Too soon! Papillary thyroid carcinoma (PTC) in a 4 year-old child 16 months following treatment for neuroblastoma (NB)

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 459-496-Thyroid Neoplasia & Case Reports
Clinical
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-470
Melissa Anne Buryk*1, Jeffrey Simons2, Peter H Shaw2, Randy M Windreich2, Todd Wine2, Judith Joyce3, Susan Creary2, Jennifer Picarsic4, Melvin Deutsch5, Sarah E Monaco3, Yuri E Nikiforov6 and Selma Feldman Witchel4
1Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, 2Children's Hospital of Pittsburgh of UPMC, 3University of Pittsburgh Medical Center, 4Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, 5University of Pittsburgh Medical Center Cancer Centers, 6Univ of Pittsburgh, Pittsburgh, PA
Background: Thyroid carcinoma is rare in children, particularly in the very young. Children treated for neuroblastoma (NB) have an increased risk to develop PTC.[i] Both external beam radiation and use of I-131 MIBG therapy are associated with this increased risk.[ii] The shortest reported duration from treatment to PTC detection is 2 years in a patient who received high dose I-131 treatment.[iii] We report a patient in whom PTC was detected 16 months after treatment of NB without use of high dose I-131.

Clinical case:  A 4 year old female with a history of NB presented to the pediatric otolaryngology clinic following an incidentally discovered right thyroid nodule on surveillance chest CT. After diagnosis of stage IV NB at 2 years of age, she received induction chemotherapy followed by autologous stem cell transplantation, external beam radiation to abdominal tumor site (total 35Gy (estimated 3cGy to thyroid)), I-123 MIBG scans (estimated 60 cGy to thyroid), and immunotherapy. Potassium iodide was given as thyroid protection for MIBG scans. Radiation was complete 16 months prior and she was declared disease free from her neuroblastoma 8 months prior to detection of thyroid nodule.

At initial otolaryngology visit (4 years of age), a right thyroid nodule was palpable on examination. Thyroid function tests were within normal ranges. A thyroid ultrasound demonstrated a 2.9 x 1.4 x 1.8cm heterogeneous solid mass in the right lobe of the thyroid. Ultrasound guided fine needle aspiration (FNA) showed follicular neoplasm by The Modified Bethesda System for Reporting Thyroid Cytopathology. Molecular mutations (BRAF, RAS, PAX8/PPARg, and RET/PTC) were not detected in the FNA sample. Immunostains performed on the FNA excluded neuroblastoma.  A right thyroidectomy was performed.  Histopathology showed follicular variant of PTC. Subsequent completion thyroidectomy was uncomplicated.

Conclusion: This is the shortest duration from NB treatment to detection of thyroid cancer in a child that we are aware of. Radiation doses to the thyroid were low and associated with <1% risk of thyroid cancer in the general population. Therefore, it is unlikely that these relatively low radiation doses are responsible for the development of PTC in this child. More likely, this child possesses genetic and/or environmental susceptibility for tumor development. Genetic studies are proceeding to assess for potential risk factors responsible for her apparent susceptibility to tumor formation.

[1]. Bhatti P, et al.. Risk of second primary thyroid cancer after radiotherapy for a childhood cancer in a large cohort study: an update from the childhood cancer survivor study. Radiat Res. 2010;174:741 [1]. van Santen HM, et al.,. Differentiated thyroid carcinoma after 131I-MIBG treatment for neuroblastoma during childhood: description of the first two cases. Thyroid. 2012 ;22:643   [1]. Acharya S, et al.,  Thyroid neoplasms after therapeutic radiation for malignancies during childhood or adolescence. Cancer 2003;97:2397

Nothing to Disclose: MAB, JS, PHS, RMW, TW, JJ, SC, JP, MD, SEM, YEN, SFW

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm