Indian Journal of Pathology and Microbiology

: 2018  |  Volume : 61  |  Issue : 2  |  Page : 239--241

Pindborg tumor: Pathology with special stains

Swati Shrikant Gotmare, Treville Pereira, Subraj Shetty, Kashmira S Kesarkar 
 Department of Oral and Maxillofacial Pathology and Microbiology, D Y Patil University School of Dentistry, Navi Mumbai, Maharashtra, India

Correspondence Address:
Swati Shrikant Gotmare
Department of Oral and Maxillofacial Pathology and Microbiology, D Y Patil University School of Dentistry, Sector 7, Nerul, Navi Mumbai - 400 706, Maharashtra


Odontogenic tumors constitute a wide spectrum of lesions ranging from malignant and benign neoplasms to dental hamartomas, all derived from the epithelial and ectomesenchymal remnants of the tooth forming apparatus. Calcifying epithelial odontogenic tumor (CEOT) is an uncommon, benign epithelial odontogenic tumor first described by Pindborg in 1956. It is a universally accepted eponym for this neoplasm. Pindborg tumor or CEOT is a locally aggressive neoplasm that accounts for 1% of the total odontogenic tumors, with recurrence in 14% of cases. The etiology of this tumor remains an enigma to the clinician. Pindborg suggested that the tumor arises from the remnants of reduced enamel epithelium of an unerupted tooth. Recent studies in literature report that the tumor arises from stratum intermedium. We report a case of Pindborg tumor in a 22-year-old male patient in the left mandibular posterior region. Radiographically, a well-defined radiolucency was associated with unerupted mandibular second molar which was displaced to the inferior border of the mandible. Along with routine haematoxylin and eosin stains, this case reports histopathological findings using Congo red stain and modified Gallegos stain.

How to cite this article:
Gotmare SS, Pereira T, Shetty S, Kesarkar KS. Pindborg tumor: Pathology with special stains.Indian J Pathol Microbiol 2018;61:239-241

How to cite this URL:
Gotmare SS, Pereira T, Shetty S, Kesarkar KS. Pindborg tumor: Pathology with special stains. Indian J Pathol Microbiol [serial online] 2018 [cited 2021 Nov 27 ];61:239-241
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Full Text


Pindborg tumor, also known as calcifying epithelial odontogenic tumor (CEOT), is a rare and unusual epithelial benign odontogenic neoplasm, accounts for 1% of all odontogenic tumors. This neoplasm affects individuals in fourth-to-fifth decades of life and shows no gender predilection. Clinically presents as a slow-growing, painless expansile hard bony swelling, associated mostly with an impacted tooth in the posterior mandibular region.[1] The etiology of this tumor is disputatious. Literature reveals that it arises from the epithelial remnants from enamel organ, but whether reduced enamel epithelium, stratum intermedium, or dental lamina remnants are involved in the etiology still remains an enigma.[2] CEOT, according to the clinical presentation and histopathology is differentiated as central or intraosseous (87.8%), peripheral or extraosseous (6.1%), or as a hybrid tumor in combination with adenomatoid odontogenic tumor (AOT). This neoplasm has the tendency to recur, as recurrence occurs in 15% of the cases.[3]

 Case Report

A 22-year-old male presented with a chief complaint of swelling in the lower left posterior region for 5–6 months. On examination, intraorally, a small swelling in the left retromolar area was observed [Figure 1]a. On palpation, the swelling was firm in consistency and nontender. Radiographically, a well-defined radiolucency was seen on the left side, extending from 35 to 38 region anteroposteriorly and from the alveolar crest to inferior border of the mandible involving inferior alveolar nerve canal. The inferior border of the mandible appears to be intact and continuous, 36 remains to be supraerupted and 37 is displaced to the inferior border of the ramus [Figure 1]b. The provisional diagnosis was ameloblastoma, AOT, and dentigerous cyst. An incisional biopsy was performed and the histopathological report revealed sheets and cords of polyhedral epithelial cells with abundant eosinophilic cytoplasm. The cellular outlines were distinct with prominent intercellular bridges. Nuclei were large and hyperchromatic. Areas of extracellular, eosinophilic, and amyloid-like material with occasional concentric calcifications called as Liesegang rings were also evident [Figure 2]a and [Figure 2]b. Congo red stain showed apple-green birefringence under polarized microscopy [Figure 2]c and modified Gallegos stain, which stained red for the calcifications when seen under microscope [Figure 2]d. On the basis of histopathological report, the final diagnosis given was CEOT.{Figure 1}{Figure 2}


The Pindborg tumor (CEOT) was first reported by Pindborg in 1955, also referred as unusual ameloblastoma by Tuy, cystic odontoma by Stoppack, and Adenoid adamantoblastoma by Thoma.[2] Although the etiology remains uncertain, literature suggests that the epithelial cells of Pindborg tumor are remnants of sequestered material in the stratum intermedium layer of the enamel organ. This is based on the ideology that the tumor cells are morphologically similar to the cells of stratum intermedium and shows a high activity of alkaline phosphatase and adenosine triphosphate. Literature also states that the amyloid deposits within the Pindborg tumor are an immunologic response to these stratum intermedium cells. Some authors state that it arises from the remnants of dental lamina which are more likely to be the true progenitor cell.[4] Our case was rare as it was observed in the second decade of life, compared with the age listed in literature, as most of the cases occurred with the mean age of 40 years.[5] Pindborg reported 2 clinicopathological variants: intraosseous (central) and extraosseous variant (peripheral) with an incidence of 96% and 4%, respectively. According to his observations, the central tumors are derived from stratum intermedium of enamel organ in comparison to the extraosseous form which arises from the dental lamina.[6] Histopathologically, CEOT consists of large sheets, islands, cords, rows, and strands of polyhedral epithelial cells with a scanty connective tissue stroma. The cells show distinct cellular outline, with prominent intercellular bridges and abundant eosinophilic granular cytoplasm. Moderate degree of pleomorphism and rare atypical mitosis may be noticed in these neoplastic cells. These neoplastic cells show centrally located pleomorphic, hyperchromatic, and bizarre nuclei, which often show large nucleolus. The characteristic findings of this tumor are the presence of rounded pale, eosinophilic amyloid-like masses within the sheets of tumor cells. Because of its affinity with mineral salt, this material can undergo calcification leading to the concentric lamellar bodies termed as Liesegang rings. Large pools of homogeneous eosinophilic material may be noticed in the surrounding tissue along with diffusely deposited calcium salts in some areas. This amyloid-like material appears as an apple-green birefringence under polarized microscope when stained with Congo red.[2],[7] Several variants of this tumor are the clear cells, Langerhans cells, bone and cementum-like component, and myoepithelial cells. Combined lesions of CEOT with ameloblastoma and AOT are also documented in literature.[8] The present case showed characteristic histopathologic features of CEOT, such as large sheets and islands composed of epithelial cells with a scanty, loose fibrous connective tissue stroma. The epithelial sheets were composed of polyhedral tumor cells with an eosinophilic cytoplasm with large dense hyperchromatic nuclei. The epithelial cells were compactly arranged and showed intercellular bridges. The homogeneous eosinophilic globular masses were observed majorly in the epithelium resulting in a cribriform appearance. Liesegang's rings were also evident. Various researchers analyzed the amyloid material and stated that its derivation still remains a mystery like its etiology. These studies conclude that a degenerative process involving cytokeratin intermediate filaments in tumor cells is responsible for amyloid degeneration, while others concluded that it involves degeneration of type IV collagen associated with basement membrane.[8],[9] The present case, when subjected to Congo red stain, amyloid deposits appeared as bright orange-to-red hue, while when exposed to polarize light, it demonstrated birefringence to distinctive green-yellow color described as apple green. In addition, we performed modified Gallegos stain, which differentiates histochemically hard tissue structures of the oral cavity, in which the enamel stains pink, dentine and bone stains green, and cementum stains red.[10] In our case, we found that amyloid-stained pink, while the calcifications and Liesegang's rings stained pinkish blue. This is in favor of various theories put forward by the researchers in the literature that the amyloid derives from the epithelial cells of the odontogenic apparatus.[8]


CEOT is a rare benign odontogenic tumor. The diagnosis of which can be confirmed by its classic histopathological features. However, the exact nature of the tumor and the pathogenesis is obscure till date.

Declaration of patient consent

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

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Conflicts of interest

There are no conflicts of interest.


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