Gene rearrangement of immunoglobulin as a marker of thyroid lymphoma

Flow cytometric, gene rearrangement, and karyotypic analyses of 110 cases of primary thyroid lymphoma: a single-institutional experience in Japan

Ancillary studies for primary nodal lymphomas have been well documented; however, studies of primary thyroid lymphoma (PTL) are limited. Here, we aimed to clarify the clinicopathological, flow cytometric, gene rearrangement, and karyotypic characteristics of PTL by investigation of a large series at a single institute. We performed flow cytometric, IgH rearrangement, and karyotypic analyses of 110 PTL tissues surgically resected at Kuma Hospital between January 2012 and April 2017. All PTLs were of B-cell origin, including mucosa-associated lymphoid tissue lymphoma (MALTL; 89 patients, 80.9%), diffuse large B-cell lymphoma (DLBCL; 18 patients, 16.4%), and follicular lymphoma (FL; three patients, 2.7%). In 96 (87.3%) patients, anti-thyroid antibodies were positive. For flow cytometry using aspirated and resected materials, light chain restriction was observed in 73.7% and 69.2% of examined cases, respectively. Heavy chain JH DNA rearrangement was observed in 65.4% of PTLs (58.1% of MALTL cases, 100% of DLBCL cases, and 100% of FL cases). Chromosomal abnormalities were detected in 49.0% of PTLs, and translocation was most frequently detected (24.0%), followed by addition (20.8%) and trisomy (18.8%). The most frequent (9.4%) karyotype was t(3;14)(q27;q32). Both FLs harbored t(14;18)(q32;q21), and the karyotype was not detected in patients with MALTL and DLBCL. The negative rate for all three examinations was 3.8%. We concluded that thyroid MALTL was cytogenetically different from that in other organs. Our results suggested that pre-operative flow cytometry analysis using aspirated materials was as reliable as that using resected materials.

Thyroid ultrasonography

BACKGROUND

The recent prevalence of ultrasonography (US) has facilitated the early detection and qualitative evaluation of thyroid nodules. Furthermore, novel technical developments are extending the application range of US for other thyroid diseases.

METHODS

The use of US to differentiate between thyroid carcinoma and benign nodule, between a metastatic lymph node and a reactive node, between thyroid lymphoma and chronic thyroiditis, and between destruction-induced thyrotoxicosis and Graves' disease is introduced.

RESULTS

Classification systems for thyroid nodule have shown high diagnostic accuracy for thyroid carcinomas except follicular carcinoma. US diagnosis of lymph node metastasis showed high specificity but low sensitivity. Patients who were suspected of thyroid lymphoma based on US findings should undergo incisional biopsy or thyroidectomy for diagnosis of the histologic type if fine-needle aspiration biopsy findings suggest lymphoma. Patients should be carefully followed even if they were diagnosed as negative based on cytologic findings. Measurement of thyroid blood flow is helpful for diagnosing destruction-induced thyrotoxicosis, such as painless thyroiditis, by distinguishing the lesion from Graves' disease.

CONCLUSIONS

Ultrasonography is useful for diagnosing various thyroid diseases, including thyroid carcinoma. The remaining issue to be resolved is the diagnosis of follicular carcinoma. Trials using novel techniques to differentiate these lesions are expected.

Primary T-cell lymphoma of the thyroid associated with Hashimoto's thyroiditis, histologically mimicking MALT-lymphoma

Most of thyroid lymphomas are B-lineage, and T-cell lymphomas are rare. Here, we report a case of primary thyroid T-cell lymphoma associated with Hashimoto's thyroiditis. A 48-yr-old woman presented with incidentally found neck mass. Histologically, the resected right lobe of the thyroid was replaced by monomorphic small atypical lymphoid cells with lymphoepithelial lesion-like change, most of which were immunoreactive for CD3, CD8, betaF-1, and TIA-1. Peripheral T-cell lymphoma, unspecified, was finally diagnosed after molecular study for TCR-gamma gene rearrangement. This is the second case of cytotoxic T-cell lymphoma reported in the thyroid gland so far. Unique association between thyroid follicles and neoplastic lymphocytes may be characteristic feature of this type of T-cell lymphoma.

Usefulness of ultrasonography for diagnosis of malignant lymphoma of the thyroid

BACKGROUND

Recent developments in ultrasonography (US) and the prevalence of ultrasound-guided fine needle aspiration biopsy (US-FNAB) has enabled physicians to detect and diagnosis thyroid diseases, including thyroid malignant lymphoma, much more easily.

METHODS

We describe our diagnostic strategy for malignant lymphoma on US screening. We screened possible malignant lymphoma patients by US characteristics such as enhanced posterior echoes.

RESULTS

Among 170 patients suspected of malignant lymphoma between 2000 and 2004, 74 (43.5%) were also diagnosed as having or suspected of lymphoma by US-FNAB. Five patients dropped out, and 67 of 69 patients who underwent surgical examination were pathologically diagnosed as having lymphoma. Finally, 79 (47.9%) of 165 US-suspected patients were confirmed as having lymphoma. Only 21.5% of lymphoma patients complained of rapidly growing goiter.

CONCLUSION

US screening for goiters contributes markedly to diagnosis of lymphoma at an early phase, facilitating early initiation of therapy.

Expression of the Components of the Cip/Kip Family in Malignant Lymphoma of the Thyroid

OBJECTIVE

For evaluating the characteristics of human neoplasms, investigation of regulators of cell cycle progression is important. We studied three components of the Cip/Kip family, p57, p27 and p21, in malignant lymphomas of the thyroid.

METHODS

We immunohistochemically investigated the expression of the three proteins for 49 cases of thyroid lymphomas, as well as 10 cases of chronic thyroiditis.

RESULTS

In infiltrating lymphocytes in chronic thyroiditis, p57 and p27 were diffusely expressed, whereas p21 immunoreactivity was only occasionally observed. In lymphoma, decreased expression of p57 (less than 50% of lymphoma cells were positive) was observed in 24 cases (49.0%). p57 expression was inversely linked to the MIB-1 labeling index, grade of malignancy and aberrant p53 expression. Decreased expression of p27 was observed in 25 cases (51.0%), which was also related to the MIB-1 labeling index and aberrant p53 expression. On the other hand, p21 expression was occasional, and when the cut-off value was set at 3%, 38 cases (77.6%) were regarded as negative. P21 expression was not linked to any clinicopathological parameters.

CONCLUSION

These findings suggest that, among the 3 components of the Cip/Kip family, p57 and p27 play a role in negatively regulating the cell proliferation of thyroid lymphoma cells and decreased expression of them contributes to the progression of this disease.

Nongastric mucosa-associated lymphoid tissue lymphomas

Nongastric mucosa-associated lymphoid tissue (MALT)-derived lymphomas arise from various extranodal locations and are usually related to a particular pathogenesis with a possible external (environmental or autoimmune) event inducing the disease. We reviewed 165 patients with nongastric MALT lymphoma among the 243 patients with MALT lymphoma in our database and reviewed reports in the literature to analyze the clinical features of nongastric MALT lymphomas. The site of clinical presentation was related to the lymphoma location and was usually indolent. Dissemination of the disease at diagnosis was noticed in 48% of cases because of the involvement of multiple mucosal sites (48%) or because of a nonmucosal site involvement such as bone marrow, spleen, or liver (52%). With a median follow-up of 4 years, the estimated 5-year overall survival and 5-year freedom-from-progression rates were 89% and 50%, respectively, without any difference between patients with localized or disseminated disease or among different locations. Treatment recommendations for localized disease are based on surgery, local therapy, or chlorambucil. For disseminated disease, treatment recommendations include chemotherapy with fludarabine or chlorambucil or chemotherapy with CHOP (cyclophosphamide/doxorubicin/vincristine/prednisone) in cases of large tumor mass

Cdc2 Expression in Primary Thyroid Lymphoma: Its Relationship with Biological Aggressiveness and G2 Cyclins

Previous studies have demonstrated that the G2-M modulators contribute to the progression of human neoplasms. In this study, we investigated the expression of these modulators, cyclin-dependent kinase 1 (cdc2), and G2 cyclins, cyclin A and cyclin B1, in primary thyroid lymphoma. Cdc2 immunoexpression was observed in 51.0% of the 49 cases examined and was related to grade of malignancy, high Ki-67 labeling index, and aberrant p53 expression. The incidences of immunoexpression of cyclin A and cyclin B1 were 63.3% and 40.9%, respectively, and they were also related to the above three parameters. Furthermore, a correlation was found between the immunoexpression of cdc2 and G2 cyclins. These findings suggest that the cdc2 and G2 cyclins play an important role in the progression of thyroid malignant lymphoma.

Excessive survivin expression in thyroid lymphomas

Thyroid lymphoma occurs most commonly in the thyroid glands with a background of Hashimoto's thyroiditis. Therefore, it is occasionally difficult to distinguish lymphoma from Hashimoto's thyroiditis because of some cellular and histologic similarities. We have examined whether survivin or human telomerase reverse transcriptase (hTERT) expression can differentiate between the 2 disorders. Surgically removed tissue samples from 6 patients with thyroid lymphoma and 6 patients with Hashimoto's thyroiditis were analyzed for mRNA levels of survivin and hTERT by real-time quantitative reverse-transcription polymerase chain reaction. Expression of survivin protein was examined by immunohistochemical stain using a polyclonal antibody. Survivin mRNA levels were greater in thyroid lymphoma than in Hashimoto's thyroiditis: 49.1 +/-36.4 versus 6.6 +/-2.7 pg/ng rRNA (mean +/- SD) (P <0.005). Immunohistochemical stain confirmed an abundance of survivin protein in lymphoid cells of thyroid lymphoma. The amount of hTERT mRNA did not differ in the 2 disorders. Our study shows that measuring survivin mRNA levels or immunohistochemistry of the protein expression can be useful to aid the diagnosis of thyroid lymphoma when histologic diagnosis is difficult.

DNA sequence of immunoglobulin heavy chain variable region gene in thyroid lymphoma

Patho-epidemiological studies have shown that thyroid lymphoma (TL) develops in thyroid affected by chronic lymphocytic thyroiditis (CLTH). CLTH is categorized as an organ-specific autoimmune disease, in which activated B-lymphocytes secrete a number of autoantibodies. Because antigenic stimulation might be involved in the pathogenesis of TL, the variable region in heavy chain (V(H)) genes was characterized in 13 cases with TL and 3 with CLTH. Clonal rearrangement of the V(H) gene was found in 11 cases of TL, and cloning study with sequencing of complimentary determining region (CDR) 3 revealed the presence of a major clone in 4. Three of the 4 cases used V(H) 3 gene, with the homologous germline gene of V3-30 in two cases and VH26 in one case. A biased usage of V(H) 3 and V(H) 4 genes with the homologous germline gene of VH26 in V(H) 3 gene was reported previously in cases with CLTH. A high level of somatic mutation (1-21%, average 12%) with non-random distribution of replacement and silent mutations was accumulated in all cases. The frequency of the occurrence of minor clones ranged from 29-44% per case, indicating the presence of on-going mutation. DNA sequencing of immunoglobulin V(H) gene suggests that TL develops among activated lymphoid cells in CLTH at the germinal center stage under antigen selection.