Tubular adenoma with focal squamous metaplasia of the ascending colon

A case of tubular adenoma with focal squamous metaplasia of the ascending colon in a 66-year-old male is reported. The tumor was a pedunculated polyp with a size of 1.5 X 1.4 X 0.9 cm. Histologically, the tumor showed tubular adenoma with moderate to severe atypia, was accompanied by focal squamous metaplasia. It is thought that squamous epithelial polyp may be derived from colonic adenoma with squamous metaplasia, and that the malignant change of colonic adenoma with squamous metaplasia may lead to squamous cell carcinoma, adenosquamous carcinoma, and mucoepidermoid carcinoma. Only seven cases of colonic adenoma with squamous metaplasia have been reported previously in the literature, and it is yet necessary to discuss the histogenesis, significance, and natural history of colonic adenoma with squamous metaplasia.     

TUBULAR ADENOMA WITH FOCAL SQUAMOUS METAPLASIA OF THE ASCENDING COLON

A case of tubular adenoma with focal squamous metaplasia of the ascending colon in a 66-year-old male is reported. The tumor was a pedunculated polyp with a size of 1.5 × 1.4 × 0.9 cm. Histologically, the tumor showed tubular adenoma with moderate to severe atypia, was accompanied by focal squamous metaplasia. It is thought that squamous epithelial polyp may be derived from colonic adenoma with squamous metaplasia, and that the malignant change of colonic adenoma with squamous metaplasia may lead to squamous cell carcinoma, adenosquamous carcinoma, and mucoepidermoid carcinoma. Only seven cases of colonic adenoma with squamous metaplasia have been reported previously in the literature, and it is yet necessary to discuss the histogenesis, significance, and natural history of colonic adenoma with squamous metaplasia. ACTA PATHOL. JPN. 35 : 507–515, 1985.     

Basal cell adenoma with extensive squamous metaplasia and cellular atypia: a case report with cytohistopathological correlation and review of the literature

Basal cell adenoma (BCA) is a rare benign basaloid neoplasm of the salivary gland. There are four histopathological types of BCA: solid, tubular, trabecular, and membranous. It is known that focal squamous metaplasia may be seen in some BCAs, but it is rare to see extensive squamous metaplasia, especially with cellular atypia. Here, a 25-year-old male with right parotid swelling is presented. Ultrasonography revealed a 2-cm well defined mass in his parotid gland. Fine-needle aspiration (FNA), performed prior to surgical excision, showed a highly cellular tumor composed of basaloid cells, forming small duct-like or tubular structures containing basement membrane-like material, as well as squamous cells with hyperchromatic, enlarged, pleomorphic, and bizzare nuclei. We made a cytopathological diagnosis of "basaloid neoplasm" and also reported that the differential diagnosis included BCA, cellular pleomorphic adenoma, basal cell adenocarcinoma, and carcinoma ex pleomorphic adenoma. The patient underwent total parotidectomy. Both frozen and permanent sections showed a BCA with membranous, tubulotrabecular pattern, and extensive squamous metaplasia. Some of the squamous cells showed significant nuclear hyperchromasia, enlargement, and pleomorphism. As far as we know, this is the first case of BCA with extensive squamous metaplasia and prominent cellular atypia. This case has been presented to show that squamous metaplastic cells with hyperchromatic, enlarged, bizarre, and pleomorphic nuclei can be seen on FNA smears of a benign tumor like BCA. Also, the differential diagnosis of BCA of the salivary gland is discussed here.     

Squamous metaplasia following necrosis of the adenohypophysis and of a chromophobe adenoma of the pituitary

Summary Two cases of pituitary necrosis are presented, one occurring post partum in an otherwise normal gland, the other in a large chromophobe adenoma. In both cases the necrotic tissue became surrounded by squamous epithelial nests that developed through metaplasia from glandular cells of the adenohypophysis and adenoma cells respectively. The squamous elements were seen 6 days after the clinical events leading to pituitary necrosis in the first case and 20 days after pituitary apoplexy (hemorrhagic necrosis of an adenoma) in the second case. In contradistinction to the commonly found squamous nests which are usually located in the pars tuberalis and presumably develop through a slower process, the changes in the present two cases indicate that squamous metaplasia can develop quite rapidly at the margins of a necrotic process of the pituitary, either deep in the gland as in case 1 or occupying the entire circumference of a necrotic tumor as in case 2.     

Malignant pleomorphic adenoma (malignant mixed tumor) of the trachea. Report of a case

Malignant pleomorphic adenoma arising in the trachea has not been reported in the literature. We report here a case of malignant pleomorphic adenoma (malignant mixed tumor) occurring in the trachea of a 65-year-old woman. The tumor metastasized to the lung and the chest wall 11 years after complete resection of the primary tumor, which was a polypoid submucosal tumor, 1.3 cm in diameter. Light microscopic examination of the primary and metastatic tumors showed the presence of epithelial and stromal elements, consisting of grandular structures, foci of squamous metaplasia and a myxochondroid stroma. Many tumor cells showed myoepithelial cell features by electron microscopy, and immunoreactivity for S-100 protein and GFAP was also seen in many of them. These findings were consistent with those of pleomorphic adenoma. However, the epithelial elements were cytologically atypical with prominent mitotic figures. Infiltration of the tumor cells into the surrounding soft tissue was also seen. No foci of benign pleomorphic adenoma were found in the primary tumor. These findings indicate that this tumor was not a carcinoma ex pleomorphic adenoma, but a true malignant pleomorphic adenoma (true malignant mixed tumor) of the trachea.     

Wnt Signaling as a Possible Promoting Factor of Cell Differentiation in Pleomorphic Adenomas

There are well known that Wnt signaling was some roles of cell differentiation at the development tissues, especially the oral and maxillofacial regions of some developmental stages. Therefore, to determine Wnt signaling in the pleomorphic adenoma tissues, we examined. The expression of Wnt1 and β-catenin as well as the distribution of various cytoskeletal proteins CK7 and CK13 was examined in 30 cases of pleomorphic adenoma by immunohistochemistry. Wnt1 was detected in almost all tumor cells. The peripheral columnar cells in squamous metaplasia and small cuboidal cells in duct-like structures were strongly positive to Wnt1. Although β-catenin was clearly localized on the cell membrane of tumor cells, nuclear translocation was observed in small cuboidal cells and in some basaloid cells. The immunofluorescent staining pattern of Wnt1 and CK7 as well as Wnt1 and CK13 was consistent with IHC results. Thus, in pleomorphic adenoma, Wnt is involved in tumor cell differentiation of peripheral columnar cells forming solid nests and small peripheral columnar cells forming duct-like structures. Moreover, among the three currently known Wnt pathways, β-catenin is the suggested pathway working during cell differentiation. Furthermore, peripheral columnar cells in solid tumor nests and in squamous metaplasia are governed by another Wnt pathway other than β-catenin. Therefore, Wnt signaling through β-catenin pathway may be involved in the ''mixed'' differentiation characteristic of pleomorphic adenoma although another pathway may also be possibly working in other parts of the tumor tissue.     

MALIGNANT PLEOMORPHIC ADENOMA (MALIGNANT MIXED TUMOR) OF THE TRACHEA. Report of a Case

Malignant pleomorphic adenoma arising in the trachea has not been reported in the literature. We report here a case of malignant pleomorphic adenoma (malignant mixed tumor) occurring in the trachea of a 65-year-old woman. The tumor metastasized to the lung and the chest wall 11 years after complete resection of the primary tumor, which was a polypoid submucosal tumor, 1.3 cm in diameter. Light microscopic examination of the primary and metastatic tumors showed the presence of epithelial and stromal elements, consisting of grandular structures, foci of squamous metaplasia and a myxochondroid stroma. Many tumor cells showed myoepithelial cell features by electron microscopy, and immunoreactivity for S-100 protein and GFAP was also seen in many of them. These findings were consistent with those of pleomorphic adenoma. However, the epithelial elements were cytologically atypical with prominent mitotic figures. Infiltration of the tumor cells into the surrounding soft tissue was also seen. No foci of benign pleomorphic adenoma were found in the primary tumor. These findings indicate that this tumor was not a carcinoma ex pleomorphic adenoma, but a true malignant pleomorphic adenoma (true malignant mixed tumor) of the trachea. ACTA PATHOL JPN 38: 1215∼1226, 1988.     

Notch as a Possible Cell Differentiation Factor in Pleomorphic Adenomas

The expression of Notch in 30 cases of pleomorphic adenoma was examined by immunohistochemistry. Comparing the results of our study with previous literatures, from the partial CK7 expression and substantial Notch expression in ductal epithelial cells as well as the Notch expression in solid tumor nests, it can be inferred that Notch is involved in cell differentiation. CK13 expression was observed in cells undergoing squamous metaplasia and Notch expression was seen in the nucleus of basal and squamous cells. The intense Notch expression in basal cells and weak expression in squamous cells suggests that Notch is involved in the differentiation from basal to squamous cell. Moreover, the loss of nuclear expression on the inner layer would signify that differentiation is about to end or has been terminated. Notch was expressed in the cytoplasm of cartilage cells and in the cell membrane of mucous cells but not in the nucleus indicating that differentiation has been concluded. Notch involvement is suspected in cell differentiation in areas showing ductal structures and squamous metaplasia. In summary, Notch is involved in cell differentiation of ductal cells in PA. Nuclear expression was shown in tumor cells in solid nests and surrounding structures. Moreover, Notch is expressed by basal cells undergoing squamous metaplasia suggesting the participation of Notch in cell differentiation in PA.     

43例腮腺Warthin 瘤的细针穿刺细胞学分析

目的：探讨腮腺腺淋巴瘤的细针穿刺细胞学特点。方法：收集并复习43例腮腺腺淋巴瘤，每例均备有巴氏染色、HE染色涂片及细胞块。结果：43例均发现嗜酸性细胞及淋巴细胞，40例发现细胞碎屑，9例发现带有淋巴间质的嗜酸性细胞乳状结构，35例发现巨噬细胞，5例出现鳞状上皮化生，3例发现肥大细胞。结论：腺淋巴瘤是腮腺的常见肿瘤，细针穿刺一般可以作出准确诊断，但应注意与多形性腺瘤、腺样囊腺癌、腺泡细胞癌、慢性腮腺炎、淋巴上皮囊肿、鳞癌鉴别。     

乳头汗腺瘤样腺瘤1例及文献复习

目的 探讨乳头汗腺瘤样腺瘤的临床病理和免疫表型特点及诊断与治疗。方法 通过HE及免疫组化染色观察1例乳头汗腺瘤样腺瘤,并结合文献讨论。结果 肿瘤发生于乳头,由上皮细胞形成的不规则巢、小条索或小管在致密的纤维间质及平滑肌之间呈浸润性生长,其中可见“蝌蚪状”细胞巢及角化囊肿,病变边界不清。免疫表型：CK阳性,p63、SMA部分阳性,ER、PR及GCDFP-15均阴性。结论 乳头汗腺瘤样腺瘤是一种呈局部浸润性生长的非常罕见的乳头部良性肿瘤,局部切除后可复发,但不转移。组织学上主要应与乳头管腺瘤、导管内乳头状瘤伴鳞化及管状癌鉴别。适当的治疗应该包括肿瘤及其周边充分的正常组织完整切除,且标本切缘阴性。     

Colonic adenoma with squamous metaplasia

Squamous metaplasia arising within colon adenomas is a rare occurrence, with a 0.4% incidence noted predominantly in elderly males. A case of squamous metaplasia arising in a tubulovillous adenoma of the cecum, associated with adenocarcinoma, is described. Squamous metaplasia was immunoreactive for beta-catenin, but negative for cytokeratin 20, CDX2, p63, estrogen receptor, progesterone receptor, p16, and human papilloma virus. Squamous differentiation may serve as a precursor lesion for squamous neoplasia of the colorectum.     

Respiratory tract lesions in noninhalation studies

This paper reviews respiratory tract lesions observed in rodents administered various chemicals by noninhalation routes. Chemicals administered by inhalation caused lesions in the respiratory tract and were well described; however, when chemicals were administered by noninhalation routes the effort to evaluate tissues for lesions may have been less or not considered, especially in the upper respiratory tract, and some lesions may have gone undetected. Lesions described in this review mostly occurred in rodent chronic noninhalation studies conducted by the National Toxicology Program; however, some were noted in studies of shorter duration. The nasal cavity was vulnerable to damage when chemicals were administered by noninhalation routes. Changes included respiratory epithelial hyperplasia, degeneration and necrosis of olfactory epithelium, olfactory epithelial metaplasia, adenoma, adenocarcinoma, squamous cell carcinoma, and neuroblastoma. In the lung, compound-related lesions included alveolar histiocytosis, alveolar epithelial hyperplasia, bronchiolar metaplasia of the alveolar epithelium, squamous metaplasia, alveolar/bronchial adenoma and carcinoma, and squamous tumors. Pathogenesis of these lesions included regurgitation of volatiles, metabolites arriving from the blood stream, and additional metabolism by olfactory epithelium or Clara cells. The presence of respiratory tract lesions in noninhalation studies emphasizes the need for a thorough examination of the respiratory tract including nasal passages, regardless of the route of administration.     

Histogenesis of Gallbladder Carcinoma from Investigation of Early Carcinoma and Microcarcinoma

Carcinomas of the gallbladder can be grossly divided into two types: carcinoma in adenoma (CIA) and carcinoma without adenoma (CWA). The histogenesis of both types of gallbladder carcinoma (CIA and CWA) was investigated in association with metaplastic changes in 35 early carcinomas larger than 5 mm in diameter and 16 microcar-cinomas up to 5 mm in largest diameter. In five early ClAs and two micro-CIAs, the carcinoma was surrounded by the adenoma, and the areas of both carcinoma and adenoma mainly showed gastric-type metaplasia (GM). On the other hand, 90% of the other 30 early CWAs showed GM and/or intestinal-type metaplasia (IM) in the tumor, and all of them were surrounded by GM and/or IM. Seven of the other 14 micro-CWAs showed GM and/or IM in the tumor as well as in the surrounding mucosa, and had non neoplastic metaplastic glands underneath the carcinoma tissue. The remaining seven micro-CWAs showed no or only mild metaplasia in the tumor and were surrounded by proper mucosa without metaplasia. From these data, it is concluded that carcinoma of CIA possibly arises from adenoma mainly with GM, and that CWA originates either from the upper part of the metaplastic mucosa or from the proper mucosa of the gallbladder. In addition, some CWA may undergo secondary metaplastic changes during tumor growth. Acta Pathol Jpn 39: 235–244, 1989.     

Precursor lesions of the urinary bladder

The classification of neoplastic precursor lesions in the urinary tract has evolved slowly with the gradual accumulation of clinicopathological data. Current nomenclature was codified most recently by the 2016 WHO classification, which is based on primary data with clinical outcome, consensus group statements and considerations of practical utility in routine diagnosis. This review discusses precursor lesions of urothelial, squamous and glandular lineage. For urothelial neoplasia, both flat lesions with atypia and early ‘difficult‐to‐classify’ proliferations are considered. Subtypes of squamous metaplasia, florid non‐invasive squamous proliferations and frank squamous dysplasia are also addressed. Finally, rare glandular precursors of adenocarcinoma are reviewed, to include intestinal metaplasia, glandular dysplasia and villous adenoma. For each category, morphology (including differential diagnostic considerations), immunohistochemistry and any known molecular correlates are detailed. The goal is to provide a concise, practical up‐to‐date overview of this complex topic.     

Primary adenocarcinoma of the renal pelvis with special reference to histochemical observations

A case of adenocarcinoma of the renal peivis is presented. The patient was an 84-year-old man suffering from longstanding right-sided nephrolithiasis. Surgical resection of the right kidney revealed adenocarcinoma with slight stromal invasion. A tubulovillous adenoma, which was morphologically similar to an adenoma of the large Intestine, was also found adjacent to the adenocarcinoma. The pelvic epithelium neighboring the lesion revealed Intestinal metaplasla. Histochemical studies revealed that the tumor In the patient and adenocarcinomas or adenomas of the large intestine have similar properties of cytoplasmic mucin. These findings suggest that the epithelium with intestinal metaplasia may have developed into the adenoma and flnally transformed into the adenocarclnoma. In addition, only tumor cells with severe atypia, most of which morphologically corresponded to adenocarcinoma, demonstrated positive nuclear staining for anti-p53. This suggests that p53 may play an important role In the malignant transformation of adenomas into adenocarcinomas, as is the case in the large intestine.     

Immunohistochemical analysis of morules in colonic neoplasms: morules are morphologically and qualitatively different from squamous metaplasia.

Morules develop in several neoplasms and have been considered as a type of squamous metaplasia despite the absence of keratinization and intercellular bridges. The objective of this study was to clarify the pathological significance of morules and to distinguish morules from squamous metaplasia in colonic neoplasms. Ten cases of morule-associated colonic neoplasms (4 adenocarcinomas, 1 adenoma with carcinoma in situ, and 5 adenomas), and 3 cases of squamous metaplasia in colonic adenocarcinoma were examined morphologically and immunohistochemically. Morules were well-defined structures composed of small, oval to short-spindled cells with bland nuclei, and frequently associated with intranuclear inclusions that were positive for biotin and biotin-binding enzymes (pyruvic acid carboxylase and propionyl CoA carboxylase). On immunohistochemical examination, morules characteristically showed nuclear overexpression of beta-catenin, cyclin D1 and p63, low Ki-67 labeling index (<1%), cytoplasmic overexpression of CD10, and no expression of cytokeratin 20. These molecules were useful for the differentiation of morules. Furthermore, p63 and 34betaE12 positivities in morules suggested that they have a basal/stem cell phenotype. Thus, morules were morphologically and qualitatively different from squamous metaplasia. We consider that morules in colonic neoplasms are cell clusters with a basal/stem cell phenotype, and have less proliferative and less invasive potential than other cancer cells.     

Primary mucin-producing adenosquamous carcinoma of the thyroid gland

A rare case of mucin-producing adenosquamous carcinoma of the thyroid gland is reported in a 57-year-old woman. Light microscopically, much of the tumor showed a feature of mucin-producing adenosquamous carcinoma; squamous cells and mucous signet ring cells. In the lower portion of the tumor, a calcified area containing small foci of follicular carcinoma and its squamous cell metaplasia was accompanied. Histochemically, neutral, non-sulphated and sulphated acid mucins were found in the mucous cells, and no thyroglobulin or calcitonin was detected in the tumor cells. Electron microscopically, some tonofibrils and mucin production were observed concomitantly in the tumor cells. These findings suggested the possibility that this mucin-producing adenosquamous carcinoma originated from squamous cell metaplasia of pre-existing follicular carcinoma.     

Salivary gland components involved in the formation of squamous metaplasia.

Squamous metaplasia is not an uncommon feature of a number of salivary gland lesions. Arterial ligation of rat submandibular and sublingual salivary glands was used for study of the processes and cell types involved in the development of the squamous metaplasia that occurs in ischemic and infarcted portions of gland parenchyma 6 to 8 days following vessel ligation. Light and electron micrographs show that the principal portion of salivary gland tissue undergoing squamous metaplasia is the acinar-intercalated duct cell complex. Early stages of this process involve a gradual dedifferentiation of acinar cells and hyperplasia of acinar, duct luminal cells, and myoepithelium. Subsequently, both luminal and myoepithelial cells have increasing accumulation of tonofilaments and formation of desmosomes, and centrally located cells may undergo keratinization. Immunohistochemical staining of ischemic salivary gland tissue with developing squamous metaplasia was performed with the use of rabbit antisera to human epidermal and Mallory body cytokeratins. The two antisera gave complementary patterns in normal acini and ducts, with antibody to epidermal cytokeratin (ECK) staining only myoepithelial cells and antibody to Mallory body cytokeratin (MBCK) staining mainly luminal epithelial cells. In early phases of squamous metaplasia (6 days after ligation), antibody to ECK stained central and peripheral (myoepithelial) cells, but by 8 days after ligation only central cells were stained. At 6 days after ligation, a proportion of central cells in squamoid clusters stained with antibody to MBCK, and myoepithelial cells were unstained. By 8 days after arterial ligation, cell clusters exhibiting squamous metaplasia were completely unstained with antibody to MBCK, despite the presence ultrastructurally of numerous tonofilament bundles in both types of cells forming these clusters. The propensity for squamous alteration of acinar-intercalated duct complexes has important connotations for salivary gland tumors such as pleomorphic adenoma and mucoepidermoid carcinoma.     

Coexistence of primary squamous cell carcinoma of thyroid with classic papillary thyroid carcinoma

Primary squamous cell carcinoma of the thyroid gland is very rare and its histogenesis is poorly defined so far. Although there have been some cases of squamous cell carcinoma with variant types of papillary thyroid carcinoma (PTC), the present case is the first primary squamous cell carcinoma with classic PTC to be reported. A 43‐year‐old woman presented with a 20 year history of neck mass. Neck ultrasound indicated a 6 × 4 × 3 cm large mass. The patient underwent total thyroidectomy. Histopathology indicated a well‐differentiated squamous cell carcinoma and squamous metaplasia in conjunction with classic PTC. On immunohistochemistry cytokeratin 7 was positive in papillary carcinoma and squamous metaplasia, thyroglobulin was positive only in papillary carcinoma, and p63 was positive in squamous metaplasia and squamous cell carcinoma. Postoperatively, the patient received 59.4 Gy adjuvant radiotherapy, hormonal therapy and radioactive iodine therapy. At 8 months after surgery the patient remained disease free.