Page 40 - AAOMP Meeting 2019

POSTER ABSTRACTS - TUESDAY, JUNE 11, 2019

#31 CELL CYCLE PARAMETERS IN DYSPLASTIC LESIONS OF THE ORAL MUCOSA
Dr. Marcelo Sperandio (Faculdade São Leopoldo Mandic), Dr. Matheus Dominguete (Faculdade São
Leopoldo Mandic), Dr. Andresa Soares (Faculdade São Leopoldo Mandic), Dr. Fernanda Mariano
(University of Campinas (UNICAMP)), Dr. Vera Araújo (Faculdade São Leopoldo Mandic)
Introduction: Risk assessment of oral potentially malignant disorders (OPMD) using ploidy analysis is based
on cell cycle parameters, such as the proportion of cells in G1, S-phase, G2, as well as the percentage of cells
with a DNA content beyond G2. Although aneuploidy has been associated with a high risk of malignant
transformation, little is known on the contribution of individual cell cycle parameters to the prognosis of
OPMD. The aim of this study was to compare the distribution of the aforementioned cell cycle parameters
between grades of dysplasia (OED) and carcinoma (SCC). Methods: Nuclei suspensions were enzymatically
prepared from formalin-fixed paraffin embedded tissue and stained with propidium iodide for flow-cytometry.
Histograms were analysed for the proportion of nuclei in G1, S-phase, G2 and 5c-exceeding rate (5cER),
according to published criteria. Epithelial dysplasia was graded prior to preparing the suspensions and DNA
ploidy was established for each OED (none, mild, moderate and severe) as well as SCC (positive control).
Results: A positive correlation was observed between the degree of OED and ploidy, with higher degrees of
dysplasia tending to be aneuploid (Spearman r= 0.54, 95%CI 0.35 - 0.68, p
<0.0001). Severe dysplasias showed the highest elevations in fractions of S-phase, G2 and 5cER (ANOVA and
Tukey tests, p<0.05) when compared to the lesions without dysplasia, which were very similar to SCC (p>0.05).
G2 and 5cER were the most relevant parameters, though the highest S-phase fraction was observed in mild and
severe OED. Conclusion: Individual cell cycle parameters, especially S-phase fraction, may be able to identify
different risk levels between lesions. Follow-up data to establish sensitivity and specificity are currently
underway.

#32 ORAL MUCOSAL MELANOMA IN PREADOLESCENT IDENTIfiES LI-FRAUMENI
SYNDROME.
Dr. Catherine Flaitz (Ohio State University), Dr. John Hicks (Texas Children’s Hospital and Baylor
College of Medicine)
Introduction: Li-Fraumeni Syndrome (LFS) is a rare entity leading to cancer development at a young age
with the potential for multiple primary cancers, caused by TP53 mutation. Typically, in children, LFS is
characterized by adrenocortical carcinoma, brain tumors, and sarcomas.
Clinical Presentation and Pathology Findings: An 11-year-old female presented with a pigmented right
maxillary gingival enlargement. Biopsy showed mucosal melanoma (ovoid to spindled tumor cells, positive for
S100, HMB45, MelanA, Ki67 proliferation index=60%). Next generation sequencing (NGS) of tumor
(somatic) and peripheral blood mononuclear cells (constitutional) revealed TP53 mutation. Parents sought
alternative therapy for oral tumor. Approximately 6 months later, patient returned with intraoral tumor
progression and bilateral cervical lymphadenopathy. Right posterior maxillectomy and bilateral lymph node
dissection showed primary intraoral melanoma with lymph node metastases. One lymph node showed
microscopic focus of metastatic papillary thyroid carcinoma (PTC). A 3cm right thyroid nodule showed PTC on
fine needle biopsy. Total thyroidectomy was performed. Oncologic management for melanoma was completed.
Left ovarian mass was noted 3 years later with oophorectomy demonstrating melanoma (positive for S100,
HMB45, MelanA). Oncologic management was completed. Two years later, a right femur mass was diagnosed
as chondroblastic osteosarcoma (COS) on biopsy. Following oncologic management and limb salvage, tumor
had a poor histologic response (35% tumor necrosis) and chemotherapy was intensified. Two years later, right
lung single 0.5 cm nodule, left femur 0.6 cm intramedullary nodule, and L5 vertebral lamina lesion were
identified on radiologic examination. Resection proved to be COS, and the child underwent oncologic
management.
Conclusion: Mucosal melanoma is rare in the pediatric population. NGS utility in identifying TP53
somatic and constitutional mutations and in the diagnosis of LFS is demonstrated with the current case. LFS
diagnosis allowed for close surveillance and oncologic management of multiple primary and metastatic
tumors.