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

Somatostatin and Somatostatin Receptors in Tumour Biology

Somatostatin (SST), a growth hormone inhibitory peptide, is expressed in endocrine and non-endocrine tissues, immune cells and the central nervous system (CNS). Post-release from secretory or immune cells, the first most appreciated role that SST exhibits is the antiproliferative effect in target tissue that served as a potential therapeutic intervention in various tumours of different origins. The SST-mediated in vivo and/or in vitro antiproliferative effect in the tumour is considered direct via activation of five different somatostatin receptor subtypes (SSTR1-5), which are well expressed in most tumours and often more than one receptor in a single cell. Second, the indirect effect is associated with the regulation of growth factors. SSTR subtypes are crucial in tumour diagnosis and prognosis. In this review, with the recent development of new SST analogues and receptor-specific agonists with emerging functional consequences of signaling pathways are promising therapeutic avenues in tumours of different origins that are discussed.

Surgical Treatment of Primitive Thyroid Lymphoma

Aims and Background

Primitive thyroid lymphoma, although rare, is becoming more frequent. Its incidence is increasing, from 0.5% in the sixties to 1-5% of all thyroid neoplasms today. The diagnosis of such neoplasms is not always straightforward. In fact, it is often the result of pathologic findings on a gland resected for an apparently benign disease. Surgical dissection may prove more complicated than in standard cases of thyroidectomy for the possible tight adhesions existing between the gland's capsule and the surrounding structures. In cases of capsular infiltration, postoperative external local radiotherapy is indicated.

Methods

A retrospective observational analysis was performed to establish whether patients with incidental thyroid lymphomas who underwent total thyroidectomy for another pathology had major surgical complications and worse prognostic results than patients with an accurate preoperative diagnosis.

Results

Six cases of thyroid lymphoma were retrospectively reviewed: 4 diffuse large B-cell lymphomas and 2 MALT lymphomas. Of these, 2 were correctly preoperatively identified by fine-needle aspiration biopsy and 4 were an unexpected finding at histology: 3 cases of total thyroidectomy carried out for huge hypothyroid goiter in patients affected by Hashimoto's thyroiditis and in 1 case of total thyroidectomy carried out for anaplastic carcinoma in a patient affected by Hashimoto's thyroiditis.

Conclusions

In our experience, a correct preoperative diagnosis was extremely difficult (33%). In patients who underwent fine-needle aspiration, a correct diagnosis was made in 66% of cases. All patients with stage IE lymphoma who underwent total thyroidectomy had equivalent surgical complications and prognosis.

Poorly Differentiated and Anaplastic Thyroid Cancer

BACKGROUND

Poorly differentiated thyroid carcinoma (PDTC) and anaplastic (undifferentiated) thyroid carcinoma (ATC) comprise a small subset of thyroid tumors that are associated with a poor prognosis and account for a significant portion of the morbidity and mortality related to thyroid cancer. Since management strategies vary between these two entities, it is important for clinicians to be able to differentiate PDTC from ATC.

METHODS

We reviewed the literature on PDTC and ATC and compared clinical and histopathologic features important in defining the disease process.

RESULTS

Both PDTC and ATC display aggressive behavior with increased locoregional and distant disease. In most cases, patients are older and have large, locally advanced tumors. PDTC may represent an intermediate entity in the progression of well-differentiated thyroid carcinoma to ATC. The use of surgical management may be curative or palliative and differs between PDTC and ATC. The roles of radiotherapy and chemotherapy have not been well described.

CONCLUSIONS

PDTC and ATC are rare diseases that carry a poor prognosis. Recognition of their different clinicopathologic features is important to the optimal management of these tumors.

Aggressive variants of follicular cell derived thyroid carcinoma; the so called 'real thyroid carcinomas'

The pathological diagnoses and classification schemes for thyroid carcinoma have changed over the past 20 years and continue to do so. New entities have been described and molecular analyses have suggested better characterisation and grouping of certain tumours. Because some of the lesions have been named differently by different authors, clinicians and patients may be confused as to what a specific patient's lesion represents. In this review, we discuss the thyroid tumours of follicular origin which are clinically unusual but important to recognise as their behaviour may be aggressive, they may not respond to radioiodine treatment and they may cause significant mortality. This paper describes these important but rare lesions, their pathological features, important clinicopathological correlations, molecular correlates and prognostic implications.

Hashimoto thyroiditis: a century later

More than a century has passed since the first description of Hashimoto thyroiditis (HT) as a clinicopathologic entity. HT is an autoimmune disease in which a breakdown of immune tolerance is caused by interplay of a variety of immunologic, genetic, and environmental factors. Thyrocyte injury resulting from environmental factors results in expression of new or hidden epitopes that leads to proliferation of autoreactive T and B cells. Infiltration of thyroid by these cells results in HT. In addition to the usual type of HT, several variants such as the fibrous type and Riedal thyroiditis are also recognized. The most recently recognized variant is immunoglobulin G4(+) HT, which may occur as isolated thyroid limited disease or as part of a generalized Ig4-related sclerosing disease. The relationship between HT and Riedel thyroiditis remains unclear; however, recent evidence seems to suggest that it may also be part of the spectrum of Ig4-related sclerosing disease. HT is frequently associated with papillary thyroid carcinoma and may indeed be a risk factor for developing this type of cancer. The relationship between thyroid lymphoma and HT on the other hand appears well established.

Small-cell (basaloid) thyroid carcinoma: a neoplasm with a solid cell nest histogenesis?

In the past, undifferentiated (anaplastic) carcinoma of the thyroid included a small-cell variant with either a diffuse or a compact morphology. After the mid-1980s, with the advance of immunohistochemistry, almost all those rare tumors with the former characteristic were reclassified as low-grade lymphomas and those with the latter characteristic as small-cell variants of medullary carcinoma and poorly differentiated ("insular") carcinoma. Since then, no primary thyroid small-cell carcinoma has been reported in the literature, with the exception of a case of a small-cell (neuroendocrine) carcinoma, an exceedingly rare neoplasm akin to medullary carcinoma, with expression of neuroendocrine markers but lacking calcitonin immunoreactivity. Here, the authors report a primary small-cell carcinoma of the thyroid displaying a basaloid appearance and lacking any signs of neuroendocrine or C-cell differentiation.

The pathology of extrapulmonary small cell carcinoma

Extrapulmonary small cell carcinomas (EPSCCs) are uncommon malignant neoplasms with a reported incidence of 0.1% to 0.4% in the United States. Since their first description in 1930, they have been seen in nearly every organ system. Like their more common pulmonary counterparts, EPSCCs are thought to arise from a multipotential stem cell. However, there is recent molecular evidence that small cell elements may arise as a late-stage phenomenon in the genetic progression of more organ-typical carcinomas. The morphologic, immunohistochemical, and ultrastructural features are similar to those described in pulmonary small cell carcinomas (PSCCs). The differential diagnosis of EPSCC includes PSCC, other neuroendocrine tumors, small round blue cell tumors, metastatic melanoma, lymphoma, and poorly differentiated non-small cell carcinomas. Molecular alterations reported to occur in EPSCCs include abnormalities described in PSCC and changes found in carcinomas more typically encountered in the organ from which they arise. In this article we discuss the pathology of EPSCC with a review of theories of histogenesis, sites of occurrence, diagnostic features, differential diagnosis, molecular alterations, and clinical behavior.

Small cell carcinoma of the head and neck: a review

Small cell carcinoma (SCC) has become recognized as a distinct, though relatively infrequent, clinical pathology that occurs in multiple sites throughout the head and neck. Excluding cases that are considered to arise from skin, SCC in the head and neck has been found to develop in nearly all structures associated with the upper aerodigestive tract. Among the head and neck sites, the frequency of SCC is greatest in the larynx, with salivary glands and the sinonasal region comprising the other principle areas of origin. Controversy exist as to whether SCC can develop as a distinct entity in the thyroid, with most tumors that previously would have been considered as SCC now found to be lymphomas or variant forms of other types of thyroid malignancy. While there seems to be some differences among tumors arising from the various subsites, in general all SCC that originate in the head and neck have a tendency for aggressive local invasion and a strong propensity for both regional and distant metastasis. Treatment may include surgical resection, radiotherapy, chemotherapy, or some combination of these modalities. Due to the infrequency of these tumors, it is very unlikely that any large, controlled study will ever be done. For this reason, recommendations for treatment of SCC arising in the head and neck are based primarily on retrospective data from various small case series and on comparative data for treatment of SCC of bronchogenic and other extrapulmonary origin. Although patients with truly limited local disease may enjoy some prolonged survival, most patients with this tumor do poorly despite all current attempts at treatment.

Anaplastic Thyroid Carcinoma, Thyroid Lymphoma, and Metastasis to Thyroid

Anaplastic thyroid carcinoma, thyroid lymphoma, and secondary metastasis to the thyroid gland are uncommon thyroid malignancies. They represent significant challenges for the surgeon owing to difficulties in diagnosis, aggressive biology, and the infrequency of their presentation. An awareness and appreciation of multimodality treatment strategies is essential for their management.

Anaplastic Thyroid Carcinoma: Biology, Pathogenesis, Prognostic Factors, and Treatment Approaches

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive solid tumors known to affect humans and carries a dismal prognosis. Our primary aim was to review its epidemiology, biology, risk factors, and prognostic indicators. We also reviewed the individual and combined roles of surgery, radiotherapy, chemotherapy, and newer therapeutic options in the management of ATC.

METHODS

An extensive literature review was conducted to include all published reports on ATC. The changing trends in the management of anaplastic thyroid cancer were analyzed to summarize the current practice of management of ATC.

RESULTS

Although ATC is rare, there has been a decline in its incidence worldwide. ATC accounts for more than half of the 1200 deaths per year attributed to thyroid cancer. Long-term survivors are rare, with >75% and 50% of patients harboring cervical nodal disease and metastatic disease, respectively, at presentation. ATC can arise de novo or from preexisting well-differentiated thyroid cancer. Surgical management has shifted from tracheostomy only for palliation to curative resection when possible. Tracheostomy is performed for impending obstruction rather than for prophylaxis. Radiotherapy has evolved from postoperative administration only to preoperative treatment, combining preoperative and postoperative treatment and using higher doses, along with hyperfractionating and accelerating dose schedules. Chemotherapy has changed from monotherapy to combination therapy, and newer drugs such as paclitaxel show promise. Similarly, novel angiogenesis-inhibiting agents are currently being used, with early reports of some benefit.

CONCLUSIONS

Despite multimodality approaches, ATC still carries a dismal prognosis. This should provoke innovative strategies beyond conventional methods to tackle this uniformly lethal disease.

Prognostic factors of anaplastic thyroid carcinoma

BACKGROUND AND PURPOSE

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive malignancies. We tried to elucidate the possible prognostic factors.

METHODS

A retrospective review was conducted of ATC patients in National Taiwan University Hospital from 1978 to 2003. Their demographic characteristics, clinical presentations, laboratory data and treatment modalities were reviewed. Possible prognostic factors for survival were evaluated.

RESULTS

Forty-five patients (14 males and 31 females) of mean age 61.9 +/- 12.6 yr were included in this study. The median survival time was 94 days (range 6 to 776 days). The overall survival rate was 27% at 6 months and 10% at 1 yr. Thirty-two patients receiving intervention regimens had a median survival of 106 days, while 13 patients receiving palliative therapy had a median survival of 39 days. The difference in survival is statistically significant (logrank test, p = 0.017). Adjusted with sex and age, increment in white blood cell count (per 10(9)/l) and serum albumin (per 1.0 g/l) had a hazard ratio of 1.12 (Cox regression, p < 0.001) and 0.92 (p = 0.041), respectively. Patients with leukocytosis [white blood cell (WBC) count > 10(10)/l] or hypoalbuminemia (serum albumin < 35 g/l) had significant shorter survival than patients without leukocytosis or hypoalbuminemia (logrank test p = 0.008 and p = 0.032, respectively). Patients with serum T4 levels lower than 64.35 nmol/l had significantly shorter survival than patients without hypothyroxinemia (median survival 24 vs 128 days, logrank test, p = 0.004).

CONCLUSIONS

ATC is an aggressive malignancy. Leukocytosis, hypoalbuminemia and hypothyroxinemia indicated poor prognosis. Survival time might be prolonged if intervention treatment is tolerable.

Anaplastic thyroid cancer

Anaplastic thyroid carcinoma is one of the most aggressive malignancies, with a poor prognosis. Although rare, representing only 2% of clinically recognized thyroid cancers, the overall median survival is limited to months. Most patients are elderly and seek treatment with a rapidly growing mass. Almost half the patients seek treatment with distant metastases, with as many as 75% developing distant disease during their illness. In most the patients, complete surgical resection is not possible. There are, however, a few patients with resectable disease reported in the literature who have demonstrated long-term survival with aggressive multimodal therapy that included surgery, radiation, and chemotherapy. Preclinical studies in human anaplastic thyroid carcinoma cell lines show promise that new approaches to the management of this disease will be found in the future. Until such time when an effective regimen is found, all patients with anaplastic thyroid carcinoma should be evaluated for multimodal therapy in the setting of a clinical trial.

Anaplastic thyroid carcinoma: a 50-year experience at a single institution

BACKGROUND

Anaplastic thyroid carcinoma (ATC) is among the most aggressive of human malignancies. However, there have been few large studies of histologically well-defined ATC. We report the results of a 50-year experience of this lethal malignancy.

METHODS

We reviewed all cases of ATC managed in this institution between 1949 and 1999. One pathologist (J.R.G.) reviewed all pathologic material. Clinical details were obtained from medical records, and current status of all patients was determined.

RESULTS

There were 134 cases, with a female-to-male ratio of 1.5:1 and a mean age of 67 years. Benign thyroid disease was present in 27 cases (20%) and well-differentiated thyroid carcinoma in 31 (23%). Sixty-two patients (46%) had distant metastases at diagnosis, and 98% of the tumors were locally invasive. Primary treatment was surgical for 96 patients (72%). Complete resection was achieved in 29 cases (30%), with "minimal residual disease" in 25. Neither extent of operation nor completeness of resection affected survival (P > .4). Postoperative radiotherapy gave slightly longer median survival (5 vs 3 months), which was not significant (P < .08). Multimodal therapy, including operation, chemotherapy, and radiotherapy, did not improve survival.

CONCLUSIONS

The outlook for patients with ATC remains grim. Novel treatments for ATC are desperately needed.

Anaplastic thyroid carcinoma: current diagnosis and treatment

BACKGROUND

Anaplastic thyroid carcinoma (ATC), accounting for 5% to 15% of primary malignant thyroid neoplasms, is one of the most aggressive solid tumors in humans. Generally, it is rapidly fatal, with a mean survival of six months after diagnosis. Multimodality treatment with surgery and/or external beam radiotherapy and chemotherapy are of fundamental importance for local control of disease and to enhance survival.

DESIGN

We evaluated consecutive patients with ATC observed at the Mayo Clinic from 1971 to 1993 and reviewed relevant articles published in major English-language medical journals. We used the MEDLINE database, selected bibliographies, and articles available in our personal files.

RESULTS

ATC usually does not concentrate radioiodine or express thyroglobulin. It is essential to verify the diagnosis histologically because insular thyroid cancer, lymphomas, and medullary thyroid cancer are occasionally confused with undifferentiated neoplasms. Immunohistochemical study is helpful in establishing the diagnosis. Multimodal therapy and the development of effective systemic chemotherapeutic agents should result in improvements in survival, although no single agent has yet been identified.

CONCLUSIONS

Aggressive multimodality treatment regimens show promise in improving local control in patients with ATC. However, survival rates remain low. Despite intense application of such therapy, no standardized successful treatment protocol has been established.

Treatment of anaplastic thyroid carcinoma with paclitaxel: phase 2 trial using ninety-six-hour infusion. Collaborative Anaplastic Thyroid Cancer Health Intervention Trials (CATCHIT) Group

Anaplastic thyroid carcinoma is a rare, lethal disease with no effective systemic therapies. Preclinical studies demonstrated antineoplastic activity of paclitaxel. This prompted a prospective phase 2 clinical trial to determine activity of paclitaxel against anaplastic thyroid carcinoma in patients with persistent or metastatic disease despite surgery or local radiation therapy. Twenty patients, entered through 6 of 12 study sites, were treated with 96-hour continuous infusion paclitaxel every 3 weeks for 1 to 6 cycles; the first 7 patients received 120 mg/m2 per 96 hours and the rest received 140 mg/m2 per 96 hours. Total responses to therapy were assessed using modified criteria with response durability acceptable at 2 or more weeks, due to the exceedingly rapid growth rate of this tumor. Plasma samples were obtained for pharmacokinetic analyses. Off-protocol, data showed that 9 patients were later treated with 225 mg/m2 paclitaxel as weekly 1-hour infusions. Nineteen evaluable patients demonstrated a 53% total response rate (95% confidence interval, 29%-76%) with one complete response and nine partial responses (including one off protocol). Results of historical review off-protocol showed 2 of 7 patients, with prior partial responses to the 96-hour infusion, had subsequent partial responses to weekly treatment and 1 of 2 prior nonresponders gained a partial response to weekly therapy. No toxicities greater than grade 2 were seen with 96-hour infusions, while peripheral neuropathy (up to grade 3) was most common with postprotocol weekly infusions. Paclitaxel appears to be the only agent with significant clinical systemic activity against anaplastic thyroid carcinoma; however, it is not capable of altering the lethality of this malignancy, suggesting the need for additional therapeutic innovations. Decreased time intervals between paclitaxel infusions may be more efficacious.

Primary T-cell lymphoma of the thyroid

BACKGROUND

The routine use of immunocytochemical analysis has led to the recognition that many thyroid neoplasms previously diagnosed as anaplastic or small cell carcinomas are actually lymphomas of the thyroid. The great majority are B-cell lymphomas which can be associated with Hashimoto's thyroiditis. In spite of this, thyroid lymphomas are still not commonly recognized as a significant part of thyroid differential diagnosis.

METHODS

A rare case of a primary T-cell lymphoma of the thyroid gland is presented along with general clinical history and physical findings which should make the practitioner suspicious of a thyroid lymphoma. The usefulness of radiology scans and fine-needle aspiration are discussed.

RESULTS

Both prognosis and treatment options are very different for thyroid lymphomas and anaplastic carcinoma.

CONCLUSIONS

Cyclophosphamide/adriamycin/vincristine/prednisolone chemotherapy/radiotherapy regimens have proven to be very effective for most thyroid lymphomas.

Anaplastic thyroid carcinoma: a therapeutic challenge

Anaplastic thyroid carcinoma is an extremely aggressive solid tumor that resists most therapeutic efforts and is almost always fatal. It typically arises as a terminal dedifferentiation of unrecognized long-standing differentiated thyroid carcinoma. Current chemotherapeutic agents are not capable of consistent beneficial therapeutic responses, although rare patients may gain additional months of survival. Aggressive local tumor control with surgery and external beam radiotherapy may provide palliation and delay eventual death from distant metastatic disease. This disease challenges clinicians and researchers to develop new systemic therapies as well as to aggressively treat differentiated thyroid cancers before they become anaplastic tumors.

Computer-assisted image analysis of small cell lymphoma of the thyroid gland. Comparison of nuclear parameters of small lymphocytes in lymphomas and Hashimoto's thyroiditis

The nuclear parameters of the small lymphocytes in nine cases of small cell lymphomas of the thyroid gland and 17 cases of Hashimoto's thyroiditis were assessed by computer-assisted image analysis. The nuclear area, maximal, minimal and averaged Ferret diameters, perimeter, regularity factor and elongation factor were gauged. Statistically, the nuclear area was ascertained to be the optimum descriptor discriminating between small neoplastic and reactive lymphocytes. Application of a novel variable, combining a nuclear area cut-off value of 14 microm2 with a nuclear averaged Ferret diameter cut-off value of 4.5 micron, allows for the distinction - with a high degree of sensitivity and specificity - between small neoplastic lymphocytes in thyroidal lymphomas and the reactive lymphocytes in Hashimoto's thyroiditis.

Anaplastic thyroid carcinoma: behavior, biology, and therapeutic approaches

Anaplastic thyroid carcinoma (ATC), although exceedingly rare, is the most aggressive solid tumor known. Early studies on the effects of different therapies may be biased by the inclusion of responsive "small cell" ATC patients, which are now known to be mostly lymphoma patients. Local control of disease with surgery and/or external beam radiotherapy (XRT) is of fundamental importance to enhance survival. Ultimately, nearly all ATC patients die from their disease, which is widely metastatic. Development of effective systemic chemotherapy agents would provide the best chance for long-term survival of patients. Early preliminary data suggest that paclitaxel may be helpful, although no agent has yet been identified to result in dramatic improvements in survival. Select patients may benefit from aggressive multimodal therapy, although it is important to provide appropriate palliative care when desired.