Expanding the cytological and architectural spectrum of mucoepidermoid carcinoma: The key to solving diagnostic problems in morphological variants.

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor. Varying sized cysts and sheets composed of three cell types (epidermoid, intermediate, and mucous cells) with varying degrees of atypia form the characteristic histological appearance of MEC. MEC frequently contains a wide variety of modified tumor cells and can be entirely cystic or completely solid. Under these circumstances, MEC requires critical differentiation from many mimickers, ranging from simple cysts and benign tumors to high-grade carcinomas. Tumor-associated lymphoid proliferation and sclerotic changes in the stroma also contribute to diagnostic difficulties. Several well-known diagnostically challenging variants (oncocytic, clear cell, spindle cell, and sclerosing) exist in MEC. With the advent of studies on specific CRTC1/3::MAML2 fusion genes in MEC, newly proposed subtypes have emerged, including Warthin-like and non-sebaceous lymphadenoma-like MECs. In addition to the recently defined mucoacinar variant with a serous cell phenotype, MEC devoid of squamous differentiation has also been reported, implying the need to reconsider this basic concept. In this article, we outline the general clinical features and MAML2 status of conventional MEC and review the cytoarchitectural subtypes, with an emphasis on a pitfall in the interpretation of this histologically diverse single entity.

Revisiting the History of Odontoma, with Special Reference to Its Original Illustration.

BACKGROUND: Practically every facet of the most common odontogenic tumor, odontoma, has been covered by an extensive volume of literature. However, uncertainty about its precise history has persisted. MATERIALS AND METHODS: The historical evolution of odontoma was traced with reference to the original illustrations that accompanied European and American reports published at the beginning of the 19th century and also at the turn of the century. RESULTS: The prevailing views regarding the first description of odontoma by Oudet of Paris in 1809 and the original designation "odontome" by Broca of Paris in 1867 are not entirely accurate. Before Broca's suggested term, "exostose dentaire" (dental exostosis) and "tumeur dentaire" (dental tumor) proposed by Oudet and Forget of Paris, respectively, were popular terms adopted in France, while in Briatin the terms "warty tooth" and "supernumerary teeth" proposed by Salter and Tomes of London, respectively, were widely coined. The original illustrations of complex odontoma were published by Wedl of Vienna in 1851, and in 1862 Tomes published the first drawing of compound odontoma denticles. Before the advent of diagnostic radiography in the early 1900s, spontaneous exposure or eruption of odontoma followed by secondary infection was very common. In 1887-1888, Bland Sutton of London criticized Broca's monumental research and formulated the first modern classification which, in essence, remains valid today. At that time, large osteomas of the maxilla were inappropriately classified as odontomas by many pathologists because of Bland Sutton's influential view. Interestingly, the first radiographic evidence of odontoma was published by the American oral surgeon Gilmer in 1899. CONCLUSION: In view of their fundamental achievements, the names of Wedl, Salter, Broca and Bland Sutton have been closely associated with the true history of odontoma.

Warthin Tumor of the Parotid Gland: The History of an Eponym.

The eponymous history of Warthin tumor (WT) is a fascinating issue in the field of salivary gland pathology. The late decades of the nineteenth century and the turn of the century saw notable German and French contributions on WT. Especially, the seminal 1910 paper of Albrecht and Arzt of Vienna is the foundation for the current knowledge of WT. It is generally believed that prior to this pioneering study, Hildebrand of Göttingen accurately described the lesion of WT in 1895. However, the historical origins of WT appear to be unsettled, and only a few German pathologists and surgeons are aware that dating back to 1885, the first recognizable reference to WT was that by the renowned German-Swiss pathologist Zahn, whose name is eponymously associated with "Zahn infarct" and "lines of Zahn". Two noted French surgeons with a major interest in pathology, Albarrán in 1885 and Lecéne in 1908, did not contribute to the topic. Since the 1950s, a mostly American group of pathologists and surgeons gradually adopted the term WT to replace the very accurate histologic descriptor "papillary cystadenoma lymphomatosum" coined by Warthin himself in 1929. It is our opinion that from a historical viewpoint, there is no particular reason why this tumor should have been named WT.

Case report: Rapid development of amyloid A amyloidosis in temporal arteritis with SAA1.3 allele; An unusual case of intestinal amyloidosis secondary to temporal arteritis.

Temporal arteritis (TA) is a large-vessel vasculitis mostly seen in older patients. Amyloid A (AA) amyloidosis secondary to a chronic inflammation induces multiple organ dysfunctions, including a dysfunction of the gastrointestinal tract. Herein, we present a case of TA complicated by AA amyloidosis that was resistant to oral and intravenous steroids. An 80-year-old man with a history of new-onset headache, jaw claudication, and distended temporal arteries was referred to our department. On admission, the patient presented with tenderness and a subcutaneous temporal nodule in both temple arteries. Ultrasonography of the nodule revealed an anechoic perivascular halo surrounding the right temporal artery. Following the diagnosis of TA, high-dose prednisolone therapy was initiated. However, the patient presented with recurrent abdominal pain and refractory diarrhea. Due to the unclear origin of refractory diarrhea, an extensive workup, including biopsy of the duodenal mucosa, was performed. Endoscopy revealed chronic inflammation in the duodenum. Immunohistochemical analysis of duodenal mucosal biopsy samples revealed AA amyloid deposition resulting in the diagnosis of AA amyloidosis. After tocilizumab (TCZ) administration, refractory diarrhea reduced; however, the patient died of intestinal perforation 1 month after the start of TCZ administration. Gastrointestinal involvement was the main clinical manifestation of AA amyloidosis in the present case. This case highlights the importance of bowel biopsy screening for amyloid deposition in patients with unexplained gastrointestinal tract symptoms, even in a recent onset of large-vessel vasculitis. In the present case, the carriage of the SAA1.3 allele likely contributed to the rare association of AA amyloidosis with TA.

Histological improvement in chronic hepatitis C-autoimmune hepatitis overlap syndrome by glecaprevir and pibrentasvir.

A 60-year-old man with type-2 diabetes and chronic hepatitis C (HCV) was diagnosed with single hepatocellular carcinoma (HCC) of 67 mm in the hepatic posterior right lobe. Lenvatinib 8 mg was initiated but discontinued because of grade 3 liver injury. The patient continued to have prolonged liver injury and persistently high immunoglobulin G levels. Antinuclear antibody titer increased from 1:40 to 1:320. Histopathological examination of a liver biopsy specimen revealed interface hepatitis with lymphocyte and plasma cell infiltration, rosette formation, and emperipolesis, suggesting the possibility of autoimmune hepatitis (AIH). First, treatment with prednisolone was initiated; however, the response was poor. After starting glecaprevir/pibrentasvir (GLE/PIB) as direct-acting antivirals (DAA), HCV RNA rapidly disappeared, and serological liver function improved. After confirmation of sustained virological response 24, HCC recurrence was observed, and partial hepatectomy was performed. Background liver findings showed that liver parenchymal inflammation improved compared with that before DAA treatment. This is the first case of HCV-AIH overlap syndrome treated with DAA using GLE/PIB. Liver function improved within a short treatment period of 8 weeks, as confirmed using serology and histology.

The True History of Cementoblastoma.

REVIEW OF THE LITERATURE: Cementoblastoma (CB) is unique among odontogenic tumors because its gross pathological anatomy is pathognomonic in most cases, i.e., a rounded calcified growth that is fused to the root of a tooth and completely encapsulated by fibrous tissue. The resulting radiographic appearance is a well-defined, globular mixed radiopaque/lucent or completely radiopaque mass obliterating some details of the root, with a thin radiolucent zone surrounding the central opacity. Although hundreds of publications have covered the clinicopathologic features of CB, almost nothing is known about its true history. Also it seems there is little understanding about how the term "CB" was originally introduced as a pathologic entity. This report covers some overlooked papers on CB dating back to the 19th century, including the first complete description in 1888 and the first radiographic presentation in 1906.

Quantitative analysis of tissue area of endoscopic ultrasound-guided liver biopsy specimens using 19-gauge fine-needle biopsy needle in patients with diffuse liver disease: A single-center retrospective study.

BACKGROUND/PURPOSE: Endoscopic ultrasound-guided liver biopsy (EUS-LB) is a novel liver biopsy technique. We aimed to evaluate the efficacy and safety of EUS-LB in comparison with percutaneous liver biopsy (PLB). METHODS: This retrospective study evaluated the safety and efficacy of EUS-LB using a 19-gauge fine needle biopsy (FNB) needle compared with PLB using a spring-loaded 16-gauge needle in patients with diffuse liver disease at our hospital from April 2017 to December 2020. The primary outcomes included the total hepatic tissue surface area and the total number of portal tracts. Secondary outcomes included the success and adverse event rates. RESULTS: Twenty patients each underwent EUS-LB and PLB. There was no statistical difference in the sum of liver tissue surface area (22 mm2 vs 22.6 mm2 , P = .910) and the total number of portal tracts (29 vs 25, P = .916). The success rate was 95% (19/20) for EUS-LB and 100% (20/20) for PLB (P = 1). There were two adverse events in the PLB group but none in the EUS-LB group (P = .487). CONCLUSIONS: Endoscopic ultrasound-guided liver biopsy using FNB has an optimal tissue yield and success rate and is safe compared to PLB. Thus, EUS-LB may be a new alternative to PLB.

Salivary gland polymorphous adenocarcinoma: Clinicopathological features and gene alterations in 36 Japanese patients.

BACKGROUND: Polymorphous adenocarcinoma is a common intraoral minor salivary gland carcinoma in Western countries but is extremely rare in Japan. The current study aimed to characterize the clinicopathological features and status of molecular alterations of polymorphous adenocarcinoma-associated genes, such as PRKD1/2/3, ARID1A, and DDX3X, in a large cohort of Japanese patients with polymorphous adenocarcinoma. METHODS: We examined the cases of 36 Japanese patients with salivary gland polymorphous adenocarcinoma and 26 cases involving histopathological mimics. To detect gene splits, fluorescence in situ hybridization was carried out for polymorphous adenocarcinoma-associated genes. Additionally, we applied a SNaPshot multiplex assay to identify PRKD1 hotspot mutations. RESULTS: This study revealed the indolent clinical course of polymorphous adenocarcinoma with a high 10-year overall survival rate (92.9%), accompanied by occasional local recurrences and cervical lymph node metastasis (23.3%). Twenty cases (55.6%) of polymorphous adenocarcinoma (but none of the mimics) exhibited alterations in at least one polymorphous adenocarcinoma-associated gene. Rearrangement of polymorphous adenocarcinoma-associated genes and PRKD1 E710D were identified in 17 (47.2%) and 4 (11.1%) cases, respectively; one case showed coexisting PRKD3 split and PRKD1 E710D. In the multivariate analysis, high clinical stage (p = 0.0005), the presence of prominent nucleoli (p = 0.0003), and ARID1A split positivity (p = 0.004) were independent risk factors for disease-free survival. CONCLUSION: Japanese patients with polymorphous adenocarcinoma showed clinicopathological features similar to those reported in Western countries. This study disclosed that polymorphous adenocarcinoma-associated genetic alterations were common and specific findings in polymorphous adenocarcinomas. The diagnostic role and possible prognostic significance of polymorphous adenocarcinoma-associated genetic alterations in polymorphous adenocarcinomas were suggested.

Oncocytic Polyp in a Unicystic Mucoepidermoid Carcinoma of the Palate: A Unique Presentation.

We report a palatal mucoepidermoid carcinoma (MEC) with unusual pathological features showing salivary duct cyst-like architecture, varied epithelial linings (excretory duct, mucous goblet cell, and apocrine epithelium phenotypes), scarce luminal tumor plaques, and a large intraluminal oncocytic polyp. To our knowledge, such a unicystic variant of MEC with pedicled oncocytic proliferation in the lumen is unprecedented in the literature. In this particular case, the microscopic diagnosis of MEC is problematic because of the large number of potential mimics.