POORLY DIFFERENTIATED PAPILLARY THYROID CARCINOMA (PDTC) WITH TRABECULAR-INSULAR-SOLID (TIS) AREA: MANAGEMENT CONTROVERSIES

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-484
Coromoto Palermo*1, Jose Hernan Martinez2, Oberto Torres3, Frieda Silva4, EVA Gonzalez3 and Maria de Lourdes M Miranda5
1San Juan City Hospital, San Juan, PR, 2San Juan City Hospital, 3SAN JUAN CITY HOSPITAL, 4SCHOOL OF MEDICINE UPR, 5San Juan City Hosp, Bayamon, PR
Background: Differentiated thyroid cancer, accounts for the vast majority of thyroid cancers. Of the differentiated cancers, papillary cancer comprises about 85% of cases compared to about 10% that have follicular histology, and 3% that are Hurthle cell or oxyphil tumors. Others poorly differentiated aggressive tumor histologies include trabecular, insular, and solid subtypes (< 1%) (1-4). Poorly differentiated Thyroid carcinoma (PDTC) define aggressive, follicular-derived thyroid carcinoma with behavior intermediate between follicular/papillary and anaplastic carcinoma. Among the variable histologic patterns, trabecular-insular-solid (TIS) areas usually are predominant (1). Although most authors agree that PD carcinoma is defined by the presence of ≥ 75% TIS areas, other studies found that insular or solid components comprised as low as 10% of tumors (1).

Clinical Case: A 47-year women  without past history, showed painless mass in the anterior neck,  4 years ago.  Denied symptoms of hypo/hyperthyroidism and neck radiation. No family history of thyroid malignancy. Physical examination: visible goiter, painless,  multinodular, predominantly in the right lobe. TSH: 2.02 uIU/mL. Thyroid ultrasound: right thyroid nodule (5 x 4 x 4 cm). Fine needle aspiration biopsy: suspicious of Follicular Neoplasm in the right lower thyroid lobe. NIH Pathology report after Total Thyroidecty: Papillary Carcinoma of Thyroid poorly differentiated, predominant follicular variant; with areas of insular and solid differentiation at right lobe 5 cm limited to Thyroid gland. Areas of capsular infiltration are present. No lymphatic or vascular invasions. Hashimoto’s thyroiditis. Pathological staging: T3 NxMx. Anti-Thyroglobulin levels: 8.92 IU/ml. Thyroglobulin levels: 8.11. TSH: 3.370 uIU/ml. Patient was treated with radioiodine ablation therapy.

Conclusion: to our knowledge, there are not established treatments for PDTC-TIS. The impact of radioiodine treatment on the prognosis of patients with TIS carcinoma is not well known. In a previous study, many patients showed higher iodine uptake that were treated shortly after surgery compared with the uptake in patients who were treated at the time of local recurrence or distant spread. This was not the experience of other authors, who reported poor iodine uptake in a variable percentage of patients. In view the above evidences, in our patient, as the vast majority of patients, a homogeneous therapeutic approach were adopted, including total thyroidectomy and radioiodine therapy.  We used the same dosage and timing as patients with well differentiated carcinoma who had disease of a similar stage and with similar clinical features.  We recommended establishing the most helpful scoring system to define TIS carcinoma that carry a higher risk of aggressive behavior and also the impact of radioiodine treatment on the prognosis of patients with PDTC-TIS.

1.- Volante M., Cancer. 2004 Mar 1;100(5):950-7 Poorly Differentiated Carcinomas of the Thyroid with Trabecular,  Insular, and Solid Patterns . A Clinicopathologic Study of 183 Patients. 2.- ATA Guidelines on differentiated thyroid cancer. Thyroid vol 19, n 11, 2009 . 3.- Kini H., J Cytol 2012 Jan;29(1):97-9. Poorly differentiated (insular) thyroid carcinoma arising in a long-standing colloid goitre: A cytological dilemma 4.- Htwe TT., Singapore Med J 2012 Mar;53(3):e49-51. Follicular thyroid carcinoma with insular component: a retrospective case study, immunohistochemical analysis and literature review.

Nothing to Disclose: CP, JHM, OT, FS, EG, MDLMM

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