8042 A Rare Case of Papillary Thyroid Carcinoma in a Patient with Li-Fraumeni Syndrome

Abstract

Abstract Disclosure: K.M. Bakhtawar: None. G. Jaiswal: None. Li-Fraumeni syndrome (LFS) is an autosomal dominant syndrome with a high lifetime probability of cancer at an early age. The spectrum of cancers primarily includes osteosarcoma, soft tissue sarcoma, breast cancer, brain tumors, leukemia, and Adenoid cystic carcinoma. Prior studies have estimated the cumulative cancer risk to be about 50% by age 40 and as high as 90% by age 60. As screening for TP53 mutations has improved and more patients are identified, the LFS cancer spectrum has expanded to include thyroid cancer. However, the occurrence of thyroid cancer in LFS has not been extensively assessed in the literature. A recent study examined cancer patients carrying the Brazilian p.R337H TP53 mutation which demonstrated that out of 101 patients, 11 had thyroid cancer (10.9%). In our case, a 45-year-old female with a past medical history of Li-Fraumeni syndrome, Von Willebrand disease, Pulmonary embolism, HER-2 positive invasive ductal carcinoma of the left breast status post chemotherapy, and bilateral mastectomy presented for evaluation of papillary thyroid carcinoma (PTC). An enlarged thyroid was initially identified on physical exam by the PCP with a follow-up thyroid ultrasound showing bilateral nodules. The right upper pole 1.9 x 1.3 x 1.6 cm nodule was biopsied revealing PCT. Following neck ultrasound demonstrated mildly enlarged lymph nodes on the right side, level 2A 1.5 cm and level 3 1.6 cm. The patient subsequently underwent total thyroidectomy and lymph node dissection. The pathology report revealed a 1.4 cm PTC in the upper right pole, a 0.9 cm PCT in the isthmus, and a 0.8 cm PTC in the left midpole. 4/62 lymph nodes were positive with the largest deposit of 1 cm. All margins were negative for carcinoma with no angioinvasion or lymphatic invasion. She was staged as T1bN1bM0. We are awaiting post-operative Thyroglobulin level to assess the need for Radioactive iodine. BRAFV600E and P53 mutation was identified. The patient carries known heterozygous mutation p.R1755H in the TP53 gene with an estimated lifetime cancer risk of 93%. This particular mutation has not been associated with thyroid cancer in prior studies. Although thyroid cancer is an uncommon manifestation of LFS, this case begs the importance of further studies to explore this association which may then lead to early screening and treatment of thyroid cancer in individuals with founder TP53 mutations. Presentation: 6/1/2024