Rare Mixed Thyroid Carcinomas: A Report of Two Cases

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Thyroid cancers represent 0.5%-1% of all malignancies, with differentiated types being most prevalent.
• Mixed thyroid carcinomas are exceptionally rare, accounting for only 0.5% of thyroid cancers.
• Diagnosing these rare tumors via fine needle aspiration cytology (FNAC) presents significant challenges.

Observation:

• Two cases of mixed thyroid carcinomas are presented: a 21-year-old female with predominantly medullary carcinoma and follicular carcinoma areas, and a 45-year-old female with mixed medullary and papillary components.
• Both patients were initially diagnosed with medullary thyroid carcinoma via FNAC.
• Histopathology and immunohistochemistry confirmed the mixed nature of the tumors in both cases.

Findings:

• Fine needle aspiration cytology (FNAC) can be difficult in diagnosing mixed thyroid carcinomas.
• Histopathological examination combined with immunohistochemistry is essential for accurate diagnosis.
• Identifying the medullary component is critical for appropriate patient management.

Implications:

• Increased awareness of rare mixed thyroid carcinomas is vital for clinicians to avoid diagnostic dilemmas.
• Immunohistochemistry plays a crucial role in confirming the diagnosis of these rare entities.
• Accurate diagnosis facilitates appropriate treatment strategies for patients with mixed thyroid carcinomas.