synchronous oral squamous cell carcinoma and ameloblastoma

- 170 -

Taiwan J Oral Maxillofac Surg 台灣口外誌

Introduction

Ameloblastoma is a common odontogenic

tumor in the jaw. It can be divided into

subgroups according to di f ferent cl inical

features or microscopic patterns. Although

most o f ameloblastomas exhib i t speci f ic

odontogenic features by hematoxylin and

eosin (H&E) histopathological examination,

there are cases that have been misdiagnosed

in the first set of biopsy.1-3 Simultaneous or

chronological occurrence of malignant neoplasm

Synchronous Oral Squamous Cell Carcinoma and Ameloblastoma in a Patient and Using CK8

Expression as An Aid to Differential Diagnosis — Case Analysis

Ya-Wei Chen*, Wing-Ying Li** and Shou-Yen Kao*

* Oral & Maxillofacial Surgery, Department of Stomatology, Taipei Veterans General Hospital,

Taipei, Taiwan, R.O.C.

** Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.

Abstract

We report a case of double oral tumor in two nearby location of the oral cavity. The patient was transferred from a local hospital where the diagnosis of squamous cell carcinoma of both lesions was made. The patient was received the operation in our hospital and surprisingly, the final pathological diagnosis disclosed simultaneous occurrence of oral squamous cell carcinoma (OSCC) and acanthomatous ameloblastoma. We found this case was easily misinterpreted diagnosed if the pathologist is not expert at oral pathology and the pathological examination was made merely by plain H&E stain. To clearly define different histological characteristics between the two lesions, immunohistochemistry (IHC) was applied. It showed different expression of cytokeratin 8 (CK8) in the two lesions. Further CK8 staining in other 20 cases of ameloblastomas and 15 cases of OSCC affirm the finding that ameloblastomas were strong to moderately immunoreactive to CK8 while OSCC were not. Our finding suggests that CK8 may be helpful in distinguishing ambiguous ameloblastomas from OSCC.

Key words: ameloblastoma, cytokeratin 8, oral squamous cell carcinoma.

Taiwan J Oral Maxillofac Surg19: 170-178, September 2008 台灣口外誌

- 171 -

台灣口外誌 Using CK8 Expression as An Aid to Differential Diagnosis ─ Case Analysis

and ameloblastoma in the oral cavity is rare,

but this has been reported.1-6 The following

case report descr ibed the s imul taneous

occurrence of a squamous cell carcinoma (SCC)

and an acanthomatous ameloblastoma in two

nearby regions—the tongue and the gingiva.

Immunohistochemistry (IHC) was employed by

our pathologists in order to clearly identify the

different characteristics of the two lesions. It was

found that cytokeratin 8 (CK8) immunoreactivity

were totally different in these two lesions. Further

CK8 immunostaining was performed in the other

20 cases of ameloblastomas and 15 cases of

OSCC and the result confirmed this finding. The

case drew our attention because it was at first

misdiagnosed pathologically as SCC at another

hospital, and such misdiagnosis could lead to

inappropriate therapies. In such circumstances,

we showed that CK8 IHC is helpful for differential

diagnosis between the ameloblastomas and the

squamous cell carcinomas.

Case Report

A 43-year-old male presented to our

hospital with the chief complaint of pain and

chronic wound over the right side border of the

tongue and also a progressively growing mass

over the right lower gingiva. The problem began

2 months prior to the admission. He has visited

another hospital 1 week before and biopsy was

done there. The pathological diagnosis was SCC

in the tongue and the gingiva. He was then

referred to our hospital for therapeutic treatment.

The patient was a healthy-looking man whose

medical history and general physical examination

were unremarkable. Oral examination disclosed a

2 × 1 cm ulcerative tumor on the right side border

of tongue and a 1 × 1 cm papillomatous lesion

with a bulging buccal plate over the right lower

gingiva. Computed tomography (CT) revealed a 3

× 2 cm ill-defined, heterogeneous mass with bony

destruction over the right side parasymphysis

region of mandible. The lesion over the tongue

was not depicted clearly on CT images; neither

was significant neck lymphadenopathy (Figure 1).

Under general anesthesia, resection of the

tongue lesion and the papillomatous lesion at

lower gingival was performed. The specimens

were sent to our pathologist for diagnosis. At the

microscopic level, the tumor of the tongue showed

a picture of moderately differentiated SCC.

The tumor of the lower gingiva was dominated

by acanthomatous type of ameloblastoma and

exhibited cystic degeneration in the squamous

components (Figure 2). The pattern might confuse

acanthomatous ameloblastoma with SCC if the

pathologist is not familiar with the oral pathology.

Further special stains were performed to study

the histological features of the two lesions.

We found different expression of CK8 between

OSCC and acanthomatous ameloblastoma by

immunohistochemistry. The ameloblastoma had

strong to moderate CK8 immunoreactivity and

the OSCC are negative for CK8 (Figure 3).

Two weeks later, a marginal mandibulectomy

was performed under the diagnosis of ameloblas-

toma in the right lower gingiva. After the surgery,

the patient kept regular outpatient follow-up in

our hospital and no tumor recurrence was found

in 5 years.

Material & Method

Surgical specimens were collected from

21 ameloblastomas and 16 oral squamous cell

carcinomas (OSCC) including the present case.

All tissue specimens were harvested from the

- 172 -


Fig. 1. Head and neck computed tomography scan of the patient. A heterogeneous soft-tissue mass

about 3 × 2 cm over the right side paramedian mandible with bone destruction was noted.

Fig. 2. Section of the two tumors with hematoxylin

and eosin staining in the patient (a)

squamous cell carcinoma of the tongue

(or ig ina l magn i f i ca t ion x 200) ; (b )

ameloblastoma of the gingiva and mandible

(original magnification x 100); and (c)

acanthomatous region of the ameloblastoma

(original magnification x 200).

- 173 -


patients treated in Taipei-Veterans General

Hospital between year 2001 and 2006. The

clinicopathological features including age, gender,

site, and subtypes of ameloblastomas were

recorded (Table 1).

All samples were fixed by formalin and

embedded in paraffin. They were sectioned

into 3 μm in width and mounted on slides

(Muto-glass, silane coating micro slides). The

immunohistochemical detection of cytokeratin

8 (CK8) was carried out using immunodetection

kit manufactured by Becton Dickinson. All the

sectioned slides were incubated for 60 min in a

heat bath at 60 Celsius degree, deparaffinized

in xylene and re-hydrated by immersion in a

graded series of ethanol dilutions. They were

immersed in 10 mM sodium citrate solution,

in a microwave oven, to retrieve antigenicity.

Sections were quenched with 3% fresh H2O2 for

10 min to inhibit endogenous tissue peroxidase

activity, and rinsed with 1x phosphate-buffered

saline (PBS) for 5 min twice. They were further

incubated in blocking serum for 30 min and then

for 33 minutes with prediluted anti-cytokeratin

8 (CAM5.2) in a humid chamber. After washing

with 1x PBS for 5 min twice, sections were then

incubated with biotinylated secondary antibody

solution for 30 min. LAB-SA_streptavidin-

Avidin-Biotin detection reagent (Zymed, South

San Francisco, CA, USA) was subsequently

added evenly over the sections and incubated for

30 min. The sections were washed with 1x PBS

for 5 min twice, incubated with freshly prepared

3,3’-Diaminobenzidine tetrahydrochloride

(Zymed, South San Francisco, CA, USA)

substrate solution for 15 min and then washed

with 1x PBS. All IHC staining was performed

at room temperature. The sections were finally

counterstained with hematoxylin, washed with 1x

PBS and deionized distilled water, dehydrated,

washed, and then mounted. An identical section

without the addition of the primary antibody

was processed in the same manner as a negative

control. The extent of immunoreactivity was

Fig. 3. Representative pictures of the results of immunohistochemical staining with CK8 in the patient

(a) squmaous cell carcinoma over the tongue shows grossly negative CK8 immunoreactivity; and

(b) the epithelial components of the ameloblastoma shows strong CK8 immunoreactivity. (original

magnification x 400).

- 174 -


Table 1. Clinicopathological features including age, gender, site, the pathology and the IHC

results in the 20 ameloblastomas and the 15 oral squamous cell carcinomas treated in

Taipei-Veterans General Hospital between year 2001 and 2006.

- 175 -


scored based on the percentage of positively

stained tumor cells found in each tissue section.

Cell content >75% was considered strong positive

(+++), 30-75% was considered moderate positive

(++), 10-29% was considered weak positive (+),

0-9% was considered negative (-).

Results

Excluding the current case, there was totally

twenty patients with primary ameloblastoma

examined, with age ranging from 12 to 78 years.

The ratio of males and females was 15 to 5. Four

of the tumors were in maxilla and 16 in mandible.

The histological subtypes of ameloblastomas

included plexiform pattern (n = 8), acanthomatous

pattern (n = 6), follicular pattern (n = 5), and

mixed plexiform and follicular pattern (n = 1). All

the specimens of ameloblastomas had strong to

moderate CK8 immunoreactivity and the 15 cases

of OSCC are negative for CK8 immunostaining

(Table 1 and Fig 3).

Discussion

Odontogenic tumors are neoplasms of jaws

derived from epithelial and / or ectomesenchymal

elements of the tooth-forming apparatus.

Ameloblastomas are one of the most prevalent

odontogenic tumors with the incidence ratio of

22.7~69.8%.7-9 They are tumors of odontogenic

epithelium with multiple microscopic subtypes,

such as follicular, plexiform, acanthomatous,

granular cell, and basal cell pattern. Although

these odontogenic tumors have particular

histological characteristics, it is not uncommon

for them to be misdiagnosed by pathologists

who are not familiar with oral pathology. For

ameloblastomas that do not show the obvious

characteristic features of dental epithelium

or when they are predominated by squamous

component with invasive growth pattern,

the diagnosis is sometimes dif f icult. This

is particularly eminent for acanthomatous

ameloblastoma since squamous metaplasia may be

present.10

In this article, we present a case of simul-

taneous occurrence of OSCC and acanthomatous

ameloblastoma which was at first diagnosed as

SCC both in other hospital. For the proximity of

the two lesions and the provisional diagnosis, it

would be possible that someone who took over

the case would follow the misinterpreted diagnosis

and perform a commando surgery for the patient.

Actually, the clinical appearance of the

papillomatous lesion on the right lower buccal

gingival was quite different from the ulcerative

tumor over the right tongue border. The lesion

on the tongue was small and could not be

depicted clearly on CT image. The lesion on the

right side mandible was larger and present with

bone destruction. To be cautious, we performed a

tumor resection on the tongue lesion and biopsy

on the papillary tumor of right mandible. The

histopathological diagnosis were finally confirmed

by a series of special stains that the two tumors

were totally different. Based on the diagnosis,

a definite treatment for the ameloblastoma was

performed by marginal mandibulectomy. No

further neck dissection was administered because

the SCC over the tongue was only on stage T1.

The result showed that immunohistochemical

(IHC) staining may be useful in differential

diagnosis of odontogenic tumors and SCC

by cytokeratin expression. The subsets of

cytokeratins which an epithelial cell expresses

are related to the type of epithelium, the moment

in the process of terminal differentiation and

- 176 -


the stage of development. Immunohistochemical

expression of cytokeratins in odontogenic

epithelium or neoplasms has been studied

before. Cytokeratin (CK)14, a basal cell type of

cytokeratin, was expressed in all cells of dental

germs and reduced epithelium of the enamel

organ but not in preameloblasts and secreting

ameloblasts. Cytokeratin7 was expressed in the

cells of the Hertwig root sheath and the stellate

reticulum. It was also found that cytokeratin13

was expressed in the dental lamina and stellate-

like structure in the ameloblastoma.11 Fukumashi

et al12 reported that different kinds of cytokeratin

have positive immunoreactions in different

histological patterns of ameloblastomas. But only

cytokeratin8 (CK8) reacted constantly to the

constituting cells in all types of ameloblastomas.

CK8 belongs to type B subfamily of high-

molecular-weight keratins and is primarily

found in non-squamous epithelium or secretory

epithelium of human tissue. The CK8 antibody

(CAM5.2) stains most ectodermal-derived tissue,

including liver and renal tubular epithelium. Thus

it can be used for diagnosis of hepatocellular

carcinoma and renal cell carcinomas. In this

case, CK8 IHC can differentiate the SCC at the

tongue from ameloblastoma at the gingiva in the

same patient. The same protocols were used

to study the other 20 ameloblastomas and 15

OSCC, and the results showed consistency that

ameloblastomas were immunoreactivity to CK8

while OSCC were not.

Conclusion

This report presented a case of two

synchronous tumor with different diagnosis. It is

therefore important to carefully diagnose each

of the tumors in such circumstances. Using CK8

IHC we can differentiate ambiguous amelobla-

stoma from OSCC.

References

1. Nishimura T, Nagakura R, Ikeda A, Kita

S. Simultaneous occurrence of a squamous

cell carcinoma and an ameloblastoma in the

maxilla. J Oral Maxillofac Surg 58: 1297-

1300, 2000.

2. Tucker MR, Dechamplain RW, Jarrett JH.

Simultaneous occurrence of an ameloblastoma

and a squamous cell carcinoma of the

mandible. J Oral Maxillofac Surg 42: 127-

130, 1984.

3. Nakamura N, Higuch i Y, Tash i ro H,

Shiratsuchi Y. Mandibular ameloblastoma

associated with salivary gland tumor. Int J

Oral Maxillofac Surg 17: 103-105, 1988.

4. Ueta E, Yoneda K, Ohno A, Osaki T.

Intraosseous carcinoma arising from mandi-

bular ameloblastoma with progressive

invasion and pulmonary metastasis. Int J Oral

Maxillofac Surg 25: 370-372, 1996.

5. Ide F, Shimoyama T, Horie N, Shimizu S.

Intraosseous squamous cell carcinoma arising

in association with a squamous odontogenic

tumour of the mandible. Oral Oncol 35: 431-

434, 1999.

6. Baden E, Doyle JL, Petriella V. Malignant

transformation of peripheral ameloblastoma.

Oral Surg Oral Med Oral Pathol 75: 214-219.

1993.

7. Jing W, Xuan M, Lin Y, Wu L, Liu L, Zheng

X, Tang W, Qiao J, Tian W. Odontogenic

tumours: a retrospective study of 1642 cases

in a Chinese population. Int J Oral Maxillofac

Surg 36: 20-25. 2007.

8. Ledesma-Montes C, Mosqueda-Taylor A,

- 177 -


Carlos-Bregni R, de Leon ER, Palma-Guzman

JM, Paez-Valencia C, Meneses-Garcia A.

Ameloblastomas: a regional Latin-American

multicentric study. Oral Dis 13: 303-307,

2007.

9. Okada H, Yamamoto H, Tilakaratne WM.

Odontogenic tumors in Sri Lanka: analysis of

226 cases. J Oral Maxillofac Surg 65: 875-

882, 2007.

10. Velez I, Siegel MA. Head and neck diagnostic

challenge. N Y State Dent J 70: 22-23, 2004.

11. Crivelini MM, de Araujo VC, de Sousa SO,

de Araujo NS. Cytokeratins in epithelia of

odontogenic neoplasms. Oral Dis 9: 1-6,

2003.

12. Fukumash i K , Enok i y a Y , I noue T .

Cytokeratins expression of constituting cells

in ameloblastoma. Bull Tokyo Dent Coll 43:

13-21, 2002.

- 178 -


Received: May 5, 2008Accepted: June 28, 2008Reprint requests to: Dr. Ya-Wei Chen, Dr. Shou-Yen Kao, Chair, Oral & Maxillofacial Surgery,

Department of Dentistry, Taipei Veterans General Hospital, No 201, Sec 2, Shih-Pai

Road, Taipei, Taiwan 11217.

利用CK8免疫螢光染色鑑別診斷同時發生的

造釉細胞瘤及口腔鱗狀細胞癌–病例分析

陳雅薇*　李永賢**　高壽延*

* 台北榮民總醫院口腔醫學部口腔顎面外科

** 台北榮民總醫院病理科

摘　　要

在本文之病例報告中，描述發生於口腔鄰近但不同部位之雙發腫瘤

(double tumors)。病患原先是在另一家醫院就診，被診斷是口腔鱗狀細胞

癌。至本院進行手術後，才發現是兩個不同的腫瘤—口腔鱗狀細胞癌及棘狀

型(acanthomatous type)造釉細胞瘤。我們發現如果單純以H&E染色的顯微鏡

觀察，加上非專精於此領域的醫師來進行診斷，這種雙發性的腫瘤其實也很

容易被誤診。由於本例曾於外院被誤診，我們另外利用免疫螢光染色尋找可

用於鑑別診斷兩種不同腫瘤的工具。結果發現CK8在本病例中之兩種不同的腫

瘤有完全不同的表現。造釉細胞瘤利用CK8染色呈現中度至強度的免疫反應，

而口腔鱗狀細胞癌則完全無反應。另外再取20例造釉細胞瘤及15例口腔鱗狀

細胞癌進行CK8的染色，仍有相同的結果，顯示CK8有助於顯微鏡下難辨之造

釉細胞瘤及口腔鱗狀細胞癌之鑑別診斷。

關鍵詞：造釉細胞瘤，cytokeratin 8，口腔鱗狀細胞癌。

synchronous oral squamous cell carcinoma and ameloblastoma

Documents