. Unfortunately, 10 months postoperatively, tumor recurrence was noted as peritoneal dissemination, and the patient passed away 13 months postoperatively. Although LGFMS may be diagnosed histologically as a low-grade tumor by needle biopsy, in this case, it was highly malignant. Postoperative long-term regular medical follow-up is recommended considering the highly malignant nature of the tumor and the high risk of local recurrence and pulmonary metastasis.

A case of pulmonary pleomorphic carcinoma associated with cystic airspace.

Lung cancer associated with a cystic airspace is frequently misdiagnosed or overlooked. Adenocarcinoma, followed by squamous cell carcinoma, is the most typical histologic type of lung cancer connected to a cystic airspace. Here we present the rare case of lung pleomorphic carcinoma associated with a cystic airspace. We encountered a 74-year-old Japanese man diagnosed by computed tomography (CT) as having a nodule outside a cystic airspace in the lung. Several previous CT images showed that the cystic airspace preceded the nodule. Postsurgery, pathology indicated a diagnosis of pleomorphic carcinoma. Since pulmonary pleomorphic carcinomas pursue an aggressive clinical course, their early detection may contribute to an improved prognosis. Our case demonstrated that pleomorphic carcinoma can arise with cystic airspaces. For early diagnosis of those aggressive lung cancers, chest physicians should carefully examine the walls of cystic airspaces on CT.

Primary adrenal Ewing's sarcoma family of tumors with tumor thrombus of the inferior vena cava: a case report.

BACKGROUND: Ewing's sarcoma is a malignant neoplasm that mainly occurs in skeletal tissue but can rarely arise in soft tissues. Recently, small round cell tumors (including Ewing's sarcoma) caused by chromosomal translocations have been collectively termed Ewing's sarcoma family of tumors. We report a rare case of primary adrenal Ewing's sarcoma family of tumors with tumor thrombus. CASE PRESENTATION: A 22-year-old Asian woman was referred to our hospital with a left retroperitoneal tumor 19 cm in diameter. Tumor thrombus was identified from the left adrenal vein to the inferior vena cava, infiltrating the right atrium. Total tumor excision with left adrenalectomy, nephrectomy, and thrombectomy was performed under hypothermic circulatory arrest, followed by seven courses of adjuvant chemotherapy. The patient has shown no signs of recurrence as of 26 months postoperatively. CONCLUSION: Radical surgery combined with systemic chemotherapy may contribute to good prognosis in patients with primary adrenal Ewing's sarcoma family of tumors.

Allergic Bronchopulmonary Mycosis Complicated with Lung Adenocarcinoma.

Chest computed tomography (CT) of a 76-year-old woman with bronchial asthma showed multiple lung nodules with high CT densities that were compatible with high-attenuation mucoid (HAM) impactions characteristic of allergic bronchopulmonary mycosis (ABPM). Follow-up chest CT revealed increased sizes of multiple lung nodules. However, a left upper lobe nodule showed lower CT density than the other HAM impactions. A transbronchial lung biopsy of that upper lobe nodule revealed lung adenocarcinoma. Measuring the CT density is important for the differential diagnosis of lung nodules when following ABPM patients. Our patient's increased serum carcinoembryonic antigen levels were associated with peripheral blood eosinophilia. Mucoid impaction in the lung was positively stained with carcinoembryonic antigen and showed the distribution of eosinophilic granules.

Systemic Abscopal Effect of Low-dose Radiotherapy (2 Gy ×2) against Palatine Tonsil Follicular Lymphoma.

A 52-year-old man presented with palatine tonsillar swelling caused by follicular lymphoma. His tumor burden was low, but exacerbation of snoring and dysphagia was observed. Considering the first wave of coronavirus disease 2019 (COVID-19) pandemic, he received palliative 4-Gy irradiation to the tonsils in 2 fractions, which induced partial regression of tonsillar swellings and eradication of the circulating lymphoma cells. We suggest that low-dose radiotherapy triggered an abscopal effect of lymphoma, which allowed the patient time to receive COVID-19 vaccination before starting immunosuppressive chemo-immunotherapy.

Glucocorticoid-induced redistribution lymphocytosis in mantle cell lymphoma with hyaline vascular Castleman disease-like features.

We report a case of mantle cell lymphoma mimicking Castleman disease. A 76-year-old man presented with generalized lymphadenopathy, splenomegaly, anemia, polyclonal gammopathy, and pulmonary infiltrations. Lymph node biopsy revealed histological features of hyaline vascular Castleman disease. Treatment with prednisolone induced lymphocytosis with immunophenotypic and genetic features of mantle cell lymphoma. A detailed immunohistochemical study of the lymph node demonstrated a mantle cell lymphoma-mantle zone growth pattern. Glucocorticoid-induced distribution lymphocytosis has not been reported in mantle cell lymphoma. Careful observation of circulating lymphocytes during steroid treatment may enable diagnosis of the underlying occult lymphoma in a subset of patients exhibiting clinical manifestations of Castleman disease.

Successful conversion surgery after FOLFIRINOX therapy in a patient with advanced pancreatic acinar cell carcinoma with a solitary peritoneal dissemination: A case report.

BACKGROUND: Pancreatic acinar cell carcinoma is rare; it accounts for 1% of all malignant pancreatic exocrine tumors. Although surgical resection is an option for curative treatment, the safety and efficacy of conversion surgery in patients with pancreatic acinar cell carcinoma with metastasis remain unknown. CASE: A 67-year-old man with epigastric pain and a pancreatic tumor was referred to our hospital. Computed tomography revealed a large tumor with a maximum diameter of 67 mm at the pancreatic head and a 23-mm mass in the left upper abdominal cavity. Because a definitive diagnosis could not be made based on endoscopic ultrasonography-guided fine needle aspiration biopsy findings, a diagnostic laparoscopy was performed. The tumor in the greater omentum at the left upper abdomen, resected under laparoscopy, was histopathologically diagnosed as pancreatic acinar cell carcinoma. Therefore, the pancreatic tumor was diagnosed as an unresectable pancreatic acinar cell carcinoma with a solitary peritoneal dissemination. The size of the main pancreatic tumor decreased to 15 mm after 18 courses of FOLFIRINOX (5-fluorouracil, leucovorin, irinotecan, and oxaliplatin). Subsequently, the patient underwent conversion surgery, and the initial diagnosis of pancreatic acinar cell carcinoma was confirmed on pathological examination. The patient was discharged 31 days postoperatively, following which he received adjuvant chemotherapy with S-1. No sign of recurrence has been observed for 32 months after surgical resection. CONCLUSION: FOLFIRINOX may be effective in patients with pancreatic acinar cell carcinoma, and conversion surgery after FOLFIRINOX may be applicable to selective patients.

Laryngeal malignant peripheral nerve sheath tumor mixed with high- and low-grade malignancies.

Malignant peripheral nerve sheath tumors (MPNSTs), as defined by immunohistochemical evaluation, are identified along a spectrum ranging from atypical neurofibroma to high-grade MPNST because these tumors are similar in terms of cell shape and tissue components on hematoxylin-eosin (HE) staining. The patient was a 57-year-old male referred to our hospital, with a recurrent red tumor at the anterior commissure of the larynx and submucosal swelling of the right vocal fold. A surgical specimen from a right horizontal partial laryngectomy was evaluated immunohistochemically. A high-grade MPNST lesion was included in the submucosal white tumor, whereas a low-grade MPNST lesion was encountered around the high-grade MPNST lesion. This tumor may involve different malignancies even when it is small. Although intra-tumor heterogeneity in cancers has been reported recently, careful immunohistochemical examination can be important and beneficial for eradicating the tumor while preserving vocal function.

A case of mixed tumor formed by metastasis of urothelial carcinoma and malignant lymphoma to the same lymph nodes.

INTRODUCTION: Mixed tumor in the same lymph nodes is extremely rare and no previous reports have described mixed tumor comprising urothelial carcinoma and malignant lymphoma. CASE PRESENTATION: A 71-year-old woman visited a local clinic with a main complaint of hematuria. Imaging revealed right hydronephrosis and a mid-ureter tumor shadow. Positron emission tomography-computed tomography showed high uptake of fluorodeoxyglucose in para-aortic lymph nodes. Abdominal para-aortic lymph node biopsy was performed. Pathology showed urothelial carcinoma and malignant lymphoma in the same lymph nodes, where a mixed tumor was diagnosed. CONCLUSION: We encountered a case of mixed tumor of urothelial carcinoma and Hodgkin lymphoma, which metastasized to the same tissues.

Thymic mucosa-associated lymphoid tissue lymphoma with immunoglobulin-storing histiocytosis in Sjögren's syndrome.

Mucosa-associated lymphoid tissue (MALT) lymphoma arising from the thymus is extremely rare. Only 33 cases of thymic MALT lymphoma have been reported to date. We present the case of a 53-year-old Japanese woman with Sjögren's syndrome who was diagnosed with thymic MALT lymphoma. In addition, the patient had the characteristic clinical and pathological features of thymic MALT lymphoma, as found in most of the 33 previous cases, except that there was an immunoglobulin G (IgG) phenotype, i.e. Sjögren's syndrome, epithelial cysts, lymphoepithelial lesions, and marked plasmacytic differentiation. The serum IgA levels were also elevated with IgA kappa M protein. This hypergammaglobulinemia remained unchanged after operation. The serological abnormalities may not arise from MALT lymphoma itself and may arise from the immune system hyper-reactivity evoked by Sjögren's syndrome. Of further interest were marked accumulations of CD68-positive histiocytes containing abundant eosinophilic globular inclusions in their cytoplasm. These inclusions were immunopositive for IgG-kappa, suggesting immunoglobulin inclusion bodies. The globular immunoglobulin inclusion bodies have been reported in non-crystallized immunoglobulin-storing histiocytosis in only one patient with multiple myeloma. To our knowledge, this is the first case of thymic MALT lymphoma with marked accumulation of histiocytes with immunoglobulin inclusions in a patient with Sjögren's syndrome.

Primary undifferentiated carcinoma of the small intestine: an immunohistochemical study and review of the literature.

Primary undifferentiated carcinoma of the small intestine is an extremely rare neoplasm. Here, we report a case of primary undifferentiated carcinoma that arose from the ileum in a 65-year-old woman. Laboratory data revealed anemia and slightly elevated inflammatory parameters. Computed tomography showed a heterogeneous mass in the pelvic cavity, and magnetic resonance imaging revealed that the margin of the tumor mass was clear. Positron emission tomography using (18)F-fluoro-2-deoxy-D: -glucose (FDG) showed accumulation of FDG on the tumor mass with a standardized uptake value of 8.3. Partial resection of the ileum to remove the tumor was performed under a clinical diagnosis of small intestinal carcinoma. The tumor was nodulated and had a circumscribed margin 6.5 x 5.5 x 4 cm in diameter. Microscopically, the tumor was composed of giant polygonal cells with cellular atypia. Immunohistochemical examination revealed that the tumor cells expressed epithelial markers including AE1/AE3, CAM5.2, and EMA; however, lymphocytic, mesenchymal, and gastrointestinal stromal tumor markers were not expressed. We made a final diagnosis of primary undifferentiated carcinoma of the small intestine. The prognosis of patients with undifferentiated carcinoma of the small intestine is very poor. To improve the outcome of treatment, early and accurate diagnosis is essential, and additional therapy, including multimodality adjuvant therapy or the administration of novel molecular targeted drugs, should be considered.

A case of spontaneous mesenteric hematoma with diagnostic difficulty.

BACKGROUND: Spontaneous mesenteric hematoma (SMH) is a rare condition characterized by intraperitoneal hemorrhage of unknown etiology. SMH without worsening of general status allows conservative management; however, patients showing chronological changes on imaging require surgical intervention to rule out possible malignancy. CASE PRESENTATION: A 69-year-old man was referred to our hospital to evaluate an abdominal mass with no associated clinical symptoms. He had a history of chronic hepatitis C and diabetes mellitus. Six months earlier, computed tomography (CT) revealed a 75-mm tumor arising from the jejunum, suspected to be a gastrointestinal stromal tumor (GIST) of the small intestine. Following a further 6 months of observation, the patient was referred to our hospital. Abdominal contrast-enhanced CT revealed a well-defined heterogeneous round tumor with a maximum diameter of 75 mm adjacent to the upper jejunum. The tumor was accompanied by calcification at the periphery, with no evidence of augmentation over the prior 6 months. Diffuse lymphadenopathy was observed around the aorta and splenic artery. Under the diagnosis of GIST arising from small intestine, the patient underwent elective surgery. The resection revealed an elastic soft tumor at the mesentery adjacent to the upper jejunum with severe adhesion between the tumor and jejunum. The tumor origin was unclear; thus, we performed mesenteric excision and partial enterectomy without lymph node dissection. The tumor was surrounded by fibrous capsular tissue containing massive hemosiderin deposits and cholesterol crystals showing partial calcification, resulting in a diagnosis of spontaneous hematoma of the mesentery. CONCLUSIONS: We report a case of SMH mimicking small intestinal GIST. It is difficult to diagnose long-established SMH because its radiological features change with time, and more case reports are needed to improve the accuracy of diagnosis.

Immunohistochemical and electron microscopy studies of a case of hyalinizing trabecular tumor of the thyroid gland, with special consideration of the hyalinizing mass associated with it.

Hyalinizing trabecular tumor (HTT) of the thyroid gland is rare and benign, and it neither recurs nor metastasizes. In this lesion, tumor cells are arranged in trabeculae, in association with hyalinizing mass in the stroma. The origin and nature of the hyalinizing mass are still controversial. We report here a case of HTT with cytological, immunohistochemical, and ultrastructural findings, focused in particular on the hyalinizing mass. Cytologically, tumor cells exhibiting many intranuclear cytoplasmic inclusions and nuclear grooves were found in association with light green-positive, irregular, fluffy membranous structures on touch smear. Staining with antibody to collagen type IV was positive in these membranous structures. Histopathologically, tumor cells exhibited many intranuclear cytoplasmic inclusions, and were positive for staining with antibodies to S100 protein, neuron-specific enolase, thyroglobulin, and vimentin. The hyalinizing eosinophilic mass, which was positive for PAS reaction, and for staining by antibody to collagen type IV, gradually increased in the areas surrounding tumor cells. This mass then appeared to replace the tumor cells, and exhibited a peculiar filiform pattern. We demonstrated ultrastructurally that this pattern was composed of long, irregular, fine cytoplasmic processes of tumor cells and basal lamina-like substance in the hyalinizing mass. In fact, the homogeneous hyalinizing mass, similar to basal lamina-like substance, contained many degenerated cytoplasmic processes at the ultrastructural level. These results suggested that the key cytological finding in differentiating HTT from papillary carcinoma is the fluffy membranous structure, although nuclear pseudoinclusions are important as well. The filiform pattern noted at light microscopic level consisted of long cytoplasmic processes of tumor cells and hyalinized mass at the ultrastructural level.

Intrahepatic bile duct adenoma in a patient with gastric cancer.

We report a case of intrahepatic bile duct adenoma (BDA) detected during laparoscopic distal gastrectomy for gastric cancer. A 70-year-old man was referred to our hospital for the treatment of gastric cancer. Esophagogastroduodenoscopy revealed an irregular, nodular, and elevated lesion on the greater curvature side of the middle third of the stomach. Abdominal contrast-enhanced computed tomography showed wall thickening with homogeneous enhancement in the middle part of the stomach, and no lesions in the liver. The patient underwent laparoscopic distal gastrectomy with regional lymphadenectomy, and during the operation a small whitish nodule was observed on the lateral segment of the liver surface. The lesion was excised by partial resection of the liver for the purpose of both histological diagnosis and treatment. Pathological examination of the liver lesion revealed no structural or cellular atypia, no stromal invasion, and immunohistochemical positivity for CK7 and CK19, but negativity for p53. The final diagnosis was well-differentiated adenocarcinoma invading the gastric serosal layer without lymph node metastasis, and intrahepatic BDA measuring 0.4 × 0.3 cm. Following surgery, the patient remained symptom-free without evidence of recurrence for 5 months. To the best of our knowledge, this is the first case of BDA with gastric cancer. Because it is difficult to distinguish BDA from other liver tumors including metastatic cancer due to its characteristically small size and lack of specific morphological features on standard imaging, surgical resection should be considered as the most suitable approach for both accurate diagnosis and treatment.