原文題目(出處)： Mixed choristoma on the anterior dorsal tongue: a new case and review of the literature. Oral Surg 2011;4:26-9
原文作者姓名： AA Abdul Majeed & CS Farah
通訊作者學校： The University of Queensland, School of Dentistry &UQ Centre for Clinical Research, Herston, Queensland, Australia 報告者姓名(組別)： 葉育君 Intern J 組
報告日期： 2011/06/10
<內文>
Introduction
A choristoma is a benign tumour-like growth consisting of normal tissue in an abnormal site, which should be included in the differential diagnosis of any firm swelling on the tongue.
1913 Monserrat
First reported osseous choristoma on the tongue and used the term ‘lingual osteoma’
1. The lesion behaves benignly and can be treated by surgical excision with extremely rare recurrence.
1971, Krolls et al.
Introduced a more appropriate term ‘osseous choristoma’
This paper
Describe the clinical and microscopic features of osseous and cartilaginous choristomas with brief review of the literature.
Report the second case of mixed osseous choristoma to occur on the anterior dorsal tongue.
Case report
First visit：May 2008
Patent’s data：57-year-old male
S：asymptomatic pedunculated swelling on the anterior right dorsal aspect of the tongue for 3 years and could not elicit a history of trauma.
Lesion
0.8 cm in greatest dimension
Blanched slightly under pressure but appeared to arise from the underlying connective tissue
Surface mucosa：slightly keratotic showing evidence of minor chronic trauma
Hard on palpation.
Clinically
Traumatic fibroma (fibroepithelial polyp) although a peripheral ossifying fibroma was also entertained
Treatment
Excised completely under local anaesthesia
Examined by routine histopathology with haematoxylin and eosin
Lesion healed well without complication
Microscopic examination
Polypoid mass of well encapsulated cartilage and dense bone beneath a non-ulcerated non-papillated lingual mucosa
No evidence of active chondroblasts, osteoblasts or osteoclasts
Histology diagnoses
Osseous choristoma with cartilaginous components
Discussion
Osseous choristomas and cartilaginous choristomas are relatively rare benign lesions with approximately 61 and 28 cases having been reported in the literature, and only 7 cases reported to contain a mixture of these tissues
Osseous lesion
Male to female ratio：1:5
Hard pedunculated smooth surfaced lesions
Site：
Base of the tongue adjacent to foramen caecum and the circumvallate papillae
No case reported occurring at ventral tongue
Other occurring site：buccal mucosa, submental region, retromolar pad area and masticatory muscles
Presentation ranges(lingual lision)：
Age at time of initial diagnosis ranging from 8 to 73 years
Diameter(lingual lesion)：
Generally less than 2.5 cm in diameter
Histologically
Lesion consists of a well circumscribed, lamellated mass of dense viable bone with a haversian system, as well as osteocytes in lacunae
Bony mass is surrounded by dense fibrous connective tissue covered with thin stratified squamous epithelium
Cartilaginous lesions
No difference in male to female ratio
Site：
Dorsal tongue, but four cases have been reported on the ventral tongue
Other occurring site：gingiva, soft palate, buccal mucosa and palatine tonsi
Presentation ranges：
Between 3 to 75 years of age
Most commonly during the third and fourth decades of life
Diameter：
4.5 cm in greatest
Microscopically
Lesion consist of a circumscribed nodule composed of hyaline cartilage with well-defined lacunae, showing small chondrocytes
Mixed osseous and cartilaginous components
Male to female ratio of 6:1
Site：
Base of the tongue (4 cases, 57%)
Ventral tongue (2 cases, 28%)
Anterior third of the tongue (1 case, 15%)
Presentation ranges：
From 20 to 67 years
Diameter：
Varies from 0.7 to 2.5 cm
Choristomas of the tongue are mostly asymptomatic
Some reports of dysphagia, gaging, nausea, irritation and swelling in the throat.
The present case：asymptomatic
Differential diagnosis：
thyroid nodule, hyperplastic tonsils, fibroma, granular cell tumour and neural neoplasm
The present case：consistent fibroma (location and tissue consistence)
Treatment：
surgical excision, with recurrence being extremely rare
No follow-up complication of lingual choristomas has been described in the literature
Aetiology 病因學(developmental or reactive)
Developmental theory
complex embryology of the tongue leads to a developmental malformation which includes ossification of the branchial arch remnants or calcifying of the thyroid gland remnants
explain why osseous choristomas are so widely distributed in the area of foramen caecum and the circumvallate papillae
cartilaginous choristomas
from heterotopic cartilage remnants from any of the first four branchial arches
chondroblastic cells are misplaced during development and sequestered in the tongue
reactive theory
lesion is reactive in nature
central ossification similar to myositis ossification
In the case of cartilaginous choristomas, the reactive theory postulates that trauma can stimulate metaplastic change
The present case：
branchial remnants or thyroid tissue were not found histologically
history and the position of the lesion on the anterior third of the dorsal tongue makes trauma the most possible cause
suggested：
1. traumatic event such as a tongue bite that led to chronic inflammation 2. stimulating metaplastic change to fibrous, cartilaginous and finally to
osseous tissue
explaned：
lesion contained a mixture of cartilaginous elements within a solid
osseous mass
Previous literature has considered osseous and cartilaginous choristomas as separate entities
The paper propose that these two types of choristoma have a common aetiopathogenesis
Traumatic episode
local inflammation
development of hyperplastic tissue, and fibroma formation
further trauma
metaplastic ossification of a degenerating fibroma begins with cartilaginous formation
formation of bone within the lesion
osseous and cartilaginous choristomas have the same aetiopathogenesis
osseous choristomas represent a late presentation of the lesion
explain why most choristomas reported in the anterior part of tongue are cartilaginous, as they are more likely to be identified by the patient or clinician early, with ensuing diagnosis and surgical removal.
lesions develop at the base of the tongue： have more time for osseous formation given that they are asymptomatic and not identified at an early stage
conclusion
osseous and cartilaginous choristomas should be included in the differential diagnosis of any firm swelling on the tongue
lesion may occur on any region of the tongue
osseous choristomas represent a late stage in the development
Awareness of its benign behaviour is important to avoid aggressive surgical management.
題號 題目
1 Which disease is not a tumorlike grouth of microscopically noemal tissue in an abnormal location?
(a) Choristoma
(b) Soft tissue osteomas (c) Fibroma
(d) Soft tissue chondromas
答案(c ) 出處：Oral and maxillafacial pathology (third edition) p552
題號 題目
2 Where is most common location of the choristoma?
(a) Posterior tongue near foramen cecum (b) Buccal mucosa
(c) Lip (d) Gingiva
答案(a ) 出處：Oral and maxillafacial pathology (third edition) p552
