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Year : 2021  |  Volume : 64  |  Issue : 1  |  Page : 197-199
Oral lipoma with HPV-16 associated koilocytic epithelium: Expect the unexpected


Department of Oral Pathology and Microbiology, Faculty of Dental Sciences, MS Ramaiah University of Applied Sciences, MSR Nagar, Bengaluru, Karnataka, India

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Date of Submission09-May-2020
Date of Decision17-Jun-2020
Date of Acceptance30-Jun-2020
Date of Web Publication8-Jan-2021
 

How to cite this article:
Augustine D, Rao RS, Thirtha V. Oral lipoma with HPV-16 associated koilocytic epithelium: Expect the unexpected. Indian J Pathol Microbiol 2021;64:197-9

How to cite this URL:
Augustine D, Rao RS, Thirtha V. Oral lipoma with HPV-16 associated koilocytic epithelium: Expect the unexpected. Indian J Pathol Microbiol [serial online] 2021 [cited 2021 Apr 22];64:197-9. Available from: https://www.ijpmonline.org/text.asp?2021/64/1/197/306522




A 57-year-old male presented with an asymptomatic swelling in the right buccal mucosa, 1 cm away from the corner of the mouth for the past 20 years. On clinical examination the swelling was well circumscribed, oval in shape, pink in colour, sessile, smooth in texture, and soft in consistency, it measured 1.0 × 0.5 cm and had remained stable for the past 20 years. The patient's medical history was insignificant. The mass was excised in toto under aseptic conditions.

Pathologic examination by routine haematoxylin and eosin stain revealed a well encapsulated lesion surrounded by fibrous connective tissue and lined by a surface hyper parakeratotic stratified squamous epithelium [Figure 1]a and [Figure 1]b, [Figure 1]a was captured using a Slide Scanner Optimus 6T, Morphle Technologies Pvt Ltd, Bangalore, India, as the size of the tissue section did not permit photomicrography under the scanner view of a conventional microscope. The lesional cells were composed of mature adipocytes in a lobular pattern with peripherally placed nucleus separated by collagenous septae and blood vessels [Figure 1]c. A final diagnosis of lipoma was established.
Figure 1: Haematoxylin and eosin stain. (a) (2× Scanner view) well encapsulated lesion surrounded by fibrous connective tissue. (b) (20×) Surface hyper parakeratotic stratified squamous epithelium with vacuolated cells and underlying adipose tissue. (c) (20×) Mature adipocytes in a lobular pattern with peripherally placed nucleus separated by collagenous septae. (d) (20×) Epithelium with vacuolated cells (arrow) resembling koilocytes. (e) (40×) Squamous epithelial cells with peripherally placed condensed pyknotic nuclei (arrow). (f) (40×) Squamous epithelial cells with perinuclear clear spaces and eccentrically placed pyknotic nuclei (arrow)

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A striking feature observed was the koilocytic epithelium surrounding the lipoid tissue. The squamous epithelial cells presented with features of nuclear enlargement, coarse chromatin and irregular nuclear membranes [Figure 1]d and [Figure 1]e. Cells with perinuclear spaces and vacuolations were present resembling halo cells [Figure 1]f. A subsequent special staining by Papanicolaou (PAP) showed the condensed nuclei as dark pink crescent shaped structures [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]f.
Figure 2: PAP stain. (a) (10×) Surface epithelium with underlying lipomatous lesion. (b) (20×) Hyper parakeratotic stratified squamous epithelium with vacuolated cells. (c) (40×) Koilocytes exhibiting a signet ring appearance with dark blue eccentrically placed nucleus (arrow). (d) (40×) Koilocytes with perinuclear halo (arrow). (e) (40×) Squamous epithelial cells with peripherally placed condensed pyknotic nuclei (arrow). (f) (40×) Koilocytes showing bluish-pink crescent shaped nuclei (arrow)

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The koilocytosis was indicative of a Human Papilloma Virus infection (HPV) infection. The findings were further validated by immunohistochemistry (IHC) using antibody to HPV-16. Intense and diffuse nuclear and cytoplasmic staining for p16 was observed at the basal and suprabasal layers confirming the presence of HPV infection associated with an intra-oral lipoma making this case a first of its kind [Figure 3]a, [Figure 3]b, [Figure 3]c, [Figure 3]d, [Figure 3]e. Another unique finding following IHC was the presence of p16 nuclear staining in the lipoma tissue as well [Figure 3]f.
Figure 3: IHC Stain – Antibody to p16. (a) (10×) Stratified squamous epithelium with mild p16 nuclear positivity of basal cells (arrow). (b) (20×) Squamous epithelium with moderate p16 nuclear positivity of basal and suprabasal cells (arrow). (c) (20×) Squamous epithelium with intense p16 nuclear positivity of basal cells. (d) (20×) Section of squamous epithelium with p16 positive koilocytes. (e) (20×) Koilocytes with crescent shaped nuclei showing strong p16 positivity (arrow). (f) (20×) Adipocytes with p16 nuclear positivity (arrow)

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The association of Koilocytes in epithelium of benign mesenchymal lesions is extremely rare, and has been reported only once till date. PP Argyris et al., in 2014, reported the first known case of an oral fibroma associated with HPV induced koilocytic dysplasia.[1]The koilocytic epithelium noted in the present case of lipoma is of particular interest as this feature has not yet been reported or observed in either an extraoral or intraoral lipoma till date, as per our knowledge.

Lipomas are benign soft tissue tumors that rarely occur in the oral cavity. It has an incidence rate of about 1-4% of all benign oral lesions, with a prevalence rate of 0.0002%.[2]They manifest as asymptomatic, slow-growing, sessile, round-to-ovoid submucosal nodules. The lipoma is composed predominantly of mature adipocytes, possibly admixed with collagenic streaks, and is often well demarcated from the surrounding connective tissues. A thin fibrous capsule may be seen and a distinct lobular pattern may be present.[3]

Koilocytes are HPV altered epithelial cells, they contain a condensed pyknotic, hyperchromatic nucleus that is eccentrically displaced by a perinuclear vacuole. A rim of condensed cytoplasm surrounds the perinuclear cavitation, giving the cell a “halo” or cleared-out appearance around the dysplastic nucleus.[4]With the PAP stain, the condensed cytoplasm of the Koilocytes can be pink, blue, or both.[5]IHC is a diagnostic tool that can indicate the presence of HPV DNA in the tissue by p16 staining.

Koilocytosis is an indicator of HPV infection, it is important to determine the presence of low risk or high-risk HPV subtypes in a particular lesion, as high-risk HPV subtypes have a potential to cause malignant transformation of otherwise normal epithelium.[6]

The clinical significance of this report is to emphasize that persistent HPV infection is a pre-requisite for malignant transformation of koilocytic cells that are preneoplastic in nature.[7]Oral HPV has been detected in oral squamous cell carcinoma and it is believed that HPV is involved in oral carcinogenesis by transforming the keratinocytes through a mechanism involving E6 and E7 proteins.[8]

HPV infection is usually contracted during adolescent years. HPV infection may be suppressed and kept subclinical for years, an immunocompetent person can also eliminate it.[9],[10] It is difficult to ascertain in the current case reported whether the patient was a HPV carrier or had contracted a recent HPV infection. However, regular follow-up of the current case is mandatory to monitor the appearance of new potentially malignant disorders. The current case reports the first evidence of koilocytic epithelium associated with a lipoma, validated by IHC using p16 antibody.

Acknowledgment

The authors thank Mr. Rohit Hiwale (Co-founder and CEO) & Mr. Anchit Navelkar (Co-founder and CTO) from Morphle Technologies Pvt Ltd, Bangalore, India for providing the slide scanner for photomicrography.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Argyris PP, Koutlas IG. Oral fibroma with HPV-associated epithelial dysplasia: Even in fibromas you should look for the unexpected Int J Surg Pathol 2014;22:248-9.  Back to cited text no. 1
    
2.
Devi AN, Sowbhagya MB, Balaji P, Mahesh Kumar TS. An uncommon case of fibrolipoma. Indian J Dent Res 2017;28:699-701.  Back to cited text no. 2
[PUBMED]  [Full text]  
3.
Sekar B, Augustine D, Murali S. Lipoma, a rare intraoral tumor – A case report with review of literature. Oral Max Path J 2011;2:174-7.  Back to cited text no. 3
    
4.
Singh P, Sowmya SV, Rao RS, Augustine D, Haragannavar VC, Nambiar S. Koilocytes in oral pathologies. World J Dent 2018;9:149-53.  Back to cited text no. 4
    
5.
Jeronimo J, Massad LS, Schiffman M, National Institutes of Health/American Society for Colposcopy and Cervical Pathology (NIH/ASCCP) Research Group. Visual appearance of the uterine cervix: Correlation with human papillomavirus detection and type. Am J Obstet Gynecol 2007;197:47.e1-8.  Back to cited text no. 5
    
6.
Krishnappa P, Mohamad IB, Lin YJ, Barua A. Expression of P16 in high-risk human papillomavirus related lesions of the uterine cervix in a government hospital, Malaysia. Diagn Pathol 2014;9:202.  Back to cited text no. 6
    
7.
Hajdu SI. The link between koilocytes and human papillomaviruses. Ann Clin Lab Sci 2006;36:485-7.  Back to cited text no. 7
    
8.
Kim SM. Human papilloma virus in oral cancer. J Korean Assoc Oral Maxillofac Surg 2016;42:327-36.  Back to cited text no. 8
    
9.
Holder N, Ahmed N, Cabral MD. Human papillomavirus infection in adolescents. Pediatr Med 2019;2:46.  Back to cited text no. 9
    
10.
Best SR, Niparko KJ, Pai SI. Biology of human papillomavirus infection and immune therapy for HPV-related head and neck cancers. Otolaryngol Clin North Am 2012;45:807-22.  Back to cited text no. 10
    

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Correspondence Address:
Dominic Augustine
Department of Oral Pathology and Microbiology, Faculty of Dental Sciences, MS Ramaiah University of Applied Sciences, MSR Nagar, Bengaluru - 560 054, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/IJPM.IJPM_511_20

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