# Tongue Osseous Choristoma in an 11-Year-Old Female: A Case Report and Literature Review Focusing on Pediatric Cases

Authors: Satomi Arimoto; Manabu Shigeoka; Masaya Akashi
Journal: Case Reports in Dentistry
 (2021)

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## Abstract

Osseous choristoma is an uncommon benign lesion characterized by the presence of ectopic mature bone within soft tissue. In most cases, these lesions occur on the dorsum of the tongue in patients in their third and fourth decades of life. This article describes a case of lingual osseous choristoma in a pediatric patient. An eleven-year-old girl with a lingual mass was referred to our hospital from a dental clinic. Total excisional biopsy and histological examination were performed, and osseous choristoma was diagnosed. The postoperative course was uneventful with no signs of recurrence during the 12 months after surgery. Moreover, a literature review focusing on pediatric cases with lingual osseous choristoma was performed to know the etiology, clinicopathological characteristics, and course of treatment of the lesion.


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## Body

## 1. Introduction

Choristoma is defined as a tumor-like lesion that is composed of normal tissue in an abnormal location. In 1971, Krolls et al. proposed the term “osseous choristoma” for soft tissue osteoma in the head and neck region [1], and this term has been widely used since. Osseous choristoma is a rare benign lesion characterized by the presence of ectopic mature bone within soft tissue and is more often composed of bone and cartilage [2]. Lingual osseous choristoma is a rather rare entity with less than 100 reported cases in the literature [3]. The pathogenesis of these lesions has remained unexplained [4]. Most cases of intraoral osseous choristoma occur in the tongue (especially its dorsal surface) [2]. Most patients with lingual osseous choristoma are women in their third or fourth decade of life [2]. These lesions are considered self-limiting in their growth. On oral examination, they frequently appear as painless, pedunculated nodules on the tongue that are firm on palpation [5]. Lingual masses can include osseous choristoma or other lesions such as fibroma, papilloma, pyogenic granulomas, squamous cell carcinomas, or hemangiomas [6]. Even though some patients may be asymptomatic, a wide array of symptoms, including gagging, dysphagia, foreign body sensation, throat irritation, discomfort, and pain, have been reported [7]. Physical examination and diagnostic imaging may assist in identifying the mass; however, a definitive diagnosis requires histologic examination. The microscopic features of osseous choristoma include a well-circumscribed mass of viable lamellar bone with haversian canals, a well-developed mass of mature viable cartilage, or a mixture of bone and cartilage surrounded by dense fibrous connective tissue with thin stratified squamous epithelium. Only a few pediatric patients with lingual osseous choristoma have been reported so far [4]. On the other hand, no previous reports of lingual osseous choristoma have highlighted the features of pediatric patients. This report is aimed at presenting another case of lingual osseous choristoma in a pediatric patient and at reviewing the relevant literature focusing on pediatric cases. A thorough literature search was carried out on PubMed and Google Scholar using search terms like “osseous choristoma,” “soft tissue osteoma,” and “lingual” or “tongue.”


## 2. Case Presentation

An 11-year-old Japanese girl told her dentist about a mass in her tongue and was referred to our hospital. She had noticed an asymptomatic nodule at the dorsum of the tongue. However, the fear of being diagnosed with a malignant condition prevented her from consulting a doctor, at least for a while. She had been aware of its existence for 2–3 years before her first visit. She was diagnosed with pneumonia at the age of one year but had no other remarkable medical history. She was not on any long-term medications. Her clinical examination revealed a pedunculated mass covered with normal mucosa in the tongue’s posterior portion (Figure1). The lesion was approximately 7 mm in diameter. Although the lesion was asymptomatic and clinically diagnosed as a benign soft tissue tumor, the patient and her parents were concerned about the possibility of malignancy. A total excisional biopsy was thus performed under general anesthesia. Our patient’s lesion was composed of mature bone tissue surrounded by fibrous stroma and lined by normal squamous epithelium. This lesion was regarded as ectopic bone tissue localized far away from the maxilla-mandibular bone, and the histological diagnosis of osseous choristoma was made microscopically (Figure 2). Since the pathological specimen’s preparation required the resected sample’s decalcification, the final diagnosis could not be determined until ~30 days postsurgery, when the histological diagnosis was revealed as osseous choristoma. This waiting period was difficult for the patient and her family. Twelve months postoperatively, no symptoms of recurrence have been observed.Figure 1
Intraoral clinical findings of the 11-year-old female patient. A mass approx. 7 mm in dia. was observed on the posterior dorsum of the tongue. This lesion with no symptoms was diagnosed clinically as a fibroma.Figure 2
Histological findings. (a) Low-power image. A nodule consisting of matured bone surrounded by normal fibrous tissue was observed. Squamous epithelium that covered them is seen. Few inflammatory cells infiltrated into the lesion. Scale bar: 500μm. (b) High-power image. Several osteocytes are observed in the matured bone. The squamous epithelium has no atypia. Scale bar: 50 μm.
(a)(b)


## 3. Discussion

Lingual osseous choristoma is rare among pediatric patients. In this manuscript, we present another pediatric case of lingual osseous choristoma and review the relevant literature.In Japan, most children attend pediatric clinics until the age of ~12 years. Thus, we focused on patients below the age of 13 years with osseous choristoma in our literature search. To our knowledge, in the literature, 62 cases have been described on patients above the age of 13 years (Table1) [1, 3, 6, 8–45]. On the other hand, 16 cases have been described in children below the age of 13 years (Table 2) [1, 2, 4, 6, 31, 44, 46–55]. On the other hand, only one pediatric case with intraoral nonlingual osseous choristoma was found [34]. We could not detect the crucial differences in clinicopathological features between pediatric cases and the others.Table 1
Reports of cases of intraoral osseous choristomas of the tongue on >13-year-old patients.
YearAuthorPathogenesisAge (y)SexLocation on tongueSizeSymptomDurationCourse of discovered eventsDiagnostic imagingPreoperative diagnosisLocal recurrenceFollow-upReference number1950Breckenridge and LukensDevelopmental malformation theory23FRight anterior 2/31 cmØNoneUn.Un.NoneFibromaUn.Un.81956Peimer et al.Developmental malformation theory27FLeft anterior 2/30.7×0.6×0.3cmGagging, foreign body sensation5 monthsUn.NoneFibromaUn.Un.91967Cataldo et al.Developmental malformation theory39FPosterior tongue1 cmØNone4 monthsPhysical examinationNoneUn.Un.Un.101968Jahnke and DalyNot trauma, developmental malformation theory22FPosterior to CP1.3×0.8×0.7cmLump13 yearsAsymptomaticNoneUn.Un.Un.111968Begel et al.Developmental malformation theory22FArea of CP1×0.5cmDysphagia2 yearsSlowly getting biggerNoneFibromaUn.Un.121968KayeUn.26FBase of the tongue1×1cmLumpChildwoodSlowly getting biggerUn.Un.Un.Un.131971Krolls et al.Un.22FAnterior to CP0.75 cmØNone2 yearsUn.NonePapillomaUn.Un.11971Krolls et al.Un.23MArea of CP0.5×0.5×0.5cmUn.Un.Un.NoneHyperplast papillaUn.Un.11971Krolls et al.Un.23MArea of FCUn.Un.Un.Un.NonePapillomaUn.Un.11971Krolls et al.Un.25FPosterior tongue0.5 cmØUn.4 monthsUn.NoneFibromaUn.Un.11971Krolls et al.Un.39MArea of CP0.6×0.6cmNoneUn.Un.NoneHyperplast papillaUn.Un.11971Krolls et al.Un.73MPosterior tongueUn.GaggingSeveral yearsUn.NonePapillomaUn.Un.11971Goldberg et al.Un.65MLateral border1 cmØNoneUn.Un.Un.Un.Un.Un.141975McClendonUn.15FArea of FC1.4×0.6×0.5cmLumpNonePhysical examinationThyroid scan: failed to show ectopic thyroid tissue, a thyroid scintigram: normalLingual thyroidUn.Un.151975McClendonUn.20MPosterior tongue0.7 cmØNoneNonePhysical examinationNoneUn.Un.Un.151976Engel and CherrickDevelopmental malformation theory31MMid third right border2 cmØLump3 yearsOral cavity examinationDental X-PUn.No2 years161979Sugita et al.Un.29FArea of FC0.8×0.8×0.5cmNone12 monthsSlowly getting biggerDental X-PUn.No6 months171981Ohno et al.Un.44MPosterior to FC0.4×0.8×0.5cmUn.6 yearsSlowly getting biggerDental X-PBenign tumorUn.Un.181981Sato et al.Un.14FAnterior to CP0.4 cmØLump4 yearsSlowly getting biggerNoneUn.Un.Un.191982Esguep et al.Developmental malformation theory63FRight border0.5 cmØLumpUn.Un.Un.Un.Un.Un.201983Wasserstein et al.Developmental malformation theory50FMid third1.5×0.75cmLump3 monthsOral cavity examinationNoneUn.Un.Un.211984MainThe posterior tongue: embryological developmentThe anterior tongue: trauma or inflammation54FPosterior to FC1.5 cmØLumpChildwoodUn.NoneUn.No1 month221984SheridanUn.20FAnterior to CP1 cmØLumpFrom birthUn.NoneUn.Un.Un.231984Shimono et al.Not trauma, developmental malformation theory37FArea of FC1.5×1.5×0.7cmLump8 yearsUn.NoneLingual thyroidUn.Un.241984Shimono et al.Not trauma, developmental malformation theory47FPosterior tongue1 cmØLump12 monthsSlowly getting biggerDental X-PBenign tumorUn.Un.241985WeitznerDevelopmental malformation theory25FPosterior tongue0.8×0.4×0.4cmLumpNonePhysical examinationNoneCystNo6 weeks251985WeitznerDevelopmental malformation theory27FPosterior tongue0.8×0.7×0.3cmLumpNonePhysical examinationNoneBenign tumorNo7 weeks251985WeitznerDevelopmental malformation theory52FMid third1×0.6×0.5cmNoneNonePhysical examinationNoneBenign tumorNo2 months251987Markaki et al.Un.25FPosterior to FC0.8×0.4×0.3cmLump5 monthsAsymptomaticThe thyroid gland was normal to palpationUn.Un.Un.261987Tohill et al.Un.26FRight anterior 2/30.9×0.9×0.5cmNoneNoneOral cavity examinationNoneFibromaUn.Un.271987Tohill et al.Un.31FAnterior to CP1×0.8×0.7cmNoneUn.ExaminationNoneLingual thyroid, fibroma, salivary gland neoplasmUn.Un.271987Tohill et al.Un.68MLeft posterior 1/30.7×0.5×0.3cmNone2 yearsOral cavity examinationNonePapillomaUn.Un.271987Van Der Wal and van der WaalDevelopmental malformation theory61FAnterior to CP2 cmØNone15 yearsSlowly getting biggerNoneUn.No2.5 years281988Cannon and NiparkoUn.51FPosterior tongueUn.Lump20 yearsUn.Un.Un.Un.Un.291989Bernard et al.Un.21FArea of FC2 cmØLump12 yearsPhysical examinationCT: densely ossified massUn.NoUn.301993Ishikawa et al.Developmental malformation theory53FArea of FC0.8 cmØForeign body sensation3 daysForeign body sensationNoneBenign tumorNoUn.311996Wei Cheong et al.Developmental malformation theory23FPosterior to FC1.5 cmØUn.13 yearsSlowly getting biggerThe thyroid gland was normal to palpationLingual thyroid, fibromaNo12 months321996ManganaroUn.27MPosterior tongue1.0×0.5cmGaggingUn.Slowly getting biggerNoneUn.Un.Un.331996ManganaroUn.44MPosterior tongue0.7×0.6cmGaggingSeveral monthsSlowly getting biggerNoneUn.Un.Un.331998Lin et al.Not trauma, the posterior tongue: developmental malformation, other site: trauma21FPosterior tongue1.2 cmØLump5 yearsAsymptomaticNoneFibromaNo4 years341998Supiyaphun et al.Un.19FArea of FC1.1×0.7×0.7cmNone11 yearsUn.NoneUn.NoUn.61998Supiyaphun et al.Un.21FArea of FC1.5×1.3×0.8cmLump5 yearsUn.NoneUn.NoUn.61998Supiyaphun et al.Un.22MArea of FC0.9×0.8×0.6cmNoneUn.ExaminationNoneUn.NoUn.61998Supiyaphun et al.Un.25FArea of FC0.7×0.5×0.4cmLump12 monthsUn.NoneUn.NoUn.61998Supiyaphun et al.Un.27FArea of FC1.2×0.9×0.6cmNoneUn.ExaminationNoneUn.NoUn.61998Supiyaphun et al.Un.28FArea of FC1×0.8×0.6cmThroat irritation4 yearsUn.NoneUn.NoUn.61998Supiyaphun et al.Un.35FArea of FC0.7×0.5×0.5cmNoneUn.ExaminationNoneUn.NoUn.61998Vered et al.Un.27MPosterior to CP1×0.5cmPain, gaggingNoneSlowly getting biggerNoneUn.Un.Un.351998Vered et al.Un.44MPosterior to CP0.7×0.6cmGagging, nausea, dysphagiaSeveral monthsUn.NoneUn.Un.Un.352007Benamer and ElmangoushUn.14FMidline posterior 1/31 cmØGaggingMore than ten yearsPainless but slowly getting biggerNoneUn.Un.Un.362007Demirseren and AydinNot trauma28MAnterior 2/32×1.5×1cmGagging4 yearsSlowly getting biggerNonePyogenic granulomaNo48 months372008Andressakis et al.Local trauma from dentures72MArea of CP1.5×1.0cmPain, dysphagiaSeveral yearsAsymptomaticNoneUn.Un.Un.382009Naik et al.Not trauma25FPosterior tongue1.2×1.1×0.5cmLump5 yearsSlowly getting biggerUn.Un.Un.Un.392011Liu et al.Not trauma17MArea of FC0.5×0.5cmLumpSeveral yearsAsymptomaticNoneUn.NoUn.402016Adhikari et al.Not trauma15FArea of FC0.5cmØThroat irritation12 monthsPainless but gradually swellingNoneFibromaNo5 months412016Adhikari et al.Not trauma21FArea of FC0.5 mØPainUn.Oral cavity examinationNoneUn.No48 months412016Turan et al.Un.41FPosterior tongue1×0.5cmThroat irritation6 monthsExaminationUltrasonographic evaluation: normal thyroid glandLingual thyroid, mucocele, lingual thyroglossal duct cystNo4 months422017Heinz et al.Not trauma21FBase of the tongue0.5 cmØLumpUn.AsymptomaticFiberoptic examinationUn.No3 months432020Sun et al.Un.23MBase of the tongue0.8×0.7×0.5cmLumpUn.Un.NoneBenign tumorUn.Un.32020Sun et al.Un.27MBase of the tongue0.8×0.5×0.5cmLump3 monthsUn.NoneBenign tumorUn.Un.32020Leigh et al.Developmental malformation theory37FBase of the tongue0.7×0.4×0.3cmGagging3 monthsPhysical examinationUltrasonographic evaluation: normal thyroid glandUn.No26 months442020Hemmi et al.Not trauma89MBase of the tongue1 cmØCoughUn.Prolonged coughCervical spine CT: well-defined, rounded, high-density massUn.No15 months45CP: circumvallate papillae; FC: foramen caecum; M: male; F: female; CT: computed tomography; Un.: unknown.Table 2
Reports of cases of intraoral osseous choristomas of the tongue on <13-year-old patients.
YearAuthorAge (y)SexLocation on tongueSizeSymptomDurationPathogenesisCourse of discovered eventsDiagnostic imagingPreoperative diagnosisLocal recurrenceFollow-upReference number1964Church11FArea of FC0.5 cmØDysphagiaUn.Un.Slowly getting biggerNoneUn.Un.Un.461971Krolls et al.9FArea of FCUn.Gagging2.5 yearsUn.Un.NoneFibromaUn.Un.11971Krolls et al.11FPosterior tongue2 cmØUn.12 monthsUn.Un.NonePapillomaUn.Un.11977Busuttil8FArea of CPPea-sizedLump9 monthsUn.Slowly getting biggerNoneUn.Un.Un.471986Cabbabe et al.5FBase of the tongue0.6×0.5×0.3cmLump2 yearsNot trauma, developmental malformation theoryAsymptomaticNoneFibromaUn.Un.481992Maqbool et al.8FRight vallecula5×4cmDysphagia, distressUn.Not trauma, developmental malformation theoryUn.Un.Un.Un.Un.491993Ishikawa et al.5FAnterior to CP0.3 → 0.8 cmØLump1-month follow-up: 16 monthsDevelopmental malformation theoryAsymptomaticNoneFibromaNoUn.311993Lutcavage and Fulbright11FArea of FC1 cmØLump12 monthsEnclavement of mesenchymal cellsSlowly getting biggerA thyroid scintigram: normalUn.Un.Un.501998Supiyaphun et al.9FArea of FC0.7×0.6×0.5cmNoneUn.Un.ExaminationNoneUn.NoUn.62001Horn et al.11FPosterior tongueUn.LumpUn.Un.Un.Un.Un.Un.Un.512014Gorini et al.10FArea of FC1 cmØLumpSince the first months of lifeDevelopmental malformation theoryAsymptomaticThyroid scan: failed to show ectopic thyroid tissueUn.No12 months42014Yamamoto et al.11MPosterior to CP0.8×0.6cmDysphagia5 yearsDevelopmental malformation theorySlowly getting biggerMRI: T1 and T2WI (fat saturation): oval no-signal areaPapilla fibromaNo12 months522015Stanford et al.11MBase of the tongue1.1×0.9×0.8cmThroat irritationUn.Un.ExaminationThyroid uptake scan: normalCT: densely calcified lesionUn.Un.Un.532016Davidson et al.11MBase of the tongueUn.Foreign body sensationUn.Un.Slowly getting biggerThyroid scan: failed to show ectopic thyroid tissueCT: a calcified ovoid massUn.Un.Un.22018Yoshimura et al.7FPosterior tongue0.5 cmØ → 0.6 cmØNoneUn.Ectopic bone formation by secretion of BMPsSlowly getting biggerT1- and T2-weighted images: low-signal intensityDermoscopy dental X-P: radiopaque trabeculated massBenign tumorNo36 months542018Macêdo et al.9MPosterior 1/32.3×2.0×0.8cmSymptomatic3 monthsDevelopmental malformation theory associated with adenoidectomyOral cavity examinationCT: pseudotumorUn.No2.5 years552021Present case11FPosterior tongue0.7 cmØLump2–3 yearsDevelopmental malformation theoryOral cavity examinationNonePapillomaNo12 monthsCP: circumvallate papillae; FC: foramen caecum; M: male; F: female; CT: computed tomography; MRI: magnetic resonance imaging; Un.: unknown.We summarized the characteristics of the 17 cases with pediatric lingual osseous choristoma including our case in Table2. Most pediatric patients with lingual osseous choristoma are females (4 males, 13 females). Although these findings are consistent with previous reports [4, 54], we could not identify the reason for the sexual predisposition. The patients’ ages ranged from 5 years to 11 years (mean 9.3 years, median 10 years using Excel function). It has been demonstrated that most of the lesions develop as symptomless 3–50 mm masses located in the tongue’s posterior third in the area of circumvallate papillae or close to the foramen caecum [4, 54]. The findings reported in our manuscript are in line with previous reports. It has been reported that dysphagia, a gapping sensation, pain, vomiting reflex, and nausea are the most frequent symptoms of this condition [4]. Five patients had a history of these symptoms (29.4%). Moreover, a systematic review reported a correlation between these symptoms and lesion size [4]; however, another review concluded that there was no correlation between them [6]. Hemmi et al. reported an adult case of lingual osseous choristoma with prolonged cough. They concluded that the cough was due to gastroesophageal reflux disease. Regarding the correlation in pediatric cases, we could not conclude from only 5 cases (29.4%). To resolve this discordance, it is necessary to recruit more cases [45]. The follow-up period ranged from one year to three years. No evidence of spontaneous loss or malignant transformation has been reported. No case of pediatric lingual osseous choristoma showed any sign of recurrence [7], while only two recurrent nonpediatric cases of the buccal mucosa lesion were reported [56, 57]. Long et al. reported that the recurrent lesion could have arisen as a result of the surgical trauma caused by the removal of the original lesion; however, this theory could not explain the occurrence of the original lesion because the patient denied any history of trauma [56]. Besides, according to Dalkiz et al., lesions do not recur once excised and the recurrent lesion might have been caused by a new fibrotic region that underwent ossification an uncalcified lesion that subsequently ossified [57]. Although the mechanisms of recurrence remain uncertain, cases of extralingual lesions should have a longer follow-up period. Our patient’s clinical findings were consistent with previous reports. Taking into account the fact that our patient was referred from a private dental clinic, not only head and neck clinicians but also dentists should be familiar with the clinical features of this disease.The pathogenesis of osseous choristoma is not yet known, a “developmental malformation hypothesis” and a “chronic trauma-associated reactive hypothesis” were proposed [4, 16, 41, 54, 58]. The involvement of systemic diseases has not been reported. With respect to the former, the lesion arises at the line of fusion of the first and third brachial arches between the anterior two-thirds and posterior one-third of the tongue [41]. Additionally, some researchers indicated that the lingual thyroid remnant ossification is associated with developmental malformation theory due to it occurring at the posterior tongue near the foramen cecum [12, 30]. However, no thyroid tissue was observed in the current case. With respect to the latter, on the other hand, the osseous lesion on the tongue appeared due to a reactive or posttraumatic center of ossification [41]. There were no previous cases that support the reactive hypothesis. In the current case, there was no evidence of irritational factors. Moreover, our patient’s microscopic findings showed no reactive epithelial change, including acanthosis and cell atypia, and little inflammatory cell infiltration and fibrosis were observed. From these clinicopathological features, the “developmental malformation hypothesis” seems likely to apply in this case.Finally, it cannot be overlooked that the 30-day waiting period until the histological diagnosis of the patient’s lesion was stressful for the patient and her family. Although the reason for the long waiting time was the need to decalcify the bone tissue, the psychological care we provided was insufficient. It was speculated that the information provided by imaging modalities can help reduce patients’ anxiety. Diagnostic imaging was conducted in five pediatric cases. Given that no attending surgeons considered the possibility of an osseous choristoma, we did not conduct any imaging examination in this case. An earlier study reported computed tomography (CT) images are useful for the radiological diagnosis of lingual osseous choristoma [45]. Also, Yoshimura et al. reported the usefulness of not only radiographic examination for the surgical specimen. Additionally, they proposed developing a miniaturized, flexible dermoscopy that enabled the detailed examination of the whole oral cavity [54]. However, it is difficult for children to follow instructions when undergoing a CT scan, which often leads to motion artifacts [45]. It is also important to consider the effect of radiation exposure in pediatric patients. Furthermore, a case that occurred in the choroid was diagnosed using ultrasonography [59]; however, there are no reports of ultrasonography being used to diagnose lingual osseous choristoma as it might be difficult to use ultrasonography on the base of the tongue. Therefore, radiographic examination of the surgical specimen might be the most useful tool in the diagnosis of lingual osseous choristoma in pediatric patients.In conclusion, we presented a pediatric case of lingual osseous choristoma and conducted a review of the literature to identify the characteristics of pediatric cases of the lesion.



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