Expression of cholecystokinin-B/gastrin receptors in medullary thyroid cancer

OBJECTIVE

To characterise the cholecystokinin (CCK) receptor subtypes in medullary thyroid cancer by measuring the expression of CCK-A and CCK-B/gastrin receptor mRNA.

DESIGN

Open study.

SETTING

Teaching hospital, Sweden.

SUBJECTS

6 patients with medullary thyroid cancer.

INTERVENTION

Pentagastrin stimulation test and measurement of calcitonin concentration. Biopsy specimens were analysed using reverse transcription polymerase chain reaction (RT-PCR).

MAIN OUTCOME MEASURE

Presence of CCK-A and CCK-B/gastrin receptors.

RESULTS

All 6 patients with medullary thyroid cancer had positive pentagastrin tests preoperatively. CCK-B/gastrin receptors but not CCK-A receptors were detected by RT-PCR in all six biopsy specimens. By contrast, no CCK receptors were found in normal thyroid tissues or in other thyroid tumours (follicular adenoma, papillary carcinoma, or anaplastic carcinoma).

CONCLUSION

The presence of CCK-B/gastrin receptors in medullary thyroid tumours may have important clinical implications.

Apoptosis and cell proliferation in medullary carcinoma of the breast: a comparative study between medullary and non-medullary carcinoma using the TUNEL method and immunohistochemistry

BACKGROUND AND OBJECTIVES

Medullary carcinoma of the breast has generally been considered to result in better prognosis than ordinary invasive ductal carcinoma, which would seem to be discrepant when one considers its anaplastic histology and high mitotic rate. We attempted to elucidate the prognostic implications of apoptosis and cell proliferation in medullary carcinoma of the breast.

METHODS

Formalin-fixed, paraffin-embedded specimens of 50 cases of typical medullary carcinoma (MC) of the breast and those of 50 control cases of non-medullary invasive ductal carcinoma (N-MC), which were matched to the MC cases in both age and TNM classification, were investigated utilizing the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemistry for p53, bcl-2, and Ki-67.

RESULTS

Mean values of the apoptotic index (AI), the proliferative index (PI), and the ratio of AI to PI (AI/PI) were significantly higher in MC than in N-MC (P < 0.0001). MC exhibited significantly lower positivity for bcl-2 than N-MC (P = 0.00003), while there was no significant difference in p53 positivity between MC and N-MC.

CONCLUSIONS

A high frequency of apoptosis may be related to a favorable prognosis in MC, even though it demonstrates a high proliferative activity, exhibiting a rapid cell turnover.

Factor analysis of dynamic series (FADS) in somatostatin receptor imaging

The aim of this article was to study the physiopathology of tumoral uptake of 111In-pentetreotide using factorial analysis of dynamic series (FADS) and to assess the usefulness of this analysis in somatostatin receptor scintigraphy.

METHODS

Forty-one patients were included, 24 women and 17 men. After intravenous injection of 111 MBq 111In-pentetreotide, dynamic image acquisition (68 images of 30 s) began in front of the suspected tumoral site: thoracic in 10 patients with medullary carcinoma of the thyroid and 2 patients with bronchogenic carcinoid, and abdominal in 12 cases of midgut carcinoid and 17 cases of other gastroenteropancreatic neuroendocrine tumors. FADS was performed with FAMIS software. Static images were obtained 4 h and 24 h later. For every patient, surgery and/or clinical follow-up (4 y) was used to classify results as true (T) or false (F) positive (P) or negative (N) and to evaluate both the sensitivity of static images and the usefulness of FADS.

RESULTS

Of the 14 cases of carcinoid tumor, 5 patients were TN; 9 patients were TP with static images but only 8 were TP with FADS (a bronchogenic carcinoid of 6 mm was missed). Of the 17 cases of gastroenteropancreatic neuroendocrine tumor, static images were TP in 9 patients, and FADS were TP in 5 of these patients (and 4 FN). Static images and FADS were FN in 4 patients and TN in 3 patients, and in the 2 last patients static images were FP, but FADS were TN. Of the 10 cases of medullary carcinoma of the thyroid, static images and FADS were TN in 1 patient, static images were TP in 3 patients and FADS were TP in 2 of these patients (and 1 FN). In the six last cases, static images were FN, but FADS were FN in 3 patients and TP in 3 patients, showing an infiltrate.

CONCLUSION

FADS demonstrates that tumoral kinetics are similar to those of the spleen. FADS can show a diffuse tumoral uptake corresponding to tumoral infiltrate in medullary carcinoma of the thyroid or in hepatic miliaria, whereas static images were normal or doubtful.

Blood group antigens in differentiated thyroid neoplasms

Alteration of cell-surface blood group antigens during malignant transformation is a well-known phenomenon that has not yet been sufficiently investigated in thyroid gland neoplasms. We evaluated 50 normal thyroid glands and 141 differentiated thyroid neoplasms (29 follicular adenomas, 30 follicular carcinomas, 56 papillary carcinomas, and 26 medullary carcinomas) both by the immunoperoxidase technique, using monoclonal antibodies against blood group antigens (A, B, H, Le(a), Le(b), Le(x), and Le(y)) and precursor substances (T, Tn, and sTn), and by affinity to the lectin from Arachis hypogea, to determine the usefulness of these antigens as tumor markers and prognostic factors. Neoplastic tissues showed immunostaining with concordant and nonconcordant expression of ABH antigens. There were statistically significant differences between normal and neoplastic tissues but not among the different neoplasms. Statistically significant differences in Lewis antigen expression were noted between normal and neoplastic tissues and between benign and malignant tumors. Tn and sTn antigen expression showed statistically significant differences between normal and neoplastic tissues. In conclusion, blood group antigens are tumor markers that are expressed more frequently in malignant than in benign neoplasms. The presence of metastases was correlated with enhanced peanut lectin receptors and a loss of A or B antigens.

Angiogenesis in poorly differentiated medullary carcinoma of the stomach

We studied the role of angiogenesis in patients with medullary type poorly differentiated adenocarcinoma (MTPDA) of the stomach. Immunohistochemical analyses were conducted using antibodies against factor VIII (endothelial cells), vascular endothelial growth factor (VEGF) and its receptors (KDR andflt-1), and basic fibroblast growth factor (bFGF) and its receptors (bek andflg). Archival specimens of MTPDA (n=22) and non-MTPDA (n=47) were studied. The expression of VEGF and bFGF, the vessel count, and positivity of KDR on endothelium were all significantly higher in MTPDA than in non-MTPDA. The vessel count correlated with the VEGF expression in MTPDA. The vessel count and VEGF expression increased with the increasing stage of disease in MTPDA but not in non-MTPDA. The expression of bFGF and its receptors did not correlate with the vessel count and stage of disease in either type. These findings thus suggest that the biological behavior of medullary type poorly differentiated adenocarcinoma of the stomach is angiogenesis-dependent. The correlation of the VEGF expression and its endothelial receptors with the vessel count and the stage of disease thus suggests that VEGF is a factor responsible for the induction of angiogenesis in this type.

Medullary carcinoma of the thyroid glad: diagnostic cytopathological characteristics

Sixty fine needle aspiration biopsy samples of the medullary carcinoma of the thyroid, 49 primary and 11 recurrent/metastatic, were reexamined in order to determine diagnostic features and value of auxiliary techniques. In the smears, tumor cells were present either as single cells or in loose cohesive groups; in about one third of cases, three-dimensional groups predominated. Cells were of different shapes round-to-oval, polyhedral and spindle. The aspirates contained one or all three cell types. Large mononucleated cells were present in 47/60 cases and, in addition, in 34 of these multinucleated cells with nuclei arrayed in semicircular rows were present. Plasmacytoid and dendritic cells, observed in 58/60 cases, appear to be an important diagnostic feature. Red cytoplasmic granules and amyloid deposits could serve as an additional diagnostic clue. Among the auxiliary techniques, the demonstration of calcitonin and CEA immunoreactive cells proved to be the most helpful.

Evaluation of fluorodeoxyglucose-positron emission tomographic scanning and its association with glucose transporter expression in medullary thyroid carcinoma and pheochromocytoma: a clinical and molecular study

BACKGROUND

Imaging of metastatic sites of medullary thyroid carcinoma (MTC) is successful in less than 60% of cases of residual or recurrent disease. Positron emission tomography (PET) with [18F]fluoro-2-deoxy-D-glucose (FDG) takes advantage of the fact that malignant tumors are capable of increased uptake and use of glucose, which is mediated by the members of the glucose transporter family of proteins (GLUT 1 through GLUT 5).

METHODS

FDG-PET images of 10 patients with recurrent or persistent MTC after primary operation were compared with images by computed tomography or magnetic resonance imaging. Identified metastatic lesions were assessed by intraoperative findings and pathology reports. Expression of GLUT 1 through GLUT 5 was examined by Western blot analysis of tumor tissue from eight of the patients evaluated and an additional panel of 10 MTCs and seven pheochromocytomas.

RESULTS

FDG-PET identified 31 foci of FDG accumulation in 10 patients, and 16 of these metastatic sites were resected and confirmed by histologic analysis. Only 11 foci were demonstrated by computed tomographic or magnetic resonance imaging. None of the glucose transporters examined displayed significant expression. Two pheochromocytomas were successfully imaged by FDG-PET.

CONCLUSIONS

FDG-PET imaging can be useful in the localization of cervicomediastinal MTC metastases and pheochromocytoma. The increased glucose uptake in these tumors, as evidenced by FDG-PET, does not appear to be attributable to the expression of the glucose transporter proteins GLUT 1 through GLUT 5.

Amphicrine medullary carcinoma of the thyroid with luminal differentiation: report of an immunohistochemical and ultrastructural study

A case of amphicrine medullary carcinoma of the thyroid is presented. The patient was an 18-year-old female with nonhereditary MEN IIb, submucosal neuromas in the oral cavity, and a thyroid tumor that metastasized to regional lymph nodes. Histologically the thyroid tumor was composed of polygonal cells arranged in a solid/trabecular pattern admixed with mucus-producing goblet cells and displaying focal cytoplasmic lumen formation. Immunohistochemical stains were positive for calcitonin, carcinoembryonic antigen, and chromogranin. Electron microscopy demonstrated C-cells containing neurosecretory granules as well as intestinal-type microlumina. The presence of goblet cells and intestinal-type microlumina in medullary carcinoma of the thyroid is reminiscent of amphicrine tumors of the gastrointestinal tract and supports the hypothesis that the parafollicular C-cells of the thyroid may be of endodermal derivation.

S-100 protein is a differentiation marker in thyroid carcinoma of follicular cell origin: an immunohistochemical study

S-100 protein, a dimer of S-100 alpha and S-100 beta subunits (S-100 alpha and S-100 beta), is widely distributed in human tissue, and several papers describing S-100 protein expression in follicular cells of the thyroid have been published. In the present study, 105 cases of thyroid carcinoma (of which 96 were papillary, four follicular, two undifferentiated, and three medullary) were analyzed immunohistochemically for the expression of S-100 protein, S-100 alpha, S-100 beta, and thyroglobulin. In papillary carcinoma, 188 lesions were studied and classified into well differentiated types (56 papillary, 45 follicular) and poorly differentiated types (41 trabecular, four solid, eight squamoid, three tall, and one insular), because the histological structure of each tumor was heterogeneous. The percentage of lesions which expressed positively for S-100 protein and S-100 alpha, respectively, according to type were: papillary, 96 and 99%; follicular, 96 and 100%; trabecular, 95 and 100%; solid, 50 and 50%; squamoid, 50 and 75%; and tall, 33 and 100%. The insular type was negative for both. For papillary carcinoma, well differentiated lesions showed stronger S-100 alpha expression than poorly differentiated lesions. S-100 alpha expression was weaker in follicular and undifferentiated carcinoma than in papillary carcinoma. Medullary carcinoma also expressed S-100 alpha. S-100 beta was positive in lesions that expressed S-100 alpha strongly. Expression of S-100 protein and S-100 alpha protein correlated with thyroglobulin synthesis in the follicular cells. It was concluded that S-100 protein, mainly S-100 alpha, exists in thyroid follicular cells, that it exists in higher quantity in most of the well differentiated lesions but in lower quantity in poorly differentiated or undifferentiated lesions, and that S-100 protein, especially S-100 alpha, is a differentiation marker in carcinoma of thyroid follicular cell origin.

The RET proto-oncogene in medullary and papillary thyroid carcinoma. Molecular features, pathophysiology and clinical implications

The evolution of cancer is a multistep phenomenon, and multiple cellular genetic lesions are involved in the emergence of the malignant neoplasm. Several early events have been implicated in the neoplastic transformation of thyrocytes, and recent reports have described the involvement of specific genetic alterations in different types of thyroid neoplasms: ras point mutations are frequently observed in tumours with follicular histology, gsp-the mutated form of the alpha subunit of the Gs-protein-is encountered in up to 73% of papillary or follicular thyroid carcinomas, and a high prevalence of p53 point mutations has been found in anaplastic thyroid carcinomas but not in differentiated follicular tumours. More recent studies revealed that the RET proto-oncogene is involved in the oncogenesis of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) by activation of its tyrosine kinase either by point mutation or rearrangement. In this review the most important recently published data on alterations of the RET proto-oncogene in heritable and sporadic MTCs and in PTCs will be summarized. Emphasis will be directed to the pathophysiological mechanisms of tumour initiation, the indications and limitations of DNA testing, and the clinical implications of identified RET defects in thyroid lesions.

Poorly differentiated colonic adenocarcinoma, medullary type: clinical, phenotypic, and molecular characteristics

Clinicopathological evidence has accumulated that colorectal adenocarcinoma with minimal or no glandular differentiation constitutes two entities with different prognosis. In a series of 20 predominantly nonglandular, poorly differentiated adenocarcinomas, histological features, DNA content, p53 protein expression, Ki-ras mutation, and microsatellite instability were analyzed and correlated to the biology of the tumors. In addition, the presence of Epstein-Barr virus (EBV) transcripts was tested by RNA in situ hybridization and EBV DNA was demonstrated by nested polymerase chain reaction. Histologically, 13 tumors showed small uniform cells and 7 tumors showed large pleomorphic cells. Tumors with uniform cells exhibited more commonly an expansive growth pattern (69.2% versus 0%; P < 0.025) and a dense peritumor lymphoid infiltrate (84.6% versus 14.3%; P < 0.01) resembling their gastric counterpart, solid or medullary carcinoma. These tumors showed less frequent lymph node as well as hematogeneous metastases than pleomorphic carcinomas. In addition, they were usually diploid (84.6% versus 28.6%; P < 0.05) and lacked stabilization of the p53 protein (0% versus 42.9%; P < 0.05). No significant difference between the medullary and the pleomorphic tumor type was found with respect to bcl2 expression and the occurrence of Ki-ras mutations at codon 12. In contrast, microsatellite instability was almost totally restricted to poorly differentiated adenocarcinomas of the medullary type (100% versus 14.3%; P < 0.001). Finally, polymerase chain reaction revealed EBV DNA in 5 tumor specimens, which was, however, restricted to the peritumor lymphoid infiltrate as shown by in situ hybridization. Correlation with the biology of the tumors revealed that only one patient with the uniform cell type died due to metastastic disease during the follow-up period (median, 31 months), which was the case in five of the seven patients with the pleomorphic-type carcinoma (P < 0.025). Our results clearly indicate that the poorly differentiated colonic carcinoma with minimal or no glandular structures constitute two different entities, a medullary and a pleomorphic variant, which markedly differ in their phenotype, genotype, and prognosis.

Mixed medullary-follicular carcinoma of the thyroid. A morphological, immunohistochemical and in situ hybridization analysis of 11 cases

Mixed medullary-follicular carcinomas (MMFC) of the thyroid are rare tumours showing the morphological and immunochemical properties of both parafollicular and follicular cell lineages. Their recognition is based on a classical WHO definition, although several other patterns have been described in recent years. We investigated 11 cases of MMFC by immunohistochemistry and in situ hybridization (ISH) to analyse the structural features, the immunophenotypic profile and the calcitonin (CT) and thyroglobulin (TG) gene expression of the neoplasm. Histologically, 10 cases had mixed parafollicular and follicular cell populations in the primary tumour and 1 only in the lymph node metastasis. All cases were immunoreactive for CT (in medullary areas) and TG (in follicular areas and also in the solid component of 8/11 cases). These findings were confirmed by ISH analysis. Combined ISH and immunostaining showed that most cases had separate CT and TG gene expression, although rare cells with concurrent CT and TG gene expression were identified in 2 tumours. We conclude that (a) MMFC display heterogeneous morphological patterns and are a special type of thyroid tumour undergoing divergent differentiation; (b) in MMFC, CT and TG genes are generally not simultaneously expressed by the same cell, although dual expression of CT and TG was present in rare neoplastic elements; and (c) the origin of MMFC, whether they are derived from the ultimo-branchial body or result from neoplastic transformation of different cell populations following common oncogenic stimuli, is unclear.

Telomerase expression in human breast cancer with and without lymph node metastases

Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA onto the ends of chromosomes, thereby preventing the replication-dependent shortening of these ends. Telomerase activity is detected in a wide range of cancers of various tissues, and its expression may be a critical step in tumor progression. The telomeric repeat amplification protocol was used to compare telomerase activity in breast cancers with and without lymph node metastases, as well as in fibroadenomas and normal breast tissue. Expression of telomerase was detected in 22 (79%) of 28 primary breast cancers, which included 16 (73%) of 22 cancers positive and 6 (100%) of 6 cancers negative for axillary lymph node metastases. It was detected in 1 (11%) of 9 fibroadenomas but was negative in 13 normal breast tissues. There was no statistical difference in expression of telomerase between axillary node-negative primary breast cancers and similar tumors with nodal metastasis (P = .289). Further, no statistical association was found between telomerase activity and tumor size (P = .679) or hormonal status (P = .178). The difference in telomerase activity among breast cancers vs fibroadenomas and normal breast tissues, however, was statistically significant (P < .001). Although normal breast tissue does not express telomerase, both node-positive and node-negative breast cancers express telomerase. The possible significance of telomerase expression in fibroadenomas remains open to further investigation.

Molecular analysis of the RET proto-oncogene in patients with sporadic medullary thyroid carcinoma: a novel point mutation in the extracellular cysteine-rich domain

Germline point mutations in the RET proto-oncogene are associated with multiple endocrine neoplasia type 2 (2A and 2B) and familial medullary thyroid carcinoma. On the other hand, somatic point mutations of RET have been described in a subset of sporadic medullary thyroid carcinomas (MTCs). We examined tumor and blood DNA of thirteen apparently sporadic MTC patients for mutations in RET exons 10, 11, 13, 15 and 16 to determine whether they had true sporadic tumors or either de novo or occult germline mutations. Three different somatic missense mutations were documented in seven patients. In five patients a mutation in exon 16, codon 918, (ATG-->ACG) causing a Met-->Thr substitution was found. In the remaining two patients the mutation affected exon 11: codon 630 in one case and codon 634 in the other. In both cases a T-->C transversion was identified causing a Cys-->Arg substitution. In conclusion, absence of a germline mutation in RET exons 10, 11, 13 or 16 is evidence against an inherited form in all cases. In seven patients, identification of a somatic mutation supported the previous clinical diagnosis of sporadic medullary thyroid carcinoma; in one of them we identified a hitherto undescribed somatic point mutation at codon 630.

Regulatory peptides and other neuroendocrine markers in medullary carcinoma of the thyroid

Medullary thyroid carcinoma (MTC) is an APUDoma (APUD refers to amine precursor uptake and decarboxylation) arising from the parafollicular cells. Diarrhoea has been reported in some 30% of patients, variously attributed to excess production of calcitonin (CT), serotonin (5-HT), vasoactive intestinal peptide (VIP) or other factors. The regulatory factors in MTC were examined employing immunocytochemistry and RIA to tumours and their extracts. The patients were followed up for more than 15 years. CT and calcitonin gene-related peptide were universally expressed in all the tumours. The neuroendocrine markers chromogranin A (and its fragments pancreastatin and WE-14), neurone-specific enolase, protein gene product 9.5 and carcino-embryonic antigen were found in the majority of MTCs and might be useful as immunocytochemical markers. 5-HT, substance P, neurokinin A, glucagon and VIP could not be detected, excluding them as candidates in the diarrhoea of MTC.

Immunoelectron microscopic demonstration of regulated pathway for calcitonin and constitutive pathway for carcinoembryonic antigen in the same cells of human medullary carcinomas of thyroid glands

The human medullary carcinomas are well known to secrete calcitonin (CT) as a neuroendocrine peptide and carcinoembryonic antigen (CEA) as a serum protein that is integrated into the cell membrane. This ultrastructural study is designed to elucidate whether CT and CEA are secreted via two different intracellular secretory pathways, a regulated pathway and a constitutive pathway. The immunoelectron microscopic postembedding method, performed on four cases of the human medullary carcinomas of the thyroid using plastic embedding material, disclosed two distinct different localization patterns for CT and CEA. CT was localized exclusively in dense cored secretory granules. CEA was present in the cell membrane and in the secretory vesicles. The secretory granules were completely negative for CEA. The trans-Golgi networks were also positive for CT and CEA. Electron microscopic double staining confirmed these localization in the same carcinoma cells. These observations suggest the presence of two distinct pathways in the endocrine cancer cells, i.e., the regulated pathway for CT and the constitutive pathway for CEA.

[Histopathological and immunohistochemical studies on medullary thyroid carcinoma]

In order to study the multidifferentiation of medullary carcinoma of the thyroid gland (MCT), 24 cases of MCT were examined for the presence of immunoreactive calcitonin (CT), thyroglobulin (Tg), chromogranin A (CgA), somatostatin (SS), serotonin (5-HT), S-100 protein (S-100), neuron-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), adrenocorticotrophin (ACTH) and neurofilament protein (NF) by using immunohistochemical ABC methods. Results showed that CT-immunoreactive cells were present in all tumors. Tg was present in three tumors. 23 cases contained CgA-immunoreactive cells. 14 tumors contained 5-HT-immunoreactive cells, 10 cases were immunoreactive to NSE and SS. 4 tumors contained VIP-immunoreactive cells and only one cases was positive for S-100. The demonstration of immunoreactivity for multiple antigens in 24 cases suggests that the origin of medullary thyroid carcinoma may originate from neuroectoderm cells potentially capable of producing numerous hormone substances. In addition, as the neoplastic cells in 12% of the tumors containing hormone substances as well as thyroglobulin, it is suggested that follicular epithelial differentiation and mixed medullary thyroid carcinoma may be more common than previously suspected. Recent studies indicate that mixed carcinoma of the thyroid may be derived from common stem cells in posterior branchia capable of differentiating into both follicular and parafollicular tumor cells.

Multivariate analysis of prognostic factors in sporadic medullary carcinoma of the thyroid. A retrospective study of 109 consecutive patients

BACKGROUND

Because of the rarity of medullary thyroid carcinoma, adequate information for determination of the prognostic characteristics and clinical course of this disease can be obtained only from a database that serves a large population.

METHODS

A retrospective review of 109 patients with sporadic medullary thyroid carcinoma was conducted; all were diagnosed and treated at a single institution over a 30-year period. The series included 57 males and 52 females with a median follow-up of 5.3 years. Statistical univariate analysis of relapse free survival and overall survival was done for 18 clinicopathologic variables, including sex, age, TNM staging, completeness of surgical resection, postoperative calcitoninemia, histologic subtype, tumor size, thyroid capsule invasion, amyloid, katacalcin, calcitonin, and calcitonin gene-related peptide immunostaining patterns of the primary tumor.

RESULTS

Risk factors for unfavorable outcome were male sex, age > 60 years, incomplete tumor resection, mixed cell subtype, tumor size > 4 cm, extrathyroid tumor invasion, lack of amyloid, N1 and M1 categories, and heterogeneous calcitonin and katacalcin immunostaining pattern. In the multivariate analysis, only capsule status, M category, and age at diagnosis remained in the final model for overall survival. In the final model for relapse free survival, capsule status remained, together with sex and amyloid status.

CONCLUSIONS

Extrathyroid tumor invasion, the presence of distant metastases, and age > 60 years are characteristic of patients at high risk of death from disease sooner, whereas extrathyroid invasion, male sex, and the absence of amyloid characterize patients who are at high risk for recurrence. Extrathyroid tumor invasion appears to be the worst prognostic factor and may allow for the breakdown of patients into two categories, amenable to different therapeutic regimens.

Medullary breast carcinoma vs. poorly differentiated ductal carcinoma: an immunohistochemical study with keratin 19 and oestrogen receptor staining

Sixty breast carcinomas previously indexed as medullary carcinomas over a 24-year-period were reviewed and reclassified according to definitions suggested by Ridolfi et al. as typical medullary carcinoma, atypical medullary carcinoma, and non-medullary carcinoma. Paraffin sections of tumour tissue were examined by an avidin-biotin complex method using two keratin 19-specific monoclonal antibodies (BA17, DAKO and clone 170-2-14, Boehringer) and a monoclonal oestrogen receptor antibody (DAKO). For comparison 52 ductal carcinomas of grade II and grade III were immunostained as well. The results showed that all 60 tumours with medullary features and all 52 ductal carcinomas reacted moderately to strongly positive with anti-keratin 19 (Boehringer). The staining was diffuse in all cases, except one case of ductal carcinoma (grade III), which stained focally. Immunostaining with the second keratin 19 antibody (BA17) revealed similar results with positive staining in 59 (95%) cases of carcinomas with medullary features and 51 (98%) cases of ductal carcinomas. Only one case in each group did not express keratin 19 (BA17), one re-classified case of non-medullary carcinoma with neuroendocrine features and one case of ductal carcinoma of grade III. None of the 13 cases of typical medullary carcinoma were oestrogen receptor positive and only seven (12%) of the carcinomas with medullary features (2 atypical, 5 non-medullary) were oestrogen receptor positive with quantitative values from 20 to 100%. The 52 ductal carcinomas of grade II and III were oestrogen receptor positive in 56% and 47% of cases. It is concluded that keratin 19 staining is of no particular value in differentiating medullary from poorly differentiated ductal carcinoma. A carcinoma with positive oestrogen receptor staining is not likely to be a typical medullary carcinoma.

[Histologic and immunohistochemical characterization of medullary thyroid carcinoma]

14 cases of medullary thyroid carcinoma are investigated. The variability of the structure and cell composition of tumors is demonstrated. Stroma amyloidosis is one of the most frequent features of the tumor (83% of cases). The use of immunohistochemistry aiming to show a positive reaction of tumor cells to calcitonin is necessary for diagnosis confirmation. The tumors are found with thyroglobulin-positive cells. One tumor was observed with histologic and immunohistochemical features of mixed medullary-follicular thyroid carcinoma the histogenesis of which needs further studies.

Comparison of octreotide scintigraphy and conventional imaging in medullary thyroid carcinoma

We evaluated the clinical utility of positive somatostatin receptor scintigraphy in patients with medullary thyroid cancer (MTC).

METHODS

Twenty-four MTC patients with increased calcitonin levels underwent somatostatin receptor scintigraphy using 111In-pentetreotide (120-200 MBq) with early (4 hr after injection) and delayed (24 hr) whole-body scans and liver SPECT imaging. In Group 1 (12 patients), conventional imaging modalities demonstrated the presence of tumor sites prior to somatostatin receptor scintigraphy; in Group 2 (12 patients), conventional imaging modalities were negative or inconclusive.

RESULTS

Somatostatin receptor scintigraphy had positive results in 9 of 24 patients (37%): of Group 1 patients, 7 of 12 had positive somatostatin receptor scintigraphy results. Of these patients cases, somatostatin receptor scintigraphy demonstrated several involved organs and tumor sites either identical (two patients) or smaller (five patients) in size than conventional imaging modalities. Only two patients in Group 2 had positive somatostatin receptor scintigraphy results which demonstrated significant mediastinal uptake previously classified as indeterminate on conventional imaging modalities. No new tumor site was identified nor were therapeutic options modified by the somatostatin receptor scintigraphy results.

CONCLUSION

Somatostatin receptor scintigraphy only demonstrates part of tumor sites and cannot visualize small tumor sites (< or = 1 cm). We believe that somatostatin receptor scintigraphy has a limited role in the management of MTC patients.