Peculiar Presentation of Papillary Thyroid Cancer

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-463
Salima Ali*1, Ramona Dadu2, Charles Lu3, Elizabeth Grubbs3, Dean Blevins1 and Maria Cabanillas4
1University of Texas Houston Health Science Center, Houston, TX, 2MD Anderson Cancer Center, 3MD Anderson Cancer Center, Houston, TX, 4The University of Texas MD Anderson Cancer Center, Houston, TX
Introduction:

Papillary thyroid cancer (PTC) ranges in presentation from an incidental well confined mass, to a diffusely metastatic, devastating carcinoma. Distant metastases of differentiated thyroid cancer are infrequent, occurring 4-15% of patients, and most commonly spreads to the lungs and bones. Adrenal metastases are rare, often asymptomatic and incidentally found. Although PTCs are differentiated by definition, they occasionally dedifferentiate into more aggressive tumors, which are less responsive to radioactive iodine. We discuss an unusual presentation of PTC, as an isolated poorly differentiated adrenal metastasis in the setting of a well differentiated primary tumor.

Clinical Case:

A 66 year old Hispanic man presents with 1 month of progressively worsening left sided abdominal pain, radiating to the right flank. In this time frame he also developed a productive cough, and presented to his primary physician for further evaluation.  His physical exam was significant for thyromegaly with palpable left sided thyroid nodules, and left sided abdominal pain with palpation. PET/CT scan revealed a highly metabolic, 10 cm adrenal mass and bilateral cervical lymph node metastases with low FDG uptake.  Laboratory data revealed - TSH 0.05uIU/mL (0.27-4.2 uIU/mL), free T4 1.10ng/dL (0.93-1.70ng/dL), thyroglobulin 13ng/mL (<55ng/mL), WBC 30K/uL (4-11K/uL), platelets 536 K/uL (140-440K/uL), and hemoglobin 9g/dL (14-18g/dL), negative thyroglobulin antibodies and plasma metanephrines. CT chest showed no intrapulmonary metastases. The patient underwent bronchoscopy, with paratracheal node biopsy, consistent with well differentiated follicular variant of PTC. Biopsy of the left adrenal mass surprisingly demonstrated poorly differentiated thyroid carcinoma. The adrenal mass was positive for BRAF V600E mutation and negative for RAS mutations. Insufficient tumor was available for testing of the primary lesion. Thyroidectomy and adrenalectomy were considered, however the patient was not a surgical candidate. Embolization of the adrenal mass was attempted, but not possible due to the hypovascularity of the lesion. Systemic treatment was initiated with carboplatin and paclitaxel. After two cycles, the patient had disease progression, with the adrenal mass increasing in size to 20.1 x 14.2cm; neck disease remained stable. Vemurafenib, a selective BRAF inhibitor, was recently initiated; follow up images will be presented.

Discussion:

PTC rarely presents with large, symptomatic, and rapidly progressive adrenal metastasis. This case illustrates a rare presentation of an aggressive PTC, but more importantly, that metastatic disease may behave differently than the primary tumor due to dedifferentiation. Individualized consideration should be given to patients with metastatic disease, in reference to acquisition of metastatic tumor for pathologic and genetic testing.

Disclosure: MC: Clinical Researcher, Roche Diagnostics, Clinical Researcher, Exelixis, Inc., Clinical Researcher, Eisai, Advisory Group Member, Exelixis, Inc., Advisory Group Member, Eisai. Nothing to Disclose: SA, RD, CL, EG, DB

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