Epithelial markers in thyroid carcinoma: an immunoperoxidase study

Malignant Priapism as a Result of Metastatic Thyroid Cancer: A Hard Reality

Metastasis to the penis is an extremely rare entity. Malignant priapism is defined as a persistent, nonsexual erection that is refractory to pharmacologic treatment, corporal aspiration, and surgical shunts. Furthermore, it is typically a hallmark of an advanced cancer that has metastasized, most commonly from regional organs like the prostate or bladder. We report an unusual case of malignant priapism in the setting of metastatic follicular thyroid carcinoma. To date, this is the second reported case of penile metastasis due to thyroid carcinoma and the first incidence of priapism secondary to follicular thyroid carcinoma metastasis.

Papillary Thyroid Carcinoma and Related Thyroid Neoplastic Lesions: A Light Microscopic Study with Emphasis on Nuclear Changes

A total of 187 thyroid lesions consisting of 2 cases of Grave's disease, 21 cases of multinodular goiter, 40 follicular adenomas and 124 low-grade papillary thyroid carcinomas were studied to identify intermediate neoplastic lesions in the spectrum of nuclear changes between benign reactive thyroid follicles and low-grade thyroid papillary carcinoma. The lesions were examined and classified on the basis of the following nuclear features: fine chromatin seen in the thyroid papillary carcinomas and coarse chromatin seen in follicular carcinomas. Cases with Hürthle cell changes were excluded from the study. Cases with nuclei containing coarse chromatin were classified in the group of follicular adenomas with a coarse chromatin pattern. The neoplastic thyroid lesions containing fine chromatin showed a spectrum of nuclear changes ranging between reactive follicular lesions and papillary thyroid carcinoma with lymph node metastasis. Such lesions were classified as follicular adenomas with a fine chromatin pattern. The nuclei of these lesions were graded into mild to marked "nuclear atypia with a fine chromatin pattern". The degree of atypia depended on the degree and extent of nuclear changes. Encapsulated follicular adenomas with a fine chromatin pattern and with mild atypia (11 cases), moderate atypia (13 cases), marked atypia (27 cases), and encapsulated or nonencapsulated papillary thyroid carcinoma were characterized by uniform nuclei; with mild, moderate and marked nuclear atypia in less than 2/3 of the cell population and marked nuclear atypia in more than 2/3 of the cell population; and measuring 5.4-6.3, 6.0-7.2, 6.3-9 and 7.2-10 microns in diameter, respectively. Follow-up of cases of papillary thyroid carcinoma fulfilling the above criteria showed lymph node metastasis in 33% of cases, whereas follicular adenomas with a fine chromatin pattern, including cases originally diagnosed as papillary carcinoma, showed no evidence of lymph node or distant metastasis in a follow-up period of 30 months to 15 years. In the thyroid tissue surrounding papillary thyroid carcinoma or encapsulated follicular adenoma with a fine chromatin pattern and marked atypia, adenomatous nodules with a fine chromatin pattern and with low-grade nuclear atypia were identified. The adenomatous nodules with a fine chromatin pattern and with mild, moderate and marked atypia showed architectural, cytoplasmic and nuclear features similar to those of follicular adenoma with a fine chromatin pattern of the same grade. Of interest, a large number of cases of follicular adenoma with a fine chromatin pattern had areas with features of follicular adenoma with a coarse chromatin pattern.

Expression of p63 and Bcl-2 in Malignant Thyroid Tumors and their Correlation with other Diagnostic Immunocytochemical Markers

INTRODUCTION

Bcl-2 is a marker recently studied in thyroid tumours and proposed to have prognostic significance. p63 is expressed in a proportion of papillary thyroid carcinoma cases and may have a role in tumour progression.

AIM

To study expression of Bcl2 and p63 in thyroid tumours and correlation of Bcl-2 with diagnostic markers including Thyroglobulin, Calcitonin and Carcinoembryonic antigen.

MATERIALS AND METHODS

Cytology smears of 35 cases of thyroid cancer were studied over a period of 18 months. In 20 cases histopathology was available. Immunocytochemistry for Bcl-2 and p63 was done, and diagnostic markers were applied as and when required.

RESULTS

p63 showed focal nuclear expression in 46.1% of papillary thyroid carcinoma cases, and was negative in all other tumours. Bcl-2 was positive in 88.9% of follicular carcinomas, 100% of papillary carcinomas and 83.3% of medullary carcinoma cases, and showed focal weak expression in 40% of Anaplastic Carcinoma (ATC) cases, thereby signifying down regulation (p-value = 0.001). There was significant down regulation of Thyroglobulin (Tg) in ATC vs well differentiated follicular derived tumours (p-value ≤ 0.016). Positive correlation was noted between expression of Bcl-2 and Calcitonin (0.93) and Bcl-2 and Carcinoembryonic Antigen (CEA) (0.89), and weak positive correlation (0.65) between Tg and Bcl-2.

CONCLUSION

Bcl-2 is downregulated in anaplastic carcinomas as compared to well differentiated thyroid tumours, and shows correlation with differentiation associated tumour antigens. Thus, loss of Bcl-2 was associated with loss of differentiation in thyroid tumours. Anaplastic carcinoma as such is associated with worse prognosis and loss of Bcl-2 may be partly responsible for the same. p63 is specific but less sensitive marker for PTC. Further studies are required to determine the role of Bcl-2 and p63 in thyroid tumours.

PAX8 immunostaining of anaplastic thyroid carcinoma: a reliable means of discerning thyroid origin for undifferentiated tumors of the head and neck

Anaplastic thyroid carcinoma can be difficult to diagnose because it does not show thyroid differentiation morphologically or immunohistochemically. Depending on the histologic variant, anaplastic thyroid carcinoma may be confused with sarcoma or squamous cell carcinoma of the head and neck. PAX8 is a transcription factor expressed in normal and neoplastic thyroid follicular epithelium and only a few other tissues. This restricted expression suggests that PAX8 staining could be useful when dealing with spindled or squamoid tumors of the neck. The purposes of this study were to determine the frequency of PAX8 staining in anaplastic thyroid carcinoma and to evaluate PAX8 immunohistochemistry as a means of distinguishing its squamoid variant from head and neck squamous cell carcinoma. PAX8 immunohistochemical staining was performed on 34 anaplastic thyroid carcinomas and 118 head and neck squamous cell carcinomas. PAX8 staining was present in 26 (76%) anaplastic thyroid carcinomas including 16 (100%) of 16 squamoid variants, 7 (58%) of 12 giant cell/pleomorphic variants, and 3 (50%) of 6 spindled variants. All head and neck squamous cell carcinomas were negative for PAX8. PAX8 expression is often retained in anaplastic thyroid carcinomas including the squamoid variant, but it is not expressed in head and neck squamous cancers. PAX8 staining is an excellent marker for carcinomas of follicular epithelial origin, including those carcinomas that are undifferentiated in other respects. The tissue specificity of PAX8 expression may be useful in resolving the differential diagnosis of anaplastic thyroid carcinoma such as the distinction between its squamoid variant and squamous cell carcinoma of the head and neck.

Application of immunohistochemistry to thyroid neoplasms

CONTEXT

Thyroid lesions with nodular architecture and follicular pattern of growth often pose difficulties in accurate diagnosis during the assessment of cytologic and histologic specimens. The diagnosis of follicular neoplasm on cytology or of follicular tumor of uncertain malignant potential on histology is likely to cause confusion among clinicians and delay effective management of these lesions. Occasionally, thyroid tumors represent unusual or metastatic lesions and their accurate diagnosis requires immunohistochemical confirmation.

OBJECTIVE

To review the literature on the applications of immunohistochemistry in the differential diagnosis of thyroid tumors.

DATA SOURCES

Relevant articles indexed in PubMed (National Library of Medicine) between 1976 and 2006.

CONCLUSIONS

Our review supports the use of ancillary techniques involving a panel of antibodies suitable for immunohistochemistry and molecular analysis in the assessment of thyroid nodules. These tools can improve diagnostic accuracy when combined with standard morphologic criteria.

Thyroglobulin immunoreactivity in lymph node histiocytes: a potential diagnostic pitfall

AIMS

Strong thyroglobulin immunoreactivity within sinus histiocytes in a lymph node draining a papillary thyroid carcinoma was observed in a recent case. This prompted the investigation of whether thyroglobulin immunoreactivity is common in regional lymph nodes in cases of thyroid malignancy.

METHODS

Eighty seven lymph nodes were studied from 21 cases of thyroid malignancy. These comprised papillary carcinoma (n = 12), follicular carcinoma (n = 4), medullary carcinoma (n = 3), and one case each of squamous and anaplastic carcinoma. Eleven cervical lymph nodes from patients with no evidence of thyroid disease were included as controls. Sections were stained with a monoclonal antibody against thyroglobulin.

RESULTS

In the cases of thyroid malignancy, 32 of 87 lymph nodes showed positive staining for thyroglobulin of histiocytes within the subcapsular and medullary sinuses. In an additional four cases, there was positive staining of lymph within lymphatic channels. Positivity was present in at least one node in 15 of 21 cases. There was no positivity in the control cases. There was no correlation between the size of the primary tumour and the presence of thyroglobulin positivity.

CONCLUSIONS

Positive staining with antithyroglobulin occurs not uncommonly in sinus histiocytes in lymph nodes draining thyroid tumours. This positivity could be the result of the destruction of normal thyroid follicles, with the release of thyroglobulin, which is taken up by histiocytes, which subsequently drain to local lymph nodes. Pathologists should be aware of this phenomenon and should be careful not to interpret this as metastatic tumour.

Use of cytokeratins 7 and 20 in determining the origin of metastatic carcinoma of unknown primary, with special emphasis on lung cancer

Metastatic carcinoma of unknown primary is a common problem, accounting for up to 10-15% of all solid tumours at presentation. Proper identification of the site of origin has prognostic and therapeutic significance. Prior immunohistochemical methods to identify the site of origin have been useful in a limited number of cases. Differential cytokeratin staining may be useful in this setting, particularly in identifying metastases from lung cancer. We have identified 144 cases of metastatic carcinoma of unknown primary to bone, lung or liver at Brigham and Women's Hospital between 1 January 1997 and 1 July 1998. Cytokeratin (CK) 7 and CK20 were used in 75 of these cases to narrow down the possible sites of the primary tumours. All of these cases were ambiguous as to the site of the primary tumour. Forty-five cases were CK7+/CK20-, 15 cases were CK7-/CK20-, 9 cases were CK7-/CK20+ and 6 cases were CK7+/CK20+. Three of the cases were selected for detailed presentation and discussion as well as a discussion of the pertinent literature. Overall, the CK7+/CK20- phenotype favours a lung primary, the CK7+/CK20+ phenotype strongly favours transitional cells (urothelial) carcinoma, the CK7-/CK20+ phenotype favours colorectal carcinoma, while the CK7-/CK20- profile is not helpful.

Primary intrathyroidal paraganglioma with metachronous carotid body tumor: report of a case and review of the literature

A case of primary intrathyroidal paraganglioma is reported, and the light microscopic and immunohistochemical findings are described. Primary paragangliomas of the thyroid region are extremely uncommon and are therefore often confused clinically and histopathologically with more common intrathyroidal mass lesions. The diagnostic difficulties are underscored by the present case, which was misdiagnosed twice, firstly as a medullary thyroid carcinoma and secondly as a follicular thyroid carcinoma. Immunohistochemistry may be very helpful in arriving at the correct diagnosis. The case was further complicated by a second neck mass contralateral to the original thyroid nodule, which was interpreted as consistent with metastasis. The second lesions was proved angiographically and histologically to be a carotid body paraganglioma.

Tall cell variant of papillary thyroid carcinoma: a reassessment and immunohistochemical study with comparison to the usual type of papillary carcinoma of the thyroid

A review of 92 consecutive cases of papillary thyroid carcinoma diagnosed at The Methodist Hospital revealed 11 tall cell variant (TCV) cases in nine women and two men. There was a greater average age and larger tumor diameter of TCV cases compared with papillary thyroid carcinoma of the usual type (UPTC), but these differences were not statistically significant. Extrathyroidal extension of tumor was noted in nine of 11 TCV cases and was intraoperatively evident in five cases. The presence of extrathyroidal extension represented a statistically significant difference between TCV and UPTC (p = 0.0001) in a multivariate stepwise logistic regression analysis, with controls for variables of age, sex, tumor size, and lymph node metastases. In 11 TCV patients, tumor recurrence was present in two cases, and there was one tumor-associated death with 1 to 4 years of follow-up. Immunohistochemical stains for thyroglobulin, vimentin, keratins, and Leu-7 were positive in all TCV cases and in 16 of 16 UPTC. Immunoreactivity with antibodies to Leu M1 antigen, a myelomonocytic marker included in cluster designation group (CD 15), which is present in many adenocarcinomas, was present diffusely in all TCV, in contrast to UPTC (with sparse immunostaining in only one of 16 cases). Immunoreactivity with antibodies to ZC-23, an anti-carcinoembryonic antigen (CEA) monoclonal antibody with cross-reactivity to nonspecific cross-reacting antigen and biliary glycoprotein antigen, was present in all TCV but was not present in UPTC. COL-1, a CEA-specific monoclonal antibody, was nonimmunoreactive with all TCV and UPTC cases. Epithelial membrane antigen (EMA) was present in all TCV but was also present focally in eight of 16 UPTC, sometimes in a membranous pattern in epithelium surrounding cystic or hemorrhagic spaces. Strong immunoreactivity with antibodies to Leu M1 and EMA in papillary carcinomas of the thyroid has been associated with advanced stages of disease and tumor-associated mortality. The pattern of immunoreactivity in TCV is dissimilar to that in UPTC and is supportive evidence that TCV is a neoplasm that is distinct from papillary thyroid carcinoma of the usual type.

The immunohistochemical localization of S100 in the diagnosis of papillary carcinoma of the thyroid

In general, the diagnosis of papillary carcinoma of the thyroid is readily achieved based on a defined aggregate of histopathologic features. A papillary architecture is an important but not pivotal component of the diagnosis. The recognition of classic nuclear features is the essential diagnostic element. However, both the architectural and cytological hallmarks may be encountered in other conditions and produce problems in histopathologic interpretation. A papillary architecture may be encountered in hyperplastic areas of follicular neoplasms, multinodular goiter, and Graves' disease. Moreover, there may be scattered cells within several thyroid lesions that display some of the nuclear characteristics of papillary carcinoma. The distinction of these lesions from papillary carcinoma has important implications for clinical management. Thus, the availability of supportive diagnostic evidence would be helpful. In the authors' experience, the strong expression of S100 is of value in identifying papillary neoplasia and distinguishing it from examples of papillary hyperplasia. It is of supportive but not conclusive use in distinguishing follicular adenoma from the follicular variant of papillary carcinoma. The authors stress that the overwhelming factor in the distinction remains the identification of the nuclear characteristics of a papillary carcinoma. However, the authors have encountered several cases wherein the latter are either focal or absent for reasons addressed previously and have found immunohistochemistry a valuable adjunct to diagnosis. In examining papillary foci within Graves' disease, caution must be exercised; S100 expression is a phenomenon of the hyperplastic, hyperfunctional state.

The immunology of thyroid cancer

This article reviews the immunologic aspects of thyroid cancer, including thyroid-specific effector elements on thyroid cancer, and discusses the potential antigens, unique molecular markers, and transcription factors that could serve as targets for immunotherapy. The potential role of this type of treatment for thyroid cancer is examined also.

Differentiation of thyroid neoplasms by evaluating epithelial membrane antigen, Leu-7 antigen, epidermal growth factor receptor, and DNA content

The expression of epithelial membrane antigen (EMA), Leu-7 antigen, epidermal growth factor receptor (EGFr), and deoxyribonucleic acid (DNA) content in 40 thyroid nodules was investigated to identify those factors that might differentiate these lesions or correlate to their prognosis. There were 22 carcinomas (16 papillary, 4 follicular, 1 anaplastic, 1 medullary) and 18 benign lesions prospectively obtained between 1989 and 1993. Patients' charts were reviewed to establish a database of known clinical prognostic indicators. Expression of EMA and Leu-7 was significant in malignant lesions when compared to benign lesions (P < 0.02 and P < 0.001). EMA was expressed significantly more frequently by follicular carcinomas than by follicular adenomas (P < 0.03). Leu-7 antigen was expressed by all papillary carcinomas. Neither of these antigens showed any association with known clinical prognostic indicators. EGFr expression neither differentiated benign from malignant lesions nor correlated with prognostic factors. The presence of aneuploidy correlated with poor tumor differentiation (P < 0.02), but did not distinguish benign from malignant lesions. These results suggest that EMA expression may be useful for confirming malignancy in follicular neoplasms and that the expression of Leu-7 antigen can assist in distinguishing papillary carcinoma from benign lesions with pseudopapillae.

An immunohistochemical study of epithelial membrane antigen, cytokeratin, and vimentin in papillary thyroid carcinoma. Recognition of lethal and favorable prognostic types

METHODS

Immunoreactivity for epithelial membrane antigen (EMA), cytokeratin, and vimentin was investigated in 15 papillary thyroid carcinomas (PTC) with distant metastases, 25 PTC without distant metastases, and 34 occult PTC without distant metastases that were found incidentally at autopsy.

RESULTS

More than 50% of the tumor cells were positive for EMA in 7 (47%) of 15 PTC with distant metastases, 0 (0%) of 25 PTC without distant metastases, and 1 (3%) of 34 occult PTC. The incidence of EMA positivity in PTC with distant metastases was significantly different from that of both PTC without distant metastases and occult PTC (P < 0.001). Cytokeratin reactivity was similar in the three groups, and almost all PTC stained strongly for cytokeratin. Concerning vimentin positivity, there were no significant differences in three groups; however, PTC with distant metastases tended to stain more weakly or focally than PTC without distant metastases or occult PTC.

CONCLUSIONS

These results suggest that EMA reactivity may be a useful factor for anticipating the individual risk of distant metastasis or death from PTC at the time of initial surgical treatment.

Diagnostic usefulness of dipeptidyl aminopeptidase IV monoclonal antibody in paraffin-embedded thyroid follicular tumours

Monoclonal antibodies to dipeptidyl aminopeptidase IV (DAP IV, EC 3.4.14.5) were raised and selectively applied to paraffin-embedded sections of thyroid carcinoma. Five monoclonal antibodies were found to stain paraffin sections of thyroid carcinomas. Using one of these antibodies (44-4), we studied retrospectively aberrant expression of DAP IV in thyroid carcinoma to determine whether immunohistochemical staining with DAP IV antibody is useful in pathological diagnosis. In almost all cases of thyroid follicular and papillary carcinoma, tumour cells were positive (99.0 per cent) with DAP IV, whereas the cases of follicular adenoma showed a low incidence (27.1 per cent) of positive staining. Follicular adenoma with incomplete capsular invasion had a higher positive incidence (50 per cent) than follicular adenoma without incomplete capsular invasion (9.6 per cent). In positive staining cases previously diagnosed as benign tumours, 11 benign cases reacting positively with DAP IV were rediagnosed as carcinoma after re-examination of more thyroid paraffin block sections or serial sections. These findings suggest that DAP IV monoclonal antibody is very useful in distinguishing thyroid follicular carcinoma from follicular adenoma.

The macrofollicular variant of papillary thyroid carcinoma: a study of 17 cases

We report 17 cases of a distinctive variant of encapsulated papillary carcinoma that is likely to be confused with macrofollicular adenoma or nodular goiter. The tumors showed the unusual combination of macrofollicles and foci of the conventional follicular variant of papillary carcinoma. Macrofollicles occupied over 50% of the cross-sectional areas of the tumors. The macrofollicles were lined either by cells with large ground-glass nuclei, cells with large but less pale nuclei with stippled chromatin, or cuboidal cells with hyperchromatic nuclei. Solid foci were present in four tumors, and a focal insular growth pattern was noted in a fifth tumor. All patients were females ranging in age from 15 to 69 years (mean, 35.4 years). Despite the large size of the tumors (mean diameter, 4.8 cm), only two metastasized to cervical lymph nodes. One of these neoplasms showed extrathyroidal extension, while the other widely invaded the thyroid tissue through the tumor capsule. Multicentric foci of papillary carcinoma with a follicular nonsclerosing growth pattern were demonstrated in the contralateral lobe in two thyroid glands. All patients with follow-up were alive and symptom-free 2 months to 6 years following surgery.

Gross, histologic, cytochemical, and immunocytochemical study of medullary thyroid carcinoma in sixteen dogs

The gross, histomorphologic, cytochemical, and immunocytochemical findings in 16 dogs with medullary thyroid carcinoma were evaluated. Grossly, the neoplasms were encapsulated, firm, lobulated, and grey-white to tan. The typical histologic pattern was groups or sheets of round to polygonal cells with fibrovascular stroma, which was thickened and hyalinized in places. Variants of clear cell (two dogs), giant cell (one dog), and oxyphil cell (one dog) types were also seen. In all 16 dogs, Grimelius-stained sections of the neoplasms revealed intracytoplasmic silver granules; ten tumors contained amyloid and four contained mucin. Immunohistochemically, the neoplasms reacted to AE1/AE3 (n = 13), S-100 protein (n = 5), neuron specific enolase (n = 14), synaptophysin (n = 11), calcitonin (n = 16), somatostatin (n = 4), gastrin (n = 7), and serotonin (n = 6). Only one neoplasm was positive for vimentin. None of the neoplasms reacted to antibodies for neurofilaments, thyroglobulin, insulin, glucagon, or adrenocorticotrophic hormone. Eleven neoplasms contained multiple (two to four) peptides, in various combinations. It was concluded that in dogs, gross and histologic features can be used to distinguish medullary thyroid carcinoma from other thyroid malignancies. Cytochemical and immunocytochemical studies with neuron specific enolase, synaptophysin, and calcitonin can be used to establish the diagnosis of medullary thyroid carcinoma in dogs.

Alcian blue and epithelial membrane antigen are useful markers in differentiating benign from malignant papillae in thyroid lesions

Immunohistochemistry for epithelial membrane antigen (EMA) and histochemistry for alcianophilic substances were performed in 17 cases of papillary thyroid carcinoma (PTC) and 11 cases of benign thyroid lesions showing papillary changes (7 diffuse hyperplastic goitres-Graves' disease; 4 colloid cystic goitres). In all PTCs the glycocalix of the cells lining the papillary structures was strongly positive with anti-EMA antiserum. Alcian blue pH 2.5 stain (AB 2.5) was also positive in 15 of these cases. In contrast, no cases of benign thyroid lesions showed AB 2.5 positivity in the cells lining the papillary structures and the positivity with anti-EMA antiserum, present in only 5 out the 11 cases, was focal and very weak. These results indicate that the presence and distribution of EMA and alcianophilic substances may be useful in distinguishing benign from malignant thyroid lesions containing papillae.

Lung carcinoma metastatic to microfollicular adenoma of the thyroid. A case report

A 75-year-old woman with lung adenocarcinoma in whom autopsy revealed metastasis to microfollicular adenoma of the thyroid is described. A thyroid tumor specimen from this patient was initially interpreted as representing primary encapsulated follicular carcinoma of the thyroid associated with a component of poorly differentiated carcinoma of follicular cell origin. The widespread involvement of the lungs and other sites was also interpreted as metastases from the poorly differentiated carcinoma component within the encapsulated follicular carcinoma of the thyroid. Subsequent meticulous histologic examination revealed that the thyroid tumor was a microfollicular adenoma, and that the component of poorly differentiated carcinoma within it was the same as the lung carcinoma. Immunohistochemical investigation revealed that the poorly differentiated carcinoma cells within the thyroid tumor were stained positively with polyclonal and monoclonal antibodies against carcinoembryonic antigen (CEA) and negative for thyroglobulin and calcitonin. The carcinoma cells from the lungs and other sites also showed positive staining for CEA. These findings support the view that the component of poorly differentiated carcinoma was a metastatic lesion from the primary lung carcinoma to the microfollicular adenoma of the thyroid. The present study emphasizes that attention should be directed to thyroid metastasis, even if it is within a thyroid primary neoplasm.

Anaplastic carcinoma of the thyroid. A clinicopathologic study of 121 cases

One hundred twenty-one cases of anaplastic carcinoma of the thyroid treated at M.D. Anderson Cancer Center, Houston, were reviewed. Anaplastic carcinoma is a rapidly growing neoplasm with a dismal prognosis. The mean survival of our patients was 7.2 +/- 10 months. A significant percentage of our patients (35%) had areas of well-differentiated thyroid carcinoma elsewhere, supporting the hypothesis that anaplastic thyroid carcinoma arises from preexisting well-differentiated thyroid carcinoma. Twenty-four of 30 tumors analyzed (84%) stained for keratin, 28 (93.3%) stained for vimentin, and ten (33%) stained for epithelial membrane antigen. Younger patients lived longer than older patients, and patients whose disease was earlier-stage at presentation responded better than patients with metastases at presentation. Radical surgery alone did not significantly increase survival duration over less radical surgery. The role of multimodality therapy needs further evaluation.

The utility of some modern techniques in understanding thyroid pathology

A number of evaluating techniques have moved from the research laboratory into the purview of the diagnostic pathologist and have been applied to the analysis of thyroid lesions. Some of these have already proved diagnostically and prognostically useful, whereas some have produced insights into pathogenesis of specific thyroid lesions and disorders. Rapid proliferation and application of these techniques should allow for increased understanding of human thyroid disease in the near future.

Thyroid thymoma in childhood

A nontoxic thyroid nodule was detected in a female infant soon after birth. At 4 years of age, the nodule was removed. Histological examination disclosed a Iobulated spindle-cell neoplasm with focal epithelioid differentiation. The tumor demonstrated diffuse immunopositivity for low-molecular-weight keratins with scattered cells staining for S- 100 protein or leukocyte common antigen; the tumor was negative for calcitonin and thyroglobulin. By electron microscopy, the spindle-shaped cells contained bundles of intracytoplasmic tonofilaments and desmosomes. The light- and electron-microscopical features and immunohistochemical profile of this tumor were those of the recently described primary thyroid thymoma. Thymoma should be considered as a possible, albeit rare, cause of a thyroid mass in infancy or childhood.

Epithelial markers in pancreatic carcinoma: immunoperoxidase localisation of DD9, CEA, EMA and CAM 5.2

Paraffin wax embedded, formalin fixed sections of 22 adenocarcinomas of the exocrine pancreas were stained with four mouse monoclonal antibodies: DD9-E7, an antibody raised against a human pancreatic tumour xenograft; carcino-embryonic antigen (CEA); epithelial membrane antigen (EMA); and cytokeratin (CAM 5.2). An indirect immunoperoxidase technique without enzyme pre-digestion and an affinity-purified sheep anti-mouse peroxidase conjugate were used. All of the tumours were positive for DD9-E7, EMA, and CAM 5.2. Twenty out of 22 were focally positive for CEA and the staining was often weak. As all of these adenocarcinomas were DD9-E7 positive, absence of staining for DD9-E7 in a tumour makes the diagnosis of adenocarcinoma of the exocrine pancreas very unlikely, and this is of value in distinction from endocrine carcinomas with a marked acinar pattern. The weak CEA staining distinguished pancreatic carcinomas from colorectal tumours. Because the distribution of staining for EMA and CAM 5.2 was no different from that previously seen in adenocarcinomas from other sites, these markers are likely to be of limited value in the differential diagnosis of abdominal adenocarcinomas of uncertain origin.

Carcinoembryonic antigen and nonspecific cross-reacting antigen in medullary carcinoma of the thyroid

Carcinoembryonic antigen (CEA) and nonspecific cross-reacting antigen (NCA) were studied immunohistochemically in formalin-fixed, paraffin-embedded tissues of 73 cases of medullary carcinoma of the thyroid (MTC) using 2 polyclonal antibodies (CEA antisera cross-reactive with or without NCA), 3 monoclonal antibodies recognizing epitopes only on CEA, and one monoclonal antibody against NCA. The staining patterns of the 5 antibodies against CEA in MTCs were not different, and they reacted with 86.3% of all cases. With regard to the effects of fixatives on the staining patterns, samples fixed with formalin or 4% paraformaldehyde demonstrated CEA immunoreactivity in both the cell membrane and cytoplasm. In Bouin-fixed tissue, the immunoreactivity was predominant on the cell membrane, whereas cytoplasmic positivity predominated in alcohol-fixed specimens. Thus the difference in fixatives used in previous studies does not appear to be a major reason for the difference in the reported incidence of CEA-positive MTCs. It is concluded that CEA is still a useful tumor marker for MTC and that it is detectable only in thyroid tumors originating from C cells, as seen in our series. The epitope defined by monoclonal antibody F106-88, present only on NCA, was found in 42.5% of all cases (49.2% of CEA-positive MTCs). The NCA immunoreactivity was located in the tumor cell cytoplasm as globular aggregates, which were also labeled for CEA.

An immunohistochemical study of cytokeratin and vimentin in benign and malignant thyroid lesions

Intermediate filaments in benign and malignant thyroid lesions were immunohistochemically studied using polyclonal and monoclonal anti-cytokeratin (CK), and monoclonal anti-vimentin antibodies. Antigenicity of CK and vimentin was almost completely destroyed during formalin fixation in normal thyroid and all thyroid lesions except for some cases of papillary and squamous cell carcinoma, although the latter showed negative immunostaining with anti-vimentin antibody. In sections fixed with Carnoy's fixative, most cases of papillary carcinoma showed an intense reaction product for polyclonal anti-CK, monoclonal anti-CK-7, CK-19 and anti-vimentin antibodies. The reaction product for anti-CK antibodies was located mainly in the apical cytoplasm and that for anti-vimentin antibody in the basal cytoplasm. However antigenicity was still destroyed by the fixative in many specimens of normal thyroid, benign thyroid lesions and follicular carcinoma. In frozen sections, all specimens showed preserved antigenicity for both antigens with an intense reaction product in papillary carcinoma, but this was weaker in normal thyroid, benign thyroid lesions and follicular carcinoma. Therefore, follicular cells under normal and pathological conditions contain intermediate filaments of CK and vimentin in their cytoplasm and co-expression of the antigens is significantly increased in papillary carcinoma.

Applications of immunocytochemistry to diagnostic cytopathology

Immunohistochemical technique is now successfully applied to the cytologic materials. This review article describes details of staining procedures for immunocytochemistry at both light and electron microscopic levels. The clinical application of the technique includes aspiration biopsy cytology for breast lesions, thyroid lesions, lymph nodes, the nervous system, and others. The establishment of carcinoma cells in the body fluid by the demonstration of carcinoembyronic antigen (CEA) and the establishment of specific diagnoses in small-cell or large-cell anaplastic tumors by immunocytochemistry warrants special emphasis.

Mixed medullary-follicular carcinoma of the thyroid. Immunohistochemical and electron microscopic studies

A case of mixed medullary-follicular carcinoma of the thyroid is reported. Grossly, the tumor was a solid, grayish-white, well circumscribed mass without lymph node metastasis. Microscopically, the tumor showed both medullary and follicular areas. The follicular areas occupied discrete portions of the tumor, and were considered to be neoplastic. Tumor cells in the medullary area were polyhedral or spindle-shaped. There was no amyloid deposition within the tumor. Immunohistochemically, tumor cells in the medullary area were positive for calcitonin and negative for thyroglobulin. Some cells lining the follicles were positive for thyroglobulin. By electron microscopy, two types of tumor cell were observed. One type contained numerous cytoplasmic secretory granules, whereas the other type had few granules and showed a prominent rough endoplasmic reticulum. These findings suggested that this mixed medullary-follicular carcinoma of the thyroid presented neoplastic changes within a common cell lineage.

Primary thyroid thymoma: a distinct clinicopathologic entity

A 51-year-old man presented with a paratracheal tumor. He had undergone resection of a thyroid tumor 15 years previously; at that time, the histologic diagnosis had been anaplastic carcinoma. When the tumor recurred, the presumptive clinical diagnosis was medullary thyroid carcinoma. Histologic examination revealed a poorly differentiated epithelial tumor with immunoreactivity for keratins, carcinoembryonic antigen, and, focally, S-100 protein. The tumor was negative for calcitonin and thyroglobulin. There were scattered lymphocytes and plasma cells. Ultrastructural examination showed elongated epithelial cells with prominent desmosomes and bundles of cytoplasmic tonofilaments but no secretory granules; amyloid was not present ultrastructurally or histochemically. The characteristic ultrastructural and immunocytochemical features and the clinical behavior of this tumor verify the existence of primary thyroid thymoma. This new primary thyroid neoplasm is of clinical importance, considering the more benign behavior of primary thyroid thymoma than of other tumors in the differential diagnosis of this lesion.

Thyroglobulin immunostaining in follicular thyroid carcinoma: relationship to the degree of differentiation and cell type

A series of 47 primary and seven metastatic thyroid follicular carcinomas, including well, moderately and poorly differentiated, were tested for thyroglobulin (Tg) using immunohistology. In addition, three combined follicular undifferentiated carcinomas, 17 undifferentiated carcinomas and five renal cell carcinomas metastatic to the thyroid were examined. Only two follicular carcinomas did not stain for thyroglobulin. Some inter-tumour differences in Tg staining were found but there was no absolute correlation between this and the degree of tumour differentiation. The two tumours that failed to stain for Tg were poorly differentiated; thyroglobulin positive poorly differentiated tumours demonstrated a clearly weaker staining pattern for Tg. All but one of 15 oxyphilic follicular carcinomas stained positively for Tg but the staining intensity was often weak. Five of six clear cell follicular carcinomas were positive for Tg but the staining reaction was generally faint and there were often large areas devoid of positive cells. Positive staining was demonstrated in the differentiated areas of combined follicular undifferentiated carcinomas. Undifferentiated carcinomas and metastatic renal cell carcinomas gave negative results. Thyroglobulin is a reliable marker for thyroid follicular carcinoma but the patchy staining pattern, particularly in the less well-differentiated tumours may produce less reliable results in small biopsies.

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.

Prognostic factors in medullary thyroid carcinomas. Survival in relation to age, sex, stage, histology, immunocytochemistry, and DNA content

Patients with medullary thyroid carcinomas (MTC) were analyzed according to age, sex, and tumor stage. In addition, the MTC were screened for the predominant histologic pattern, immunocytochemical spectrum (60 tumors), and DNA content (DNA cytophotometry and DNA flow cytometry, 25 tumors). These findings were correlated with follow-up data available for 45 of these patients. Forty-eight percent of the tumors revealed a polygonal cell pattern, whereas 22% showed spindle-cell predominance. All tumors contained cytokeratin, chromogranin A, and calcitonin (CT). Calcitonin gene-related peptide (CGRP) was present in 92%, carcinoembryonic antigen (CEA) in 77%, neuron-specific enolase (NSE) in 75%, and vimentin in 53% of cases. Positivity for neurotensin, somatostatin, neurofilaments, bombesin, and alpha human chorionic gonadotropin (a-hCG) and serotonin ranged between 3% and 27%. All MTC were negative for substance P, adrenocorticotropic hormone (ACTH), thyroglobulin (TG), or S-100 protein. Local recurrences and regional lymph node metastases revealed identical staining patterns as the primaries. Prognosis of MTC was found not to be related to histologic features (dominant architectural pattern, cellular shape, presence of amyloid deposits) or immunocytochemical pattern. Instead, survival was significantly correlated to age, sex, and stage of disease. The best prognosis was seen in women younger than 40 years and revealing an early stage of disease. DNA measurements added valuable information in assessing the prognosis of MTC.

Patterns of expression of cytoskeletal proteins in human thyroid gland and thyroid carcinomas

By two-dimensional gel electrophoresis of proteins insoluble in detergents and high-salt buffer and immunofluorescence microscopy with a panel of polypeptide-specific antibodies to proteins of intermediate filaments (IF) and desmosomes, we have characterized the cytoskeletons of normal human thyroid gland, several kinds of benign lesion (goiter, Hashimoto's and Graves' diseases, adenomas), and the major thyroid carcinomas (follicular, papillary, medullary, and anaplastic). In all these tissues, desmoplakins and cytokeratins 7, 8, 18, and 19 were identified. While cytokeratins 8 and 18 occurred in all epithelial cells and cytokeratin 7 was also rather widespread, cytokeratin 19 occurred in amounts variable between the different types of tissues and in normal thyroid gland was restricted to certain clusters of follicular epithelial cells. Of all samples studied, in none did we detect cytokeratins commonly associated with stratified epithelia such as cytokeratins 4-6, 10, and 13-17, indicating that these are infrequent, if at all present, in such tissues. Coexpression of cytokeratins with vimentin appears to occur constitutively in follicular epithelial cells of normal thyroid gland and is also frequent in the diverse carcinomas, though to various degrees. Medullary carcinomas are exceptional, not only because they express neuroendocrine markers, but also because they coexpress combinations of cytokeratin IFs with neurofilaments and/or vimentin IFs in some cases, but not all. The results are discussed in relation to states of cell differentiation in normal and diseased thyroid gland and with respect to their value in tumor diagnosis.