Gastric MALT Lymphoma with Increased Plasma Cell Differentiation Showing Unique Endoscopic Features

A 62-year-old woman was diagnosed with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) with increased plasma cell differentiation of the stomach. Esophagogastroduodenoscopy showed slightly elevated, whitish lesions in the gastric body. Magnifying endoscopic observation revealed that the gastric surface epithelium was swollen, but the structure was not destroyed or diminished. Elongated, tortuous vasculature was observed on the surface of the whitish lesions. The patient underwent eradication treatment for Helicobacter pylori, which resulted in complete remission. Although the appearance of abnormal vessels and the destruction of gastric epithelial structure are the typical features of gastric MALT lymphoma during magnifying endoscopy, the present case showed different features, which were rather similar to those observed in a previously reported case of gastric plasmacytoma. The current case indicates that magnifying endoscopic features are not uniform among gastric MALT lymphomas.

Contribution of Immunocytochemistry to the Diagnosis of Usual and Unusual Lymphoma Cases

Some of the limitations of fine needle aspiration (FNA) in the cytodiagnosis of lymphoma include problems encountered in differentiating reactive hyperplasia from low-grade non-Hodgkin lymphoma (NHL), lower cytodiagnostic accuracy for NHL with a follicular (nodular) pattern and nodular sclerosis type of classical Hodgkin lymphoma (HL), and overlapping morphological features between T-cell-rich B-cell lymphoma (TCRBCL), anaplastic large cell lymphoma (ALCL), and HL. Immunocytochemistry may be of help in such situations. The B-cell lymphomas such as small lymphocytic lymphoma/CLL, follicular lymphoma (FL), mantle cell lymphoma (MCL), MALT lymphoma, Burkitt lymphoma (BL), and diffuse large B-cell lymphoma (DLBCL) have pan-B-cell markers (CD19, CD20, CD22, CD23, and CD79a). The FL (centrocytic), MCL, and MALT lymphoma can be differentiated with the use of a panel consisting of CD5, CD10, and CD23. In addition, FL is BCL2+ and MCL is BCL2+ as well as cyclin D1+. The DLBCL is BCL6+ in 60–90% cases. Besides pan B-cell marker, the immunocytochemical profile of BL includes CD10+, BCl6+, EBV±, and Ki67+ (100% cells). TCRBCL, a rare variant of DLBCL can be immunocytochemically differentiated from anaplastic large cell lymphoma (CD45+, CD30+, CD15‒, T±, B‒, EMA+, ALK1±) and classical HL (CD30+, CD15+, CD45‒, B‒, T‒, EMA‒). Unlike classical HL, the nodular lymphocytic predominant HL has a phenotype that includes LCA+, CD20+, CD79a+, CD15‒, and CD30‒. Whereas the immature neoplastic cells of T-lymphoblastic lymphoma (LBL) are CD3+, CD20‒, and Tdt+, the rarely encountered mature T-CLL/T-PLL are immunophenotypically CD3+, CD4+, CD5+, CD7+, CD8‒, CD20‒, CD23‒, and Tdt‒.

Multi-institutional study of fine-needle aspiration for thyroid lymphoma

INTRODUCTION

Primary thyroid lymphoma is a rare neoplasm accounting for 1% to 5% of thyroid malignancies. We study the efficacy of fine-needle aspiration (FNA) in diagnosing thyroid lymphoma.

METHODS

Pathology databases from our three institutions were searched for thyroid FNA biopsies having a diagnosis of lymphoma or atypical lymphoproliferative cells, or a corresponding tissue diagnosis of thyroid lymphoma having a prior FNA biopsy.

RESULTS

Sixty-eight cases were retrieved from 64 patients; 67 cases with histologic confirmation. Forty-six specimens were from women (68%), ages 21 to 87 years (mean = 60). Forty-seven aspirates were diagnosed as lymphoma (n = 29) or suspicious (n = 18) for lymphoma (sensitivity = 73%), 11 atypical, 7 benign, 2 unsatisfactory, and 1 suspicious for carcinoma. Follow-up surgical diagnoses included diffuse large B-cell lymphoma (n = 43), classical Hodgkin lymphoma (5), chronic lymphocytic leukemia (5), and other cases (11). Only 12 of 64 patients (13 specimens) had a known diagnosis of lymphoma prior to FNA. Light chain restriction was detected in 34 specimens (by flow cytometry [FCM] in 32 cases or polymerase chain reaction, in 2 cases). FCM was polyclonal (n = 7) or inconclusive (2) with 25 cases not having FCM performed or not having enough viable cells for evaluation. Four cases showed lymphocytic thyroiditis on surgical follow-up with 2 of these cases having a small monoclonal lymphoid population detected by FCM.

CONCLUSIONS

Diffuse large B-cell lymphoma was the most common lymphoma in this series (63%). The sensitivity of FNA with the optional use of FCM was 71% with a specificity of 99%.

Cytological findings for the diagnosis of primary thyroid mucosa-associated lymphoid tissue lymphoma by fine needle aspiration

OBJECTIVE

We examined cytological findings for the diagnosis of primary thyroid mucosa-associated lymphoid tissue (MALT) lymphoma by fine needle aspiration.

STUDY DESIGN

During the study period of 4 years, a total of 101 cases including 51 MALT lymphomas, 20 Hashimoto's thyroiditis (HT), and 30 diffuse large-cell B-cell lymphomas were cytologically examined. MALT lymphomas were divided into 44 common MALT and 7 MALT lymphomas with extreme plasmacytic differentiation (MALT-EPCD).

RESULTS

(1) Small- to medium-sized cells displaying irregularly shaped nuclei with prominent nucleoli (ISN-PN) were neoplastic cells. (2) In the case of a frequency of plasma cells (PC) below 15%, the accuracy rate for distinguishing common MALT from HT was 97% for ISN-PN cell frequencies above 20% in combination with the presence of lymphoepithelial lesion clusters (LELC) and mountain range-like clusters (MRLC). The frequency of large-sized cells was below 15% in common MALT. (3) In the case of a frequency of PC above 15%, cases with a sum of PC and ISN-PN cells above 30% were MALT-EPCD. (4) MRLC were cell clusters derived from regions of follicular colonization, and LELC were cell clusters from lymphoepithelial lesions of MALT lymphomas.

CONCLUSION

Useful cytological criteria for the diagnosis of thyroid primary MALT lymphoma, such as neoplastic cells and cell clusters, were defined.

Cytopathology in the diagnosis of lymphoma

FNA is a simple, safe, and an inexpensive sampling technique that plays an important role in the evaluation of lymphadenopathy. The key to enhancing the accuracy of FNA diagnosis of lymphoma is the multi parameter approach in which the cytomorphologic features are evaluated in correlation with the results of ancillary studies and clinical context. A full understanding of the current lymphoma classification, clinical features associated with each lymphoma subtype and the impact of the diagnosis on patient management is essential in FNA diagnosis of lymphoma. It is also important to recognize the limitations of FNA in the primary diagnosis of some subtypes of lymphoma, and tissue biopsy should be recommended for a definitive diagnosis and subclassification in such cases.

Cytologic findings and differential diagnoses of primary thyroid MALT lymphoma with striking plasma cell differentiation and amyloid deposition

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.