Letter to the Editor

Sclerosing odontogenic carcinomapin_2749 75..76

To the Editor:We were intrigued by the recent letter to the editor by Ideet al.1 The authors had previously introduced a case ofprimary intraosseous squamous cell carcinoma (PIOSCC)2

as sclerosing odontogenic carcinoma (SOC). After reviewingthis letter to the editor, we believe that there are some majorissues regarding their arguments. Our points of concern areas follows.

First, in this letter to the editor and the previous report ofPIOSCC,2 they did not provide sufficient evidence or reason-ing to support their claim that this lesion was a carcinoma.Although the authors presented figures (eg fig. 2a) in theirletter to the editor1 that demonstrate the invasion of ‘perivas-cular tissue’ by this tumor, which was composed of basaloidcells reminiscent of Malassez’ epithelial rests (as describedin a previous report of PIOSCC), the major evidence of malig-nancy is still lacking because it is known that even benignodontogenic tumors such as intraosseous ameloblastomaexhibit infiltration of surrounding structures (e.g. mandibulartumors invade the perineural tissue of the inferior alveolarnerve).1 Thus, in the first case report of SOC,3 the authors’claims that malignancy of SOC was based on the invasion ofskeletal muscle (not the invasion of ‘perivascular tissue’ inthe connective tissue that was located close to the tumormass), and perineural invasion (not the invasion of ‘perineu-ral tissue’), may not be valid, and more conclusive evidenceof malignancy is needed.

Second, it was not appropriate that the authors had previ-ously reported this case as PIOSCC. Because the authorshad earlier described that this tumor lacked a mature squa-mous phenotype in their previous report,2 based on the cri-teria of the 2001 Armed Forces Institute of Pathology (AFIP)publication4 and 2005 WHO classification,5 such a tumorwithout any conventional squamous cell carcinoma compo-nent should not have been diagnosed as PIOSCC or primaryintraosseous carcinoma (PIOC); the authors should havediagnosed this tumor as ‘malignant odontogenic tumor’ or‘odontogenic carcinoma’ during the initial diagnosis.

Third, there was no description about the immunohis-tochemical analysis neither in this letter to the editor1 nor in theprevious report of PIOSCC.2 In order to support their claim thatthis tumor was SOC, the immunohistochemical results of p63,CK5/6, CK7, CK8/18, CK19, CK20, MIB-1, S-100, SMA, etc.,which have all been previously demonstrated as useful differ-ential diagnostic markers of SOC,3,6 should have been pre-sented as images for diagnosis of exclusion.

Fourth, the authors claimed that they found two possiblecases of SOC with benign fibro-osseous lesion (BFOL). Inone of the papers cited by the authors from Jones et al.7 nodefinite finding of malignancy in the odontogenic epitheliumwas presented in the histopathological figure, nor did theyoffer any description about malignancy of this lesion. Theauthors should have clarified how to evaluate the basis ofmalignancy of the odontogenic epithelium in the case pre-sented by Jones et al. which was compatible with SOC,based on the descriptions and figure in the paper. Moreover,in another paper cited by the authors from Bennett et al.8 thepresented figures were only that of newly formed bone tra-beculae, islands of epithelium, and typical conventionalsquamous cell carcinoma. The authors should have givenmore objective reasoning as to why they believed that thiscase of odontogenic squamous cell carcinoma with osseousmetaplasia was similar to SOC on the basis of such fewfigures, whose findings were not sufficient enough to supportthe authors’ claims. Furthermore, in the previous report ofSOC,3,6 no definite component of conventional squamous cellcarcinoma was observed in the SOC. The authors shouldhave provided strict descriptions on how to distinguish SOCfrom different odontogenic tumors (e.g. central odontogenicfibroma, ameloblastic carcinoma, clear cell odontogenic car-cinoma, primary intraosseous carcinoma, etc.) based on thedescriptions and figures in the papers of Jones et al.7 andBennett et al.8 According to the issues described above, theauthors’ various and numerous speculations based on theprevious reports of two possible cases of SOC should nothave been presented in this letter to the editor.

Tarou Irié,1,5 Ikuko Ogawa,2 Takashi Takata,3

Satoru Toyosawa,4 Tomohide Isobe,1 Chie Hokazono,1

Tetsuhiko Tachikawa1 and Yoshio Suzuki51Department of Oral Pathology, Showa University

School of Dentistry, Tokyo, 2Center of Oral ClinicalExamination, Hiroshima University Hospital, Hiroshima,

3Department of Oral and Maxillofacial Pathobiology,Graduate School of Biomedical Sciences, Hiroshima

University, Hiroshima, 4Department of Oral Pathology,Osaka University Graduate School of Dentistry, Osaka,and 5Department of Pathology, Asahi General Hospital,

Chiba, Japan

REFERENCES

1 Ide F, Kikuchi K, Kusama K. Sclerosing odontogenic carcinoma.Pathol Int 2011; 61: 259–61.

Pathology International 2012; 62: 75–76 doi:10.1111/j.1440-1827.2011.02749.x

© 2011 The AuthorsPathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd

2 Ide F, Mishima K, Saito I, Kusama K. Diagnostically challengingepithelial odontogenic tumors: A selective review of 7 jawbonelesions. Head Neck Pathol 2009; 3: 18–26.

3 Koutlas IG, Allen CM, Warnock GR, Manivel JC. Sclerosingodontogenic carcinoma: A previously unreported variant of alocally aggressive odontogenic neoplasm without apparent meta-static potential. Am J Surg Pathol 2008; 32: 1613–9.

4 Sciubba JJ, Fantasia JE, Kahn LB. Atras of Tumor Pathology.Tumor and Cysts of the Jaw. Washington, DC: Armed ForcesInstitute of Pathology, 2001; 129–31.

5 Eversole LR, Siar CH, van der Waal I. Primary intraosseoussquamous cell carcinoma. In: Barnes L, Eveson JW, Reichart P,

Sidransky D, eds. World Health Organization Classification ofTumor. Pathology and Genetics of Head and Neck Tumor. Lyon:IARC Press, 2005; 290–1.

6 Irié T, Ogawa I, Takata T et al. Sclerosing odontogenic carcinomawith benign fibro-osseous lesion of the mandible: An extremelyrare case report. Pathol Int 2010; 60: 694–700.

7 Jones GM, Eveson JW, Shepherd JP. Central odontogenicfibroma. A report of two controversial cases illustrating diagnosticdilemmas. Br J Oral Maxillofac Surg 1989; 27: 406–11.

8 Bennett JH, Jones J, Speight PM. Odontogenic squamous cellcarcinoma with osseous metaplasia. J Oral Pathol Med 1993; 22:286–8.

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© 2011 The AuthorsPathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd