Abstract • 192

The purpose of our study was to evaluate the effect of ALL treatment on the thyroid. We studied 50 patients with ALL, (12 to 21 years of age) 7 to 12 years after completion of full chemotherapy of BFM ALL protocols including 12-18 Gy irradiation for prophylaxis of neuroleukemia. We found in 12 pts (29%) benign thyroid nodules, in 36 pts (72%) juvenile thyroid hyperplasia, and thyroid cancer in 2 girls (4%).

Case history 1: A 11 year-old girl presented with ALL in 1992 and completed her full chemotherapy course in 1995. In January 1998 an enlarged hypoechogenic thyroid tumor ( 0.8 × 0.7 cm) with regional lymph node involvement was seen. Blood, bone marrow and biochemical tests were normal. A subtotal thyroidectomy was performed. Histology confirmed an infiltrative metastatic papillar thyroid carcinoma.

Case history 2: A 14 year old female had been successfully treated for ALL. 12 years later thyroid biopsy for symptoms of hypothyroidism and obesity, without evidence of relapsing ALL suggested thyroid cancer. Histologic evaluation after subtotal thyroidectomy was read as differentiated papillar thyroid carcinoma.

Conclusions: We believe that thyroid dysfunction and neoplastic transformation following ALL therapy result from complex interrelationships between pre-treatment thyroid function and individual responses to irradiation and chemotherapy.