Synchronous Hürthle cell and medullary thyroid carcinomas.

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Hürthle cell carcinoma (HCC) and medullary thyroid carcinoma (MTC) are rare thyroid cancer subtypes, each comprising approximately 3% of all thyroid malignancies.
• Thyroid cancer management requires accurate histological subtyping for appropriate treatment strategies.

Observation:

• A septuagenarian woman with a history of multiple primary cancers presented with a neck mass.
• Initial surgery revealed two distinct malignant tumors: one HCC and one MTC.
• The patient later developed nodal metastasis of HCC and further intrathyroidal MTC with extranodal HCC extension.

Findings:

• This case represents the first reported instance of a collision tumor comprising both HCC and MTC.
• The patient required completion thyroidectomy and neck dissection due to disease progression.

Implications:

• Collision tumors of HCC and MTC are exceptionally rare, necessitating a high index of suspicion.
• Multidisciplinary team discussions are crucial for managing complex cases of rare thyroid cancers.
• Further research into the optimal management strategies for such collision tumors is warranted.