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 Table of Contents  
Year : 2022  |  Volume : 34  |  Issue : 1  |  Page : 66-68

Immune periapical granuloma with Mott cells: Endodontic significance and need for identification

1 Department of Oral Pathology and Microbiology, Bharati Vidyapeeth (Deemed to be University) Dental College and Hospital, Sangli, Maharashtra, India
2 Department of Oral Pathology and Microbiology, Mahatma Gandhi Vidyamandir's Karmaveer Bhaurao Hire Dental College, Nashik, Maharashtra, India
3 Expedent Dental Clinic, Navi Mumbai, Maharashtra, India
4 Department of Oral Pathology and Microbiology, Rural Dental College, Pravara Institute of Medical Sciences, Loni, Maharashtra, India

Date of Submission30-Aug-2021
Date of Decision09-Nov-2021
Date of Acceptance24-Dec-2021
Date of Web Publication25-Mar-2022

Correspondence Address:
Dr. Uma Vasant Datar
Department of Oral Pathology and Microbiology, Bharati Vidyapeeth (Deemed to be University) Dental College and Hospital, Sangli, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/endo.endo_163_21

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Periapical granulomas (PGs) respond well to endodontic treatment. In case of refractory response to the treatment apicectomy and finally, extraction is the treatment of choice. Herein, we present a case of endodontically failed PG with an excessive amount of Mott cells (MCs). MCs are plasma cells with spherical aggregates in their cytoplasm. The extensive accumulation of MCs in a periapical lesion is hitherto underreported and might elucidate the cause of refractory treatment outcomes of certain periapical lesions. The lesion was diagnosed with immune PG with multiple MCs. To the best of our literature search, there have been only two similar reports till date. Additional case reports and long-term follow-up are necessary to understand the nature and significance of such lesions. This article aspires to further the awareness regarding such unique presentation to aid appropriate diagnosis and also highlights the importance of subjecting apicectomy specimen to histopathological examination.

Keywords: Endodontics, histopathological examination, Mott cell, periapical granuloma, Russell bodies

How to cite this article:
Datar UV, Mahajan AM, Chaudhari V, Patil RB. Immune periapical granuloma with Mott cells: Endodontic significance and need for identification. Endodontology 2022;34:66-8

How to cite this URL:
Datar UV, Mahajan AM, Chaudhari V, Patil RB. Immune periapical granuloma with Mott cells: Endodontic significance and need for identification. Endodontology [serial online] 2022 [cited 2022 May 23];34:66-8. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/1/66/340832

  Introduction Top

Nonsurgical endodontic treatment is often the treatment of choice for nonhealing or persistent Periapical granulomas (PGs).[1],[2] PG are histologically of two types, nonimmune granulomas, which predominantly show macrophages and giant cells, and immune granulomas that are rich in lymphocytes and plasma cells.[3] Mott cells (MCs) are plasma cells that produce large amounts of immunoglobulin, which are contained mainly in large vesicles.[3] Russell body (RBs) are eosinophilic, multiple, variable-sized, spherical inclusions of immunoglobulins within the MCs.[4],[5] MCs are observed in various pulpitis,[6],[7] chronic inflammatory lesions,[7],[8],[9] and benign and malignant neoplasms.[5],[10] Abundant MCs are noted in malignancies like plasmacytoma/multiple myeloma,[10] which may occur in the periapical region. However, till date, to the best of our knowledge, only two cases of abundant MCs in periapical lesions have been reported.[3],[8] Their presence in abundant numbers in the periapical area is not only perplexing but also a plausible indication of refractory treatment outcome in certain periapical lesions. Herein, we report a rare case of PG rich in MCs with emphasis on its histopathological features, differential diagnosis and treatment outcome.

  Case Report Top

A 35-year-old female presented with a complaint of pain and swelling in the anterior region of the upper jaw. Intraoral examination revealed a discrete swelling in relation to maxillary right central and lateral incisors and a draining sinus in relation to maxillary right central incisor. The patient had undergone root canal treatment for the same tooth elsewhere 3 years ago. On the intraoral periapical radiograph, it was evident that incisors were endodontically treated and a diffuse, ill circumscribed radiolucency of two centimeters in diameter was noted in relation to the root of the maxillary right central incisor [Figure 1]. Patient's medical history and general physical examination were noncontributory. Provisional diagnosis of the radicular cyst was considered. On the patient's request, the tooth was extracted and the tissue was sent for histopathological examination. On microscopic examination, loosely arranged fibrocellular connective tissue stroma with the fibrous wall in the periphery was noted. Diffuse dense chronic inflammatory cell infiltrates rich in plasma cells and numerous MCs showing Russell bodies (RBs) and few mitotic figures were noted [Figure 2]. Variation in the size and number of RBs within the (MCs) was noted. To rule out malignancy, immune histochemical analysis was done using kappa and lambda light chain [Figure 3]. The plasma cells and MCs showed positivity for both and kappa: lamda ratio was approximately 2:1, thus suggesting their polyclonality and reactive nature of the lesion ruling out malignancy. The lesion was diagnosed with immune PG with multiple MCs.
Figure 1: Intraoral periapical radiograph showing unilocular radiolucency associated with root apex of maxillary right central incisor

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Figure 2: (a) Sheets of plasma cells and dispersed Mott cells (H and E, ×40). (b) Arrowhead pointing at Mott cell containing multiple variable sized RBs (H and E, ×40). (c) Mott cell at higher magnification (H and E, ×100). (d) Illustration showing immune profile of Mott cell

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Figure 3: (a) Mott cells showing strong immunoreactivity for kappa light chain. (b). Mott cells showing immune-reactivity for lambda light chain (×40)

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  Discussion Top

MCs have acquired their name from F. W. Mott, who first identified these cells. He called these cells as Morular cells (from the Latin morus meaning, mulberry) and identified them to be plasma cells.[5] RBs present within MCs are believed to be the result of cellular indigestion in the endoplasmic reticulum. RBs represent mutated immunoglobulin which are neither secreted nor degraded, resulting in excessive accumulation of immunoglobulins in the endoplasmic reticulum, thus greatly distending it and manifesting as homogenous eosinophilic inclusions.[5] Researchers have also put forth a possible role of type I proinflammatory cytokines in the over-production of immunoglobulins in pulp and periapical areas.[9] Moreover finally, the root canal microorganisms have been implicated to trigger the overproduction of RB in plasma cells of periapical lesions.[9] Subsequently, it may be presumed that MCs are aberrant responses to a certain antigenic stimulus. The exuberant host immune response to an elusive stimulant and subsequent accumulation of immunoglobulin might be the reason why few PGs are refractory to nonsurgical endodontic treatment. Nonhealing lesions can be treated with or without surgery, but surgical endodontic treatment will marginally have better treatment outcomes in such lesions.[11],[12]

In the present case, clinical and radiographic findings were indicative of a periapical lesion. Histopathological findings were also supportive of the same. However, striking features noted were sheets of mature plasma cells, few lymphocytes, and other inflammatory cells. In addition, abundant, evenly dispersed MCs were noted throughout the lesional tissue. These features indicated the possibility of plasmacytoma which are known to occur periapically.[10] Mature plasma cells of plasmacytoma are monoclonal and show kappa or lambda chain restriction. In the present case, immune-expression of both kappa and lambda chain by the plasma cells ruled out plasmacytoma, in addition, the ratio of kappa-positive cells to lambda-positive cells was studied to confirm the reactive nature of the lesion. Moreover, destructive infiltrative growth, nuclear atypia, pleomorphism, and mitotic activity, which are hallmarks of malignancy, were lacking.

Over-diagnosing these lesions as malignancy should be avoided, especially in the absence of other clinical or histological indicators of malignancy. Immunohistochemical markers may be beneficial. MCs show expression for CD11b, CD43, CD5, CS45, CD138, CD78 and kappa and gamma [Figure 2]d.[5],[8],[9]

Till date, two cases[3],[8] of abundant MCs accumulation in periapical lesions have been reported. The age of the patients was nineteen and twenty-four and the patients were female and male, respectively.[3],[8] In both cases, the lesion was reported in the maxillary anterior region, similar to the present case. Interesting finding was that both the lesions had a history of trauma. In both cases, the lesion was excised, but the details about the fate of the involved teeth are not available.[3],[8] Due to the paucity of literature, it is unclear whether the occurrence of MCs in the periapical lesion is a chance finding or indicative of chronicity of the lesion or an altered immune response.

  Conclusion Top

The actual occurrence of MT-rich periapical lesions is obscure since not all the surgically removed tissues are sent for histopathological examination. Hence, this case highlights the necessity of subjecting all surgically removed tissue from the periapical lesions to histopathological examination. Moreover, if these cases are unique; it remains to be seen whether their clinical outcomes different than other PG and if endodontic treatment with periapical surgery is remedial in such cases. The significance of their occurrence, their nature and the diagnostic implication is unexplored and warrants further research.

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 name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Karamifar K, Tondari A, Saghiri MA. Endodontic periapical lesion: An overview on the etiology, diagnosis and current treatment modalities. Eur Endod J 2020;5:54-67.  Back to cited text no. 1
Alghamdi F, Alhaddad AJ, Abuzinadah S. Healing of periapical lesions after surgical endodontic retreatment: A systematic review. Cureus 2020;12:e6916.  Back to cited text no. 2
Shreelatha S, Karnaker VK, Nair S. Mott cells: The herculean plasma cell. J Clin Diagn Res 2019;13:EJ01-2.  Back to cited text no. 3
Bain BJ. Russell bodies and Mott cells. Am J Hematol 2009;84:516.  Back to cited text no. 4
Bavle RM. Bizzare plasma cell – Mott cell. J Oral Maxillofac Pathol 2013;17:2-3.  Back to cited text no. 5
[PUBMED]  [Full text]  
Tagger E, Tagger M, Sarnat H. Russell bodies in the pulp of a primary tooth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;90:365-8.  Back to cited text no. 6
Giardino L, Savoldi E, Pontieri F, Berutti E. Russell bodies in dental pulp of permanent human teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;98:760-4.  Back to cited text no. 7
Arora M, Desai K, Mane D. Multiple Mott cells in periapical lesion of the oral cavity. J Coll Physicians Surg Pak 2017;27:373-5.  Back to cited text no. 8
Dos Santos JN, Ramos EA, Gurgel CA, Barros AC, de Freitas AC, Crusoé-Rebello IM. Russell body apical periodontitis: An unusual case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:903-8.  Back to cited text no. 9
Radhika MB, Thambiah LJ, Paremala K, Sudhakara M. Multiple myeloma: Periapical location can challenge diagnostic skills. J Int Clin Dent Res Organ 2010;2:49-54.  Back to cited text no. 10
  [Full text]  
Del Fabbro M, Corbella S, Sequeira-Byron P, Tsesis I, Rosen E, Lolato A, et al. Endodontic procedures for retreatment of periapical lesions. Cochrane Database Syst Rev 2016;10:CD005511.  Back to cited text no. 11
Karunakaran JV, Abraham CS, Karthik AK, Jayaprakash N. Successful nonsurgical management of periapical lesions of endodontic origin: A conservative orthograde approach. J Pharm Bioallied Sci 2017;9 Suppl 1:S246-51.  Back to cited text no. 12


  [Figure 1], [Figure 2], [Figure 3]


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