Histologic variant of the epithelial-myoepithelial carcinoma of the salivary gland: A case report

Background. Epithelial-myoepithelial carcinoma (EMC) of the salivary gland is a low-grade carcinoma. It has been widely accepted as a clinicopathologic entity only in the past decade. Histologically, the classical bimodal differentiation of inner eosinophilic ductal cells and outer layer of clear myoepithelial cells has been well documented by many authors. However, the proportion of each component may vary in different tumors or within the same tumor, and different histologic patterns have been described. The clinicopathologic findings of an epithelial-myoepithelial carcinoma of the parotid gland in a 73-year-old man are presented. Methods. Light microscopy including immunohistochemistry and ultrastructural studies were done. Results. The various histologic patterns and bimodal differentiation of the tumor were noted. Conclusions. The present case demonstrates the myriad of histologic patterns that can occur in epithelialmyoepithelial carcinoma. Differentiation from malignant mixed tumor is essential and possible. The importance of the awareness of its histologic variants is emphasized. © 1995 Jons Wiley & Sons, Inc.     

Clear cell papillary cystadenoma of the epididymis and mesosalpinx: immunohistochemical differentiation from metastatic clear cell renal cell carcinoma

Clear cell papillary cystadenoma is a rare epithelial tumor of the epididymis, which may present as an isolated lesion or as a component of von Hippel-Lindau disease (VHLD). Recently, tumors have also been described in the female genital tract with similar histology. Recognition of clear cell papillary cystadenoma is critical because of its association with VHLD and its potential diagnostic confusion with metastatic renal cell carcinoma because of a shared architecture and clear cells. In this study, we report on the immunohistochemical differentiation of 5 clear cell papillary cystadenomas, 3 of the epididymis and 2 of the mesosalpinx, from metastatic renal cell carcinoma. In 2 cases, there was a history of renal cell carcinoma in the setting of VHLD; and in 1 of these cases, an epididymal papillary cystadenoma was initially considered to be metastatic renal cell carcinoma. Immunohistochemically, tumor cells were moderately intensely positive for cytokeratin AE1/AE3 and epithelial membrane antigen, strongly positive for CK7 and negative for CK20 and RCC. Four of 5 cases were negative for CD10. This staining profile contrasts with that reported for clear cell renal cell carcinomas, which are typically negative for CK7 and immunoreactive for renal cell carcinoma (RCC) and CD10. Our findings indicate that, in cases where there is uncertainty about the histologic diagnosis of clear cell papillary cystadenoma, the above immunohistochemical panel helps to rule out metastatic renal cell carcinoma.     

Inference of the Basal epithelial phenotype in breast carcinoma from differential marker expression, using tissue microarrays in triple negative breast cancer and women younger than 35

Abstract: Basal‐cell phenotype breast carcinoma has been associated with high‐grade and metaplastic morphology, expression of basal‐type cytokeratins, uniform negativity for ER and HER2, and decreased overall survival. Breast cancers occurring in young women are usually T2 disease at presentation, high‐grade and of poor prognosis. We compared two groups of breast cancers, (a) ER‐, PR‐, HER2‐ (triple negative) [TNBrCa] and (b) non‐triple negative breast cancers (non‐TNBrCa) occurring in women under 35, using tissue microarray technology to characterize expression of the basal/myoepithelial cytokeratins (CK5/6, CK7, and CK14), luminal cytokeratins (CK8, CK18, and CK19), EGFR, p‐cadherin, c‐kit, p63, and p53. We also sought to identify characteristic histomorphologic features indicative of basal‐like phenotype. The triple negative group showed preferential staining versus the age <35 group for CK5/6 (22% versus 4% p = 0.05), CK14 (44% versus 15%, p = 0.013), EGFR (83% versus 24%, p < 0.0001) and c‐kit (19% versus 0% p = 0.026). Conversely, non‐TNBrCa in women younger than 35 demonstrated increased expression of the luminal CK8 (92% versus 60%) compared with the triple negative patients (p = 0.006). The TNBrCa have characteristic histologic features including higher tumor grade, pushing tumor border, geographic necrosis, syncytial growth pattern, brisk mitotic activity, lack of/minimal in situ component, medullary‐like and metaplastic differentiation. Invasive carcinomas in women younger than 35 usually have an associated in situ component, prominent nucleoli, central acellular fibrotic zone, and infiltrative tumor border. Triple negativity for ER/PR/HER2 coupled with EGFR, c‐kit, and basal/myoepithelial cytokeratins (CK5/6, CK14) expression, and distinctive histomorphologic features predict morphology consistent with basal‐cell phenotype.     

Sebaceous epithelial-myoepithelial carcinoma of the salivary gland: clinicopathologic and immunohistochemical analysis of 6 cases of a new histologic variant

Epithelial-myoepithelial carcinoma (EMC) of the salivary glands is an uncommon, low-grade malignant tumor. A recent report demonstrates sebaceous differentiation in this tumor even though its significance has never been documented as a precise histologic variant. Six cases of EMC exhibiting sebaceous differentiation (sebaceous EMC) of the parotid gland were analyzed for their clinicopathologic features and immunohistochemical characteristics. In addition, primary salivary sebaceous carcinomas were also examined for comparison. In our series, the incidence of sebaceous EMC was 0.2% among 3012 cases of parotid gland tumors and 14.3% of all EMC cases. The 6 patients comprised 2 men and 4 women, age ranging from 77 to 93 years (mean, 83.7 y). Neither cervical lymph node nor distant organ metastases were found in any cases of sebaceous EMC and no patients died of disease, though local recurrences developed in 1 patient. Conversely, cervical lymph node metastasis was detected in 2 of 3 patients with sebaceous carcinoma, 1 of whom died of disease at 12 months. Histologically, all 6 tumors had an area of sebaceous differentiation admixed with features of bilayered ductal structures typical of EMC. A component of sebaceous differentiation was distributed diffusely in 4 tumors and focally in 2. Cytologic atypia of sebaceous EMCs was lesser than that of sebaceous carcinomas. Immunohistochemically, putative myoepithelial markers such as alpha-smooth muscle actin, calponin, p63, cytokeratin 14, S-100 protein, and vimentin were highly expressed in sebaceous EMC. However, the expression of the latter 4 markers was also observed in primary sebaceous carcinomas, whereas these tumors were all negative for alpha-smooth muscle actin and calponin. Positive immunoreactivity for epithelial membrane antigen, adipophilin, and perilipin confirmed sebaceous differentiation in EMC. These results indicate that sebaceous EMC is a low-grade malignancy, similar to conventional EMC. Our data also suggest that immunohistochemical examination of specific myoepithelial markers is helpful in distinguishing sebaceous EMC from sebaceous carcinoma, which may occasionally be associated with an aggressive clinical course.     

Histopathological and Immunohistochemical Characteristics of Two Canine Lipid‐Rich Mammary Carcinomas

Clinicopathological and immunohistochemical findings of two uncommon canine lipid‐rich mammary carcinomas are described. The predominant histological feature in both tumours was the presence of at least 80% of cells with intracytoplasmic vacuoles which stained positively with Sudan IV but not with alcian‐blue periodic acid‐schiff method. In both tumours, small groups of non‐vacuolated cells were identified among the vacuolated cells. However, histological and immunohistochemical differences were also found between these tumours. Thus, one of them was composed of tumour cells with a large and single vacuole, which were arranged in lobular pattern, while the other neoplasm showed an intraductal growth of tumour cells with a fine vacuolated cytoplasm. Immunohistochemically, in the first tumour most vacuolated cells were positive for CK (cytokeratin)8‐7, indicating a secretory epithelial immunophenotype while CK5 and CK8‐7‐expressing non‐vacuolated cells were associated with luminal duct immunophenotype. However, in the second tumour the expression of CK14 in most of vacuolated cells and α‐smooth muscle actin (α‐SMA) in non‐vacuolated cells, alone or in combination with CK5 suggested a myoepithelial immunophenotype for both cell types. These results suggest heterogeneity of the cell type and growth pattern for this type of canine tumour as has been described in women but not in dogs.     

Immunohistologic attempt to find carcinogenesis from hepatic progenitor cell in hepatocellular carcinoma

AIM: To clarify whether hepatocellular carcinoma (HCC) originates from hepatic progenitor cells and whether there is any correlation with the clinicopathologic factors of HCC, we reviewed 217 resected HCC specimens. METHODS: Immunohistochemical examination of cytokeratin (CK) 7, CK19, CD34, and CD117 (c-KIT) was performed. Overexpression of CK7 and CK19 indicates differentiation from cholangiocellular and hepatic progenitor cells, while overexpression of CD34 and CD117 indicates hepatic stem cells. Fresh specimens were obtained from 20 HCC patients for mutation of the c-KIT gene. RESULTS: CK7, CK19, and CD117 were positive in 41, 9.7, and 0.9% of the HCC specimens, respectively, and CD34 was never positive. None of the fresh HCC specimens demonstrated a c-KIT mutation. CK19 positivity was significantly correlated with a positive hepatitis B core antibody, and with poor survival outcome, and tended to correlate with poor histologic differentiation. CONCLUSION: These results suggest that: (i) about 10% of HCCs with typical histologic features originate from an intermediate hepatic progenitor cell, such as the canal of Hering and oval cells in the rat, or acquire the characteristics of cholangiocellular epithelium by metaplasia; (ii) HCC with typical histologic features rarely originates from hepatic stem cells, and (iii) patients with CK19-positive HCC have a poor prognosis.     

Calcifications in a clear cell mucoepidermoid carcinoma: a case report with histological and immunohistochemical findings.

The aim of this study was to report an unusual case of mucoepidermoid carcinoma (MEC) in a 39-year-old woman. The tumor showed a prominent population of clear and intermediate basal cells. Clear cells rarely predominate over other cell types. Such cases are called clear cell variant of MEC. The case also revealed a variable amount of calcified material in the tumor mass. Calcifications are rare in clear cell MEC. These structures were periodic acid-Schiff positive and diastase resistant, excluding glycogen origin. Immunohistochemistry was performed, and the epidermoid component was positive for cytokeratin (CK)7, CK13, CK14, and CK19. The mucous and clear cells presented mild staining for CK7. Cytokeratins 7, 13, and 19 stained luminal cells, and intermediate cells exhibited positivity for CK7, CK14, and vimentin. The origin of the calcifications is speculated to be the result of dystrophic calcification of the amorphous eosinophilic material secreted by intermediate basal cells.     

Renal cell carcinomas in children and young adults: increased incidence of papillary architecture and unique subtypes.

Renal cell carcinomas in children and young adults are rare, and the pathologic features of these tumors have not been well described. We reviewed 24 renal cell carcinomas in children and young adults ages 6 to 29 years, 14 of whom were younger than 18 years of age. Fourteen were female. In 19 (79%) of 24 cases, the tumor met histologic criteria for papillary renal cell carcinoma, with at least 50% papillary architecture. Four of the remaining five cases were typical clear cell tumors in patients known to have von Hippel Lindau syndrome, and one case was of chromophobe type. In the papillary tumors, calcifications, high nuclear grade, extracapsular extension (American Joint Commission on Cancer stage T3), and lymph node metastases were common. Among these papillary tumors, four distinct histologic patterns could be identified. Collecting duct-like tumors (two cases) involved the large collecting ducts, were multifocal and predominantly papillary, and had focal tubular and solid areas. These tumors were reactive for epithelial membrane antigen (EMA) and keratins, including CK7, but negative for Ulex europeaus and high molecular weight keratin 34BE12. Voluminous cell tumors (four cases) were composed of cells with extremely voluminous clear cytoplasm and, although predominantly papillary, had areas that also resembled clear cell tumors. These tumors were reactive for keratins AE1/AE3 but were otherwise negative for all other keratins, EMA, and U. europeaus. One of these tumors showed an X;7 translocation. Adult type tumors (12 cases) resembled papillary tumors of adults. These tumors were reactive for EMA and keratins, including CK7, and all but one were negative for U. europeaus and keratin 34BE12. This last case had trisomies of chromosomes 7, 16, 17, and 20. The final neuroendocrinelike case was multifocal, organoid, and composed of nests of small cells in a neuroendocrinelike pattern. Three of 13 patients were alive with disease at last follow-up, and three additional patients died of disease, all within 2 years. Progression was highly associated with lymph node involvement at the time of resection. We conclude that the clinicopathologic features of renal cell carcinomas in children and young adults differ from those arising in older adults. These tumors are characteristically high-grade, high-stage, papillary tumors with numerous calcifications, and several subtypes can be identified based on histologic, immunohistochemical, and cytogenetic features. Some subtypes appear to be unique to this age group.     

Recurrent and fatal epithelial–myoepithelial carcinoma of the parotid

Epithelial–myoepithelial carcinoma (EMC) is a rare tumour of the salivary glands typically arising in the parotid. It is recognized as a low-grade malignant tumour that is prone to local recurrence and may metastasise. We report on a case of EMC of the parotid gland that recurred three times in a 16-month period. Although tumour resections were performed in each recurrence and tumour-free margins were always obtained, the patient died nearly 9 years after the initial diagnosis with brain metastases. Diagnosis, clinical behaviour and treatment of EMC are also reviewed. Level of Evidence: Level V, therapeutic study     

Myoepithelioma of the soft palate: Review of the literature and report of a case with immunohistochemical study

Background

Myoepitheliomas of the salivary glands are rare neoplasms accounting for less than 1.5% of all salivary gland tumours. They are classified into four cell types: spindle, clear, epithelioid and plasmacytoid. The plasmacytoid cell type appears to have a predilection for the oral cavity, especially the palate.

Case presentation

A 56-year-old man was admitted to the ENT department complaining of a painless soft palate mass that had shown progressive growth over the past 9 months. At oral examination, a firm, nodular, ovoid-shaped lesion measuring 2.5cm in diameter with a well-delimited border, was palpated at the posterior midline portion of the soft palate. The overlying mucosa was intact. Computed tomography (CT) showed a hypodense tumour image. The clinical picture was suggestive of a tumour of the small salivary glands. The patient underwent a complete surgical resection of the tumour. The latter was located in the submucosa. It consisted of polygonal cells with round, eccentric nuclei and eosinophilic cytoplasm. Focal necrosis was not observed. The mitotic index was 2/10 high-power fields. Immunohistochemically, the tumour cells showed positivity for S-100 protein, vimentin, GFAP and negativity for CK 14 and SMA. The immunoreactivity of Ki-67 was sporadic, confirming the diagnosis of benign myoepithelioma.

Conclusion

Myoepithelioma composed predominantly of plasmacytoid myoepithelial cells is a rare neoplasm that occurs in the soft palate. Wide excision with tumour-free margins is the treatment of choice.     

CK19表达及其在结肠癌淋巴结微转移诊断中的应用

目的：研究用免疫组化方法检测CK19及其在结肠癌淋巴结微转移诊断中的应用与临床病理意义。方法：取材于50例结肠癌病人肿瘤组织及癌周淋巴结255枚，同时进行HE染色组织学检查和抗角蛋白19抗体的免疫组化检测。结果：50例结肠癌组织中CK19表达均为阳性。255枚淋巴结用HE染色检查阳性者56枚(22．0％)，皆同时表达CK19阳性；另20枚淋巴结HE染色阴性，而CK19表达阳性。50例中有12例淋巴结中发现微转移，其中6例常规组织学检查属淋巴结转移阴性而免疫组化染色诊断表现为转移阳性。占常规病理检查淋巴结转移阴性者的21．4％(6／28)。随着肿瘤分期增加,淋巴结CK19表达阳性率亦增加。CK19表达阳性者预后较阴性者为差。结论：CK19免疫组化法是检测结肠癌淋巴结微转移的敏感而便捷的方法，而检测结肠癌微转移有助于判断肿瘤进展程度与预后。特别对在筛选组织学检查淋巴结阴性但存在微转移的病人有实用价值。     

Calcifying Epithelial Odontogenic Tumour with Clear Langerhans Cells: A Novel Variant,Report of a Case and Review of the Literature

Clear cell calcifying epithelial odontogenic tumour (CCEOT) is a rare variant of calcifying epithelial odontogenic tumor (CEOT). While it is not surprising to find clear cells in odontogenic lesions, the exact nature of the clear cells in CCEOT has not been elucidated. Herein, we report a case of peripheral CCEOT of anterior mandible in a 37 year old black female. Histologically, the tumour consisted of cords and small nests of clear cells surrounded by dense deposits of amyloid and basophilic calcifications. The cells possessed abundant clear cytoplasm and eccentrically located indented nuclei. Admixed with the clear cells were eosinophilic cuboidal to polyhedral cells. The clear cells were PAS negative and immunoreactive for S100 protein, CD1a and Langerin. The clear cells were negative for MNF-116, SMA, Desmin and CK-19. It is therefore recommended to recognize two variants of CCEOT, namely, CEOT with clear cell change and CEOT with clear Langerhans cells (LC). We further suggest that the contradictory term “non-calcifying variant of calcifying epithelial odontogenic tumour with LC” to be abandoned, as the current case clearly indicates that LC could be seen in CEOT irrespective of the presence or absence of calcifications.     

体外人骨髓间充质干细胞向汗腺细胞表型转化的实验研究

目的:研究骨髓间充质干细胞(MSCs)向汗腺细胞分化的可行性.方法:体外分别分离培养、扩增并鉴定MSCs和汗腺细胞,将汗腺细胞置于47℃环境中1 h建立汗腺细胞体外休克模型,继续孵育3～5 d,收集上清液作为条件培养基对MSCs分化诱导,应用免疫组织化学和流式细胞仪法检测对比共培养10 d后MSCs细胞表型的改变.结果...     

CK19mRNA测定在乳腺癌腋淋巴结微转移诊断中的应用

研究敏感的方法检测乳腺癌腋窝淋巴结微转移。方法:对15例乳腺癌者的61个腋淋巴结和5个正常对照淋巴结同时进行HE染色组织学检查和CKl9逆转录-聚合酶链式反应(CK19RT-PCR)检测。结果:15例乳腺癌组织均有CK19mRNA表达,而5个正常淋巴结中均末见表达。61个腋窝淋巴结中7个组织学检查证实转移,其CK19mRNA亦表达阳性。组织学检测无转移的54个淋巴结中有12个CK19RT-PCR表达阳性,42个阴性;提示该12个淋巴结存在微转移只能用CK19RT-PCR方法检测出。经统计学分析,CK19RT-PCR与组织学检查二者有显著差异(X~2检验,P<0.01)。结论:CK19表达于恶性乳腺细胞,正常淋巴细胞无表达,CK19能作为组织特异基因进行RT-PCR扩增以检测乳腺癌腋淋巴结微转移。CK19 RT-PCR方法比组织学方法更敏感,特别对在筛选组织学检查淋巴结阴性而具有高度复发危险性的病人将有实用价值。     

Pericyte coverage decreases invasion of tumour cells into blood vessels in prostate cancer xenografts

Androgen-independent prostate cancer is an aggressive disease with high angiogenic and metastatic potential. Increased microvessel density and altered invasion properties have previously been described in LNCaP-19, an androgen-independent subline to LNCaP. To characterize the differences in angiogenesis and invasion, the vessels of these tumour xenografts were investigated with immunohistochemistry, and the influence of tumour cells on endothelial cell migration, proliferation and tube formation was studied in vitro. The blood vessels of LNCaP were found to be stabilized by pericytes more frequently than vessels in LNCaP-19. Further, tumour cell invasion was decreased in pericyte-covered blood vessels in both the tumour types. LNCaP-19 displayed an increased potential to induce endothelial cell migration in vitro. In conclusion, pericyte coverage seems to be important for the invasion of tumour cells into blood vessels. Further, LNCaP-19 has lower pericyte coverage and an increased potential to induce endothelial cell migration, which reflects its high microvessel density.     

Recurrent Hyalinizing Clear Cell Carcinoma of the Base of Tongue with High-Grade Transformation and EWSR1 Gene Rearrangement by FISH

Hyalinizing clear cell carcinoma (HCCC) is a rare, low-grade salivary gland tumor with clear cells and hyalinized stroma. Prognosis of HCCC is excellent with few cases metastasizing to the lymph nodes and lung. We present a case of a 61-year-old male with recurrent HCCC on the base of tongue. Histologic examination revealed sheets of clear and eosinophilic cells with a background of a myxoid-like matrix. In addition, large, bizarre malignant cells, focal necrosis, and atypical mitotic figures were identified. By immunohistochemistry, the clear cells were positive for CK18, EMA and vimentin, focally positive for CK7 and CD10, but negative for p63, HMWK, SMA and calponin. A metastatic renal cell carcinoma was considered a possibility but the tumor was called “poorly-differentiated carcinoma, NOS”. The patient underwent primary radiotherapy. A recurrence was identified at 10 months follow-up. A biopsy of the recurrent tumor showed clear cell differentiation and a predominant cribriform pattern with focal cords of eosinophilic cells invading the stroma. In contrast to the original tumor, no mitotic figures, atypia or necrosis were identified. The combination of lower grade and different architectural patterns appeared markedly different than the previous biopsy and the immunohistochemical pattern was also different. The recurrent tumor showed diffuse positivity for p63 and HMWK. It was negative for CD10, vimentin, SMA and calponin. Fluorescence in situ hybridization (FISH) analysis was positive for rearrangement of the EWSR1 gene in both samples, confirming that this represented a recurrence of the same tumor. It also confirmed that the initial tumor was a HCCC with high-grade transformation.     

Low-grade intraductal carcinoma of salivary gland: report of 3 cases with marked apocrine differentiation

Low-grade intraductal carcinomas (LG-IDCs) of salivary gland are rare neoplasms that resemble atypical ductal hyperplasia or LG-IDCs of the breast. They have been referred to as "low-grade salivary duct carcinomas" or "low-grade cribriform cystadenocarcinomas." Herein, we describe 3 additional cases of LG-IDCs, 2 were pure intraductal carcinomas, although 1 demonstrated increasing cytologic atypia and progression to an invasive adenosquamous carcinoma. The latter had been present for 7 years before demonstrating clinical and pathologic progression to a widely invasive malignancy. The intraductal component in all cases exhibited a remarkable degree of apocrine differentiation. The tumor cells were positive for AE1:AE3, Cam 5.2, high molecular weight keratin, CK7, CK19, BRST-2, and androgen receptors (ARs). S-100 was positive in 2 cases and negative in 1 case. The intraductal neoplastic cells were surrounded by myoepithelial cells positive for CK14, actins, calponin, high molecular weight keratin, and p63. All the tumors were negative for CK20, estrogen and progesterone receptors, Her2Neu, and p53. Extensive apocrine differentiation, expression of ARs, CK7, and CK19, and progression to a widely invasive carcinoma after a long clinical latency have not been reported in LG-IDCs previously. These tumors share some histopathologic features with salivary duct carcinoma including apocrine differentiation, and expression of ARs and BRST-2. The terms "low-grade salivary duct carcinomas" and "low-grade cribriform cystadenocarcinomas" should be abandoned in favor of LG-IDC of salivary gland, which better reflects their predominantly noninvasive, intraductal nature.     

间质细胞-上皮细胞转化与人胚胎表皮细胞发生的研究

目的探讨胚胎期表皮细胞形态发生与间质表皮细胞转化(MET)及其调节因子之间的关系。方法对早期胚胎标本分别采用间质细胞标记物波形蛋白(Vim)和α平滑肌肌动蛋白(αSMA)、胚胎表皮特异性蛋白细胞角蛋白(CK)8和18、表皮干细胞特异性蛋白CK19和相关调节因素转化生长因子β1(TGFβ1)及其受体(TGFβRⅠ)标记物进行免疫组化、免疫荧光染色和组织形态学观察。结果在人胚胎胎龄(EGA)6～8周期间,外胚层Vim+和αSMA-细胞向CK8和18+和CK19+表皮干细胞转变,并检测到中等强度(++)TGFβRⅠ信号,但TGFβ1信号十分微弱(±);至EGA10周以后这些细胞呈现表皮细胞的组织形态学特征。结论EGA6～8周是人胚胎表皮细胞经由MET发生的重要时期,TGFβRⅠ信号通路可能参与了MET调节过程,但其配体TGFβ1起源及其作用机制有待进一步研究。     

Esophageal gland duct adenoma: immunohistochemical comparison with the normal esophageal gland and ultrastractural analysis

Esophageal gland duct adenomas are extremely rare tumors. Here, we report the case of a 75-year-old Japanese man who had undergone total gastrectomy for advanced gastric cancer. Esophageal gland duct adenoma was incidentally found in the lower esophagus. It appeared to be detached from the site of gastric cancer and was well demarcated without a capsule. Histologic analysis revealed papillary and cystic structures mainly comprising eosinophilic cells with minimum nuclear atypia. Immunohistochemical analysis revealed that the tumor were diffusely positive for the S100 protein with preserved alpha-SMA-positive myoepithelial cell layers and a characteristic cytokeratin expression pattern similar to that in normal esophageal gland ducts (CK5/6+++, CK7+++, CK17+, CK18+, CK19+++, CK20-, HMWCK+++). In addition, differentiation into the terminal duct was confirmed by a combination of mucin staining and immunohistochemical and ultrastructural examinations. This is the first report that refers to the ultrastructural findings of an esophageal gland duct adenoma and describes terminal duct differentiation. We believe that the possibility of an esophageal gland duct adenoma should be considered when diagnosing a ductal or glandular lesion of the esophagus.