Lymphadenoma: a report of three cases of an uncommon salivary gland neoplasm

Nonsebaceous Lymphadenoma of the Salivary Glands: A Potential Overdiagnosis Pitfall

Nonsebaceous lymphadenoma is a rare benign salivary tumor. It is easily misdiagnosed as lymphoepithelial carcinoma, leading to overtreatment. Some patients experience sequelae after undergoing cervical lymph node resection and adjuvant treatment, so it is critical to distinguish these entities. We describe the histopathological and immunohistochemical features of this rare entity in 3 cases and discuss the differential diagnosis and histogenesis. Nonsebaceous lymphadenoma can be distinguished from lymphoepithelial carcinoma by the following histological features: There is a lymph node-like form at low magnification, with prominent proliferating epithelial nests but no destructive growth pattern; variable numbers of tubuloglandular components are always seen in proliferating epithelial nests, which transition to cystically dilated salivary ducts; no lesion necrosis exists; and mitotic figures are absent or rare. No patients experienced recurrence during the 8- to 69-month (mean, 29 months) follow-up.

An invasive presentation of parotid lymphadenoma: A first reported case

Lymphadenoma, a rare benign tumor recognized in the WHO salivary gland tumor classification of 2005, poses diagnostic and treatment challenges due to its rarity and distinct histopathological characteristics. We report a unique case of lymphadenoma in a 45-year-old male patient who presented with a hard, painless tumor in the right parotid gland that had been present since he was 15 years old. Distinctively, MRI and CT imaging revealed signs of infiltration into the surrounding muscle tissues, challenging the traditional notion of lymphadenomas as tumors with clear boundaries. The histopathological examination identified the characteristic epithelial and lymphoid cell proliferation, suggestive of a lymphadenoma. However, the possibility of sebaceous differentiation due to faintly pale cells within the epithelial component was inconclusive. The tumor's invasive nature and the high risk of facial nerve paralysis associated with surgical resection led to the patient's decision against treatment. Findings from this case underline the need for caution in diagnosing lymphadenoma, given its potential to show invasive images and the risks associated with a malignant diagnosis based solely on these images. Furthermore, the observations from this case present new insights into the FDG-PET findings of lymphadenoma, contributing to the overall understanding of this rare tumor's clinical implications. Future studies are warranted to provide more clarity on this condition.

Epstein-Barr Virus-Associated Lymphoepithelial Carcinoma Arising in a Salivary Sebaceous Lymphadenoma

BACKGROUND

Lymphadenomas are rare benign tumors of the major salivary glands that are further classified as sebaceous and non-sebaceous. No association with viruses has been reported so far. Little is known about the mechanisms that allow lymphadenomas to undergo malignant transformation. Among these rare instances, there has never been a malignant transformation to Epstein-Barr virus (EBV)-associated lymphoepithelial carcinoma.

METHODS

Clinical data of the reported case were retrieved from the patient's electronic medical record. Hematoxylin & eosin-stained slides, immunohistochemical tests, and in situ hybridization performed for routine diagnostic purposes were reviewed.

RESULTS

We report a salivary gland sebaceous lymphadenoma in which the luminal components were mostly replaced by malignant epithelial cells with markedly atypical nuclear features. Presence of EBV was demonstrated in all components by EBER. The morphological and immunohistochemical findings were consistent with a lymphoepithelial carcinoma arising from a sebaceous lymphadenoma.

CONCLUSION

We report the first case of an Epstein-Barr virus-associated lymphoepithelial carcinoma arising from a sebaceous lymphadenoma.

Non-sebaceous lymphadenoma arising as a painless subcutaneous nodule on the eyebrow

Salivary gland tumors can rarely present on skin excision specimens and can pose a diagnostic challenge to dermatopathologists. We present an exceptional case of a salivary gland type non-sebaceous lymphadenoma presenting as a painless subcutaneous nodule on the right medial eyebrow of a 16-year-old male, mimicking a primary cutaneous adnexal neoplasm. Histologic evaluation revealed a well-circumscribed to partially encapsulated nodule with a marked lymphoid infiltrate including reactive germinal centers. Within the lymphoid component was a central epithelial cystic neoplasm with tubuloglandular and basaloid differentiation. There was no myoepithelial component to suggest a chondroid syringoma. No sebaceous differentiation was present. The overall histological and immunohistochemical findings were consistent with a non-sebaceous lymphadenoma. Dermatopathologists should consider salivary-gland type lymphadenoma as a differential diagnosis when encountering a subcutaneous lesion with lymphoid, cystic, glandular, and basaloid components. This article is protected by copyright. All rights reserved.

Non-sebaceous Lymphadenoma of the Parotid Gland Mimicking a Pleomorphic Adenoma

Non-sebaceous lymphadenoma of the salivary glands is a rare benign lesion, first described in 1991. We present the case of a 54-year-old woman, with a right parotid mass. She underwent right superficial parotidectomy, and histopathology reported a non-sebaceous lymphadenoma due to an encapsulated lesion and multiple non-atypical epithelial inclusions without sebaceous differentiation. The etiology of non-sebaceous lymphadenoma is not yet understood, but it can arise predominantly from the parotid gland. Surgical excision is the treatment of choice.

Malignant Transformation of Parotid Gland Non-sebaceous Lymphadenoma: Case Report and Review of Literature

Non-sebaceous lymphadenoma is a sporadic benign tumor of salivary glands. Histopathologic and immunohistochemical properties, diagnostic criteria, and theories for the histologic origin of the disease have been defined and well-discussed in the literature. However, none of the cases showed malignant transformation to date. We reported a case of 54 years old female patient with a right preauricular mass. Magnetic resonance imaging demonstrated a 2 cm, well-defined contrast-enhanced mass in the right parotid gland. Fine needle aspiration cytology was undiagnostic but suspicious for malignancy. Total parotidectomy with facial nerve preservation was done. In the histopathological examination, non-sebaceous lymphadenoma regions and malignant cells with abundant cytoplasm, large vesicular nuclei, and prominent nucleoli, which occupied approximately 70% of the mass, were seen. The diagnosis was undifferentiated carcinoma arisen from non-sebaceous lymphadenoma. Adjuvant radiotherapy was given. No recurrence was detected during ten months of follow-up. This case is the first case of a malignancy developed from non-sebaceous lymphadenoma.

Lymphadenoma of the salivary gland: Report of 10 cases

Lymphadenoma of the salivary gland is rare, and the typical characteristics of lymphadenoma remain poorly understood. The aim of this study was to analyze the experience of a single institution in the clinical diagnosis, treatment and prognosis of this type of tumor of the salivary gland. All cases of lymphadenoma diagnosed at the institution between 1996 and 2012 were analyzed. The clinical information (including age, gender and tumor location, process of tumor development, imaging data, surgical treatment and follow-up information) and pathological features were evaluated. All tumors occurred in the parotid glands; three cases were sebaceous lymphadenoma (two male and one female) and seven were non-sebaceous lymphadenoma (three male and four female). The average ages of the patients were 68.3 and 42.4 years for the sebaceous and non-sebaceous groups, respectively. The majority of cases (90%) were diagnosed as pleomorphic adenoma or adenolymphoma prior to surgery, but were confirmed as lymphadenoma by pathological analysis following surgery. During the follow-up period, which ranged between 3 and 36 months with a mean of 30 months, no recurrence of the lesion was identified and the quality of life was good for each patient. In conclusion, the diagnosis of salivary gland lymphadenoma should be based on the clinical and, in particular, the pathological manifestations of the disease. Immunohistochemistry is considered as a practical and helpful adjuvant method of the diagnosis for this type of tumor. Complete surgical resection is the first choice of treatment. Further exploration of the histological origin of lymphadenoma of the salivary gland is necessary due to the insufficient number of reported cases.

Nonsebaceous lymphadenoma in the parotid gland: true neoplastic or reactive? A report of two cases

We report 2 rare cases of nonsebaceous lymphadenoma (NSL) in the parotid gland. In both cases, microscopic examination revealed central dilated duct-like structure and its surrounding many cysts in the background of the lymphoid stroma. The cysts were lined with luminal cells and abluminal cells, with the latter being predominant. Occasionally, foci of abluminal epithelial islands were observed. Immunohistochemical findings showed that these tumors had basal cell phenotypes and could support the diagnosis of NSL. The microscopic architectural pattern indicated a cystic dilated duct-glands unit and metaplasia or hyperplasia of abluminal cells. We wondered whether these NSLs were true neoplasia or an indication of a nonneoplastic reactive process. Further investigation of molecular studies of large series in, for example, the clonal or chromosomal state, would be necessary to clarify this point.

Nonsebaceous lymphadenoma of salivary gland: report of a case with immunohistochemistry and review of the literature

OBJECTIVE

Nonsebaceous lymphadenomas are rare benign neoplasms. We emphasize the role of immunohistochemistry and attempt to elucidate the pathogenesis by investigating the distribution of 2 transcription factors, MYC and BLIMP1.

STUDY DESIGN

A 70-year-old man was evaluated for a 3-cm left parotid mass. Ultrasound-guided fine-needle aspiration biopsy findings were suggestive of a diagnosis of pleomorphic adenoma. A left superficial parotidectomy was performed, and based on histopathology a diagnosis of lymphadenoma, nonsebaceous type, was rendered.

RESULTS

The tumor was positive for AE1/3, CKA, BclII, P63, CD79a, CD3, and MYC; focally positive for CK7 and epithelial membrane antigen; and negative for CD10, calponin, CD117, and BLIMP1.

CONCLUSIONS

The rarity of nonsebaceous lymphadenoma and its superficial resemblance to commoner salivary gland tumors may present a diagnostic challenge for pathologists. The expression of MYC in the ductal component and the differentiation-related expression of PRDM1 in the superficial keratinizing layers point to a potential role for these 2 transcription factors in the pathogenesis of this neoplasm.

My journey into the world of salivary gland sebaceous neoplasms

As part of this symposium honoring Leon Barnes, the authors were asked to present the case from which they learned the most. I chose a cystic sebaceous lymphadenoma (SL) as my case presentation. This paper presents this unusual case, as well as several additional sebaceous tumors that came across my desk the first few years I was in practice. These interesting cases led me to thoroughly review the literature on sebaceous tumors of the salivary glands, resulting in several publications, the largest series of sebaceous tumors published at this time as well as a careful review of all cases in the literature. The author will also review the current and previous literature on the five types of salivary gland sebaceous tumors: sebaceous adenoma, SL (and non-sebaceous lymphadenoma), sebaceous carcinoma, sebaceous lymphadenocarcinoma, and sebaceous differentiation in other types of salivary gland lesions.

Lymphadenoma of the salivary gland: clinicopathological and immunohistochemical analysis of 33 tumors

Lymphadenomas (LADs) are rare salivary gland tumors. Their clinicopathologic characteristics and etiopathogenesis are poorly understood. We examined 33 LADs in 31 patients (17 women and 14 men) aged 11-79 years (median 65 years). There were 22 sebaceous LADs in 21 patients (9 women and 12 men) and 11 non-sebaceous LADs in 10 patients (8 women and 2 men). Two patients had synchronous double tumors. Twenty-six tumors (79%) arose in parotid, three in the neck, and two each in submandibular gland and oral cavity. Extraparotid tumors were seen in 2 of 21 (10%) patients with sebaceous and 4 of 10 (40%) patients with non-sebaceous LADs. Seven of twenty-three (30%) patients had immunosuppressive therapy for unrelated diseases. The tumors were well circumscribed, encapsulated (n=28, 84%) painless masses, varying in size from 0.6 to 6 cm (median 2.2). The cut surfaces were gray-tan to yellow, homogeneous and multicystic (n=24, 72%). The epithelial cells were basaloid, squamous and glandular, forming solid nests, cords, tubules, and cysts. Sebaceous differentiation was restricted to sebaceous lymphadenoma. The epithelial cells expressed basal cell markers (p63, 34BE12, and/or CK5/6, 18/18, 100%) and the luminal glandular cells expressed CK7 (12/12, 100%). Myoepithelial cells were absent (n=10/16, 63%) or focal. The lymphoid stroma was reactive, with germinal centers in 28 (84%). There was no evidence of HPV (0/11), EBV (0/7), and HHV-8 (0/8). Malignant transformation to sebaceous and basal cell adenocarcinoma was seen in one patient each. None of the 11 patients with follow-up (1-8 years) recurred. In summary, sebaceous and non-sebaceous LADs are benign, encapsulated, solid and cystic tumors affecting older adults. Non-sebaceous LADs affect women and extraparotid sites more frequently than sebaceous LADs. Altered immune status may have a role in their etiopathogenesis. Multiple synchronous tumors, origin in buccal mucosa, and malignant transformation may rarely occur.

Rare Malignant and Benign Salivary Gland Epithelial Tumors

Although at least 24 distinct histologic salivary gland carcinomas exist, many of them are rare, comprising only 1% to 2% of all salivary gland tumors. These include epithelial-myoepithelial carcinoma, (hyalinizing) clear cell carcinoma, basal cell adenocarcinoma, cystadenocarcinoma, low-grade salivary duct carcinoma (low-grade cribriform cystadenocarcinoma), oncocytic carcinoma, and adenocarcinoma not otherwise specified. Few tumors (clear cell carcinoma and basal cell adenocarcinoma) have unique molecular correlates. Benign tumors, although histologically less diverse, are far more common, with pleomorphic adenoma and Warthin tumor the most common salivary gland tumors. Many benign tumors have malignant counterparts for which histologic distinction can pose diagnostic challenge.

Lymphadenoma: case report of a rare salivary gland tumor in childhood

Lymphadenoma of the salivary gland is a rare benign tumor with only 11 reported cases in the English language literature, most of which have occurred in adults. We report a case of a lymphadenoma occurring in the parotid gland of a 15-year-old girl. The tumor was composed of variably sized cystic cavities within abundant reactive lymphoid tissue. The cystic spaces were filled with eosinophilic secretions with occasional histiocytes. Many of these features were also apparent on cytologic preparations. The cysts were lined by epithelium lacking atypia and showed luminal and abluminal differentiation both by immunohistochemistry and by electron microscopy. Tumor cells were not cycling as determined by MIB1 immunostaining, and the tumor karyotype was normal. This is only the second case to be reported in the pediatric age group. Ultrastructural features and karyotype analysis are reported for the first time. Although this tumor is rarely encountered by pediatric pathologists, awareness of its existence is important to distinguish it from possible malignant mimics, such as lymphoepithelial carcinoma and metastatic mucoepidermoid carcinoma in a lymph node.

Misnomers in oral pathology

BACKGROUND

Diseases which involve the oral cavity usually derive their names from either Greek or Latin. These terms are customarily based on etiology or description of the lesion. However, because of various reasons, some of these terms are misnomers.

OBJECTIVE

To review commonly encountered misnomers in oral pathology.

CONCLUSIONS

Most of the misnomers encountered in oral pathology may arise from lack of understanding of underlying etiology, pathogenesis, histopathology, and/or concepts. Some misnomers are due to imprecise translations from word origins, etymological bungles, and/or factual errors. Clinical, histopathological, and/or etymological explanations are used to analyze and elucidate the nature of these misnomers. Alternative terms, where possible, have been suggested.

Advances in salivary gland pathology

This review summarizes the new findings on salivary gland pathology under the following categories: immunohistochemistry; molecular genetics; newly recognized tumour types; known tumour entities with new findings; and progression of salivary gland tumours. In the application of immunohistochemistry, CD117 can aid in highlighting the luminal cell component of various salivary gland tumours, whereas p63 or maspin can aid in highlighting the abluminal cell component. A high Ki67 index remains the most useful marker to predict adverse outcome in salivary gland carcinoma. Specific chromosomal translocations are recognized in pleomorphic adenoma (with translocation involving PLGA1 or HMGA2 gene) and mucoepidermoid carcinoma (with MECT1-MAML2 gene fusion). Newly recognized entities include: sclerosing polycystic adenosis (with recent molecular evidence supporting its neoplastic nature), sclerosing mucoepidermoid carcinoma with eosinophilia, keratocystoma, adenoma with additional stromal component (lymphadenoma, lipoadenoma and adenofibroma), cribriform adenocarcinoma of the tongue and signet ring adenocarcinoma of minor salivary gland. Known tumour entities with new findings include: salivary duct carcinoma (with newly recognized mucinous, micropapillary and sarcomatoid variants), intraductal carcinoma (with controversies in terminology), mucoepidermoid carcinoma (with newly proposed grading parameters and oncocytic variant), epithelial-myoepithelial carcinoma (with newly recognized morphological variants), small cell carcinoma (with most cases being related to Merkel cell carcinoma), extranodal marginal zone B-cell lymphoma (with specific chromosomal translocation) and chronic sclerosing sialadenitis (being a component of IgG4-related sclerosing disease). Progression of salivary gland tumours can take the form of malignant transformation of a benign tumour, progression from low-grade to high-grade carcinoma, dedifferentiation, or stromal invasion of an in situ carcinoma.

Non-sebaceous lymphadenoma of the salivary gland: case report with immunohistochemical investigation

Non-sebaceous lymphadenoma (NSL) is a rare, recently described, benign salivary gland tumor characterized by a dense lymphoid infiltrate and absence of sebaceous differentiation. To our knowledge, only seven previous cases have been reported. In this paper, we describe an additional example of NSL along with an extensive analysis of its keratin (CK) profile. The patient was a 50-year-old woman presenting with a slowly growing painless mass in the right parotid gland. The tumor was encapsulated and measured 3 x 2 x 2 cm. Microscopically, the tumor comprised islands of epithelial cells with centrally located duct-like structures within a dense lymphoid stroma. Immunohistochemically, the tumor regularly expressed CKs 7, 8/18, and 19, which are typical for columnar differentiation and CKs 17 and 5/6, which are most typically expressed in basal cells of complex epithelia. CK14 was only expressed in rare scattered cells and eventually in groups of cells. The expression of CK10/13, which correlates with squamous differentiation, was negative. Additionally, immunostaining for smooth muscle actin, vimentin, and S-100 was also performed. The immunohistochemical findings in the neoplastic epithelial component of our case suggest a differentiation of "intercalated duct phenotype" without myoepithelial cell participation.

Epithelioid Cell Clusters With an Extensive Lymphoid Background

Context.—Fine-needle aspiration of salivary gland lesions can be particularly challenging for pathologists. There are numerous neoplasms that occur in this area and several cytologic variations of each specific lesion.

Objective.—To present and discuss a practical pattern recognition approach to fine-needle aspiration diagnosis, which includes categorizing lesions that share a certain overall cytologic architectural pattern, followed by identifying unique cellular characteristics that are specific to a certain lesion. An extensive discussion of one cytologic common pattern of salivary gland lesions, “epithelioid cell clusters with an extensive lymphoid background,” is presented. The pathologic entities that fall under this architectural pattern group are discussed, with an emphasis on neoplasms.

Data Sources.—Published literature and personal experience.

Conclusions.—A practical cytologic architectural pattern method can aid the pathologist in rendering a correct diagnosis when evaluating salivary gland lesions. One common pattern in salivary gland cytopathology is epithelioid cell clusters with an extensive lymphoid background. This pattern is often associated with Warthin tumor; however, other benign and malignant entities fall under this diagnostic group. Unique cytologic features separate these lesions into their respective diagnostic category.