ECP 2017 - Abstract Book

Majority of the cases were intraosseous (76 %) amongst which mandible

(87.5 %) was the most frequent site. An attempt was made to categorize all

cases according to 2005 WHO classification, but due to fragmented biopsies,

inadequate clinical and radiological correlation, a large percentage (40.5%) of

cases were classified as

“

uncategorized

”

. Solid/multicystic variant was pre-

dominant (21.4 %).

Conclusion:

Ameloblastoma is a rare neoplasm, a fact highligted by our

recording only 42 biopsied cases over a span of 6 years. Even though the

tumour has a predilection for higher age group and males, we recorded cases

in both extremes of age. Therefore, ameloblastoma should be considered in

differential diagnosis of odontogenic tumours at either extreme of age.

Ameloblatoma has strong tendency for recurrence and recurrence rates vary

for different variants. We emphasis the importance of adequate and accurate

clinical information and radiographic correlation for proper categorization of

this tumour.

OFP-01-013

TERT promoter region mutations in head and neck squamous cell

carcinomas

I. Yilmaz

, S. Ozturk Sari, B. E. Erkul, G. Narli, G. Unverengil, M. Celik,

M. Ulusan, B. Bilgic

Sultan Abdulhamid Han TARH, Pathology, Istanbul, Turkey

Objective:

It is well known that head and neck squamous cell carcinomas are

characterized by genetic alterations, instability and different immune defects

and there are ongoing studies to find newmutations and its effective treatment

modalities. Telomerase reverse transcriptase promoter (TERT) mutations

have been reported in variety of tumours and often shown to be associated

with aggressive behavior. The aim of the present study was to assess the

prevalence of TERT promoter mutations in head and neck squamous cell

carcinomas and correlate the results with patients

’

clinicopathological data.

Method:

Total genomic DNAs of 213 head and neck squamous cell carci-

nomas were extracted from formalin-fixed paraffin embedded tissue samples.

Mutations in the promoter region of the TERT gene (chr5, 1,295,228C>T/A

and 1,295,250C>T) were analyzed using PCR-based direct sequencing

method.

Results:

Of 213 patients, 23 test samples were excluded from the study

due to inadequate DNA quality. Of 190 patients with head and neck

squamous cell carcinoma, TERT mutation was detected in 78 of 104

(75 %) oral cavity, 5 of 59 (8.4 %) larynx, 1 of 6 (16.6 %) hypopharynx

and 0 of 21 (0 %) oropharynx locations. TERT promoter region mutations

in patients with oral cavity carcinoma was higher than oropharynx, larynx

and hypopharynx significantly (

< 0.05). Sequencing revealed that

65.4 % (51/78), 7.7 % (6/78) and 26.9 % (21/78) of oral cavity squamous

cell carcinoma tumour tissues contained C228T, C228A and C250T mu-

tations, respectively.

Conclusion:

Oral cavity exhibits higher TERT promoter region

mutations than other head and neck squamous cell carcinomas.

It may play an important target for therapy and pathogenesis.

OFP-01-014

Diagnosis and characterisation of a new HPV-related tumour of the

head and neck region

P. Morbini

, G. Ferrario, P. Alberizzi

University of Pavia, Dept. of Molecular Medicine, Italy

Objective:

We reviewed all sinonasal adenoidocystic carcinomas

(ACC) previously diagnosed at our center to identify possible

cases of the recently described HPV-related sinonasal carcinoma

with ACC morphology

Method:

p16 immunostain; high risk HPV DNA and mRNA in situ

hybridization (ISH); HPV DNA amplification and genotyping. Patient

follow-up data were reviewed.

Results:

Fifteen ACCwere diagnosed between 1994 and 2016, 9 in the nasal

cavity and 6 in paranasal sinuses. Eight patients were males (53 %); mean age

was 58 years (34

–

75). One high-grade, solid ACC from the nasal cavity of a

67 year-old female showed diffuse p16 and HPV mRNA ISH expression

(6 %); LiPA SPF10 amplified HPV DNA but no specific genotypes; DNA

ISH was negative. In all other cases, p16 stain was luminal and ISH negative;

3 were positive for HR HPVDNA. The tumour recurred 2 years after surgery

and radiotherapy, and at 5 years the patient was alive with progressive disease.

Three other patients (21 %) experienced tumour recurrence

Conclusion:

HPV-mediated oncogenesis accounts for a small subset of

sinonasal ACC. Diffuse p16 positivity with high-grade solid architecture

requires confirmation with molecular tests, but PCR may be negative, even

with prominent mRNA expression. The prognostic implications of this diag-

nosis are still need clarification.

OFP-01-015

Human papillomavirus in laryngeal lymphoepithelial carcinoma

G. Acuna

, L. Alós, J. Ordi, A. Nadal

Hospital Clínic, Pathology, Barcelona, Spain

Objective:

To investigate the involvement of Human papillomavirus

(HPV) in Laryngeal Lymphoepithelial Carcinoma (LLEC).

Method:

Four cases of LLEC were retrieved from our files from the period

2006

–

2016. Epstein-Barr virus (EBV) was tested in all cases with in situ

hybridization with the INFORM EBER Probe (Ventana Medical Systems).

Tissue was available for additional studies in three cases. P16 expression was

analyzed with CINtec® p16 Histology (Ventana) and HPV DNAwas tested

through Polymerase Chain Reaction with SPF10 primers and INNO-LiPA

HPV Genotyping Extra II (Innogenetics).

Results:

All four cases were EBV negative. Three out of three cases were

immunohistochemically p16 positive with an intense and diffuse pattern and

were also positive for HPV-16 as detected by PCR. These results indicate that

HPV was transcriptionally active in these cases.

Conclusion:

Unlike nasopharyngeal carcinoma, LLEC is not related to

EBV. The presence of transcriptionally active HPV suggests that it plays a

role in LLEC.

OFP-02-001

Mutational landscapes of chemical hepatocarcinogenesis

S. Aitken

, F. Connor, T. Rayner, C. Feig, M. Lukk, D. Odom

University of Cambridge, CRUK Cambridge Institute, United Kingdom

Objective:

Hepatocellular carcinoma (HCC) shows molecular heterogeneity

that reflects its diverse aetiology. Although next-generation sequencing of

human liver tumours has defined recurrent mutations in HCC, few studies

have compared these mutational landscapes to those present in commonly

used mouse models of liver cancer.

Method:

We used the well-established diethylnitrosamine (DEN) proto-

col to initiate liver tumours in 15-day-old C3H/HeOuJ mice, and collect-

ed spontaneous liver tumours arising in aged untreated C3H mice. Whole

exome sequencing and histopathological analyses were performed in

treatment-induced (

= 50) and spontaneous (

= 25) dysplastic nodules

and HCCs.

Results:

Exome-wide analyses of DEN-induced neoplasms revealed a

high mutational burden of nonsynonymous single nucleotide variations.

There were distinct mutational signatures in DEN-induced and spontane-

ous neoplasms although histopathologically they were indistinguishable.

Activating Hras mutations were confirmed as the most common driver of

DEN-induced hepatocarcinogenesis, followed by Egfr. Truncating Apc

Sunday, 3 September 2017, 17:15

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19:15, G106-107

OFP-02 Digestive Diseases Pathology - Liver and Pancreas

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