Case presentation: A 47-year-old female presented for pancytopenia screening. She was diagnosed with papillary thyroid carcinoma eighteen months earlier and had undergone a complete thyroidectomy accompanied by radioiodine (I-131) therapy for nodal and tiny pulmonary metastases. The total radioactive iodine dosage was 312 mCi.
She responded well to radioiodine therapy and stayed healthy for the next year. However, after fifteen months of therapy, there was a gradual reduction in her complete blood count.