Recurrent and metastatic papillary thyroid microcarcinoma presenting as toxic multinodular goiter
*Dr. Shelton Tacang Department Of Nuclear Medicine, Jose R. Reyes Memorial Medical Center, Manila, Philippines
*Corresponding Author: Dr. Shelton Tacang
Department Of Nuclear Medicine, Jose R. Reyes Memorial Medical Center, Manila, Philippines Email:email@example.com
Published on: 2019-08-07
Background: Hyperthyroidism does not safeguard individuals from developing thyroid cancer. Papillary thyroid microcarcinoma, notwithstanding its torpid course and low risk classification, has a propensity to induce significant morbidity despite radioactive iodine treatment. Clinical case: We present the unusual case of a 37-year old, Filipino male who demonstrated typical signs and symptoms of toxic multinodular goiter (TMG) including anterior neck mass, tremors, weight loss, excessive sweating, palpitations, easy fatigability and bilateral proptosis. The patient, upon follow up, was found to have agranulocytosis attributed to being on anti-thyroid medication for two years. The patient was then subjected to total thyroidectomy with a histopathology report showing colloid goiter with concomitant papillary thyroid microcarcinoma (0.9 cm in widest diameter). Initial radioactive iodine (RAI) therapy was initiated following surgery and subsequent 131I whole body survey (WBS 131I) a year after, showing a negative result; however, after 2 months of WBS 131I, there was locoregional recurrence detected by neck ultrasound and CT scan, and eventually confirmed on lymph node biopsy after modified radical neck dissection (MRND). In an attempt to ablate the probable micrometastases, a second RAI therapy with a higher dose was administered; and subsequent post-therapy scan revealed recurrence of cancer on the thyroid bed and distant metastasis on the right lower quadrant of the abdomen. Currently, the patient is on suppression therapy and constantly monitored for progression of the disease. Conclusion: Even when aided with strict protocols, clinicians must recognize that guidelines are not surrogate to clinical judgment and that prompt institution of treatment is critical to circumvent potential pitfalls. This case further illustrates the avenue of championing the use of radioactive iodine (RAI) therapy just as in the low risk stratification.
Thyroid cancer was, for decades, considered mutually incompatible with hyperthyroidism. For these conditions to occur at the same time was rare.1 The assumption was that hyperthyroidism helped protect the thyroid from developing cancer.2 Recent studies, however, reveal the increasing association between the two. Incidence of toxic multinodular goiter (TMG), one of the most common causes of hyperthyroidism, harboring a malignancy is highly variable and reaches to 9.26 percent.3,4 Furthermore, a literature review spanning 20 years of the analysis show a 1.6 percent incidence rate of concurrent hyperthyroidism and thyroid cancer.5 While incidental papillary thyroid microcarcinoma (PTMC) carries an excellent prognosis, it is not without complication. Albeit nodal and distant metastases are documented in reported series, the incidence rates are low. This report presents a locoregional recurrence and distant metastasis from PTMC presenting as toxic multinodular goiter (TMG), which was presumed to be benign.