Journal of Oral and Maxillofacial Radiology

REVIEW ARTICLE
Year
: 2020  |  Volume : 8  |  Issue : 2  |  Page : 30--35

“CALCIFIC ISLANDS:” A cone-beam computed tomography review of soft-tissue calcifications in head-and-neck region


Ajay Parihar1, Arushi Shastri1, Arvind Jain2, Ashish Saxena3, Amit Rawat4, Mamta Singh5,  
1 Department of Oral Medicine and Radiology, Index Institute of Dental Sciences, Indore, MP, India
2 Department of Endodontics and Conservative Dentistry, Index Institute of Dental Sciences, Indore, MP, India
3 Department of Pedodontics and Preventive Dentistry, Index Institute of Dental Sciences, Indore, MP, India
4 Department of Oral Medicine and Radiology, Government College of Dentistry, Index Institute of Dental Sciences, Indore, MP, India
5 Department of Oral and Maxillofacial Surgery, Index Institute of Dental Sciences, Indore, MP, India

Correspondence Address:
Ajay Parihar
Department of Oral Medicine and Radiology, Government College of Dentistry, Indore, Madhya Pradesh
India

Abstract

Soft-tissue calcification of the head-and-neck region is now commonly seen because of the advent and increased usage of cone-beam computed tomography (CBCT) in dentistry. The purpose of this study is to construe the radiographic characteristics in CBCT of the soft-tissue calcifications in the head-and-neck region. The soft-tissue calcifications of the head-and-neck region may arise from pathological mineralization by deposition of calcium phosphate essentially in an unorganized manner known as “heterotopic calcification.” The three types of heterotopic calcifications are dystrophic calcifications, metastatic calcifications, and idiopathic calcifications (calcinosis). These calcifications can include sialoliths, calcified lymph nodes, carotid artery calcifications, and many more which present themselves with different radiographic presentations. These calcifications can be detected by different two-dimensional and three-dimensional imaging techniques, among which CBCT proves to be the best radiographic tool in most of the cases. The anatomic location, number, distribution, pattern, and size of calcifications are important interpretative criteria in radiographic evaluation of soft-tissue calcifications. Soft-tissue calcifications though usually asymptomatic are quite common in the head-and-neck region. An apt radiographic imaging aids in reaching up to the precise diagnosis which may enhance their approach and management by clinicians.



How to cite this article:
Parihar A, Shastri A, Jain A, Saxena A, Rawat A, Singh M. “CALCIFIC ISLANDS:” A cone-beam computed tomography review of soft-tissue calcifications in head-and-neck region.J Oral Maxillofac Radiol 2020;8:30-35


How to cite this URL:
Parihar A, Shastri A, Jain A, Saxena A, Rawat A, Singh M. “CALCIFIC ISLANDS:” A cone-beam computed tomography review of soft-tissue calcifications in head-and-neck region. J Oral Maxillofac Radiol [serial online] 2020 [cited 2020 Nov 27 ];8:30-35
Available from: https://www.joomr.org/text.asp?2020/8/2/30/297221


Full Text



 Introduction



The soft-tissue calcifications of the head-and-neck region may arise from physiological or pathological mineralization by deposition of calcium phosphate essentially in an unorganized manner known as heterotopic calcification. The three types of heterotopic calcifications are dystrophic calcifications, metastatic calcifications, and idiopathic calcifications (calcinosis).[1] According to Kirsch, physiological mineralization is restricted to specific sites in skeletal tissues, including growth plate cartilage, bones, and teeth, while the uncontrolled or pathological mineralization can occur in any soft tissue including articular cartilage, blood vessels, and ligaments.[2] According to Shroff and Shanahan, while the skeletal mineralization is a complex physiological process involving a well-balanced interplay between stimulatory and inhibitory components induced by well-timed developmental cues, an active cell-mediated process resulting from imbalance between the promoters and inhibitors of mineralization induced by dysregulated and inappropriate environmental cues leads to pathological soft-tissue calcifications.[3] The heterotropic calcification occurs when calcium salts are deposited in an unorganized fashion in soft tissue.[4]

 Pathogenesis of Soft-Tissue Calcifications



The soft-tissue calcifications can be subdivided into three major classes: dystrophic, metastatic, and idiopathic calcifications.

 Significance of Radiography



Soft-tissue calcifications are usually asymptomatic and inevident clinically and are detected incidentally on radiographs only being taken for some other provisional diagnoses or routine radiographic examinations. Furthermore, some of these calcifications (especially dystrophic) may suggest the presence of a systemic condition and represent a manifestation of more potentially ominous sequelae.[5] A thorough knowledge and understanding of anatomy of the head-and-neck region and radiographic appearances of various normal and pathologic structures is, therefore, essential and will aid the dental clinician in the early diagnosis.

 Conventional Radiography and Soft-Tissue Calcification of Head-And-Neck Region



Soft-tissue calcifications have usually been identified on panoramic radiographs owing to their greater coverage and higher frequency of use. However, this conventional method of radiography possesses two major drawbacks; one, many of the structures in the head-and-neck region are in close proximity to one another which makes localization and identification difficult. Two, detection and confirmation is complicated on conventional extraoral dental images by the fact that these radiographic images are planar and provide a two-dimensional (2D) representation of a three-dimensional (3D) object. This potentially results in both false-positive and false-negative detection of various calcifications on conventional images.[5]

 Cone-Beam Computed Tomography and Calcifications of Head-And-Neck Region



Cone-beam computed tomography (CBCT) is a newer added and important imaging tool in dentistry. It is cost-effective, time-saving, reduced and lesser radiation exposure, and user-friendly in comparison to medical computed tomography or any other ionizing radiographic technique. Its dentistry-driven software gives better 3D reconstructed images. CBCT provides 3D and multiple viewing modalities and increases the frequency and probability of detection of calcified masses. We shall be considering the conventional and CBCT views of each type of calcification in the following text to establish the fact.

 Interpretative Criteria



The following are the interpretative criteria in radiographic evaluation of soft-tissue opacities:

Anatomic locationNumberDistributionPattern of calcification or appearanceSize of the calcification.[4]

 Classification of Soft-Tissue Calcifications



Dystrophic calcifications

General dystrophic calcifications of oral regionLymph node calcificationsTonsilolithsArterial calcifications

Monckeberg's medial calcification (arteriosclerosis)Intimal calcifications (atherosclerosis)

Cysticercosis

Metastatic calcifications

Calcified stylohyoid ligamentOsteoma cutisMyositis ossificans

Idiopathic calcifications

SialolithsPhlebolithsLaryngeal cartilage calcificationTriticeous cartilage calcificationThyroid cartilage calcificationAntrolithsRhinoliths.

 General Dystrophic Calcifications of Oral Region



General dystrophic calcifications are the precipitations of calcium salts in the primary sites of chronic inflammation or dead and dying tissues, especially the chronically inflamed cysts. Common anatomic locations are gingiva, tongue, lymph nodes, and cheek. They can be single or multiple in number. Their distribution is usually in long-standing chronically inflamed cysts. Their appearance is fine grainy to larger irregular homogeneous or heterogeneous masses. Their size rarely exceeds 0.5 cm in diameter, and the best suitable radiographic tool for dystrophic calcifications is CBCT [Figure 1].{Figure 1}

 Lymph Node Calcifications



Lymph nodes in the head-and-neck region usually calcify after chronic inflammation or posttreatment for lymphomas. These lymph nodes usually enlarge during inflammatory processes. Subsequently, the nodes become fibrous, and foci of calcification start to develop.[4] Tuberculous lymphadenitis (scrofula) is probably the most prevalent disease process associated with dystrophic calcification of sclerotic nodes.[6] Submandibular, submental, and cervical lymph nodes[5] are the common anatomic locations. These calcifications can be single or multiple[5] in number and distribute in the region of involved lymph node or along the course of a nodal chain (lymph node chaining) [Figure 2]. Calcification is in the form of radiopacities with irregular borders showing cauliflower-like[5] pattern without a certainly defined size range.{Figure 2}

 Tonsiloliths



Tonsillar calcifications are oropharyngeal concretions formed as sequelae of chronic tonsillitis where residual long-standing inflammation can serve as the nidus for dystrophic calcification.[5] Other school of thought suggests stasis of saliva in the efferent ducts of the accessory salivary gland, secondary to mechanical obstruction arising from posttonsillectomy scars or chronic inflammation[4] as the etiologic factor. The common anatomic locations are tonsils – mid-ramus or lateral oropharyngeal region.[4] The histologic distribution is as follows: tonsillar tissue (69.7%), tonsillar fossa (21.2%), and palate (9%).[5] They can be single or multiple (more often) in number appearing in cluster of multiple rice grain-like[5] small radiopacities. They can be few millimeters to several centimeters[5] in size. CBCT appears to be the best suitable radiographic tool.

 Arterial Calcifications



Monckeberg's medial calcification or arteriosclerosis

Fragmentation, degeneration, and eventual loss of elastic fibers followed by deposition of the calcium salts in the medial layer of an artery[4] present in the form of arteriosclerosis. The common anatomic location is facial artery. The distribution of usually single lesion is along with the outlines of the affected artery [Figure 3]-4].[4] The pattern of calcification is in the form of parallel radiopaque lines exhibiting tram-track appearance.[4] Size is not certainly defined, and CBCT proves to be the best suitable radiographic tool.{Figure 3}

Intimal calcification or atherosclerosis

Atherosclerosis occurs by deposition of calcium in the atheromatous plaques within the intima of the arteries. The common anatomic location is carotid artery bifurcation (between the levels of C3 and C4).[4] These calcifications are usually multiple in number with vertical linear distribution. They appear as heterogeneous, irregular, well-demarcated radiopacities in soft tissues of the upper neck.[4] Their size is not certainly defined. These can be detected both by conventional (cephalometric and panoramic) radiography and CBCT.

A recent study found that arteriosclerosis (63.41%) and calcified atherosclerotic plaques (45.29%) are the most common soft-tissue calcifications. Women have been found to show greater percentage of carotid artery calcifications, especially after menopause as the protective effect of female hormones is then absent.[7]

 Calcified Stylohyoid Ligament



Another commonly calcified structure in the head-and-neck region is the stylohyoid ligament that usually occurs bilaterally and extends downward from the skull base.[4] One theory states that degeneration of the ligament with deposition of calcium salts in the fibrous tissue accounts for the calcification of stylohyoid ligament [Figure 5].[5] The other theory suggests that direct ossification of cartilaginous cells (of Reichert's cartilage) remaining in the ligament in patients of adult age contributes. They appear as single or multiple segments of calcifications distributed from the styloid process of the temporal bone inferiorly to the hyoid bone. They appear as heterogeneous, irregular, and well-demarcated radiopacities in soft tissues of the upper neck.[4] The size is variable. The best suitable radiographic tool is conventional (panoramic or any other extraoral) radiography being cheaper and sufficient in detecting the intended.{Figure 5}

 Osteoma Cutis



This rare soft-tissue calcification appears when there is normal bone formation in abnormal locations that develop secondary to chronic acne or dermatosis scar. Cheek, lips, and tongue are the common anatomic locations. They are single or multiple in number and diffuse in their distribution. They appear as tiny doughnut-shaped radiopacities with radiolucent centers that represent central marrow cavities [Figure 6].[4] Their size range is 0.1 mm–5 cm. CBCT is the best suitable radiographic tool for their diagnosis.{Figure 6}

 Sialoliths



Sialoliths are calcareous deposits in the salivary glands formed by precipitation of calcium salts around a central nidus that may consist of desquamated epithelial cells, bacterial debris, foreign body, or mucus plug.[4] Salivary stones occur most commonly in the submandibular glands (80%–90%), followed by the parotid (5%–15%) and sublingual (2%–5%) glands, and only very rarely occur in the minor salivary glands.[8] Usually, single in number sialolith (this demarcates them from lymph node calcifications of the same anatomic area which are usually multiple) appears inside the gland or the duct of the involved salivary gland [Figure 7]. Sialoliths often are homogeneously radiopaque and show evidence of multiple layers of calcification (laminated appearance).[4] Sialoliths are usually up to 1 cm in size, while occasional giant ones of up to 3 cm[9] can be seen. Sialogram is the best radiographic tool for the detection of sialoliths.{Figure 7}

 Phleboliths



Intravascular thrombi associated with hemangioma and venolymphatic malformations may get organized and mineralized forming phleboliths. The common anatomic locations are masseter and buccinator muscle regions.[10] They are usually several to dozens in number. Their distribution is diffuse [Figure 8]. They appear as round or ovoid calcified bodies with concentric calcific rings similar to section of an onion or may present bull's eye or target appearance. Their size varies with time. Both conventional radiography and CBCT are suitable radiographic tools for phleboliths.{Figure 8}

 Antroliths



Deposition of mineral salts around a central endogenous nidus leads to the formation of calcified mass in the maxillary sinus. The common anatomic location is maxillary sinus. Antroliths can be single or multiple in number. They are usually distributed just above the floor of the sinus. The appearance of antroliths may be round to ovoid and irregular, ragged, or smooth in outline. Their size range is not certain. Conventional radiographs (periapical, occlusal, and panoramic) are the best suited radiographic tools for antroliths.

 Rhinoliths



Deposition of mineral salts around a central exogenous foreign body leads to the formation of calcified mass in the nasal fossa [Figure 9]. Their common anatomic location is nasal cavity, near maxillary sinus. Rhinolith is usually single in number. Rhinoliths appear as homogeneous or heterogeneous radiopacities with varied shapes and sizes and smooth or irregular borders. Their size is variable.{Figure 9}

 Conclusion



Soft-tissue calcifications are quite common in the head-and-neck region which are usually discovered incidentally but symptomatic in certain cases and may or may not require intervention. An apt radiographic imaging technique and thorough knowledge of the anatomy aids in reaching up to the precise diagnosis which may enhance their approach and management by clinicians. Furthermore, as health-care costs continue to rise, avoiding unnecessary and unjustified diagnostic tests and referrals is a welcome consequence of an increase in the understanding of the nature of soft-tissue calcifications in the head and neck.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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