Volume 2, Issue 3 , Pages 154-157, September 2007
Congenital heterotopic gastrointestinal cyst of the neck
Article Outline
Summary
The presence of normal alimentary tissue in an abnormal location is referred to as a heterotopic gastrointestinal cyst or duplication cyst. These are thought to be congenital and rarely occur in the neck. More often found in the oral cavity, they usually present as an asymptomatic swelling and are treated with surgical excision. We describe the rare presentation and diagnosis of an 8-month-old girl with a congenital heterotopic gastrointestinal cyst in the neck.
Keywords: Congenital, Heterotopic gastrointestinal cyst, Neck
1. Introduction
Heterotopic gastrointestinal cysts, or duplication cysts, contain normal gastrointestinal tissue in an abnormal location, and are rarely found in the neck. Thought to be congenital and arising from dysembryogenesis, most cases are described in the oral cavity of young infants. We report an exceptional case of a gastrointestinal duplication cyst in the right sub-mandibular triangle of an 8-month-old girl.
2. Case report
A 6-month-old girl was referred to the tertiary paediatric otolaryngology service with a 7-week history of swelling in the right submandibular triangle (level I). She had an unremarkable past medical history, having been delivered at term following a normal pregnancy with no subsequent major illnesses or surgery. When the mother first noticed the mass the child was systemically and developmentally well, although 1 week prior to presentation she displayed poor feeding and features of infection consistent with a raised white cell count and CRP. The mass was increasing in size, and on examination was firm and mobile with poorly defined edges. There was no involvement of the overlying skin and the floor of mouth appeared normal.
An MRI scan revealed a 4.8
cm×3.4cm×3.1cm mass extending anteriorly and medially from in front of the sternocleidomastoid and carotid sheath to the right sub-lingual space. This was predominantly cystic in appearance with an enhancing, thick wall containing several locules and septa, and insinuated itself between structures to reach the sub-lingual space (Fig. 1). At this stage the differential diagnosis of the mass was branchial cleft cyst or cystic hygroma, the latter being the most likely according to radiological findings despite atypical enhancement of the cyst wall.
Fig. 1.
Magnetic resonance imaging. (A) Axial (STIR sequence) showing a high signal mass in the right submandibular triangle extending medially into the sublingual space and (B) coronal (T1 weighted, fat suppression and gadolinium contrast) showing the multiloculated cystic mass with enhancing wall.
The child underwent an excision biopsy under general anaesthetic. The mylohyoid muscle, around which the cyst was wrapped, was divided and the cyst and surrounding lymph nodes were excised.
On gross inspection, the specimen measured 50mm×35mm×20mm, with salivary gland tissue at one edge. On slicing, there was a large haemorrhagic cyst of 35mm×25mm×20mm with a tubular structure along the wall. Histologically, the cyst contained smaller locules lined by gastrointestinal type epithelium with surrounding smooth muscle and fibrous tissue (Fig. 2). Gastric body and pyloric type, small intestinal and colonic pattern mucosa were identified (Fig. 3). Focally, stratified squamous epithelium and respiratory mucosa with cilia were present (Fig. 4). There appeared to be epithelial representation of the foregut, midgut and hindgut. The tubular structure had a mucosal lining surrounded by a thick smooth muscle coat, recapitulating structure of the gut. The haemorrhagic lining seen did contain strips of epithelium within it.
Fig. 2.
Multiloculated appearance of cyst lined by gastrointestinal epithelium (hematoxylin–eosin stain [HES] 20×).
Fig. 3.
Histological section of cyst showing (A) gastric body/fundus type mucosa (HES 100×), (B) small intestine type mucosa with villi and Paneth cells (HES 100×), and (C) large bowel type mucosa (HES 200×).
Fig. 4.
Metaplastic respiratory type epithelium within the cyst (HES 200×).
The child made a good recovery, and was reviewed 6 weeks following surgery. The incision had healed well and there was no recurrence of the mass.
3. Discussion
The presence of normal gastrointestinal tissue in an abnormal location is consistent with a congenital heterotopic gastrointestinal cyst or duplication cyst. More commonly found in the gastrointestinal tract (especially the lower oesophagus and Meckel's diverticula), duplication cysts have been previously described in the head and neck region (see Refs. [1], [2]). Around 50 cases have been reported in the oral cavity since the first description by Foder [3], of which the majority are lingual [1], [2], [4], [5]. Less frequently they have been found in the larynx [6], hypopharynx [7] and nasopharynx [8], [9]. One previous case of heterotopic gastric mucosa has been reported in the midline neck region [10], and there have been two cases described within the sub-mandibular gland [11], [12].
The terminology used for duplication cysts varies depending on the embryonic origin of the tissue and the location and nature of the cyst, and can be confusing. The term choristoma describes a mass formed by histologically normal tissue present in a location other than usually found [9] and can be cystic or solid in nature. The cystic form is referred to as enterocystoma, choristomatic cyst, gastrointestinal reduplication cyst, foregut duplication cyst, and most commonly heterotopic gastrointestinal cyst, and the solid form gastric heterotopia or heterotopic gastric mucosa. We refer to the lesion in this case as a congenital heterotopic gastrointestinal cyst, as it contains both gastric and respiratory epithelium typical of the embryonic foregut as well as areas of intestinal and colonic differentiation. Although the majority of choristomas contain only one type of tissue, it is not unusual for both respiratory epithelia and gastrointestinal musoca to be found in the same cyst [13], [14].
The precise pathogenesis of the duplication of the alimentary tract is unknown but various theories exist. The most common explanation is that during the first few weeks of gestation, islands of undifferentiated endoderm becoming misplaced and entrapped elsewhere in the developmental gut or head and neck regions. Under the appropriate influences these pleuripotent cells can then differentiate into both gastrointestinal and respiratory structures in their new location. Other putative explanations have been described elsewhere [1], [2]. In the majority of reported cases the patients have been under the age of 2, supporting the hypothesis that the cysts are congenital.
While gastrointestinal mucosa was present in previous case reports, this case appears unique in having mucosal derivations from the foregut, midgut and hindgut in a cyst in the anterior submandibular triangle of the neck in an infant. The differential diagnosis of a lateral neck mass in an infant includes branchial cyst, lymphangioma (cystic hygroma) and haemangioma, with gastric duplication cysts being previously unreported. It is difficult to confirm the diagnosis on clinical signs alone as such masses are frequently painless and patients are otherwise asymptomatic, although in some cases airway obstruction and dysphagia can occur. Although radiologically the cyst in this case did not resemble a branchial cleft cyst due to septation and loculation, nor was the enhancing wall structure typical of cystic hygroma, the diagnosis of heterotopic gastrointestinal cyst could only be made histologically. The management consists of surgical excision, and according to previous reports of intestinal duplication cysts elsewhere in the head and neck region, no recurrence is expected.
4. Conclusion
Congenital heterotopic gastrointestinal cyst is an exceptionally rare differential diagnosis of a neck mass in and infant. Diagnosis is made histopathologically and treatment with surgical excision is curative. Pathogenesis is thought to be due to misplacement of embryological tissue early in foetal development, however with so few cases in the literature the development, progression and prognosis of such masses remains unclear.
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PII: S1871-4048(07)00031-7
doi:10.1016/j.pedex.2007.04.005
© 2007 Elsevier Ireland Ltd. All rights reserved.
Volume 2, Issue 3 , Pages 154-157, September 2007
