title: Cytologic findings and differential diagnoses of primary thyroid MALT lymphoma with striking plasma cell differentiation and amyloid deposition.
abstract: We report two cases of thyroid mucosa-associated lymphoid tissue (MALT) lymphoma with associated amyloid protein deposition. While other primary thyroid neoplasms sush as medullary carcinoma and plasmacytoma with associated amyloid protein are known to occur and have been previously described by fine-needle aspiration cytology (FNAC), to our knowledge, the current cases are the first of thyroid MALT lymphoma with amyloid deposition to be detailed in the cytopathology literature. Case 1 was a 73-year-old female with chronic thyroiditis. FNAC suspected MALT lymphoma. The amyloid material was not noticed, nevertheless it existed. Case 2 was a 71-year-old female with a nodule of the thyroid. Malignant lymphoma and medullary carcinoma were suspected by FNAC. The possibility of medullary carcinoma was excluded by a measurement of serum calcitonin and carcinoembryonic antigen. After follow-up for two years, the nodule was diagnosed as MALT lymphoma associated with plasma cell differentiation and amyloidosis by the fourth FNAC. When we encounter small round cell tumors associated with amyloid in thyroid FNAC, we should consider not only medullary carcinoma but also MALT lymphoma.
authors: Department of Clinical Laboratory, Kuma Hospital, Kobe, Hyogo, Japan.
authors: Yuri
authors: Y
authors: Nobuoka
authors: Mitsuyoshi
authors: M
authors: Hirokawa
authors: Seiji
authors: S
authors: Kuma
authors: Nozomi
authors: N
authors: Takagi
authors: Miyoko
authors: M
authors: Higuchi
authors: Hiroo
authors: H
authors: Masuoka
authors: Akihiro
authors: A
authors: Miya
authors: Sumihisa
authors: S
authors: Kubota
authors: Akira
authors: A
authors: Miyauchi
mesh_terms: D000368:Aged; D000686:Amyloidosis / Q000473:pathology*; D044963:Biopsy, Fine-Needle; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000473:pathology*; D010950:Plasma Cells / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology*
keywords: MALT lymphoma; amyloidosis; aspiration cytology; plasmacytoma; thyroid