A UNIQUE ENCOUNTER OF PAPILLARY THYROID CANCER AND HODGKIN LYMPHOMA IN TANDEM

Abstract

INTRODUCTION/BACKGROUND
Papillary thyroid carcinoma (PTC) comprises the largest proportion of differentiated thyroid carcinoma cases. A notably uncommon scenario involves the simultaneous manifestation of PTC and Hodgkin’s lymphoma as distinct primary malignancies.

CASE
A 35-year-old female with no history of radiation exposure presented with painless neck swelling for one year. Thyroid ultrasonography revealed 2 hypoechoic lesions over the left lobe measuring 1.8 x 1.6 cm and 0.7 x 0.9 cm (TIRADS 4) and the right lobe measuring 0.4 x 0.4 cm (TIRADS 1) with multiple prominent cervical lymph nodes. Her thyroid profile was normal. Cervical lymph node biopsy was performed and result suggestive of metastatic papillary thyroid carcinoma. She subsequently underwent total thyroidectomy with modified radical neck dissection. Histopathological examination confirmed multifocal (>5 foci) classical variant papillary thyroid carcinoma, with the largest nodule measuring 17 mm, demonstrating lymphovascular involvement and regional nodal metastasis. According to American Thyroid Association (ATA) guidelines, this case was stratified as high recurrence risk. An unexpected diagnosis of nodular sclerosis classical Hodgkin lymphoma was made during lymph node dissection. Bone marrow assessment ruled out lymphomatous involvement and her computed tomography neck, thorax, abdomen, and pelvis revealed extensive bilateral supraclavicular mediastinal and abdominal lymphadenopathy. Therefore, stage 3 Hodgkin lymphoma was diagnosed. After six cycles of escalated BEACOPP chemotherapy for Hodgkin lymphoma, her positron emission tomography (PET) scan revealed no active lymphoma and resolved thyroid bed issues. She is on TSH suppression with 100 mcg of Levothyroxine daily and plans for radio-ablation therapy. Thyroid function, calcium, and parathyroid hormone levels are all normal.

CONCLUSION
This case highlights the rarity of synchronous papillary thyroid carcinoma and Hodgkin's lymphoma. Thorough investigations are crucial to confirm both pathologies and prioritizing treatment becomes essential. Meta-analysis shows that delaying radio-ablative iodine treatment does not impact long-term overall survival in differentiated thyroid cancer. Therefore, lymphoma treatment takes precedence in this case.