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Year : 2016  |  Volume : 7  |  Issue : 2  |  Page : 111-113

Mural calcifications in keratocystic odontogenic tumor: Report of a case with a brief review

Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut, Uttar Pradesh, India

Date of Web Publication19-May-2016

Correspondence Address:
Suhasini Gotur Palakshappa
Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut - 250 002, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0976-433X.182668

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Hard tissue deposits or mineralization in the wall of the keratocystic odontogenic tumor (KCOT) are infrequent and unusual. They are usually of dystrophic calcification or cartilage type, and dentinoid formation, although reported, is a rare phenomenon. Here, a rare case of extensive mural calcifications in the wall of the KCOT involving maxillary premolar-molar area, in a 14-year-old boy is described. These calcifications were found to be dentinoid, confirmed with the use of special stains.

Keywords: Dentinoid, keratocystic odontogenic tumor, maxillary, mural

How to cite this article:
Palakshappa SG, Wadhwan V, Sharma P, Bansal V. Mural calcifications in keratocystic odontogenic tumor: Report of a case with a brief review. SRM J Res Dent Sci 2016;7:111-3

How to cite this URL:
Palakshappa SG, Wadhwan V, Sharma P, Bansal V. Mural calcifications in keratocystic odontogenic tumor: Report of a case with a brief review. SRM J Res Dent Sci [serial online] 2016 [cited 2022 May 23];7:111-3. Available from:

  Introduction Top

The term “odontogenic keratocyst” was used for the first time by Philipsen in 1956, defining an odontogenic cyst with parakeratinized epithelial surface, which is now designated by the World Health Organization as a keratocystic odontogenic tumor (KCOT).[1] Hard tissue deposits, namely dystrophic calcifications and cartilage, although rare, are reported in the wall of the KCOT. However, the formation of dentinoid in the KCOT wall represents an extremely rare phenomenon.[2]

Here, we report a case of maxillary KCOT with dentinoid formation, with a brief review of different calcifications seen in KCOT wall and insight into probable pathogenesis and differential diagnosis of these calcifications.

  Case Report Top

A 14-year-old boy reported with the chief complaint of swelling in his upper right back teeth region since several months, associated with mild pain. Extraoral examination revealed a diffuse swelling on the right middle third of the face. Intraorally, the swelling was extending from the first premolar to the second molar, causing vestibular obliteration [Figure 1]a. Panoramic radiograph revealed a well-defined multilocular radiolucency extending from the first premolar, distal to the second molar [Figure 1]b. The aspirate of the lesion revealed a thick, yellowish white cheesy material [Figure 1]c. Provisional diagnosis of KCOT was made, and incisional biopsy specimen was submitted for histopathological examination.
Figure 1: (a) Intraoral photograph showing swelling distal to maxillary first premolar, with vestibular obliteration. (b) Panoramic radiograph showing a well-defined, multilocular radiolucency in the maxillary posterior region. (c) Aspirate from the lesion revealing a thick, yellowish white cheesy material

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Examination of the H and E sections revealed a cystic cavity filled with keratin, lined by 5–8 cell layers thick, corrugated parakeratinized stratified squamous epithelium with hyperchromatic nuclei and polarized basal cells. At areas orthokeratinized stratified squamous epithelium with a prominent granular layer was also found. At this area, the basal layer was composed of cuboidal or flattened cells, and no palisaded or polarized nuclei were seen. Separation of the epithelium from the underlying connective tissue was often found. Fibrous connective tissue capsule showed infiltration by chronic inflammatory cells and cholesterol clefts associated with hemorrhagic areas. Some areas of the connective tissue wall showed diffusely spread irregular eosinophilic masses, with evidence of tubule formation and basophilic calcospherite-type mineralization, along with irregular and needle-like structures [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d. These masses stained positive for minerals (von Kossa stain) [Figure 3], for collagen (Masson's trichrome and Van Gieson) [Figure 4]a and [Figure 4]b but were negative for amyloid (Congo red), keratin (Mallory's trichrome), and fungal elements (periodic acid-Schiff stain). On the basis of these findings, a diagnosis of infected KCOT with dentinoid-like calcifications was made.
Figure 2: (a) Photomicrograph showing corrugated, parakeratinized epithelium, suggestive of keratocystic odontogenic tumor, separated from the underlying connective tissue capsule showing calcifications (shown with arrow) (H and E, ×4). (b) Photomicrograph showing extensive mural calcification and cholesterol clefts associated with hemorrhagic areas (H and E, ×4). (c) Photomicrographs showing calcospherulite-type mineralization at a higher magnification (H and E, ×40). (d) Photomicrographs showing calcospherulite-type mineralization at a higher magnification (H and E, ×100)

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Figure 3: Photomicrograph showing mineral deposits in capsule of keratocystic odontogenic tumor (von Kossa - ×40)

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Figure 4: (a) Photomicrograph showing mural calcification in keratocystic odontogenic tumor stained in blue color (Masson's trichrome ×40). (b) Photomicrograph showing mural calcification in keratocystic odontogenic tumor stained in red color (Van Geison ×40)

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  Discussion Top

Hard tissue formation in KCOT capsule is an unusual finding, with highest incidence (4.5–16.8%) of dystrophic calcifications.[2] The cartilaginous and hyaline (Rushton) bodies (undergoing calcification) are also reported.[3] The exact pathogenic mechanism of dystrophic calcification is unknown, although necrobiosis or a foreign body reaction resulting in degeneration has been suggested. Furthermore, high incidence of crystalline calcium phosphates, hydroxyapatite, and whitlockite, and inorganic phosphates was found in the aspirated fluid of the KCOT, which may be responsible for the higher frequency of calcium deposits in the walls of these lesions.[2],[3],[4] It was speculated that in other soft tissue microenvironments, namely the dermis, dystrophic calcification occurs in a homogeneous matrix produced by preexisting structures such as sweat glands, nevus cells, or even degranulation of mast cells.[3],[4] None of these cellular structures were observed in the current case. The presence of a chondroma, persistence and displacement of vestigial remains of cartilage, a possible metaplastic change of the fibrous connective tissue in response to chronic irritation, a possible induction of the cyst wall by the epithelial lining, and/or trapped glycosaminoglycans are implicated in the presence of cartilaginous tissue in KCOT wall. The inductive effect of the odontogenic epithelial component is favored explanation of dentin or dentinoid material.[2],[3],[4] Nevertheless, in the present case, no odontogenic rests were found near the dentinoid material. Metaplasia can be regarded as another probable explanation for the presence of these calcifications.[2],[3],[4] Gardener and Sapp in their ultrastructural study of the calcifications reported diffuse calcifications which form in the collagenous matrix to be dentinoid.[5] The significance of calcification in the behavior of KCOT is not clear.

Mural calcification in the form of dentinoid, which can occur as irregular eosinophilic masses with tubule formation or calcospherulite-like mineralization in KCOT, is extremely unusual. On English literature search, only three case reports [2],[3],[4] were found, with similar histological findings, the current case being fourth.

Regarding the differential diagnosis of KCOT with dentinoid-like calcification, other odontogenic cysts and tumors that commonly present with dentinoid-like calcification would be considered. The calcifying odontogenic cyst, odontoma, ameloblastic fibro-odontoma, central odontogenic fibroma, and adenomatoid odontogenic tumor [3] were the principal lesions considered here, which were excluded based on the absence of the characteristic histological findings in the above-mentioned conditions.

The histologic, histochemical data from the reported case conform to that in the literature.[3]

  Conclusion Top

A rare case of mural calcification in KCOT is presented here. Due to the lack of large series of reported cases of KCOT with dentinoid, whether hard tissues in these lesions should be regarded as a metaplastic process, or represent a true inductive effect is still to be clarified and ultrastructural studies are needed for better understanding of this rare phenomenon.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Madras J, Lapointe H. Keratocystic odontogenic tumour: Reclassification of the odontogenic keratocyst from cyst to tumour. J Can Dent Assoc 2008;74:165.  Back to cited text no. 1
Naveen F, Tippu SR, Girish K, Kalra M, Desai V. Maxillary keratocystic odontogenic tumor with calcifications: A review and case report. J Oral Maxillofac Pathol 2011;15:295-8.  Back to cited text no. 2
[PUBMED]  Medknow Journal  
Ng KH, Siar CH. Odontogenic keratocyst with dentinoid formation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;95:601-6.  Back to cited text no. 3
Shetty P, Srilatha SV. Keratocystic odontogenic tumor with mural calcification: A case report. South Asian J Cancer 2013;2:208.  Back to cited text no. 4
[PUBMED]  Medknow Journal  
Sapp JP, Gardner DG. An ultrastructural study of the calcifications in calcifying odontogenic cysts and odontomas. Oral Surg Oral Med Oral Pathol 1977;44:754-66.  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

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