Mucosa-associated lymphoid tissue (MALT) lymphoma developing in ectopic mediastinal thyroid tissue: a case report

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Ectopic mediastinal thyroid tissue is rare, originating outside the neck without connection to the thyroid gland.
• A co-occurrence of mucosa-associated lymphoid tissue (MALT) lymphoma within ectopic mediastinal thyroid tissue has not been previously documented.

Purpose of the Study:

• To report a unique case of MALT lymphoma arising in ectopic mediastinal thyroid tissue.
• To emphasize the importance of considering this rare condition in the differential diagnosis of mediastinal masses.

Main Methods:

• A 67-year-old female presented with a superior mediastinal mass detected via CT scan.
• Advanced imaging (CT, MRI) and laboratory tests were performed; the mass was surgically resected.
• Histopathological examination confirmed ectopic mediastinal thyroid tissue with MALT lymphoma and chronic thyroiditis.

Main Results:

• The resected mass was diagnosed as ectopic mediastinal thyroid tissue with MALT lymphoma and chronic thyroiditis.
• Cervical thyroid fine-needle aspiration revealed chronic thyroiditis but no lymphoma.
• The patient's postoperative thyroid function remained normal, with an uneventful recovery.

Conclusions:

• This case represents the first reported instance of MALT lymphoma developing within ectopic mediastinal thyroid tissue.
• This presentation expands the differential diagnosis for masses found in the mediastinum.