Background: Malignancy and hyperthyroidism used to be considered mutually exclusive, but increased association was observed. These two conditions incidence is variable, ranging between 0 and 9%, Graves disease is especially linked to differentiated thyroid carcinoma type.
Case presentation: We report the case of a 33 year old, female, smoker, diagnosed with BasedowGraves disease in may 2015, on methimazole 20 mg/day. She was admitted to our department with palpitations, ocular pains, bilateral exophthalmos and severe neutropenia (150/mm3). The physical exam revealed normal skin temperature, sinus tachycardia, bilateral exophthalmos with no diplopia, diffuse painless goiter. Laboratory tests showed TSH <0.004 mUI/ml, free thyroxine (FT4) 1.76 ng/dl, total triiodothyronine (TT3) 246.3 ng/dl, anti TSH receptor antibody (TRAb) 2.27IU/l. Thyroid ultrasound revealed diffusely enlarged thyroid gland with heterogeneous echotexture with increased color Doppler flow and no pathological cervical nodes. The administration of methimazole was stopped and treatment with lithium carbonate and potassium iodide was started. For the neutropenia she was given dexamethasone, injections of granulocyte colony stimulating factor. When controlled levels of thyroid hormones (T3 and T4) and neutrophils were ensured, the patient underwent total thyroidectomy. The histopathology revealed a 5 mm foci of papillary microcarcinoma of follicular type, with no invasion of the thyroid capsule.
The postoperative follow-up showed no remnant thyroid on ultrasound of the neck, Tireoglobulin (Tg), levels on LT4 <1 ng/ml, Tg antibodies in normal range. Tg antibodies are periodically measured and TSH serum level is ranged between 0.1 and 0.5 mUI/l. The patient had no more ocular complaints.
Conclusion: Thyroid cancer is an unusual finding in a patient with BasedowGraves disease, the most commonly type of cancer is papillary and follicular. The particularities of the case were the coexistence of these two conditions and the fact that severe neutropenia lead to total thyroidectomy and permitted a fast cure.
Keywords: Basedow-Graves disease, differentiated thyroid cancer, thyroidectomy