Complete congenital agenesis of all major salivary glands: a case report and review of the literature

Bony Congenital Nasolacrimal Duct Obstruction: A Novel Phenotype of Aplasia of Lacrimal and Major Salivary Glands

PURPOSE

Aplasia of lacrimal and salivary glands (ALSG) is a syndromic disorder characterized by aplasia of lacrimal and salivary systems. Reported ophthalmic manifestations of ALSG include aplasia of lacrimal glands, punctal agenesis, lacrimal sac mucocele, and membranous congenital nasolacrimal duct obstruction (CNLDO). Bony CNLDO, a rare clinical entity, has not been associated with any syndromic disorder. This study investigated the relationship between genetic mutations and bony CNLDO in 3 Chinese families with ALSG.

DESIGN

Single-center observational case study.

PARTICIPANTS

Three Chinese families with bony CNLDO, including 7 affected and 9 healthy family members.

METHODS

Slit-lamp ophthalmic examination, comprehensive physical examination, orbital computed tomography (CT) imaging, cervicofacial magnetic resonance imaging, audiometry, and whole exome sequencing on periphery blood were performed. Variants were cross-referenced with 1000 control genomes and various population databases. Pathologic variants were identified using bioinformatic tools.

MAIN OUTCOME MEASURES

Clinical examination, diagnostic imaging, whole exome sequencing, and bioinformatic analysis findings.

RESULTS

Affected patients showed decreased tear production on the Schimer I test and reduced tear breakup time. Bony CNLDO was observed on CT, showing unilateral or bilateral bony termination at the middle or terminal segment of the nasolacrimal canal. Magnetic resonance imaging showed aplasia or absence of lacrimal, parotid, and submandibular glands. Physical examination revealed normal ears, digits, and facial morphology. Audiometry and dental assessment were conducted on the pediatric patients and yielded normal results. The clinical characteristics of patients aligned with a diagnosis of ALSG. Genomic analysis revealed 3 novel heterozygous missense mutations of the Fgf10 gene: c.316T→C, c.327C→G, and c.332T→G. The inheritance pattern was autosomal dominant with variable penetrance. These variants were not observed in 1000 control genomes and population databases. These variant positions also were shown to be highly conserved across various animal species. Mutated genes and proteins were predicted as deleterious with most computational models, with a few suggesting they may be benign.

CONCLUSIONS

Bony CNLDO was identified as a novel phenotype of ALSG implicated by missense mutations of highly conserved residues in the Fgf10 gene. These cases broadened our knowledge of Fgf10-related phenotypes and prompted clinicians to consider syndromic associations in patients with bony CNLDO.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Current developments and opportunities of pluripotent stem cells-based therapies for salivary gland hypofunction

Salivary gland hypofunction (SGH) caused by systemic disease, drugs, aging, and radiotherapy for head and neck cancer can cause dry mouth, which increases the risk of disorders such as periodontitis, taste disorders, pain and burning sensations in the mouth, dental caries, and dramatically reduces the quality of life of patients. To date, the treatment of SGH is still aimed at relieving patients' clinical symptoms and improving their quality of life, and is not able to repair and regenerate the damaged salivary glands. Pluripotent stem cells (PSCs), including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and extended pluripotent stem cells (EPSCs), are an emerging source of cellular therapies that are capable of unlimited proliferation and differentiation into cells of all three germ layers. In recent years, the immunomodulatory and tissue regenerative effects of PSCs, their derived cells, and paracrine products of these cells have received increasing attention and have demonstrated promising therapeutic effects in some preclinical studies targeting SGH. This review outlined the etiologies and available treatments for SGH. The existing efficacy and potential role of PSCs, their derived cells and paracrine products of these cells for SGH are summarized, with a focus on PSC-derived salivary gland stem/progenitor cells (SGS/PCs) and PSC-derived mesenchymal stem cells (MSCs). In this Review, we provide a conceptual outline of our current understanding of PSCs-based therapy and its importance in SGH treatment, which may inform and serve the design of future studies.

Aplasia of the Major and Minor Salivary Glands: Report of a Rare Case

Background

Aplasia of the salivary glands, either partial or involving all the major and possibly the minor salivary glands, is a very rare cause of hyposalivation. The aim of this case report is to present a case of aplasia of the major and minor salivary glands and discuss the relevant literature.

Methods

A 23-year-old woman, with a non-contributory medical and family history was referred due to rampant caries, that could not be attributed to any obvious aetiology. No sicca symptoms, previous parotid gland swelling or general symptoms were reported. Clinically, oral mucosa dryness and extended dental erosions and caries were observed, while the orifices of the excretory ducts of the parotid and submandibular salivary glands were not evident. Unstimulated and stimulated saliva flow rates were severely diminished, while a diagnostic biopsy of the lower lip revealed absence of minor salivary glands. Detailed hematologic and immunological investigations to exclude systemic disorders were also within normal limits. Ultrasound and magnetic resonance imaging revealed the absence of all major salivary glands, confirming the clinical diagnosis of congenital aplasia of the salivary glands.

Results

Oral hygiene instructions and dietary advice were given while dental products with fluoride and saliva substitutes were administered and appropriate dental treatment was implemented. Regular dental follow-up was also advised.

Conclusions

Timely diagnosis of aplasia of the salivary glands is important, considering the detrimental effects of the absence of saliva on oral health. Management consists of the use of saliva substitutes, nutritional adaptation, maintenance of oral health and regular dental follow-ups.

Pediatric Salivary Gland Disease

Salivary gland disease in the pediatric population is rare, yet it encompasses a wide spectrum of disease. It is estimated that 4.3% of salivary gland disease occurs in the pediatric population, with most classified as nonneoplastic. Further extrapolation reveals that 5% of salivary gland neoplastic diseases occur in patients younger than 20 years. Moreover, salivary gland tumors represent 1% of all head and neck tumors across all ages. Regardless, clinicians across all fields should be familiar with the workup of various pediatric salivary gland diseases and appropriate referral to a pediatric otolaryngologist.

Imaging of parotid anomalies in infants and children

A wide spectrum of disorders involves the parotid glands, in infancy and childhood. Acute or chronic inflammatory/infectious diseases are predominant. The first branchial cleft anomalies are congenital lesions that typically manifest during childhood. Tumor lesions are more likely to be benign, with infantile hemangioma the most common in infancy and pleomorphic adenoma the most frequent in childhood. Malignant tumors are uncommon, with mucoepidermoid carcinoma the least rare. Infiltrative parotid diseases are rare and have some pediatric clinical specificities. These common and uncommon disorders of parotid glands during childhood and their imaging characteristics are reviewed.

Unusual Conditions Impairing Saliva Secretion: Developmental Anomalies of Salivary Glands

Salivary glands (SG) arise from ectodermal tissue between 6 and 12th weeks of intrauterine life through finely regulated epithelial-mesenchymal interactions. For this reason, different types of structural congenital anomalies, ranging from asymptomatic anatomical variants to alterations associated with syndromic conditions, have been described. Notable glandular parenchyma anomalies are the SG aplasia and the ectopic SG tissue. Major SG aplasia is a developmental anomaly, leading to variable degrees of xerostomia, and oral dryness. Ectopic SG tissue can occur as accessory gland tissue, salivary tissue associated with branchial cleft anomalies, or true heterotopic SG tissue. Among salivary ducts anomalies, congenital atresia is a rare developmental anomaly due to duct canalization failure in oral cavity, lead to salivary retention posterior to the imperforate orifice. Accessory ducts originate from the invagination of the developing duct in two places or from the premature ventral branching of the main duct. Heterotopic ducts may arise from glandular bud positioned in an anomalous site lateral to the stomodeum or from the failure of the intraoral groove development, hindering their proximal canalization. These anomalies require multidisciplinary approach to diagnosis and treatment. While ectopic or accessory SG tissue/ducts often do not require any treatment, patients with SG aplasia could benefit from strategies for restoring SG function. This article attempts to review the literature on SG parenchyma and ducts anomalies in head and neck region providing clinicians with a comprehensive range of clinical phenotypes and possible future applications of bioengineered therapies for next-generation of regenerative medicine.

Aplasia of the lacrimal and major salivary glands (ALSG). First case report in spanish population and review of the literature

Aplasia of the lacrimal and the major salivary glands (ALSG) is a rare disorder with scarce cases described in the recent literature. The pattern of genetic inheritance is autosomal dominant with variable expressivity. A 40 years male patient was referred to the Oral and Maxillofacial Service at the Hospital Universitario de A Coruña diagnosed with complete agenesis of all salivary glands. Our case it is the first of ALSG syndrome in the Spanish literature. Imaging tests are necessary to confirm the lack of formation of salivary glands and alteration of lacrimal system. A mutation of FGF10 has been proposed as the responsible of the syndrome. The management of the lacrimal alteration depends of the clinical findings. Clinical suspicion remains the principal tool to diagnose the syndrome.

Key words:ALSG, salivary glands aplasia.

Major salivary gland aplasia and hypoplasia in Down syndrome: review of the literature and report of a case

Salivary gland aplasia and hypoplasia are rarely described in the medical literature. This article presents a case of aplasia and hypoplasia of the major salivary glands in a patient with Down syndrome. A literature review, as well as an overview of the diagnosis and management of this condition, is presented.

Sialolithiasis in an Accessory Submandibular Gland Identified by Magnetic Resonance Sialography

BACKGROUND

Accessory submandibular gland is a very rare anatomical variant. There have been only 6 reported cases of this entity in the English literature, only 1 of which was identified using magnetic resonance imaging.

METHODS

We report the case of a 39-year-old female with symptoms of left submandibular sialoadenitis who was diagnosed of sialolithiasis within the left accessory submandibular gland by magnetic resonance sialography (MR-Si).

RESULTS

The calculus was palpated near the submandibular papilla and was extracted by an intraoral approach. One-year follow-up revealed no evidence of recurrence.

CONCLUSIONS

This is the first case reported to date in the English literature of a patient with sialolithiasis within an accessory submandibular gland diagnosed by MR-Si.

Complete agenesis of major salivary glands

A 4 year-old female patient was treated for persistent right-sided dacryocystitis and xerostomia. MRI was performed to screen for a dry syndrome; which resulted in the diagnosis of agenesis of the parotid and submandibular glands as well as lacrimal duct malformation. An MRI of each parent was normal. The mother's history revealed 4 days of pyrexia during the 8th week of amenorrhea. This was an isolated case, with no family history, characterized by a febrile episode during pregnancy at the period of main salivary gland genesis. Epigenetic mechanisms could be implicated.

Congenital agenesis of all major salivary glands and absence of unilateral lacrimal puncta: a case report and review of the literature

Abstract Congenital agenesis of the salivary glands is an extremely rare congenital condition, which may cause severe xerostomia, progressive dental caries, and oropharyngeal candidiasis in children. To date, there have been few documented cases of aplasia of the major salivary glands. Congenital agenesis of the salivary glands accompanied by absence of the lacrimal puncta is even more rare. We report a case of a 5-year-old boy with xerostomia and extensive dental caries. Salivary gland imaging with sodium pertechnetate 99mTcO(4) showed bilateral aplasia of the parotid, submandibular, and sublingual glands. The patient was found to lack the left lacrimal puncta through physical examination. Here we describe the clinical presentation, diagnostic essentials, and medical and dental management of the patient.