Volume 4, Issue 2 , Pages 77-79, March 2009
Aplasia of the submandibular gland with compensatory sublingual gland hypertrophy: A case report
Article Outline
Summary
Aplasia of the submandibular gland is an uncommon disorder which has been previously reported in the literature in few case reports. We report a 14-year-old boy presenting with submandibular mass. He was later diagnosed as having aplasia of the submandibular gland and a compensatory ipsilateral sublingual hypertrophy. The diagnosis was made by imaging (CT-scan and MR). The case is presented with the emphasis that aplasia of the submandibular gland followed by a presumably compensatory sublingual gland enlargement is a rare phenomenon but still should be considered in the differential diagnosis of a neck mass.
Keywords: Submandibular gland aplasia, Sublingual gland hyperplasa
1. Introduction
Aplasia of the submandibular gland is an uncommon disorder. Absence of a major salivary gland was reported to be associated with other congenital craniofacial anomalies. Several case reports have previously reported patients with submandibular aplasia. Most of the cases were asymptomatic though symptoms as dysphagia, xerostomia, dental caries and local pain were all reported [1], [2], [3], [4], [5], [6]. The following case report is, to the best of our knowledge, the youngest patient diagnosed with submandibular aplasia so far.
2. Case report
A 14-year-old boy was referred to the otolaryngology clinic for evaluation of a right submandibular swelling. He was otherwise healthy and first became aware of the mass two months previously and noticed a gradual mild increase in its size. His medical history was unremarkable. He was asymptomatic, except for the submandibular swelling, with no dysphagia, fever or night sweats. On physical examination a non-tender mass was palpated in the right anterior submandibular area without signs of inflammation (Fig. 1). The rest of the neck examination revealed no adenopathy and examination of the oral cavity and pharynx was without any pathological findings. He underwent two Fine-needle biopsies that were found to be acellular. A sonography study revealed some lymph nodes in the submandibular area, with normal appearance and size, no other abnormality was noted. The patient was referred to a contrast-enhanced CT scan of the neck followed by an MRI (Fig. 2) demonstrating aplasia of the right submandibular gland with ipsilateral enlargement of the sublingual gland.
Fig. 1.
A right anterior submandibular mass (arrow).
Fig. 2.
A coronal view T2-weighted, gadolinium enhanced MR Imaging. (A) Absence of the right submandibular gland (arrow), the left submandibular gland is present (asterisk). (B) Compensatory hypertrophy of the right sublingual gland (asterisk).
3. Discussion
Aplasia of a major salivary gland is rare. One or several glands could be absent and any of the major salivary gland may be involved. The cause of this disorder is not known and is believed to be a result of disturbance of fetal development during the fourth to eighth week of gestation.
Craniofacial development is believed to be dependent on the fibroblast-growth-factor (Fgf) signaling pathway as was demonstrated in various animal model experiments [7] where the mutation could be at the Fgf itself or in the fibroblast-growth-factor-receptor (Fgfr). With respect to submandibular gland development, a specific mutation of the FgF10 was identified therefore researchers assume that normal development of the submandibular and lacrimal glands are dependent on this specific Fgf. The nonredundant signaling pathways Fgf10/Fgfr2b and Fgf8/Fgf2c mutations could be a possible mechanism for submandibular gland aplasia [7], [8]. However, this does not clarify the reason for the aplasia of one gland with no effect on the other major salivary glands in the case presented here. Thus, we cannot conclude whether the enlargement of the sublingual gland is secondary to the submandibular gland atrophy or it is coincidental.
The clinical presentation consists of dysphagia, dry mouth and dental caries, but those symptoms are mentioned mainly with aplasia of multiple glands. In those small number of cases published with submandibular gland aplasia the patients were mainly asymptomatic. In two other cases, compensatory sublingual hypertrophy was the presenting symptom [6], [4].
Diagnosis is established mainly on imaging while MRI is the preferable method of choice, however, contrast enhanced CT scan may do as well. Further investigations such as fine needle aspiration are unnecessary. Patient reassurance and follow-up are worthwhile. Trans oral sublingual gland excision should be considered in case the swelling is aesthetically bothersome.
In conclusion, submandibular aplasia with sublingual hypertrophy is extremely rare. Though due to the fact that it is sometimes asymptomatic, the real prevalence of the disorder is not clear. The sublingual gland could be hypertrophic, as in this present case, and present as asymptomatic neck mass.
Reference
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- . Unilateral submandibular gland aplasia associated with ipsilateral sublingual gland hypertrophy. AJNR Am. J. Neuroradiol. 2006;27(November–December (10)):2214–2216
- . Unilateral submandibular gland aplasia: an isolated phenomenon of early fetal development. Otolaryngol. Head Neck Surg. 2006;135(August (2)):332–334
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- . FGF10/FGFR2b signaling plays essential roles during in vivo embryonic submandibular salivary gland morphogenesis. BMC Dev. Biol. 2005;5(June):11
PII: S1871-4048(08)00053-1
doi:10.1016/j.pedex.2008.07.002
© 2008 Elsevier Ireland Ltd. All rights reserved.
Volume 4, Issue 2 , Pages 77-79, March 2009
