Case 686 -- A 46 year old female with inconsistent thyroglobulin concentrations

Contributed by Lisa Radkay, MD and Octavia Peck Palmer, PhD


A 46 year old white female presented to the endocrine clinic for followup on hypothyroidism and a palpable thyroid nodule. Ultrasound of her thyroid on 09/02/03, revealed multiple nodules including a nodule in the upper right pole measuring 7 x 9mm, a nodule in the left aspect of the isthmus measuring 9 x 4mm (Figure 1), and a nodule in the mid pole of the right thyroid measuring 5 x 5mm. An ultrasound guided fine needle aspiration was performed on the nodule near the isthmus which showed papillary carcinoma. A total thyroidectomy with central lymph node dissection was performed on 09/26/XX which showed papillary carcinoma with one positive lymph node, T1N1MX.

Figure 1, Ultrasound image of the patient's thyroid above the trachea. A hypoechoic nodule in the left aspect of the isthmus is indicated by the two yellow lines.

Past Medical History

  1. Polycystic ovarian syndrome
  2. Type 2 Diabetes Mellitus
  3. Hypertension
  4. Hypothyroidism
  5. Acromegaly - for which she is status post a transsphenoidal resection of a large pituitary tumor in 06/02

Social History

  1. Smoking

Family Medical History

  1. Sister with thyroid cancer, type unspecified

In the past, the patient's thyroglobulin concentrations were within normal reference range and correlated with her clinical scenario. Recently, the patient's thyroglobulin concentrations were surprisingly elevated (0.48 ng/mL and 0.42 ng/mL) (Table 1) and the thyroglobulin antibody concentrations were low. Interestingly, when the samples were reanalyzed after being treated with blocking reagent, the thyroglobulin concentrations were undetectable (< 0.1 ng/ml).

Table 1: Endocrine Tests


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