Anaplastic small cell neoplasms of the thyroid: an immunoperoxidase study

American Thyroid Association guidelines for management of patients with anaplastic thyroid cancer

BACKGROUND

Anaplastic thyroid cancer (ATC) is a rare but highly lethal form of thyroid cancer. Rapid evaluation and establishment of treatment goals are imperative for optimum patient management and require a multidisciplinary team approach. Here we present guidelines for the management of ATC. The development of these guidelines was supported by the American Thyroid Association (ATA), which requested the authors, members the ATA Taskforce for ATC, to independently develop guidelines for ATC.

METHODS

Relevant literature was reviewed, including serial PubMed searches supplemented with additional articles. The quality and strength of recommendations were adapted from the Clinical Guidelines Committee of the American College of Physicians, which in turn was developed by the Grading of Recommendations Assessment, Development and Evaluation workshop.

RESULTS

The guidelines include the diagnosis, initial evaluation, establishment of treatment goals, approaches to locoregional disease (surgery, radiotherapy, systemic therapy, supportive care during active therapy), approaches to advanced/metastatic disease, palliative care options, surveillance and long-term monitoring, and ethical issues including end of life. The guidelines include 65 recommendations.

CONCLUSIONS

These are the first comprehensive guidelines for ATC and provide recommendations for management of this extremely aggressive malignancy. Patients with stage IVA/IVB resectable disease have the best prognosis, particularly if a multimodal approach (surgery, radiation, systemic therapy) is used, and some stage IVB unresectable patients may respond to aggressive therapy. Patients with stage IVC disease should be considered for a clinical trial or hospice/palliative care, depending upon their preference.

Non-Hodgkin's lymphoma of the thyroid gland: prognostic factors and treatment outcome. The Princess Margaret Hospital Lymphoma Group

PURPOSE

Non-Hodgkin's lymphoma presenting in the thyroid gland is uncommon. A review of the Princess Margaret Hospital experience was performed to assess treatment outcome and prognostic factors in this rare extranodal presentation of localized lymphoma.

METHODS AND MATERIALS

Fifty-two patients treated at the PMH between 1978 and 1986 were identified and their records reviewed retrospectively. Staging procedures revealed 16 patients with Stage I, 28 with Stage II, and eight with Stages III or IV disease. Five patients were treated on a protocol designed for anaplastic carcinoma of thyroid and they were excluded from detailed analysis. Of 39 patients with Stages I and II disease, 18 were treated with radiotherapy alone, three chemotherapy alone, and 18 combined modality therapy. Combined modality therapy was used mainly in patients with large tumor bulk.

RESULTS

The overall 5-year actuarial survival and cause-specific survival were 56% and 64%, respectively. The overall relapse-free rate was 61% at 5 years. Among the 39 patients with Stages I and II disease, the 5-year actuarial survival, cause-specific survival, and relapse-free rate were 64%, 73%, and 66%, respectively. There were no significant differences in outcome between those treated with radiotherapy alone and those treated with combined modality therapy (cause-specific survival: p = 0.25, relapse: p = 0.06). A univariate analysis showed that the only variable to reach statistical significance was tumor bulk. Age was marginally significant while stage and histology were not statistically significant, possibly due to the fairly homogeneous distribution of patients in each of these variables. Patients with progression or relapse of lymphoma after initial treatment frequently died of disease. Isolated gastrointestinal relapses occurred in three cases, representing 27% of all relapses.

CONCLUSION

Based on the above results, we recognize that the majority of patients with localized thyroid lymphoma require combined modality therapy and we recommend radiotherapy alone only for a small, select group of patients with Stage I disease and small tumor bulk.

Immunohistochemical analysis of small cell tumors of the thyroid gland: an Eastern Cooperative Oncology Group study

The majority of small cell anaplastic tumors of the thyroid gland are generally believed to be non-Hodgkin's lymphomas, including most of those formerly classified as small cell carcinomas. Using a panel of antibodies capable of detecting epithelial, neuroendocrine, and B and T cells in paraffin-embedded tissue sections, we studied 68 thyroid neoplasms in which the original diagnosis was small cell carcinoma or lymphoma. Sixty-three of the tumors were identified as lymphomas of B-cell origin on the basis of L26 reactivity used in conjunction with light chain restriction and MB2 immunostaining. Two additional tumors were classified as lymphomas of indeterminate phenotype. Immunophenotyping indicated an epithelial origin in the remaining three tumors. No cases of medullary carcinoma were detected by immunostaining. Histologic review revealed a predominance of large cell and immunoblastic lymphomas, with low-grade lymphomas of mucosa-associated lymphoid tissue histology accounting for only five cases. Our findings indicate that the majority of small cell anaplastic tumors of the thyroid are B-cell lymphomas. Although primary small cell carcinoma of the thyroid may rarely occur, this diagnosis should not be made without immunohistologic confirmation.

Immunohistochemical reclassification of anaplastic carcinoma reveals small and giant cell lymphoma

Thirty-one cases of thyroid malignancies which were originally classified as anaplastic carcinoma were reexamined immunohistochemically using PAP methods (peroxidase:antiperoxidase) for IgM, IgG, IgA, cytokeratin, calcitonin, lysozyme and alpha-1-antitrypsin. The reclassification results were compared with patient data such as clinical symptoms, treatment modalities, and clinical outcome. Postoperative radiotherapy was carried out in more than 80% of cases, chemotherapy in none. Seven of 31 tumors showed a positive staining for IgM (n = 4), IgG (n = 2), and IgA (n = 1) antibodies. All of these cases were negative for epithelial markers. Surprisingly, not only all small cell tumors (n = 3) but also 4 tissues with predominantly giant cell areas were among those reclassified as primary malignant lymphoma.

The WHO histological classification of thyroid tumors: a commentary on the second edition

This article introduces the revised WHO classification of thyroid tumors, giving an account of the major changes made and the reasons behind the changes, as well as listing the actual classification now recommended. It is intended to draw general attention to the revision, the full version of which will be published separately.

Anaplastic thyroid carcinoma. A clinical, histologic, and immunohistochemical study

Twenty-six cases of anaplastic thyroid tumor were investigated and reclassified using immunoperoxidase techniques. Sections of the neoplasms were stained immunohistologically for the following thyroid associated antigens: (1) thyroglobulin, which shows a positive reaction with follicular cells of the thyroid; (2) calcitonin, which is positive in medullary carcinoma of the thyroid; and (3) leucocyte common antigen (LC), which identifies lymphomata and Factor VIII-related antigen for hemangioendothelioma. Using these methods, five cases were reclassified. Three cases were identified as lymphomata, one case was reclassified as medullary carcinoma of the thyroid, and one case was identified as hemangioendothelioma. Eleven cases were confirmed to be anaplastic carcinoma of the thyroid and ten cases were negative for all the antigens tested. There was a significant difference in the survival of the groups of patients mentioned above. Prognostic data support the suggestion that immunohistochemical methods should be used for the precise classification of anaplastic carcinoma. In this way, tumors such as malignant lymphoma and medullary carcinoma, which resemble anaplastic carcinoma histologically but have a better prognosis, can be identified. This is important for planning surgical procedures and choosing chemotherapy and/or radiotherapy.

Diagnostic features of primary malignant lymphomas of the thyroid with monoclonal antibodies

Primary malignant lymphomas (ML) of the thyroid are rare and their conclusive morphologic diagnosis is not always possible. The authors report diagnostic features of 11 cases of ML and one case of plasmacytoma of thyroid compared with chronic lymphocytic thyroiditis and undifferentiated carcinomas of thyroid in an immunohistochemical study using monoclonal antibodies (MoAb). The lymphoid nature of tumors could be identified in all cases with three MoAb on paraffin sections. In ML, tumor cells expressed leucocyte common antigen (Dako-LC+) with negativity for epithelial membrane antigen (Dako-EMA-) and cytokeratin (KL1-). Newer MoAb identifying B-cell (LN-1, LN-2, MB2) and T-cell-associated antigens (MT1, UCHL1) not denatured by fixation, revealed B-cell nature of tumor cells in all cases of ML. Among anti-B MoAb, LN-1 and MB2 were most consistent in their reactivity. In cryostat sections of three ML cases, the tumor cells expressed one or more B-cell-associated antigens. Plasmacytoma was negative for Dako-LC and KL1 but positive for Dako-EMA and monotypic cytoplasmic Ig.

Evidence of vascular differentiation in anaplastic tumours of the thyroid--an immunohistological study

Sixteen cases of anaplastic carcinoma (ACA) and 4 cases of malignant haemangioendothelioma (HAE) of the thyroid were studied by light microscopy and immunohistochemistry. Seven cases of ACA and 3 cases of HAE were characterized by coexpression of immunohistological features of epithelial and vascular endothelial cells. Expression of vimentin was common to all tumours investigated. The present study provides evidence that ACA and HAE are partially closely related tumours showing alternating differentiation. This speaks in favour of a common neoplastic cell with the potential for epithelial and vascular endothelial differentiation.

Small cell carcinoma of the thyroid. A reclassification of cases originally diagnosed as small cell carcinomas of the thyroid

99 cases of undifferentiated carcinomas of the thyroid and nine cases of primary malignant Non-Hodgkin lymphomas of the thyroid were examined from 1967 to 1983 in our institute. Among the undifferentiated carcinomas nine cases were classified as small cell subtype. Over the years, the histopathological handling in regard to small cell subtype of undifferentiated carcinoma and primary malignant Non-Hodgkin lymphoma has changed. The frequency of primary malignant Non-Hodgkin lymphoma has increased conspicuously in the last few years, whereas the number of small cell carcinomas decreased. A reclassification, based on immunohistochemical investigation for tumor markers of the nine cases originally diagnosed as small cell carcinomas from 1967 to 1983 revealed that five cases were poorly differentiated carcinomas or undifferentiated carcinomas of the spindle cell type. In three cases the primary diagnosis had to be revised into malignant Non-Hodgkin lymphoma of the diffuse "histiocytic" type. The postmortem examination of the patient with the remaining small cell carcinoma "of the thyroid" revealed a clinically undetected small cell carcinoma of the lung with metastases to the cervical lymph nodes and the thyroid gland. These findings are in agreement with the results of several recently published papers indicating that true small cell carcinoma of the thyroid must be a very rare tumor.

The role of immunoperoxidase techniques on paraffin embedded tissue in determining the histogenesis of undifferentiated thyroid neoplasms

Twenty cases of undifferentiated thyroid tumours were reviewed histologically. In seven cases the histogenesis was difficult to determine using morphological criteria. Immunohistochemical staining with a panel of antibodies to lymphoid and epithelial cells, including monoclonal antibodies directed against the leucocyte common antigen, cytokeratin, and epithelial membrane antigen confirmed that four of these cases were lymphomas and that one was a medullary carcinoma. In the remaining two cases immunohistochemistry was unhelpful. In the thirteen histologically typical tumours, the immunohistochemical profile was in keeping with their histogenesis as determined by morphological criteria. Immunohistochemical staining with a panel of selected antibodies allows the reliable diagnosis of undifferentiated thyroid neoplasms, when this cannot be reached using routine histological techniques.

Lymphoid and epithelial markers in small cell anaplastic thyroid tumours

The expression of the lymphoid marker, common leucocyte antigen and of the epithelial marker, epithelial membrane antigen by small cell anaplastic thyroid tumours was studied in 53 tumours, using the peroxidase--antiperoxidase and avidin--biotin techniques. Common leucocyte antigen was found in 33 of the 53 tumours; six tumours were positive for epithelial membrane antigen; and the remaining 14 tumours were negative for both markers. These results support the suggestion that most small cell anaplastic thyroid tumours are of lymphoid origin. Survival data for patients with tumours positive for common leucocyte antigen showed a significantly better prognosis than did the data for patients with small cell tumours that did not express this marker (p less than 0.02).