Nkx2.3 transcription factor is a key regulator of mucous cell identity in salivary glands.

Saliva is vital to oral health, fulfilling multiple functions in the oral cavity. Three pairs of major salivary glands and hundreds of minor salivary glands contribute to saliva production. The secretory acinar cells within these glands include two distinct populations. Serous acinar cells secrete a watery saliva containing enzymes, while mucous acinar cells secrete a more viscous fluid containing highly glycosylated mucins. Despite their shared developmental origins, the parotid gland (PG) is comprised of only serous acinar cells, while the sublingual gland (SLG) contains predominantly mucous acinar cells. The instructive signals that govern the identity of serous versus mucous acinar cell phenotypes are not yet known. The homeobox transcription factor Nkx2.3 is uniquely expressed in the SLG. Disruption of the Nkx2.3 gene was reported to delay the maturation of SLG mucous acinar cells. To examine whether Nkx2.3 plays a role in directing the mucous cell phenotype, we analyzed SLG from Nkx2.3-/- mice using RNAseq, immunostaining and proteomic analysis of saliva. Our results indicate that Nkx2.3, most likely in concert with other transcription factors uniquely expressed in the SLG, is a key regulator of the molecular program that specifies the identity of mucous acinar cells.

Lymphomas Affecting the Sublingual Glands: A Clinicopathological Study.

BACKGROUND: Lymphomas affecting the sublingual glands are extremely rare and very few case reports are currently available. Therefore, the aim of the current study is to describe the clinicopathological features of a series of lymphomas involving the sublingual glands. METHODS: Cases diagnosed in four pathology services were assessed and the formalin-fixed paraffin-embedded tissue blocks were retrieved for diagnosis confirmation. Clinical data were obtained from patients' medical files. RESULTS: We obtained seven cases of lymphomas in the sublingual glands, representing two follicular lymphomas, two diffuse large B cell lymphomas not otherwise specified (DLBCL NOS), two extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphomas) and one mantle cell lymphoma (MCL). In all cases the tumor cells infiltrated the glandular parenchyma, although in two of them the neoplastic cells were located more superficially and permeated the glandular acini and ducts. Clinically, the tumors presented as asymptomatic nodules and two patients (affected by DLBCL NOS and MCL) died, while the other five patients remained alive at last follow-up. CONCLUSION: Lymphomas affecting the sublingual glands are usually of the mature B cell lineage, often represent low-grade subtypes and may clinically resemble other more common lesions in the floor of the mouth like salivary gland tumors.

Mucoepidermoid Carcinoma of Sublingual Salivary Gland: A Rare Case Report.

RATIONALE: Sublingual salivary gland tumours are very rare but are mostly malignant. As very limited literature is available, we present a rare case of mucoepidermoid carcinoma (MEC) of sublingual salivary gland. PATIENT CONCERNS: A56-year-old female presented with an asymptomatic swelling of 15-year duration in the floor of the mouth and chin region. DIAGNOSIS: Mandibular occlusal view, computed tomography scan, and ultrasonogram revealed calcification and the tumour to be of salivary origin. Incisional biopsy showed clear cell changes. TREATMENT: The sublingual and submandibular salivary gland along with the associated nodes was excised through transoral approach with midline osteotomy. OUTCOMES: The histopathologic diagnosis of excised specimen was "Intermediate grade MEC" with clear cell changes, stromal hyalinization, and local invasion. The patient was followed up for 12 months, and there was no evidence of any recurrence. TAKEAWAY LESSONS: Sublingual salivary gland malignancies show early invasion and a higher rate of metastases, thus requiring a vigilant intervention.

NUT Midline Carcinoma of the Sublingual Gland: Clinical Presentation and Review.

NUT midline carcinoma (NMC) is a rare and aggressive disease encountered in the midline of the head and neck or mediastinum. Due to its sparse incidence and subtle pathologic features, we aim to increase knowledge and awareness for this pathologic entity. We present an exemplary case of a young, healthy male presenting with oral cavity pain and cervical lymphadenopathy. This patient was initially diagnosed with an unspecified, highly aggressive sublingual gland malignancy and underwent locoregional resection with free flap reconstruction however suffered a rapid local recurrence and widely extensive metastasis within just 1 month. After rigorous analysis, final pathologic diagnosis revealed a poorly differentiated carcinoma with evidence of squamous differentiation that eventually, post-mortem tested positive for NMC. Only one prior case of sublingual gland NMC has been previously reported as we discuss the literature regarding all sublingual gland malignancies as well as the pathologic features and treatment options for NMC. We recommend consideration of testing for the NUT proto-oncogene at the time of biopsy in the clinical setting of a poorly differentiated midline carcinoma, especially with squamous differentiation, of the head or neck in order to identify patients for clinical trial enrollment and appropriately counsel on the poor clinical prognosis. Improving clinician awareness is critical to increase diagnostic accuracy and need to study prospective treatment outcomes as the first step toward improving management of this difficult disease.

Ultrastructural changes in the sublingual salivary gland of prenatal buffalo (Bubalus bubalis).

AIM: The present study was aimed to elucidate ultrastructural changes in the development of sublingual salivary gland of buffalo during prenatal life. MATERIALS AND METHODS: The study was carried out on sublingual salivary gland of 36 buffalo fetuses ranging from 13.2 cm curved crown-rump length (CVRL) (88(th) day) to full term. The fetuses were categorized into three groups based on their CVRL. RESULTS: The cells lining the terminal tubules were undifferentiated with poorly developed cytoplasmic organelles but lacked secretory granules (SGs) at 13.2 cm CVRL (88(th) day). The SGs appeared first in the form of membrane-bound secretory vesicles with homogeneous electron-dense as well as electron-lucent contents at 21.2 cm CVRL (122(nd) day); however, mucous acinar cells contained electron-lucent granules, while serous secretory cells as well as serous demilunes showed electron-dense granules at 34 cm CVRL (150(th) day) of prenatal life. At 53.5 cm CVRL (194(th) day), both mucous and serous acini were differentiated by the density of SGs. CONCLUSION: The cytoplasm of acinar cells was filled with mitochondria, rough endoplasmic reticulum, and Golgi profiles in mid and late fetal age groups. The SGs were increased in number during the late fetal age group. The myoepithelial cells (MECs) were located at the base of the acinar cells as well as intercalated and striated ducts and were stellate in shape. The ultrastructure of MEC revealed a parallel stream of myofilaments in the cytoplasm and its processes. The mucous cells were predominantly present in the sublingual salivary gland and were pyramidal in shape.

Sialolipoma of the sublingual salivary gland in a dog ­ first report / Sialolipoma na glândula salivar sublingual em cão ­ primeiro relato

This report describes a 14-year-old Pit Bull dog presenting with a soft tissue swelling of 3-month progression in the right sublingual region. Histopathological analysis of the surgically resected specimen revealed large numbers of mature adipocytes and islets consisting of mucin-containing atrophic acini and dilated ducts surrounded by a thin fibrous capsule. Findings were consistent with sialolipoma of the sublingual salivary gland. To the authors' knowledge, this is the first case of sialolipoma affecting the sublingual salivary gland in dogs.(AU)

O presente relato descreve um cão Pit Bull, de 14 anos, com aumento de volume de consistência macia em região sublingual direita com evolução de 3 meses. Após excisão cirúrgica, a análise histopatológica revelou grande número de adipócitos maduros, tecido glandular composto por ductos dilatados e ácinos atróficos contendo mucina, circundados por fina cápsula fibrosa, achados compatíveis com sialolipoma da glândula salivar sublingual. Pelo conhecimento dos autores, este é o primeiro relato de sialolipoma acometendo glândula salivar sublingual em cão.(AU)

Adenoid cystic carcinoma of sublingual salivary gland obstructing the submandibular salivary gland duct.

Sublingual salivary gland malignancies are extremely rare and account for only 0.3-1% of all epithelial salivary gland tumors. Here, we report a case of adenoid cystic carcinoma (ACC) of the sublingual salivary gland that presented as a swelling in the right anterior floor of the mouth obstructing the submandibular duct. Sublingual salivary gland ACC obstructing the submandibular duct is rare and only three cases have been reported in the literature until date. We discuss the different patterns of ACC seen during the pathologic investigations and its radiologic features.