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CASE REPORT Table of Contents  
Ahead of print publication
Osseous choristoma of the gingiva: A case report with insight to etiological theories

1 Department of Oral Pathology and Microbiology, KLE VK Institute of Dental Sciences and Hospital, KLE Academy of Higher Education and Research, KLE University, Belagavi, Karnataka, India
2 Department of Periodontology, KLE VK Institute of Dental Sciences and Hospital, KLE Academy of Higher Education and Research, KLE University, Belagavi, Karnataka, India

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Date of Submission09-Jun-2022
Date of Decision13-Jun-2022
Date of Acceptance28-Aug-2022
Date of Web Publication14-Nov-2022


Choristomas of the oral cavity are rare nonneoplastic lesions that show histologically normal development of tissues at abnormal sites. These oral lesions can remain unnoticed or can progress to sizes that interfere with routine function accompanied with or without pain and other clinical symptoms. Osseous choristomas have been documented in the oral cavity, commonly in the tongue. The present report describes the case of osseous choristoma in the mandibular gingiva of a 61-year-old female patient and highlights the associated etiopathogenesis of choristoma.

Keywords: Bone, choristoma, ectopic, estrogen, gingiva

How to cite this URL:
Kumbhojkar SV, Kumbhojkar V, Angadi PV, Desai KM. Osseous choristoma of the gingiva: A case report with insight to etiological theories. J Microsc Ultrastruct [Epub ahead of print] [cited 2023 Apr 1]. Available from: https://www.jmau.org/preprintarticle.asp?id=361123

  Introduction Top

Choristomas are rare lesions comprising normal tissues that form at ectopic locations.[1],[2],[3] The underlying pathogenesis for choristoma formation is not well defined. Choristomas showing osseous proliferations were addressed as “soft-tissue osteomas” and an equivalent of dermal “osteoma cutis.” However, Krolls et al. termed these “osseous choristoma,” a more accurate term as the lesions are not true neoplasms.[2] These heterotopic masses are classified based on their tissue composition and can form within the oral, dermal, and other body organs or sites.[1],[2],[3],[4],[5],[6] The present report describes a case of osseous choristoma affecting the mandibular gingiva.

  Case Report Top

A 61-year-old female patient reported a chief complaint of hard growth in the gingiva region of 42–43. The mass was present for a year and had progressed gradually to the current size. Extraoral examination revealed no gross abnormality or swelling. On intraoral examination, the growth was 0.8 cm × 1 cm in size and pinkish-red in color. Palpation indicated that the mass was not tender, nonpedunculate, and firm in consistency. Radiographic examination showed an ill-defined radiolucent to the radiopaque lesion. No erosion or invasion into the underlying bone was noted [Figure 1]a.
Figure 1: (a) Occlusal radiograph showing radiolucent to a slightly radiopaque lesion in the 42–43 regions. (b) Gross specimen of excised tissue. (c and d) Tissue section showing stratified squamous epithelium overlying fibrous connective tissue with an eosinophilic mass in the center (H and E, ×4) (H and E, ×10). (e) Bone showing osteocytes in lacunae and focal osteoblastic rimming (H and E, ×40). (f) Fibrous stroma with few plump-to-stellate-shaped cells (H and E, ×40)

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Postexcision, the lesion was sent for histopathological evaluation. The excised mass was about 0.6 cm × 0.6 cm in size [Figure 1]b. The hematoxylin and eosin (H and E) stained section showed a single piece of tissue having stratified squamous epithelium overlying fibrous connective tissue with an eosinophilic mass in the center [Figure 1]c and [Figure 1]d. The center of the lesion showed bone with osteocytes in lacunae and marrow cavity with delicate adipose tissue and red blood cells [Figure 1]c and [Figure 1]d. Stroma surrounding the bony mass was fibrous and the focal area showed the presence of numerous plump stellate cells resembling osteoblasts [Figure 1]e and [Figure 1]f. Based on excisional specimen histopathology, a diagnosis of osseous choristoma of the gingiva was made.

  Discussion Top

Choristoma is a histologically normal tissue proliferation that forms at an anatomic location different from its regular development site.[1] The tongue is the most frequent site for the occurrence of osseous choristoma in the oral cavity. A broad age group can be involved; however, there is a slight predilection toward females.[1],[2],[3] Choristomas can present as pedunculate or sessile, asymptomatic masses, or large lesions at sites that can lead to dysphagia, gagging, and other symptoms.[1],[2],[3]

Histologically, osseous choristoma presents as a mass of viable lamellar bone surrounded by dense fibrous connective tissue and overlying normal oral epithelium. Standard physiological components observed include osteoblasts, osteoclasts, and a well-developed Haversian system. The presence of hemopoietic or fatty marrow is also a common finding. Peripheral osteoblastic activity may be inconspicuous.[2],[3],[4],[5]

Although the etiology is unknown, theories predict the development as either embryological, due to trauma/chronic irritation, or due to a degenerating fibroma undergoing ossification.[2],[3],[4],[5] Researchers have probed into the role of bone morphogenetic proteins (BMP) concerning the ossification of osseous choristomas.[6] Hironaka et al. suggested the possible role of estrogen therapy in the development of osseous choristoma in a female patient with Turner syndrome.[7]

The function of estrogen and estrogen receptors in regulating periodontal health has been largely reviewed.[8] Research has also illustrated a key association between increased BMP-6 and estrogen receptors in bone formation.[8],[9] Alongside this, the relationship of estrogen with osteoporosis and conditioned gingival enlargements is well understood.[8],[10] On considering these, the osseous component and high prevalence in female patients, the role of hormones in particular estrogen, could be implicated as one of the factors triggering the responsive, trauma/injury-based bone formation in osseous choristomas. However, exploring the molecular mechanisms and assessing the levels of estrogen, estrogen receptors, and pro-inflammatory cytokines in cases of oral choristomas could help to ascertain this plausible link.

In conclusion, choristomas are rare lesions representing a process of normal tissue formation in an unusual location. This lesion can clinically mimic a range of neoplastic and nonneoplastic lesions of the oral cavity and need further molecular studies to understand the etiopathogenesis. Thus, documentation of these cases and examining their etiopathogenesis could enhance our understanding of tissue dynamics modulating the development of osseous choristomas.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Sheridan SM. Osseous choristoma: A report of two cases. Br J Oral Maxillofac Surg 1984;22:99-102.  Back to cited text no. 1
Krolls SO, Jacoway JR, Alexander WN. Osseous choristomas (osteomas) of intraoral soft tissues. Oral Surg Oral Med Oral Pathol 1971;32:588-95.  Back to cited text no. 2
Chou LS, Hansen LS, Daniels TE. Choristomas of the oral cavity: A review. Oral Surg Oral Med Oral Pathol 1991;72:584-93.  Back to cited text no. 3
Wasserstein MH, SunderRaj M, Jain R, Yamane G, Chaudhry AP. Lingual osseous choristoma. J Oral Med 1983;38:87-9.  Back to cited text no. 4
Bastian TS, Selvamani M, Ashwin S, Rahul VK, Cyriac MB. Osseous choristoma of the labial mucosa: A rare case report. J Pharm Bioallied Sci 2015;7:S725-7.  Back to cited text no. 5
Yoshimura H, Ohba S, Matsuda S, Kobayashi J, Ishimaru K, Imamura Y, et al. Osseous choristoma of the buccal mucosa: A case report with immunohistochemical study of bone morphogenetic protein-2 and − 4 and a review of the literature. J Oral Maxillofac Surg Med Pathol 2014;26:351-5.  Back to cited text no. 6
Hironaka S, Watanabe H, Nakai S, Hisa Y. A Case of Osseous Choristoma on the Tongue Radix. Jibi Inkoka Rinsho 2010;103:725-8. (Article in Japanese).  Back to cited text no. 7
Shapiro LF, Freeman K. The relationship between estrogen, estrogen receptors and periodontal disease in adult women: A review of the literature. N Y State Dent J 2014;80:30-4.  Back to cited text no. 8
Pan F, Zhang R, Wang G, Ding Y. Oestrogen receptors are involved in the osteogenic differentiation of periodontal ligament stem cells. Biosci Rep 2011;31:117-24.  Back to cited text no. 9
Markou E, Eleana B, Lazaros T, Antonios K. The influence of sex steroid hormones on gingiva of women. Open Dent J 2009;3:114-9.  Back to cited text no. 10

Correspondence Address:
Karishma Madhusudan Desai,
Department of Oral Pathology and Microbiology, KLE VK Institute of Dental Sciences and Hospital, KLE Academy of Higher Education and Research, KLE University, Belagavi . 590 010, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jmau.jmau_48_22


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