Warthin Tumor Incidentally Detected on PET/CT Showing Both 68Ga-DOTANOC and 18F-FDG Uptake.

ABSTRACT: A patient with moderately differentiated pancreatic neuroendocrine tumor with synchronous multifocal liver metastases was referred for further staging with PET/CT. The examinations were performed on 2 consecutive days and showed mild 68Ga-DOTANOC and intense 18F-FDG uptake in an incidental right parotid nodule. Differential diagnoses include primary or metastatic neuroendocrine tumor, malignant or benign primary parotid tumor, and intraparotid lymph node. Histology revealed characteristics of a Warthin tumor. While focal FDG uptake in Warthin tumor is frequently described, the somatostatin expression was rarely reported. This clinical case describes 68Ga-DOTANOC and 18F-FDG uptake in a parotid Warthin tumor histologically confirmed.

Juvenile sclerosing polycystic adenosis cytologically mimicking Warthin tumor.

Sclerosing polycystic adenosis (SPA) is a rare salivary gland disease. Histologically it resembles a low-grade ductal carcinoma in situ or sclerosing adenosis of the breast, characterized by lobular proliferation of ducts with apocrine cellular features surrounded by fibrosclerotic stroma. Although SPA is typically benign, recurrence is not uncommon, and cases with a malignant component have been documented. Thus, complete excision is desirable but preoperative diagnosis is challenging. A 12-year-old boy presented with a painless mass in the right neck. We identified a well-demarcated mass in the right parotid region measuring approximately 2 cm using cervical echography and magnetic resonance (MR) imaging. Fine-needle aspiration (FNA) revealed two cell types. There were loosely cohesive clusters of polymorphic epithelioid cells with irregular nuclei and abundant vacuolated cytoplasm containing zymogen granules. Some of these cells were binuclear. The other cell types represented normal ductal cells. The original cytological diagnosis was Warthin tumor. Right parotidectomy was performed. Histologically, we observed proliferation of ducts with granular, vacuolated, zymogen granules, and apocrine-like features in the cytoplasm with hyalinizing sclerotic stroma and some binuclear cells. Four years after parotidectomy, there has been no recurrence or malignant transformation.Cytological diagnosis of SPA is challenging on FNA specimens since SPA is a very rare entity of the salivary gland that can mimic other salivary gland neoplasms. A mixture of apocrine-like cells and sebaceous-like cells, nuclear pleomorphism, and zymogen granules can help to diagnose this rare lesion during the initial cytological diagnosis.

Saliva of patients affected by salivary gland tumour: An NMR metabolomics analysis.

Cancers affecting the salivary glands have been an increasing incidence. Salivary gland cancer is not detected until it reaches an advanced stage, which would generally result in a poor prognosis and survival rate. Therefore, early detection as well as the screening of high risk populations with precancerous lesions remains an unmet medical need. In the present work, we present a NMR-based metabolomic study of the saliva of patients suffering from salivary gland tumours. Analysis of data was done using a combined approach based on PRICONA quantitative analysis and statistical multivariate analysis. Interestingly, both the analytical methods indicate that individuals affected by parotid tumour have a characteristic metabolomic profile characterized by abnormalities in the concentration of several aminoacids. Among these the most significant are those relative to Alanine and Leucine suggestive of an alteration in the metabolic pathways of glycogenic aminoacids and ketone bodies. Our data, describing the preliminary metabolomics fingerprint of parotid tumour, are consistent with the recent view that oncogenic signalling corresponds to alteration in the metabolism of nutrient pull (Vander Heiden et al., 2009), rather than to a single metabolite.

Immunohistochemical Staining of Histological Fragments Derived from Salivary Gland Tumour Fine-Needle Biopsy Aspirates.

OBJECTIVES: The aim of this study was to describe a method for analysing histological fragments derived from fine- needle aspirate biopsy (FNAB) of salivary gland tumours (SGTs), and to evaluate the use of immunohistochemistry (IHC) on them. STUDY DESIGN: We reviewed all 509 FNAB pathology reports taken from SGTs at Helsinki University Hospital, Finland, between 1999 and 2009. In 51% of the cases (n = 209) "histo-fragments" had been obtained and 31 had been further analysed by IHC. Of these, 25 (81%) were available for review. We evaluated the benefit of IHC by relating its added value to the preoperative cytological diagnosis and its accuracy compared with the postoperative histological diagnosis. RESULTS: Most of the samples analysed by IHC were assigned a malignant diagnosis, with 12 different types of malignancy represented. IHC was advantageous in 76% of the cases. In the 108 studies using IHC in this series, antibodies to 36 different antigens were used. CONCLUSION: Analysis of histo-fragments in FNABs using IHC can be valuable in specific differential diagnostics and raises diagnostic accuracy in SGTs.

PRDM1 expression on the epithelial component but not on ectopic lymphoid tissues of Warthin tumour.

OBJECTIVE: To determine the role of PRDM1, a key molecule for modulating the immune cells, in Warthin tumour (WT) pathogenesis. SUBJECTS AND METHODS: Forty paraffin-embedded parotid tissues of patients (mean age: 62.08 ± 11.90) with WT were retrieved from the pathology archives of Qindu Hospital from January 2012 to December 2012. The PRDM1 expression was investigated in a cohort of WT by immunohistochemistry. RESULTS: PRDM1 was expressed only on the epithelial component but not on ectopic lymphoid tissue of the tumour. Statistically, PRDM1 expression rates between WT glandular epithelial cells (40/40 cases) and the tumour-adjacent tissues (0/9 cases), and WT germinal centres (0/34 cases) and tonsil tissues (10/10 cases) were significantly different (P < 0.001), respectively. CONCLUSIONS: The PRDM1 expression appeared to play an essential role in WT pathogenesis. A better understanding of it might give options for revealing possible novel management strategies.

99mTcO4- accumulation in scintigraphy and expression of Na+/I- symporter in salivary gland tumors.

OBJECTIVE: Warthin's tumors and oncocytomas show exceptionally good (99m)TcO4(-) (Tc) accumulation images in Tc scintigraphy. However, the mechanism of Tc accumulation in these tumors remains unclear. Sodium-iodide symporter (NIS) is a plasma membrane protein expressed in the thyroid, lactating breast, stomach and salivary glands; it facilitates uptake of I(-) and Tc. We hypothesized that Warthin's tumor cells and oncocytomas may also express NIS, which would promote uptake of Tc. We examined NIS localization and the mechanism of Tc accumulation in various salivary gland tissues. METHODS: Immunohistological localization of NIS was performed for 19 tumors from 18 patients who underwent preoperative Tc scintigraphy. Expression of mRNA for NIS in the normal salivary gland, Warthin's tumors and pleomorphic adenomas was analyzed by real-time PCR. RESULTS: In normal salivary glands, striated duct cells were strongly immunostained by anti-NIS antibodies. In Warthin's tumors, eosinophilic epithelial cells exhibited positive immunostaining, but their staining was varied among the cases. Furthermore, all Tc-positive specimens were NIS-positive, and all Tc-negative specimens were NIS-negative. Real-time PCR showed that NIS mRNA expression was detectable in normal salivary glands and Warthin's tumor cells. The expression was significantly higher in normal salivary glands compared with Warthin's tumor cells and pleomorphic adenoma. CONCLUSION: Tc-positive salivary glands expressed NIS. Our findings suggest that Tc accumulation in Warthin's tumors and oncocytomas is due to poorer Tc excretory function compared with normal salivary gland tissues, in addition to active uptake of (99m)TcO4(-) via NIS.

Increased phosphatidylcholine (16:0/16:0) in the folliculus lymphaticus of Warthin tumor.

Warthin tumor (War-T), the second most common benign salivary gland tumor, consists mainly of neoplastic epithelium and lymphoid stroma. Some proteins and genes thought to be involved in War-T were evaluated by molecular biology and immunology. However, lipids as an important component of many tumor cells have not been well studied in War-T. To elucidate the molecular biology and pathogenesis of War-T, we investigated the visualized distribution of phosphatidylcholines (PCs) by imaging mass spectrometry (IMS). In our IMS analysis of a typical case, 10 signals were significantly different in intensity (p < 0.01) between the War-T and non-tumor (Non-T) regions. Five specific PCs were frequently found in the War-T regions of all of the samples: [PC (16:0/16:0) + K](+) (m/z 772.5), [PC (16:0/20:4) + K](+) (m/z 820.5), [PC (16:0/20:3) + K](+) (m/z 822.5), [PC (18:2/20:4) + K](+) (m/z 844.5), and [PC (18:0/20:5) + K](+) (m/z 846.5). PC (16:0/16:0) was increased specifically in the folliculus lymphaticus of War-T lymphoid stroma, suggesting a different metabolism. Localization of PC (16:0/16:0) might reflect inflammation activity participating in the pathogenesis of War-T. Thus, our IMS analysis revealed the profile of PCs specific to the War-T region. The molecules identified in our study provide important information for further studies of War-T pathogenesis.

New insight into benign tumours of major salivary glands by proteomic approach.

Major salivary gland tumours are uncommon neoplasms of the head and neck. The increase of precise pre-operative diagnosis is crucial for their correct management and the identification of molecular markers would surely improve the required accuracy. In this study we performed a comparative proteomic analysis of fine needle aspiration fluids of the most frequent benign neoplasms of major salivary glands, namely pleomorphic adenoma and Warthin's tumour, in order to draw their proteomic profiles and to point out their significant features. Thirty-five patients submitted to parotidectomy were included in the study, 22 were identified to have pleomorphic adenoma and 14 Warthin's tumour. Fine needle aspiration samples were processed using a two-dimensional electrophoresis/mass spectrometry-based approach. A total of 26 differentially expressed proteins were identified. Ingenuity software was used to search the biological processes to which these proteins belong and to construct potential networks. Intriguingly, all Warthin's tumour up-regulated proteins such as Ig gamma-1 chain C region, Ig kappa chain C region and Ig alpha-1 chain C region and S100A9 were correlated to immunological and inflammatory diseases, while pleomorphic adenomas such as annexin A1, annexin A4, macrophage-capping protein, apolipoprotein E and alpha crystalline B chain were associated with cell death, apoptosis and tumorigenesis, showing different features of two benign tumours. Overall, our results shed new light on the potential usefulness of a proteomic approach to study parotid tumours and in particular up regulated proteins are able to discriminate two types of benign parotid lesions.

Human papilloma virus (HPV) is not implicated in the etiology of Warthin's tumor of the parotid gland.

CONCLUSION: The lack of human papilloma virus (HPV) sequences as well as potential HPV-activated cells such as cells that would be p16- and Ki-67 positive does not support a role of HPV in the pathogenesis of this lesion. OBJECTIVE: The exact etiopathogenesis of Warthin's tumor of the parotid gland is still unclear. The aim of the present study was to evaluate if HPV could play a role in the development of this parotid lesion. METHODS: Tissue samples from 40 Warthin's tumors of the parotid gland were investigated by PCR followed by in situ hybridization. The immunohistochemical expression of p16 and the dual immunostaining of p16 and Ki-67 were evaluated in all samples. RESULTS: Strong and diffuse p16 immunoreactivity was found in 7 of the 40 cases (17.5%). In situ hybridization showed a diffuse episomal signal in those samples. However, PCR could not reliably detect the presence of HPV genes. Furthermore, p16-expressing epithelial cells were mostly negative for the proliferation marker Ki-67.

MT1 melatonin receptor expression in Warthin's tumor.

We contribute the first immunohistochemical study of MT1 melatonin receptor in Warthin's tumor and normal parotid gland. All 14 Warthin's tumors studied showed intense cytoplasmic positivity for MT1 receptor in all cylindrical epithelial cells lining spaces and a less intense positivity in basal cells. The lymphoid component accompanying the tumor was always negative for MT1 receptor. The parotid structure surrounding the tumor showed intense cytoplasmic positivity in all cells lining excretory ducts (lobar and lobulillar), with a lesser and focal positivity in cells of the acinar component. The biological activity of MT1 receptor in epithelial cells lining parotid excretory ducts may resemble its activity in Warthin's tumor cells. Hence, we propose Warthin's tumor as a useful positive control in immunohistochemical studies of MT1 melatonin receptor.

Lymphocyte recruitment via high endothelial venules in lymphoid stroma of Warthin's tumour.

AIMS: Warthin's tumour is composed of bilayered oncocytic epithelium and organised lymphoid stroma, which resembles mucosa-associated lymphoid tissue (MALT); however, the histogenesis of the lymphoid stroma is not fully understood. We hypothesised that lymphocytes consisting of the stroma are recruited via high endothelial venules (HEVs) by the mechanism operating in normal lymphocyte homing in secondary lymphoid organs. The aim of this study was to determine immunohistochemically the molecules expressed on these HEVs. METHODS: Tissue sections of Warthin's tumour (n = 10) were immunostained for vascular addressin-related antigens including peripheral lymph node addressin (PNAd) and mucosal addressin cell adhesion molecule 1 (MAdCAM-1). An L-selectin·IgM chimera in situ binding assay was also carried out. Triple immunostaining for PNAd, CD3, and CD20/CD79α was performed to determine which lymphocyte subsets are closely associated with these HEVs. RESULTS: HEVs in the lymphoid stroma of Warthin's tumour express PNAd, which is detected by MECA-79 as well as recently developed monoclonal antibodies S1 and S2. These HEVs were bound by L-selectin·IgM chimeras in a calcium-dependent manner, and numbers of lymphocytes, particularly T cells, attached to these HEVs. CONCLUSIONS: The lymphoid stroma of Warthin's tumour is most likely developed by lymphocytes recruited via HEVs.

MTNR1A receptor expression in normal and pathological human salivary glands.

AIM: To analyze and compare the expression of MTNR1A receptor in normal and pathological major and minor salivary glands. MATERIALS AND METHODS: Twenty samples of major and minor salivary glands and 10 with Warthin's tumor were studied. Expression of the MTNR1A receptor (goat polyclonal antibody raised against a peptide mapping at the N-terminus of MEL-1A R of human origin) was analyzed. RESULTS: The excretory ducts of major salivary glands demonstrated intense intracytoplasmic positivity but scant cytoplasmic membrane positivity for MTNR1A. The studied Warthin's tumors showed intense cytoplasmic positivity for MT1 receptor in all cylindrical epithelial cells lining spaces and a less intense positivity in basal cells. The lymphoid component accompanying the tumor was negative for MT1 receptor. CONCLUSION: Intense intracytoplasmic positivity for the MTNR1A receptor in the excretory ducts of human major and minor salivary glands and Warthin's tumor was found. The intense expression of MTNR1A receptors observed in this study in the excretory ducts of major and minor salivary glands may be related to salivary regulation.

Fine-needle aspiration cytology with c-kit immunocytochemical staining in the diagnosis of Warthin's tumor.

OBJECTIVE: Although Warthin's tumor (WT) is one of a few salivary gland tumors that have distinct cytologic findings, it can be confused with malignant tumors at times. We assessed the overall accuracy, unusual features, and diagnostic points of fine-needle aspiration (FNA) of WT. STUDY DESIGN: We retrospectively collected histologically confirmed WT from 21 patients and reviewed preoperative FNA slides. Smears were subject to immunocytochemical staining for carcinoembryonic antigen (CEA) and c-kit and compared to metastatic squamous cell carcinoma. RESULTS: All of the cases were in the parotid gland; the mean size was 3.6 ± 1.2 cm. Of 21 patients, 19 were male (age 59.7 ± 9.4 years) and had a history of smoking. The initial FNA diagnoses were WT (11 patients, 52.4%), benign lesion (7 patients, 33.3%), and malignant neoplasm (3 patients, 14.3%). Only 6 patients (28.6%) showed typical FNA features of WT. The dominant cell types in the smears were macrophages (76.2%), squamous-like cells (66.7%), oncocytes (61.9%), and lymphoid cells (57.1%). Some showed atypical degenerated features, a necrotic background, and inflammatory cells, leading to misdiagnosis. CEA positivity and c-kit positivity in WT were noted in 0 and 75.0% of cases, respectively, whereas metastatic squamous cell carcinoma showed positive rates of 16.7 and 0%, respectively. CONCLUSION: Awareness of potential sources of misdiagnosis together with combination of c-kit/CEA immunostaining may result in an increased diagnostic rate of WT in FNA.

Human α-defensin (DEFA) gene expression helps to characterise benign and malignant salivary gland tumours.

BACKGROUND: Because of the infrequence of salivary gland tumours and their complex histopathological diagnosis it is still difficult to exactly predict their clinical course by means of recurrence, malignant progression and metastasis. In order to define new proliferation associated genes, purpose of this study was to investigate the expression of human α-defensins (DEFA) 1/3 and 4 in different tumour entities of the salivary glands with respect to malignancy. METHODS: Tissue of salivary glands (n=10), pleomorphic adenomas (n=10), cystadenolymphomas (n=10), adenocarcinomas (n=10), adenoidcystic carcinomas (n=10), and mucoepidermoid carcinomas (n=10) was obtained during routine surgical procedures. RNA was extracted according to standard protocols. Transcript levels of DEFA 1/3 and 4 were analyzed by quantitative realtime PCR and compared with healthy salivary gland tissue. Additionally, the proteins encoded by DEFA 1/3 and DEFA 4 were visualized in paraffin-embedded tissue sections by immunohistochemical staining. RESULTS: Human α-defensins are traceable in healthy as well as in pathological altered salivary gland tissue. In comparison with healthy tissue, the gene expression of DEFA 1/3 and 4 was significantly (p<0.05) increased in all tumours - except for a significant decrease of DEFA 4 gene expression in pleomorphic adenomas and a similar transcript level for DEFA 1/3 compared to healthy salivary glands. CONCLUSIONS: A decreased gene expression of DEFA 1/3 and 4 might protect pleomorphic adenomas from malignant transformation into adenocarcinomas. A similar expression pattern of DEFA-1/3 and -4 in cystadenolymphomas and inflamed salivary glands underlines a potential importance of immunological reactions during the formation of Warthin's tumour.

Immunohistochemical expression of CK7, CK5/6, CK19, and p63 in Warthin tumor.

Our study included a number of 24 cases with Warthin tumor, diagnosed between 2007-2011, which were analyzed in terms of clinical, histopathological and immunohistochemistry point of view, using CK7, CK5/6, CK19, and p63 antibodies. Warthin tumor is most often a tumor with a slow evolution, painless, usually affecting males (M/F 3.2/1) in the seventh decade of life. Histopathologically, it is distinguished the predominance of the typical forms of the tumor, with a balanced ratio epithelium/stroma. The immunostaining for CK7 showed positivity in all the investigated cases both in the columnar luminal cells and basal cells. The immunostaining for CK5/6 was positive in all the investigated cases in bilayer epithelial basal cells, both in the structure of the cysts and the papillae. In the case of the immunostaining for p63 we noticed limited nuclear positivity in the basal cells, while the columnar cells' nucleus were negative. The immunohistochemical study of the bilayer epithelial component of Warthin tumor showed different immunstaining of the two types of epithelia, the oncocytary columnar and the basal on, similar to those found in the salivary gland ducts.

Nonsebaceous lymphadenoma of salivary glands: proposed development from intraparotid lymph nodes and risk of misdiagnosis.

Nonsebaceous lymphadenoma (NSLA) is a rare benign salivary gland tumor composed of lymphoid and epithelial components. By definition, the epithelial component lacks sebaceous differentiation and instead displays a wide range of histological differentiation. In this study, we have collected nine cases of NSLA to characterize their histological and immunohistochemical profiles. The samples were histologically reviewed and immunohistochemical stains for CK5/6, CK7, CK14, CK18, p63, and Ki67 performed. Patients were six males and three females (mean age, 50 years). All tumors were located in the parotid gland and showed intimate intermingling of lymphoid tissue with islands or strands of epithelium with a wide spectrum of histological differentiation. The immunohistochemical profiles mirrored the epithelial differentiation; hence, areas with basaloid or lymphoepithelial differentiation strongly expressed CK5/6, CK14, and p63, while areas with ductal differentiation showed strong positivity for CK18/CK7 and CK5/6/CK14/p63 in luminal and basal cell layers, respectively. A hilus structure with salivary inclusions or D2-40 (podoplanin)-positive marginal sinus was identifiable in four and nine of the cases, respectively, supporting origin within intra-/periparotid lymph nodes. Six cases were initially misdiagnosed as other benign (n = 4) or malignant tumors (n = 2). Our study on the second largest series of NSLA reported to date provides strong evidence that NSLA belongs to the group of salivary gland tumors that pathogenetically develop from embryonic salivary gland inclusions in intra-/periparotid lymph nodes. Knowledge of the wide histological spectrum of this rare and presumably underreported tumor is important in order to avoid misdiagnosis, particularly as malignant tumor.

Expresión de SDHB en el tumor de Warthin / SDHB expression in Warthin’s tumour

Introducción: El objetivo del presente estudio es analizar la expresión de la succinodeshidrogenasa B (SDHB), enzima perteneciente al complejo mitocondrial II, en el tumor de Warthin analizando su relación con los cambios oncocíticos, un dato morfológico constante en este tipo tumoral. Material y métodos: En una serie de 10 tumores de Warthin, todos parotídeos, se analizó en los especímenes de resección tumoral la expresión de SDHB utilizando un anticuerpo monoclonal comercializado. Resultados: Los 10 tumores afectaron a 10 varones (edad media: 64, 2 años; rango: 40-80), todos ellos con antecedentes de hábito tabáquico, y 2 con afectación bilateral metacrónica. Dos pacientes presentaron de forma asociada carcinomas del tracto urotelial. El estudio de la SDHB mostró en todos los casos acusada reactividad (++/+++) del componente epitelial oncocítico, así como del citoplasma de los conductos estriados del tejido parotídeo no tumoral. Esta expresión no se vio influida por el rango de edad, la intensidad del hábito tabáquico, ni por el carácter bilateral de los tumores. Uno de los tumores presentó focos de metaplasia escamosa con negatividad a la SDHB en esa localización. Discusión y conclusiones: La constante e intensa reactividad de la SDHB encontrada en nuestras observaciones, en las células oncocíticas, orienta a considerar que los cambios oncocíticos en el tumor de Warthin no se asocian a una actividad enzimática defectiva en este componente del complejo mitocondrial II. La reactividad de SDHB se conforma como un marcador adicional de la diferenciación oncocítica existente en el caso del tumor de Warthin, aspectos ambos previamente no descritos (AU)

Introduction: Succinic dehydrogenase subunit B (SDHB) is an enzyme belonging to the mitochondrial complex II. The aim of this study is to analyse SDHB expression in a series of Warthin’s tumours, studying its relationship with oncocytic changes, constantly present in this form of tumour. Material and methods: In resection tumour specimens from a series of ten Warthin’s tumours (all from the parotid gland), immune histochemical expression of SDHB was analysed using a commercially-available monoclonal antibody. Results: The Warthin’s tumours studied affected 10 men (mean age: 64.2 yrs, range 40-80), all with smoking habits, and 2 with metachronous bilateral involvement. Two patients presented associated urothelial carcinoma. Our SDHB study showed marked reactivity (++/+++) in all cases in the oncocytic epithelial component and also in striated duct cytoplasm (+) from non-tumorous parotid tissue. Expression was not influenced by age, smoking intensity or bilateral character. One of the tumours showed squamous metaplasia foci with SDHB-negativity at this level. Discussion and conclusions: Due to the constant and intense SDHB reactivity in oncocytic cells in our observations, oncocytic changes are not considered to be associated with defective enzyme activity in the mitochondrial complex II. Strong SDHB reactivity is an additional marker of oncocytic changes in Warthin’s tumour. Neither of these facts has been described previously (AU)

[SDHB expression in Warthin's tumour]. / Expresión de SDHB en el tumor de Warthin.

INTRODUCTION: Succinic dehydrogenase subunit B (SDHB) is an enzyme belonging to the mitochondrial complex II. The aim of this study is to analyse SDHB expression in a series of Warthin's tumours, studying its relationship with oncocytic changes, constantly present in this form of tumour. MATERIAL AND METHODS: In resection tumour specimens from a series of ten Warthin's tumours (all from the parotid gland), immunohistochemical expression of SDHB was analysed using a commercially-available monoclonal antibody. RESULTS: The Warthin's tumours studied affected 10 men (mean age: 64.2 yrs, range 40-80), all with smoking habits, and 2 with metachronous bilateral involvement. Two patients presented associated urothelial carcinoma. Our SDHB study showed marked reactivity (++/+++) in all cases in the oncocytic epithelial component and also in striated duct cytoplasm (+) from non-tumorous parotid tissue. Expression was not influenced by age, smoking intensity or bilateral character. One of the tumours showed squamous metaplasia foci with SDHB-negativity at this level. DISCUSSION AND CONCLUSIONS: Due to the constant and intense SDHB reactivity in oncocytic cells in our observations, oncocytic changes are not considered to be associated with defective enzyme activity in the mitochondrial complex II. Strong SDHB reactivity is an additional marker of oncocytic changes in Warthin's tumour. Neither of these facts has been described previously.