Concordance of MTOR Pathway Mutations and the Diagnosis of Renal Low-Grade Oncocytic Tumor (LOT)

The differential diagnosis for oncocytic renal tumors spans the spectrum from benign entities to more aggressive renal cell carcinomas (RCC). Recent work has characterized a provisional renal oncocytic neoplasm, namely the low-grade oncocytic tumor (LOT), which demonstrates overlapping morphologic features with oncocytoma and chromophobe RCC, but also has a unique immunoprofile (ie, diffusely positive for KRT7, negative for KIT) and a high rate (80% to 100%) of mTOR pathway gene alterations. Given the diagnostic overlap among oncocytic tumors, we looked for concordance between mTOR pathway mutations and LOT. Thirty low-grade renal oncocytic neoplasms underwent histologic review and immunohistochemistry for KRT7 and KIT. Tumors were classified as "determinate" (eg, LOT) for tumors with solid, nested or vaguely tubular growth and diffuse KRT7 staining and negative KIT, or "indeterminate" if the morphology and/or immunostains did not fully support a definitive LOT diagnosis. Next-generation sequencing was performed without any knowledge of the diagnoses, and identified mTOR pathway mutations in 80% (12/15) of the determinate tumors, compared with 7% (1/15) in the indeterminate group. One determinate tumor was reclassified as papillary RCC (MTOR mutation negative) and 6 indeterminate tumors were confirmed to be oncocytoma (N = 4), clear cell RCC or papillary RCC with reverse polarity, respectively. Overall, integration of morphology, immunohistochemistry, and molecular data enabled a final definitive diagnosis for 70% of tumors (21 of the total 30), with a high concordance (93%) for LOT specifically in the determinate group; the remaining 9 tumors (30%) were classified as renal oncocytic neoplasm, not otherwise specified.

Characterization of Intercalated Cell Markers KIT and LINC01187 in Chromophobe Renal Cell Carcinoma and Other Renal Neoplasms

Introduction. Chromophobe renal cell carcinoma (chromophobe RCC) is the third major subcategory of renal tumors after clear cell RCC and papillary RCC, accounting for approximately 5% of all RCC subtypes. Other oncocytic neoplasms seen commonly in surgical pathology practice include the eosinophilic variant of chromophobe RCC, renal oncocytoma, and low-grade oncocytic unclassified RCC. Methods. In our recent next-generation sequencing based study, we nominated a lineage-specific novel biomarker LINC01187 (long intergenic non-protein coding RNA 1187) which was found to be enriched in chromophobe RCC. Like KIT (cluster of differentiation 117; CD117), a clinically utilized chromophobe RCC related biomarker, LINC01187 is expressed in intercalated cells of the nephron. In this follow-up study, we performed KIT immunohistochemistry and LINC01187 RNA in situ hybridization (RNA-ISH) on a cohort of chromophobe RCC and other renal neoplasms, characterized the expression patterns, and quantified the expression signals of the two biomarkers in both primary and metastatic settings. Results. LINC01187, in comparison to KIT, exhibits stronger and more uniform expression within tumors while maintaining temporal and spatial consistency. LINC01187 also is devoid of intra-tumoral heterogeneous expression pattern, a phenomenon commonly noted with KIT. Conclusions. LINC01187 expression can augment the currently utilized KIT assay and help facilitate easy microscopic analyses in routine surgical pathology practice.

Case Report: Surgery to remove adrenocortical oncocytic carcinoma from an Asian male

Adrenocortical oncocytic carcinoma is a rare type of adrenocortical tumor. Its clinical characteristics and biological behavior need to be further evaluated after the accumulation of cases. Here we report a case of adrenocortical oncocytic carcinoma in an Asian male with scoliosis. We performed an operation on this patient. Because the patient's scoliosis was limited during the operation and the tumor protruded into the chest, we decided to adopt open surgery in the supine position. During the operation, we found a tumor about 8 cm in diameter in the right adrenal region and successfully removed it. The patient recovered well after surgery, and there was no tumor recurrence after one year of follow-up. Pathological results confirmed the diagnosis of adrenocortical oncocytic carcinoma. Pathological features showed tumor cell invasion of adipose tissue, with atypical mitosis and abundant esinophilic cytoplasm. Immunohistochemistry showed that nucleus related antigen (Ki67) index was more than 15% and the positive pathological staining of Synaptophysin (Syn), Melanoma A (Melan A), Inhibin and calretinin. The incidence rate of adrenocortical oncocytic carcinoma is extremely rare. Abdominal Computed tomography (CT) scans and other imaging examination methods are not specific. For larger adrenal tumors, the diagnosis of this disease should be considered. For patients with adrenocortical oncocytic carcinoma who have not yet metastasized, we may achieve sound treatment effects and reduce recurrence by removing the tumor, retroperitoneal fat around the tumor and locoregional lymph nodes.

[Adrenocortical cancer: morphological variants, immunohistochemical characteristics]

Adrenocortical cancer (ACC) is a rare endocrine malignancy of the adrenal cortex, which has an unfavorable prognosis and extremely aggressive clinical behavior in most cases. Nevertheless, cases of a more favorable disease course with late metastasis and slow progression have been described. In 2017, the International Agency for Research on Cancer (IARC) and the World Health Organization (WHO) in the 4^th edition of the Classification of Tumors of the Endocrine Organs identified histological variants of ACC, such as classical, oncocytic, myxoid, and sarcomatoid ones, indicating the morphological heterogeneity of this tumor.

OBJECTIVE

To provide a detailed description of the morphological variants of ACC with an emphasis on their histological characteristics and the expression of immunohistochemical markers.

MATERIALS AND METHODS

A total of 75 cases of ACC were analyzed in the adult population diagnosed as having the morphological variants in accordance with the International Histological Classification of Adrenal Tumors (WHO, 2017). Monoclonal antibodies to SF1, Inhibin A, Melan A, Ki-67, p53, and antimitochondrial antibodies were used for immunohistochemical diagnosis.

RESULTS

The classic, oncocytic, and myxoid subtypes of ACC were found in 51 (68%), 15 (20%), and 9 (12%) cases, respectively. The functional activity of the tumors was observed in 43% (n=18) in the classic variant of ACC; moreover, the clinical picture was manifested by the symptoms of hypercorticism (38%) and virilization (5%). There were no significant differences in hormonal activity between different morphological variants. The characteristics of the above histological variants of the tumor was determined with a description of growth patterns that can improve the diagnosis of ACC. The diagnosis of ACC can be confirmed by an immunohistochemical study; the required minimum panel of markers should include SF1, Melan A, and Inhibin A. The Ki-67 proliferative activity index showed significant differences (p=0.0056) when it was determined in the morphological variants of ACC.

CONCLUSION

Despite the determination of a minimal immunohistochemical panel to confirm the diagnosis of ACC, it is important to remember that each histological variant may be characterized by the different expression of immunohistochemical markers. The identification of morphological variants of ACC and the use of specific, sensitive, and prognostically significant immunohistochemical markers will allow clinicians and pathologists to more accurately judge the biological properties of this tumor and the clinical course of the disease.

Analysis of the risk of malignancy associated with the basaloid and oncocytic subtypes of the salivary gland neoplasm of unknown malignant potential (SUMP) category in the Milan system

BACKGROUND

The salivary gland neoplasm of unknown malignant potential (SUMP) category reflects the cytomorphologic overlap and complexity of reporting salivary gland cytology in the Milan system. It includes neoplasms for which a diagnosis of a specific entity cannot be made and, more importantly, for which a carcinoma cannot be entirely excluded. For risk stratification, the subcategorization of SUMP based on the predominant cell type is recommended. This study was aimed at evaluating the risk of neoplasm (RON) and the risk of malignancy (ROM) of the basaloid and oncocytic subtypes of the SUMP category.

METHODS

A retrospective analysis of 482 salivary gland fine-needle aspirations from 2012 to 2019 resulted in 48 SUMP cases. The cytology of these cases was reviewed and reclassified as the basaloid or oncocytic subtype. Surgical follow-up was available for 36 cases. The RON and ROM for each subtype were calculated.

RESULTS

The RON and ROM were 100% and 23%, respectively, for monomorphic basaloid tumors and 88% and 58.8%, respectively, for monomorphic oncocytic tumors. The ROM for basaloid tumors was 8.3% without matrix/with minimal matrix and 60% with an nonfibrillary matrix. The ROM for oncocytic tumors was 50% without a cystic background and 60% with a cystic or mucinous background. The difference was not statistically significant for either of the subgroups.

CONCLUSIONS

Even though statistically not significant in our study, the differential ROMs within the oncocytic and basaloid subgroups help in the risk stratification of SUMP cases. Further subcategorization based on the stroma and background helps in limiting the differential diagnosis but does not necessarily add to the value of the risk stratification.

Adrenocortical Carcinoma: Updates of Clinical and Pathological Features after Renewed World Health Organisation Classification and Pathology Staging

Adrenocortical carcinoma (ACC) is a heterogenous group of diseases with different clinical behaviour between adult and paediatric patients. In addition, three histological variants, oncocytic, myxoid and sarcomatoid are noted on the recent World Health Organisation (WHO) classification of ACC. A review of recent literature showed that the different types of ACC have distinctive demographic data, clinical presentation, pathology, biological behaviour, genomic and patients' prognosis. In addition, recent updates of pathology staging for ACC allow refinement of prognostic grouping for planning treatment of the patients with ACC. These advances in genomic, pathology and staging have driven the development of standardisation of pathology reporting. International standardisation of pathological reporting of adrenocortical carcinoma and adaption to local pathology communities provide universal platforms for clinicians and researchers involved in the management of patients with ACC. To conclude, all these advances in the field of pathology will improve development of management strategies including improvement of clinical care, development of prognostic markers and testing of novel therapeutic approaches for patients with adrenocortical carcinoma.

Genetics, Diagnosis, and Management of Hürthle Cell Thyroid Neoplasms

Hürthle cell lesions have been a diagnostic conundrum in pathology since they were first recognized over a century ago. Controversy as to the name of the cell, the origin of the cell, and even which cells in particular may be designated as such still challenge pathologists and confound those treating patients with a diagnosis of "Hürthle cell" anything within the diagnosis, especially if that anything is a sizable mass lesion. The diagnosis of Hürthle cell adenoma (HCA) or Hürthle cell carcinoma (HCC) has typically relied on a judgement call by pathologists as to the presence or absence of capsular and/or vascular invasion of the adjacent thyroid parenchyma, easy to note in widely invasive disease and a somewhat subjective diagnosis for minimally invasive or borderline invasive disease. Diagnostic specificity, which has incorporated a sharp increase in molecular genetic studies of thyroid tumor subtypes and the integration of molecular testing into preoperative management protocols, continues to be challenged by Hürthle cell neoplasia. Here, we provide the improving yet still murky state of what is known about Hürthle cell tumor genetics, clinical management, and based upon what we are learning about the genetics of other thyroid tumors, how to manage expectations, by pathologists, clinicians, and patients, for more actionable, precise classifications of Hürthle cell tumors of the thyroid.

Thyroid Hürthle Cell Carcinoma: Clinical, Pathological, and Molecular Features

Simple Summary

Hürthle cell carcinoma (HCC) represents 3–4% of thyroid carcinoma cases. It is characterized by its large, granular and eosinophilic cytoplasm, due to an excessive number of mitochondria. Hürthle cells can be identified only after fine needle aspiration cytology biopsy or by histological diagnosis after the surgical operation. Published studies on HCC indicate its putative high aggressiveness. In this article, current knowledge of HCC focusing on clinical features, cytopathological features, genetic changes, as well as pitfalls in diagnosis are reviewed in order to improve clinical management.

Abstract

Hürthle cell carcinoma (HCC) represents 3–4% of thyroid carcinoma cases. It is considered to be more aggressive than non-oncocytic thyroid carcinomas. However, due to its rarity, the pathological characteristics and biological behavior of HCC remain to be elucidated. The Hürthle cell is characterized cytologically as a large cell with abundant eosinophilic, granular cytoplasm, and a large hyperchromatic nucleus with a prominent nucleolus. Cytoplasmic granularity is due to the presence of numerous mitochondria. These mitochondria display packed stacking cristae and are arranged in the center. HCC is more often observed in females in their 50–60s. Preoperative diagnosis is challenging, but indicators of malignancy are male, older age, tumor size > 4 cm, a solid nodule with an irregular border, or the presence of psammoma calcifications according to ultrasound. Thyroid lobectomy alone is sufficient treatment for small, unifocal, intrathyroidal carcinomas, or clinically detectable cervical nodal metastases, but total thyroidectomy is recommended for tumors larger than 4 cm. The effectiveness of radioactive iodine is still debated. Molecular changes involve cellular signaling pathways and mitochondria-related DNA. Current knowledge of Hürthle cell carcinoma, including clinical, pathological, and molecular features, with the aim of improving clinical management, is reviewed.

The Oncocytic Variant of Poorly Differentiated Thyroid Carcinoma Shows a Specific Immune-Related Gene Expression Profile

BACKGROUND

Poorly differentiated thyroid cancer (PDTC) is a rare, follicular cell-derived neoplasm with an unfavorable prognosis. The oncocytic variant of PDTC may be associated with even more adverse outcome than classical PDTC cases, but its specific molecular features are largely unknown. Our aim was to explore the immune-related gene expression profile of oncocytic and classical PDTC, in correlation with clinical and pathological characteristics (including programmed death ligand 1 [PD-L1] expression) and outcome, and in comparison with a control group of well-differentiated follicular carcinomas (WDFCs), including conventional follicular carcinomas (FTCs) and Hürthle cell carcinomas (HCCs).

METHODS

A retrospective series of 48 PDTCs and 24 WDFCs was analyzed by means of NanoString technology employing the nCounter PanCancer Immune Profiling panel. Gene expression data were validated using quantitative real-time polymerase chain reaction.

RESULTS

Oncocytic PDTCs showed a specific immune-related gene expression profile, with higher expression of LAIR2, CD274, DEFB1, IRAK1, CAMP, LCN2, LY96, and APOE, and lower expression of NOD1, as compared to conventional PDTCs. This molecular signature was associated with increased intratumoral lymphocytic infiltration, PD-L1 expression, and adverse outcome. Three of these genes, CD274, DEFB1, and IRAK1, as well as PD-L1 expression, were also the hallmarks of HCCs as compared to FTCs. By contrast, the panel of genes differentially regulated in PDTCs as compared to WDFCs was unrelated to the oncocytic phenotype.

CONCLUSIONS

Our results revealed a distinctive immune-related gene expression profile of oncocytic PDTC and confirmed a more aggressive outcome in this cancer subtype. These findings may provide guidance when exploring novel immunotherapeutic options for oncocytic PDTC patients.

Papillary-cystic neoplasms of the middle ear are distinct from endolymphatic sac tumours

AIMS

Papillary neoplasms of the middle and inner ear are rare and poorly characterised. The current World Health Organization classification divides them into two major subtypes: aggressive papillary tumours (APTs) and endolymphatic sac tumours (ELSTs). The aim of this article is to present two papillary neoplasms of the middle ear that do not fit into either the classic APT category or the classic ELST category, and compare them with three ELSTs.

METHODS AND RESULTS

The patients were a 48-year-old female and a 59-year-old male without a history of other neoplasms. Histology showed papillary-cystic growth of predominantly oncocytic (Case 1) or mucinous (Case 2) cells surrounded by a p63-positive basal layer. The overall histology was reminiscent of oncocytic sinonasal papilloma (Case 1) and pancreatobiliary or salivary intraductal papillary mucinous neoplasms (Case 2). Ovarian-type stroma, invasion and malignant features were absent. Immunohistochemistry revealed expression of cytokeratin (CK) 7, but not carbonic anhydrase IX (CAIX) or paired box gene 8 (PAX8) (except for very focal PAX8 expression in Case 1). The TST15 gene panel and HRAS sequencing revealed no pathogenic mutations in BRAF, KRAS, EGFR, AKT1, or HRAS. The TruSight RNA fusion panel revealed an MKRN1-BRAF fusion in Case 1. No fusion was detected in Case 2. The three ELSTs showed classic features of the entity, expressed CK7, epithelial membrane antigen, PAX8, and CAIX, and lacked a basal cell layer.

CONCLUSION

These novel cases suggest that papillary tumours of the ear represent a heterogeneous spectrum of distinct neoplasms unified by a prominent papillary-cystic pattern rather than a single entity. Future studies should clarify whether the MKRN1-BRAF fusion is a defining recurrent driver event, especially in those cases reported as sinonasal-type middle ear papillomas.

Oncocytic mucoepidermoid carcinoma (OMEC) of the parotid gland in a 12-year-old patient: A diagnostic challenge on cytology

Mucoepidermoid carcinoma is the most common malignant salivary gland neoplasm comprising approximately 10% of all tumours of the major salivary gland. Owing to a plethora of morphological variations, it poses a diagnostic challenge on fine-needle aspiration cytology. Oncocytic variant of mucoepidermoid carcinoma is a rare subtype seen in the age group of 20-80 years. It is crucial to make the correct diagnosis on cytology as it has therapeutic implications. Oncocytes can be present in a wide range of salivary gland lesions ranging from non-neoplastic conditions to benign and malignant lesions. We report a case of oncocytic mucoepidermoid carcinoma of the parotid gland in a 12-year-old boy which is the youngest age reported for the same. On cytology, this case was initially diagnosed as Warthin's tumour and was supported by radiology. However, histomorphological findings clinched the diagnosis of an oncocytic variant of mucoepidermoid carcinoma with the aid of immunohistochemistry.

CD117 Is a Specific Marker of Intraductal Papillary Mucinous Neoplasms (IPMN) of the Pancreas, Oncocytic Subtype

The intraductal oncocytic papillary neoplasm (IOPN) of the pancreas has been recognized by WHO classification as a unique intraductal papillary mucinous neoplasm (IPMN) category. IOPN is composed of oxyphil cells, usually expressing MUC5AC, MUC6, and Hep Par-1, and harboring PRKACA/B fusion genes as their genetic hallmark. Although IOPNs are associated with an infiltrative adenocarcinoma in up to 30% of cases, the survival rate after surgical resection approaches 100%. This highlights the importance of the correct IOPN diagnosis, above all in cases with an associated invasive component. In this study, the immunohistochemical expression of CD117 was investigated in 111 IPMNs, including 17 oncocytic, 45 gastric, 20 pancreatico-biliary, and 29 intestinal IPMNs. We also tested the expression of MUC5AC, MUC6, and Hep Par-1 in the IOPN cohort. CD117 positivity was significantly more frequent in IOPNs compared to the other IPMN subtypes (p < 0.0001). Furthermore, within IOPN, a lower or absent CD117, MUC5AC, MUC6, and Hep Par-1 expression tended to be associated with the presence of an infiltrative component. Our findings shed light into the biology of these complex lesions, which are confirmed to be a distinctive IPMN subtype; notably, CD117 emerged as a potential, additional tool in the differential diagnosis of IPMNs.

Oncocytic features in salivary duct carcinoma, a potential pitfall for misdiagnosis as Warthin tumor in fine needle aspiration specimens: A cytomorphologic analysis of 14 cases

BACKGROUND

Salivary duct carcinoma (SDC) is an uncommon and highly aggressive primary salivary gland neoplasm. Cytomorphologic features of SDC include cellular smears, nuclear atypia, prominent nucleoli, cribriform and papillary architecture, and background necrosis. The presence of oncocytic features has been described but not adequately characterized in the current literature.

METHOD

This study cohort consisted of 14 cases of histologically proven SDC with previous salivary gland fine needle aspiration (FNA). The cytologic material of each case was semi-quantitatively analyzed and evaluated for various cytomorphologic, architectural, and background features.

RESULTS

Twelve SDCs were located in the parotid gland and two in the submandibular gland. In two cases the initial cytologic diagnoses was Warthin tumor or favor Warthin tumor. Moderate to marked degree of oncocytic changes were noted in all cases except one case. Nuclear atypia was variable with most cases exhibiting moderate to high-grade nuclear features, while four cases demonstrated low-grade nuclear cytomorphology. Cytoplasmic vacuolation was seen in nine cases and variable amount of background necrosis was observed in eight cases. Cribriform and papillary architecture was recognized in only six cases. Background lymphocytes were absent in all but one case.

CONCLUSIONS

Precise diagnosis of SDC based on cytomorphologic features alone can be challenging. Oncocytic change is one of the most consistent features observed in this case series and when associated with less pronounced cytologic atypia, can potentially lead to misdiagnosis as Warthin tumor. SDC should be considered in the differential diagnosis of oncocytic salivary gland neoplasms where precise diagnosis is not possible.

DNAJB1-PRKACA fusions occur in oncocytic pancreatic and biliary neoplasms and are not specific for fibrolamellar hepatocellular carcinoma

Recently discovered DNAJB1-PRKACA oncogenic fusions have been considered diagnostic for fibrolamellar hepatocellular carcinoma. In this study, we describe six pancreatobiliary neoplasms with PRKACA fusions, five of which harbor the DNAJB1-PRKACA fusion. All neoplasms were subjected to a hybridization capture-based next-generation sequencing assay (MSK-IMPACT), which enables the identification of sequence mutations, copy number alterations, and selected structural rearrangements involving ≥410 genes (n = 6) and/or to a custom targeted, RNA-based panel (MSK-Fusion) that utilizes Archer Anchored Multiplex PCR technology and next-generation sequencing to detect gene fusions in 62 genes (n = 2). Selected neoplasms also underwent FISH analysis, albumin mRNA in-situ hybridization, and arginase-1 immunohistochemical labeling (n = 3). Five neoplasms were pancreatic, and one arose in the intrahepatic bile ducts. All revealed at least focal oncocytic morphology: three cases were diagnosed as intraductal oncocytic papillary neoplasms, and three as intraductal papillary mucinous neoplasms with mixed oncocytic and pancreatobiliary or gastric features. Four cases had an invasive carcinoma component composed of oncocytic cells. Five cases revealed DNAJB1-PRKACA fusions and one revealed an ATP1B1-PRKACA fusion. None of the cases tested were positive for albumin or arginase-1. Our data prove that DNAJB1-PRKACA fusion is neither exclusive nor diagnostic for fibrolamellar hepatocellular carcinoma, and caution should be exercised in diagnosing liver tumors with DNAJB1-PRKACA fusions as fibrolamellar hepatocellular carcinoma, particularly if a pancreatic lesion is present. Moreover, considering DNAJB1-PRKACA fusions lead to upregulated protein kinase activity and that this upregulated protein kinase activity has a significant role in tumorigenesis of fibrolamellar hepatocellular carcinoma, protein kinase inhibition could have therapeutic potential in the treatment of these pancreatobiliary neoplasms as well, once a suitable drug is developed.

Inverted Papilloma Completely Obstructing Anterior Nasal Orifice

Sinonasal inverted papilloma is a benign lesion that occurs in the nasal cavity and paranasal sinuses. Fungiform papillomas have been described as arising from the septum or the nasal vestibule, while inverted and cylindrical papillomas have been characterized as developing from an attachment site on the lateral nasal wall or a mucosal surface in the paranasal sinuses. Here, we present a rare case of an inverted papilloma that completely obstructed the anterior nasal orifice.

Oncocytic Lesions of Salivary Glands with Morphological and Immunohistochemical Findings

Objectives:

Salivary gland neoplasms are less than 5% of all head and neck neoplasms (1). Although there are morphological similarities between different neoplasms, there may be catchy morphological differences in a single tumour. According to the World Health Organization (WHO), 4^th Head and Neck Tumours Classification oncocytic salivary gland lesions are classified as nodular oncocytic hyperplasia, oncocytoma and oncocytic carcinoma. Oncocytic cells may be a component of other salivary gland neoplasms and metastatic malignities.

Methods:

In this study, salivary gland oncocytic lesions diagnosed in 2016-2017 were evaluated with Haematoxylin and Eosin (H&E) sections and PAS, diastase resistance PAS, p63, DOG1, cytokeratin7 (CK7), androgen receptor (AR) and PAX8 stains.

Results:

Nineteen cases were benign, two cases were malignant. Eighteen of the benign lesions were Warthin tumour (WT), one case was oncocytoma with nodular oncocytic hyperplasia. Acinic cell carcinoma (AciCCA) with oncocytic cells predominant was one of the malignant cases. The other case was high-grade salivary duct carcinoma (SDCA).

Conclusion:

The rarity and heterogeneity of this group of lesions may cause difficulties in diagnosis. We present histochemical and immunohistochemical findings of these lesions in light of the literature.

Bilateral multiple oncocytic cysts of the parotid gland in type 2 diabetes patients

AIMS

The hallmarks of type 2 diabetes (T2D) are hyperglycaemia and insulin resistance. These factors, at the cellular level, are associated with mitochondrial dysfunction and increased glucose uptake. Such events are poorly explored in the context of the salivary glands. In this study, we present a series of eight cases of a distinct salivary gland lesion characterised by multiple oncocytic cysts, and we provide new pathological insights regarding its pathogenesis.

METHODS AND RESULTS

Seven patients (87.5%) had confirmed T2D, and obesity was identified in five (62.5%) patients. Clinically, the patients showed bilateral parotid gland swelling with recurrent episodes of pain and enlargement. Imaging examination revealed multiple cystic lesions in both parotid glands. Microscopically, the parotid glands showed multiple cysts of different sizes, lined by oncocytic epithelial cells. Intraluminally, strongly eosinophilic glass-like crystalloid material was observed. Immunohistochemical studies were performed, and the most notable finding was glucose transporter 1 (GLUT1) overexpression in the oncocytic cysts which is not observed in any other oncocytic lesion of patients without T2D. In addition, high expressions of mitochondrial antigen, fission 1 protein and mitofusin-2 were observed in the oncocytic epithelium of the cysts. Furthermore, most of the oncocytic cysts showed a pattern of cytokeratin expression consistent with striated ducts.

CONCLUSIONS

These results strongly suggest that T2D is associated with alterations in GLUT1 expression in the cells of striated ducts with mitochondrial dysfunction, causing a hyperplastic process characterised by multiple oncocytic cysts. For this lesion, the designation of 'diabetes-associated-bilateral multiple oncocytic cysts of the parotid gland' is proposed.

Risk of malignancy associated with cytomorphology subtypes in the salivary gland neoplasm of uncertain malignant potential (SUMP) category in the Milan System: A bi-institutional study

BACKGROUND

Salivary gland neoplasm of uncertain malignant potential (SUMP) is a diagnostic category in the Milan System for Reporting Salivary Gland Cytopathology. The objective of this study was to assess the risk of neoplasm (RON) and the risk of malignancy (ROM) in SUMP cases by evaluating them based on their prominent cytomorphology.

METHODS

The pathology databases were searched for cases of fine-needle aspiration-diagnosed SUMP at The Johns Hopkins Hospital and Northwestern University from 2013 to 2018. Only cytopathology cases diagnosed as SUMP that had available surgical follow-up were included.

RESULTS

Sixty-five patients with SUMP were identified, including 31 men and 34 women who ranged in age from 15 to 87 years (mean age, 55.2 years). Sixty-five cases had histologic follow-up, including 13 (20%) with basaloid features, 13 (20%) with oncocytic features, and 39 (60%) with unspecified features. No cases with clear cell features were found. Overall, the RON in the SUMP category was 95.4% (62 of 65 cases), and the ROM was 33.8% (22 of 65 cases). The RON in SUMPs with basaloid, oncocytic, and unspecified subtypes was 92.3%, 100%, and 94.9%, respectively, whereas the ROM was 38.5%, 7.7%, and 41%, respectively. The most common benign neoplasm was pleomorphic adenoma (23.1%), whereas mucoepidermoid carcinoma (9.2%) was the most common malignant neoplasm.

CONCLUSIONS

This study shows that the ROM differs significantly based on cytomorphology subtypes, whereas the overall ROM is approximately the same as the target rate in the Milan System for Reporting Salivary Gland Cytopathology. Moreover, the RON remains high in the SUMP category among different cytomorphology subtypes. Adequate sampling, immunohistochemical staining, and familiarity with metaplastic and reactive changes may improve the diagnosis.

Short Review: Genomic Alterations in Hürthle Cell Carcinoma

Hürthle cell tumors (HCT), including Hürthle cell adenomas (HCA) and Hürthle cell carcinomas (HCCs), arise in the thyroid gland and are defined in part by an accumulation of mitochondria. These neoplasms were long considered a subtype of follicular neoplasm, although HCT is now generally considered a distinct entity. HCTs exhibit overlapping but distinct clinical features compared to follicular tumors, and several studies have demonstrated that HCTs harbor distinct genomic alterations compared to other forms of thyroid cancer. Two studies recently reported the most complete characterization of the HCC genome to date. These studies assessed complementary cohorts of HCC specimens. The study by Ganly et al. consisted of a large panel of primary HCCs, including 32 widely invasive and 24 minimally invasive primary tumors. Exome and RNA sequencing of material isolated from fresh-frozen tumor specimens was performed. The study by Gopal et al. utilized exome and targeted sequencing to characterize the nuclear and mitochondrial genomes of 32 primary tumors and 38 resected regional and distant metastases using DNA isolated from formalin-fixed paraffin-embedded tissues. Here, HCC is briefly reviewed in the context of these studies.

The key radiologic and cytomorphologic features of oncocytic and oncocytoid lesions of the salivary gland

Oncocytic and oncocytoid lesions represent a distinct subset of salivary gland lesions. True oncocytic lesions of the salivary gland are entirely composed of oncocytes. These are characterized by the presence of abundant eosinophilic granules due to the presence of abundant cytoplasmic mitochondria. Oncocytic lesions of the salivary gland include oncocytosis, oncocytoma, and oncocytic carcinoma. In addition to the true oncocytic lesion, there exists another group of salivary gland lesions, which demonstrate cells with abundant and occasionally granular cytoplasm. These are often termed as "oncocytoid" lesions. The recently proposed Milan System for reporting salivary gland cytology clearly states that fine-needle aspiration specimens representing oncocytic/oncocytoid lesions of salivary gland cannot effectively distinguish between a nonneoplastic lesion, benign and malignant neoplasms. Therefore, most lesions lacking classic cytomorphologic features will be classified under the umbrella diagnostic term of "Salivary Gland Neoplasm of Uncertain Malignant Potential" (SUMP). In this review, we discuss and illustrate key clinicopathologic and radiologic features that can help the practicing cytopathologist narrow down the differential and provide the best management based diagnosis.

Oncocytic poorly differentiated (insular) thyroid carcinoma mimicking metastatic adenocarcinoma. A case report and review of the literature

We report the cytohistologic and immunohistochemical findings of an oncocytic variant of poorly differentiated thyroid carcinoma in a 76-year old man with a prior history of prostatic adenocarcinoma. The man complained of a palpable nodule in the right thyroid lobe and cervical lymph node. Fine-needle aspiration (FNA) in both cases yielded solid clusters of cells/insulae, microfollicles, and isolated atypical cells. Considering the patient's past history, an initial diagnosis of metastasis from prostate adenocarcinoma was considered. However, immunohistochemical staining of liquid-based cytology specimens (Thin-Prep) showed diffuse positive results for TTF-1 and thyroglobulin. The patient underwent total thyroidectomy with bilateral neck dissection. Histologic and immunohistochemical evaluation showed a poorly differentiated oncocytic thyroid carcinoma with lymphovascular invasion and lymph node metastases. To our knowledge, this is the first description of the immunocytochemical evaluation of this rare variant of poorly differentiated thyroid carcinoma using FNA and liquid based cytology.

Dedifferentiation of oncocytic epithelial-myoepithelial carcinoma to mucoepidermoid carcinoma in parotid gland: A rare case report

Epithelial-myoepithelial carcinomas (EMCs) account for <1% of all salivary gland malignancies. Till now, 23 cases of dedifferentiated EMC have been reported to the best of our knowledge. However, dedifferentiation of oncocytic EMC to mucoepidermoid carcinoma is extremely rare. A 38-year-old female presented with right post aural swelling 4 cm × 2 cm in size for 6 months. Surgical excision was carried out, and we received partly skin-covered tissue 5 cm × 2 cm in size. Sections examined showed features of oncocytic EMC dedifferentiating into mucoepidermoid carcinoma. Myoepithelial component showed oncocytic change which was highlighted by p63.

Widespread Chromosomal Losses and Mitochondrial DNA Alterations as Genetic Drivers in Hürthle Cell Carcinoma

Hürthle cell carcinoma of the thyroid (HCC) is a form of thyroid cancer recalcitrant to radioiodine therapy that exhibits an accumulation of mitochondria. We performed whole-exome sequencing on a cohort of primary, recurrent, and metastatic tumors, and identified recurrent mutations in DAXX, TP53, NRAS, NF1, CDKN1A, ARHGAP35, and the TERT promoter. Parallel analysis of mtDNA revealed recurrent homoplasmic mutations in subunits of complex I of the electron transport chain. Analysis of DNA copy-number alterations uncovered widespread loss of chromosomes culminating in near-haploid chromosomal content in a large fraction of HCC, which was maintained during metastatic spread. This work uncovers a distinct molecular origin of HCC compared with other thyroid malignancies.

Challenges in surgical pathology of adrenocortical tumours

Adrenocortical carcinomas are rare tumours that can be diagnostically challenging. Numerous multiparametric scoring systems and diagnostic algorithms have been proposed to differentiate adrenocortical adenoma from adrenocortical carcinoma. Adrenocortical neoplasms must also be differentiated from other primary adrenal tumours, such as phaeochromocytoma and unusual primary adrenal tumours, as well as metastases to the adrenal gland. Myxoid, oncocytic and sarcomatoid variants of adrenocortical tumours must be recognized so that they are not confused with other tumours. The diagnostic criteria for oncocytic adrenocortical carcinoma are different from those for conventional adrenocortical carcinomas. Adrenocortical neoplasms in children are particularly challenging to diagnose, as histological features of malignancy in adrenocortical neoplasms in adults may not be associated with aggressive disease in the tumours of children. Recent histological and immunohistochemical studies and more comprehensive and integrated genomic characterizations continue to advance our understanding of the tumorigenesis of these aggressive neoplasms, and may provide additional diagnostic and prognostic utility and guide the development of therapeutic targets.

Oncocytic Schneiderian papilloma-associated adenocarcinoma and KRAS mutation: A case report

RATIONALE

Oncocytic Schneiderian papillomas (OSP) are an uncommon type of sinonasal papillomas that arise from the Schneiderian epithelium, accounting for only 6% of all sinonasal papillomas. Malignancies arising in OSP are rare and are almost always described as in situ or invasive squamous cell carcinoma, although mucoepidermoid, small cell carcinoma and sinonasal undifferentiated carcinoma have also been reported. To our knowledge, only 18 such instances have been reported in the medical literature.

PATIENT CONCERNS

Here, we report the case of an 81-year-old man presenting with a left sinonasal neoplasm, who had undergone 4 operations. The first postoperative pathology revealed a benign nasal polyp. The following several postoperative pathology revealed a novel, human papillomavirus-negative adenocarcinoma with increasing malignant features with each recurrence arising in an OSP. In addition, the most recent recurrences were associated with metastasis of cervical lymph nodes. And after the operation, the patient refused adjuvant radiotherapy. On 6-month follow-up after the last operation, the patient developed an in situ tumor recurrence 1 month after the fourth operation and refused to undergo surgery again.

DIAGNOSIS

Immunohistochemistry for Ki67, CK7, CK5/6, P53, and P63 showed a progression of malignancy. HPV assay presented the 21 most prevalent HPV types were negative. In addition, KRAS gene exon 2 G12C presented mutation in the OSP-associated adenocarcinoma.

INTERVENTIONS

During the whole course of the patient's disease, we performed four nasal endoscopic operations. And after the last operation, the patient refused adjuvant radiotherapy and KRAS-targeted therapy.

OUTCOMES

We are the first to describe adenocarcinoma arising in an OSP. To our surprise, from the first benign neoplasm to the second OSP-associated adenocarcinoma, it went through a long period of 10 years. However, after the adenocarcinogenesis, the differentiation of tumor became worse with the shorter interval of each recurrence.

LESSONS

Therefore, for elderly patients with unilateral nasal polyps, long-term follow-up is necessary. Once OSP turns into malignant, radical resection should be performed as much as possible to reduce the irritability of tumors.

ROS-induced near-homozygous genomes in thyroid cancer

A near-homozygous genome (NHG) is especially seen in a subset of follicular thyroid cancer of the oncocytic type (FTC-OV). An NHG was also observed in the metabolically relatively quiescent cell lines XTC.UC1, a model for FTC-OV, and in FTC-133, -236 and -238, the latter three derived from one single patient with follicular thyroid cancer. FTC-236 subclones showed subtle whole-chromosome differences indicative of sustained reciprocal mitotic missegregations. Reactive oxygen species (ROS) scavenger experiments reduced the number of chromosomal missegregations in XTC.UC1 and FTC-236, while pCHK2 was downregulated in these cells. Treatment with antimycin A increased ROS indicated by enhanced MitoSOX Red and pCHK2 fluorescence in metaphase cells. In a selected set of oncocytic follicular thyroid tumors, increasing numbers of whole-chromosome losses were observed toward an aggressive phenotype, but with retention of chromosome 7. Together, ROS activates CHK2 and links to the stepwise loss of whole chromosomes during tumor progression in these lesions. We postulate that sequential loss of whole chromosomes is a dominant driver of the oncogenesis of a subset of follicular thyroid tumors.

Oncocytic variant of medullary thyroid carcinoma; a rare tumor with numerous diagnostic mimics by fine needle aspiration

Oncocytic variant of medullary thyroid carcinoma is rare form of thyroid carcinoma that is easily misdiagnosed on fine needle aspiration specimens due to it is low incidence and cytomorphologic overlap with other more common Hurtle cell lesions. A correct initial diagnosis by fine needle aspiration is imperative as the clinical treatment for medullary carcinoma differs significantly from the mimickers. We present a case of this rare variant tumor that on initial fine needle aspiration was described as a Hurthle cell lesion and was subsequently correctly classified on the resection specimen. In this brief review, we describe the cytomorphologic features of medullary carcinoma, oncocytic variant of medullary carcinoma and it is most common mimickers, and we discuss the ancillary studies required to confirm the diagnosis. This case highlights the importance of a complete clinical history and radiologic correlation, which in conjunction with a careful attention to the cytologic features of the fine needle aspiration sample, should in most cases ensure a correct initial diagnosis.

Genomic and immunohistochemical characterisation of a lacrimal gland oncocytoma and review of literature

The aim of the present study was to report the genetic and immunohistochemical profile of a rare case of lacrimal gland oncocytoma. A 20-year-old male underwent magnetic resonance imaging (MRI) due to viral encephalitis. Notably, the MRI revealed a multicystic tumor in the left lacrimal gland. A lateral orbitotomy was performed and the tumor was completely excised. Four months following surgery, the patient was free of symptoms. Histopathologically, the tumor was composed of large, eosinophilic and polyhedral cells with small round nuclei. The tumor cells stained strongly for antimitochondrial antibody MU213-UC, cytokeratin (CK) 5/6, CK 7, CK 17, CK 8/18 and CK 19. The final diagnosis was an oncocytoma of the lacrimal gland without any signs of malignancy. Array-based comparative genomic hybridisation demonstrated a gain of one copy of chromosome 8 and loss of one copy of chromosome 22 as the sole genomic imbalances. These chromosomal alterations have not previously been identified in oncocytoma and may be specific to lacrimal gland oncocytoma. Sequencing of the mitochondrial genome demonstrated multiple alterations of the NADH-ubiquinone oxidoreductase chain 5 (ND5) gene involved in mitochondrial oxidative phosphorylation. This may support the notion of a common genetic background of oncocytic lesions in the lacrimal gland and other anatomical sites.

Molecular, Histologic, and Radiologic Findings of High-Grade Invasive Adenocarcinoma Arising in Oncocytic Subtype of Intraductal Papillary Mucinous Neoplasm: A Case Report and Review of Literature

Background: We present a case of adenocarcinoma arising in the oncocytic subtype of intraductal papillary mucinous neoplasm (O-IPMN), with emphasis on the molecular findings in the adenocarcinoma component. Tissue microdissection and next-generation sequencing were performed using a 26 gene panel (AKT1, ALK, APC, BRAF, CDH1, CTNNB1, EGFR, ERBB2, FBXW7, FGFR2, FOXL2, GNAQ, GNAS, KIT, KRAS, MAP2K1, MET, MSH6, NRAS, PDGFRA, PIK3CA, PTEN, SMAD4, SRC, STK11, TP53) of cancer-related genes. Case Presentation: A 69-year-old Caucasian female presented with chest pain and was found to have findings consistent with acute pancreatitis. During her work-up, computed tomography scan revealed a large cystic and solid mass in the tail of the pancreas. She recovered from her acute pancreatitis and was discharged home. She later returned for resection of her mass. Results: Evaluation of three microdissected regions of tumor demonstrated no identifiable nonsynonymous alterations in any of the three regions, within the targeted genes. Conclusion: This case demonstrates that the O-IPMN is a molecularly distinct subtype, and we conclude that adenocarcinoma arising in these neoplasms shows molecularly distinct tumorigenesis from traditional pancreatic ductal adenocarcinoma. These differences may help explain the improved survival with invasive adenocarcinoma arising from these lesions compared with traditional ductal adenocarcinoma.

A rare case of cutaneous oncocytic hidradenoma

Oncocytes are epithelial cells characterized by their abundant eosinophilic and finely granular cytoplasm. Their histologic appearance is due to excessive amounts of cytoplasmic mitochondria. Oncocytes generally occur in the setting of benign neoplasms. Oncocytomas, or tumors composed primarily of oncocytes, are typically found in the kidneys. Other common sites include the salivary, thyroid, and parathyroid glands. Oncocytic metaplasia has only been rarely reported in various cutaneous neoplasms. We report a case of an elderly male presenting with a 5 mm erythematous papule on his left scalp, who underwent a shave biopsy showing a nodular, dermal-based adnexal tumor with prominent ductal differentiation, composed of multiple small, well-formed lumina surrounded by enlarged and bland-appearing epithelioid cells. Cytokeratin 7 (CK7), epithelial membrane antigen (EMA) and monoclonal carcinoembryonic antigen (mCEA) immunohistochemical stains were positive, consistent with adnexal differentiation. Phosphotungstic acid-hematoxylin (PTAH) and Luxol fast blue (LFB) stains highlighted the cytoplasmic granules, consistent with mitochondria. The overall findings were consistent with an oncocytic nodular hidradenoma. Oncocytic hidradenoma is a very rare entity, with only 1 previously reported case in the literature.

Cytopathologic diagnosis of oncocytic type intraductal papillary mucinous neoplasm: Criteria and clinical implications of accurate diagnosis

BACKGROUND

Cytologic findings of pancreatic oncocytic-type intraductal papillary mucinous neoplasms (IPMNs)/intraductal oncocytic papillary neoplasms (IOPNs) are largely unknown.

METHODS

Five IOPNs encountered by the authors were analyzed.

RESULTS

Four IOPNs were located in the pancreatic head, and 1 was located in the pancreatic body/tail in 2 men and 3 women ages 56 to 84 years (mean age, 66 years). Radiologic diagnoses included pancreatic ductal adenocarcinoma (PDAC) in 2 patients, invasive cancer associated with IPMN in 1 patient, IPMN versus mucinous cystic neoplasm in 1 patient, and cystic mass in 1 patient. Cytologic findings included: hypercellular smears (4 of 5 cases) containing well formed clusters of oncocytic cells (5 of 5 cases) with prominent, slightly eccentric nucleoli (4 of 5 cases), predominantly arranged in sheets/papillary units (5 of 5 cases), with punched-out intercytoplasmic spaces (4 of 5 cases), and with occasional 3-dimensional groups and focal necrosis (3 of 5 cases). The intracytoplasmic mucin and thick extracellular mucin typical of other IPMNs were observed only in 2 cases and were very limited. The mean size on resection was 4.5 cm. Invasion was observed in 3 cases (0.1, 0.3, and 2.0 cm) of tubular-type IPMN. Initial cytologic evaluation was performed by the authors in 4 of 5 cases, which were diagnosed as IOPN (n = 3) and IPMN versus cystic PDAC (n = 1). One case was initially misdiagnosed as PDAC and, on resection, proved to be noninvasive IOPN.

CONCLUSIONS

Cytologic features of IOPNs are classical, similar to their histologic counterparts, and differ significantly from other IPMN subtypes. Because of their highly complex appearance, they are often radiologically misdiagnosed as PDAC; thus, failure to recognize their characteristic features on fine-needle aspiration may lead to inappropriate treatment. Patients with IOPN have an incomparably better prognosis than patients with ordinary PDAC, even when their neoplasms are invasive.

Malignant glomus tumor with oncocytic features: an unusual presentation of dysphagia

Glomus tumors in the gastrointestinal tract are unusual, as the previous series in the literature have been mainly limited to the stomach. Less than 10 cases of esophageal glomus tumors have been described in the literature. Oncocytic glomus tumors are a recently identified, rare variant of the glomus tumor. We report a 47-year-old female who presented with an approximately 3-month history of dysphagia and weight loss. Upper gastrointestinal endoscopy showed a black-purple, hypervascular, protruding lesion measuring approximately 65 mm at the 37th cm of the esophagus. The patient underwent an Ivor Lewis operation via open thoracotomy. The resected specimen had a protuberant, ulcerated mass measuring 80 × 35 mm in the posterior wall of the esophagus. Based on the histopathological, immunohistochemical and electron microscope findings, the final diagnosis was a malignant glomus tumor with oncocytic features. To our knowledge, this is the first report of a malignant glomus tumor with oncocytic features in an esophageal location.

Cytologic diagnosis of adrenal oncocytic pheochromocytoma in a lung cancer patient: Report of a case and review of the literature

Adrenal oncocytic pheochromocytoma is an extremely rare type of pheochromocytoma. To the best of our knowledge, we present the first cytological diagnosis of this variant via fine-needle aspiration in an 81-year-old male patient who was found to have an adrenal mass while undergoing workup of the recently diagnosed lung adenocarcinoma. We describe the cytomorphologic findings in our case and provide a review of the reported cases of adrenal oncocytic pheochromocytoma – all of which appear to be benign, nonfunctional, occur in adults, and have similar morphologic features. The pathologist should be aware of this uncommon diagnostic entity and its potential diagnostic pitfalls.

Papillary Cystadenoma of Minor Salivary Glands: Report of 11 Cases and Review of the English Literature

Papillary cystadenoma is a rare, benign salivary gland tumor which is well-circumscribed, containing cystic cavities with intraluminal papillary projections. Only 19 cases arising within minor salivary glands (MnSG) from the oral cavity sites have been reported in the English literature (PubMed 1958-2014). We report 11 new cases of MnSG papillary cystadenomas in conjunction with a review of the literature. Demographic information, clinical and histologic features, treatment and prognosis are compiled and discussed for all 30 cases reported in the English literature.

Oncocytic and apocrine epithelial myoepithelial carcinoma: novel variants of a challenging tumor

Epithelial myoepithelial carcinoma (EMCa) is a rare but well characterized biphasic salivary gland malignancy with several variant morphologies. Oncocytic and apocrine EMCa are uncommon variants that constitute up to 8 % of all EMCa. Both variants invoke an eosinophilic or oncocytic differential diagnosis and challenge the traditional requirement of clear myoepithelial cells for EMCa. Oncocytic EMCa occurs in patients a decade older than conventional EMCa. This variant is often papillary with calcification and associated with sebaceous components and occurs in older individuals. Apocrine EMCa is named for its apocrine ductal component, which may be mistaken for salivary duct carcinoma. In this variant, the epithelial component often shows overgrowth in a cribriform or even solid pattern and is immunophenotypically defined by androgen receptor and gross cystic disease fluid protein 15 positivity. The most important aspect of differentiating both oncocytic and apocrine EMCa from other salivary oncocytic tumors is recognition of the biphasic nature of these variants and confirmation that the abluminal outer layer consists of plump, 'activated' myoepithelial cells, regardless of tinctorial characteristics. Both oncocytic and apocrine EMCa behave very indolently in the limited literature to date.

Adrenocortical neoplasia: evolving concepts in tumorigenesis with an emphasis on adrenal cortical carcinoma variants

Adrenocortical carcinoma (ACC) is a rare, heterogeneous malignancy with a poor prognosis. According to WHO classification 2004, ACC variants include oncocytic ACCs, myxoid ACCs and ACCs with sarcomatous areas. Herein, we provide a comprehensive review of these rare subtypes of adrenocortical malignancy and emphasize their clinicopathological features with the aim of elucidating aspects of diagnostic categorization, differential diagnostics and biological behavior. The issue of current terminology, applied to biphasic tumors with pleomorphic, sarcomatous or sarcomatoid elements arising in adrenal cortex, is also discussed. We additionally present emerging evidence concerning the adrenal cortical tumorigenesis and the putative adenoma-carcinoma sequence as well.