Pure squamous cell carcinoma and mixed adenosquamous cell carcinoma of the thyroid gland

Progress in diagnosing and treating thyroid squamous cell carcinoma under the 5th edition of WHO classification

Squamous cell carcinoma of the thyroid (SCCT) is a rare thyroid gland malignancy, with only a few hundred cases reported in the literature, mostly as case reports or small sample studies. In the previous WHO classification, squamous cell carcinoma of the thyroid was defined as a carcinoma composed entirely of squamous cells without differentiated carcinoma components. It was once included in the WHO tumor classification separately. However, the 2022 WHO classification of squamous cell carcinoma of the thyroid was reclassified as a morphologic subtype of anaplastic thyroid carcinoma (ATC). The squamous cell carcinoma pattern is similar to the other histologic types of ATC, but the phenotype associated has a poorer prognosis. The typical clinical manifestation of this condition is a cervical mass, accompanied by indications and symptoms of compression on adjacent structures such as the esophagus and trachea in advanced stages. Secondary squamous cell carcinoma of the thyroid may occur due to the spread of squamous carcinoma of the larynx or esophagus or distant metastases from other sites. Diagnosis of squamous cell carcinoma of the thyroid includes neck Ultrasound (US), Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), puncture tissue biopsy, and full endoscopy to identify metastatic lesions from the nasopharynx, oropharynx, hypopharynx, larynx, esophagus, or bronchi and to help with the initial staging of the tumor. Current treatment modalities include surgery, radiotherapy, chemotherapy, or a combination. Because of the poor prognosis of patients with this disease, the short survival period, usually less than one year, and the difficulty of preoperative diagnosis, this article reviews the epidemiological features, origin, clinical features, pathological features, and differential diagnosis to improve the diagnosis and treatment of this disease by clinicians.

Primary Squamous Cell Carcinoma in the Thyroid Gland: A Population-Based Analysis Using the SEER Database

OBJECTS

To evaluate prognostic factors and treatment outcomes of primary squamous cell carcinoma in thyroid (PSCCTh) over the past decades using a large national database.

METHODS

All patients diagnosed with PSCCTh between 1973 and 2015 were identified with the Surveillance, Epidemiology, and End Results Program (SEER) 18-registry database. Relevant clinical data were collected, and prognostic factors of overall survival (OS) and disease-specific survival (DSS) were analyzed.

RESULTS

This cohort study included 242 patients, accounting for 0.12% of all primary thyroid carcinomas from 1973 to 2015 nationwide. Of the patients with PSCCTh, 75% were older than 60 years at diagnosis. Patient age older than 60 years (HR 2.242, 95% CI 1.367-3.676, P = 0.001) and a tumor size larger than or equal to 50 mm (HR 1.479, 95% CI 1.011-2.165, P = 0.044) were independent negative prognostic factors. The univariate analysis suggested that the morphological subtype (OS, P = 0.033; DSS, P = 0.048), clinical treatment modality (OS, P < 0.0001; DSS, P < 0.0001), and T stage (OS, P = 0.004; DSS, P = 0.001) were important predictive factors for OS and DSS. In contrast, gender, race, year of diagnosis, geographic location, N stage, and M stage were not prognostic factors.

CONCLUSIONS

PSCCTh is a rare malignancy with an aggressive nature and poor prognosis. Survival is predicted by the treatment modality, patient age, T stage, tumor size, and morphological subtypes. This study showed that early diagnosis and complete surgical resection plus adjuvant radiation therapy were associated with a better outcome.

Primary Squamous Cell Carcinoma of the Thyroid: Immunohistochemical Profile and Literature Review

Background

Squamous cell carcinoma accounts for 1% of primary thyroid malignancies and is characterized by a rapidly unfavorable outcome.

Case Presentation

A 64-year-old woman presented with a painless mass in the left neck, coexisting with thyroid goiter. Total thyroidectomy with lymphadenectomy was performed and a primary thyroid squamous cell cancer was confirmed histo-logically after excluding any other possible primary malignancies. The tumor's immunohistochemical profile was explored using a large panel of antibodies. The tumor featured a positive immunoreaction to cytokeratins 7–19 and to squamous cell carcinoma antigen. Low-molecular-weight cytokeratins 5–6 and epithelial membrane antigen were also expressed. The neoplasm's proliferative index (Mib1) was 60%. No immunostaining was detected for cytokeratins 10–20, thyroglobulin, TTF-1, CD5, galectin-3 or p53.

Conclusions

This case of primary thyroid squamous cell carcinoma immunohistochemically profiled using a large panel of immunoreactions may offer useful information on the histological differentiation of thyroid squamous cell carcinoma from other (uncommon) thyroid carcinomas and the distinction between primary and secondary thyroid cancers.

Primary Squamous Cell Carcinoma of the Thyroid: A Population-Based Analysis

Objectives To analyze the epidemiology and describe the prognostic indicators of patients with primary squamous cell carcinoma of the thyroid. Study Design and Setting Retrospective cohort study based on a national database. Methods The US National Cancer Institute's SEER registry (Surveillance, Epidemiology, and End Results) was reviewed for patients with primary squamous cell carcinoma of the thyroid from 1973 to 2012. Study variables included age, sex, race, tumor size, tumor grade, regional and distant metastases, and treatment modality. Survival measures included overall survival (OS) and disease-specific survival (DSS). Results A total of 199 cases of primary squamous cell carcinoma of the thyroid were identified. Mean age at diagnosis was 68.1 years; 58.3% were female; and 79.4% were white. Following diagnosis, 46.3% of patients underwent surgery; 55.7%, radiation therapy; and 45.8%, surgery with radiation therapy. Kaplan-Meier analysis demonstrated OS and DSS of 16% and 21% at 5 years, respectively. Median survival after diagnosis was 9.1 months. Multivariate Cox regression analysis showed that predictors of OS and DSS included age ( P < .001, P < .001, respectively), tumor grade ( P < .001, P = .001), and tumor size ( P < .001, P = .001). Surgical management was a predictor of OS but not DSS. Conclusion Squamous cell carcinoma of the thyroid is a rare malignancy with a very poor prognosis. Surgical resection confers an overall survival benefit. Age, tumor grade, and tumor size are predictors of OS and DSS.

Primary squamous cell carcinomas in the thyroid gland: an individual participant data meta-analysis

Primary squamous cell carcinomas arising from the thyroid gland (SCCTh) is extremely rare diseases, which have never been fully studied. Thus, we performed a systematic review and individual participant data meta-analysis of published SCCTh cases, to understand the clinical characteristics and to identify the prognostic factors of primary SCCTh. A literature search was conducted within Medline, EMBASE, Cochrane library databases and KoreaMed using the following Medical Subject Headings (MeSH) keywords: “primary,” “squamous,” “carcinoma,” “cancer,” and “thyroid.” Eighty-four patients' individual data from 39 articles and five patients' data in our institute were selected for analysis (N = 89). The mean age at diagnosis was 63.0 years (range, 24–90) and female preponderance (M:F = 1:2) was noted. The commonest complaint was the anterior neck mass, followed by dyspnea or dysphagia, and extension to the adjacent structure was found in 72%. The median survival was 9.0 months (95% CI, 6.0–23.0) and 3-year survival rate (3YSR) was 37.6% by Kaplan–Meier method, but only 20.1% by a shared frailty model for adjusting heterogeneity. Complete resection (R0) of tumors was the only significant prognostic factor in multivariable analysis, and the benefit of adjuvant treatment was not proved. The prognosis of patients with SCCTh is very poor (20% in 3YSR), but complete resection of disease is correlated with improved survival. To achieve complete surgical eradication of tumors, early detection and accurate diagnosis should be emphasized.

Clinical trial of weekly paclitaxel chemotherapy for papillary thyroid carcinoma with squamous cell carcinoma component

Papillary thyroid carcinoma (PC) can occasionally include a squamous cell carcinoma (SCC) component. In this study, we evaluated the effect of weekly paclitaxel chemotherapy in 3 patients with PC including an SCC component. None of these patients had lesions of anaplastic carcinoma on pathological examination. Weekly paclitaxel chemotherapy was performed as an induction chemotherapy for 2 patients. All 3 patients underwent locally curative surgery and weekly paclitaxel chemotherapy after surgery as an adjuvant therapy. The response to the chemotherapy was evaluated based on the RECIST guideline (version 1.1). Two patients had partial responses (PRs) and the remaining 1 had stable disease (SD). The response rate was 67% and the clinical benefit rate (PR+SD) was 100%. One patient died of the growth of lung metastases that had been detected before surgery 22 months after the diagnosis. The remaining 2 are still alive, 14 and 22 months after the diagnosis, respectively. Taken together, weekly paclitaxel may be one of the effective adjuvant therapies for PC with an SCC component.

Squamous cell carcinoma of the thyroid gland: primary or secondary disease?

OBJECTIVE

To review the aetiopathogenesis, clinical characteristics, immunohistochemical profile, prognosis and treatment options for primary thyroid squamous cell carcinoma, and to compare it with squamous cell carcinoma metastatic to the thyroid, thus providing the reader with a framework for differentiating primary and secondary disease.

METHOD

Review of English language literature from the past 25 years.

SEARCH STRATEGY

A search of the Medline, Embase and Cochrane databases (April 1984 to April 2009) was undertaken to enable a comprehensive review.

RESULTS

After applying strict criteria for the diagnosis of primary thyroid squamous cell carcinoma, 28 articles were identified reporting 84 cases. When reviewing secondary thyroid squamous cell carcinoma, we only analysed cases of squamous cell carcinoma metastatic to the thyroid gland, and found 28 articles reporting 78 cases.

CONCLUSION

It is possible to differentiate between primary and secondary thyroid squamous cell carcinoma, on the basis of combined evidence from clinical examination and endoscopic, pathological and radiological evaluation. Such differentiation is important, as the prognosis for primary squamous cell carcinoma is uniformly poor irrespective of treatment, and the most suitable option may be supportive therapy. Treatment for secondary squamous cell carcinoma of the thyroid varies with the site and extent of spread of the primary tumour.

Collision tumor of the thyroid: follicular variant of papillary carcinoma and squamous carcinoma

BACKGROUND

Collision tumors of the thyroid gland are a rare entity. We present a case of a follicular variant of papillary carcinoma and squamous carcinoma in the thyroid. To the best of our knowledge, this is the first documentation of a collision tumor with a papillary carcinoma and a squamous carcinoma within the thyroid gland. The clinicopathological features and immunohistochemical profile are reported. The theories of origin, epidemiology and management are discussed with a literature review.

CASE PRESENTATION

A 65 year old woman presented with a large thyroid swelling of 10 years duration and with swellings on the back and scalp which were diagnosed to be a follicular variant of papillary thyroid carcinoma with metastasis. Clinical examination, radiology and endoscopy ruled out any other abnormality of the upper aerodigestive tract. The patient was treated surgically with a total thyroidectomy with central compartment clearance and bilateral selective neck dissections. The histopathology revealed a collision tumor with components of both a follicular variant of papillary carcinoma and a squamous carcinoma. Immunohistochemical analysis confirmed the independent origin of these two primary tumors. Adjuvant radio iodine therapy directed toward the follicular derived component of the thyroid tumor and external beam radiotherapy for the squamous component was planned.

CONCLUSION

Collision tumors of the thyroid gland pose a diagnostic as well as therapeutic challenge. Metastasis from distant organs and contiguous primary tumors should be excluded. The origins of squamous cancer in the thyroid gland must be established to support the true evolution of a collision tumor and to plan treatment. Treatment for collision tumors depends upon the combination of primary tumors involved and each component of the combination should be treated like an independent primary. The reporting of similar cases with longer follow-up will help define the epidemiology, biology and establish standardized protocols for treatment of these extremely rare tumors.

Thyroid tumors with preoperative recurrent laryngeal nerve palsy: Clinicopathologic features and treatment outcome

BACKGROUND

The aim of this present study is to define the significance of recurrent laryngeal nerve palsy (RLNP) detected before surgery for thyroid diseases with regard to the incidence of malignancy, histopathologic distribution, extrathyroidal invasion, management, and prognosis.

METHODS

Six hundred and twenty-two patients underwent operation for various thyroid disease and were treated by the same surgeon. The study was confined to 16 (3%) patients who suffered from a thyroid tumor with preoperative RLNP.

RESULTS

Of these 16 patients, 1 had benign thyroid disease, while the other 15 had malignancy (94%). Among the 15 cancer patients, 14 had extrathyroidal invasion and needed more extensive surgical procedures than total thyroidectomy. The recurrent laryngeal nerve could be dissected from the thyroid neoplasm in 3 patients, 2 of whom experienced recovery of this nerve's function postoperatively.

CONCLUSIONS

Thyroid tumor associated with RLNP is strongly suggestive of malignancy. The RLN should be preserved if it has not been invaded by the tumor, because it offers a good chance of functional recovery postoperatively. Well-differentiated thyroid cancer accounts for only half of these patients who tend to present at an older age and feature a much higher incidence of upper aerodigestive tract invasion. The operations for these patients often are complex and should be performed by experienced surgeons. Radical excision of a resectable anaplastic or squamous cell carcinoma of the thyroid gland offers the chance, albeit small, of long-term survival in this study.

A patient with primary squamous cell carcinoma of the thyroid intermingled with follicular thyroid carcinoma that remains alive more than 8 years after diagnosis

Primary squamous cell carcinoma of the thyroid is an extremely rare tumor with a highly aggressive clinical course. We report here on a patient with primary squamous cell carcinoma of the thyroid who remains alive more than 8 years after diagnosis. A 56-year-old man presented with a hoarse voice and a rapidly progressing mass on the right side of the thyroid gland. The patient underwent a total thyroidectomy without neck lymph node dissection. Histopathologic findings revealed primary squamous cell carcinoma combined with follicular carcinoma of the thyroid. The tumors metastasized to the cervical lymph nodes, thoracic spine and lung. He underwent 5000 rads of adjuvant radiotherapy to the neck. TSH suppressive therapy with L-thyroxine was administered alone rather than radioactive iodine therapy or chemotherapy. The patient's clinical course has been remarkable over the first 7 years; he has remained stable except for a transient paraplegia due to nerve compression. The patient underwent colectomy for the diagnosis of a colon cancer. Recent evaluation has revealed a new lesion in the lung; this was diagnosed as metastatic follicular carcinoma originating from the thyroid. High dose radioactive iodine therapy was administered, and he remains alive in stable condition.

Massive squamous metaplasia of the thyroid gland – Report of three cases

Three cases of massive squamous cell metaplasia in Hashimoto's thyroiditis are reported. The patients were two men and one woman aged 24, 52, and 55 years, respectively. In all three patients, the glandular parenchyma was replaced by hypocellular fibrous tissue with scattered chronic inflammatory infiltrate. Follicular cells were almost absent; the majority of residual epithelial cells formed squamous nests that were partly solid and partly cystic. There were three types of epithelial cells - squamous, basaloid, and follicular, with oncocytic differentiation. The squamous and basaloid cells showed strong positivity high molecular weight (HMW) cytokeratin, moderate to strong expression of galectin-3 (2/3), and nuclear expression of p63 protein (2/3). The staining pattern of p63 was identical to that of HMW, with predominant positivity at the periphery of cell nests. In one case, weak but unequivocal positivity of thyroid transcription factor-1 also was present. We believe that metaplasia was caused by Hashimoto's thyroiditis. The cases presented here are extremely rare, and only two convincing similar cases have been reported in the English literature so far. They may represent a diagnostic pitfall and should not be misdiagnosed as a malignancy, in particular as squamous cell or mucoepidermoid carcinoma.

Thyroid cancer review 3: management of medullary and undifferentiated thyroid cancer

This is the last of the three review articles dealing with thyroid cancer. Over 90% of thyroid cancer is of the differentiated type associated with a very good 10-year disease-free survival rate. In contrast, the rare forms of thyroid cancer which comprise medullary thyroid cancer arising from parafollicluar C cells, Hurthle cell carcinoma, anaplastic carcinoma, thyroid lymphoma and squamous cell carcinoma are typically associated with a poorer survival rate. Management is based upon small retrospective cohort studies.

Primary squamous-cell carcinoma of the thyroid gland: new evidence in support of follicular epithelial cell origin

Primary squamous-cell carcinoma (SCC) of the thyroid gland is extremely rare. We had an opportunity to treat two such cases recently. Two elderly females presented with left lobe thyroid swelling that had a history of long-standing goiter. Fine-needle aspiration (FNA) of the thyroid nodule was done in both cases. FNA cytology showed an thyroid abscess in the first, and a Hürthle-cell neoplasm in the second case. Histopathologic diagnosis was a well-differentiated squamous-cell carcinoma with an adjacent area of lymphocytic thyroiditis in the first case, and a moderately differentiated squamous-cell carcinoma in association with a Hürthle-cell adenoma in the second case. Serial sections of the excised gland ruled out any other associated thyroid malignancy. Immunostaining for pan-cytokeratin, thyroglobulin, and calcitonin were performed. The tumor, comprising polygonal and spindle cells, showed positive staining for cytokeratin and thyroglobulin; however, calcitonin did not stain any structures. Exhaustive clinical, endoscopic, and radiological examinations, i.e., X-ray of the chest, contrast-enhanced computer tomography (CECT) of the neck and chest, and ENT checkup in both cases did not reveal any primary site of squamous-cell carcinoma as the likely source of the metastases, or any contiguous spread from neighboring structures. Both patients had ipsilateral nodal metastases, and both succumbed to the disease within 6 mo of histological diagnosis. The interesting observation in both cases was thyroglobulin positivity, indicating a follicular epithelial cell origin of the SCC.

Primary squamous cell carcinoma of the thyroid gland: an entity with aggressive clinical behaviour and distinctive cytokeratin expression profiles

AIMS

Primary squamous cell carcinoma of the thyroid gland is uncommon. This study aims to identify the clinicopathological features and the pattern of expression of cytokeratins and oncoproteins in this tumour.

METHODS AND RESULTS

Histological slides from Chinese patients with thyroid cancer treated in our institution from 1980 to 1999 were reviewed. Patients with primary squamous cell carcinoma of the thyroid were identified and their clinical records were analysed. The expression of cytokeratins (CKs), p53 and p21 in these cases were also studied by an immunohistochemical method. Four women (mean age 71 years) with squamous cell carcinoma of thyroid were found. The main presenting features were signs and symptoms of airway obstruction in three patients and neck swelling in one. The tumours were located at the right lobe (n=2), left lobe (n=1) or in both lobes of the thyroid (n=1). One patient died shortly after admission and the other three died within 4 months after thyroidectomy. The p53 protein was positive in 50% (2/4) of the tumours and p53+ tumours were poorly differentiated. The tumours were negative for p21. CK19 was expressed in all the tumours while CK7 expression was noted in 3/4 of the tumours. One carcinoma showed focal positivity to CK18. The tumours were negative for CKs 1, 4, 6, 10/13 and 20. The pattern of cytokeratin expression in squamous cell carcinoma of the thyroid gland was different from carcinoma showing thymus-like differentiation (CASTLE) of the thyroid gland and oesophageal squamous cell carcinoma.

CONCLUSIONS

Squamous cell carcinoma of the thyroid has aggressive clinical behaviour and characteristic CK expression pattern. p53 over-expression in these tumours was associated with tumour differentiation.

Squamous cell carcinoma of the thyroid: outcome of treatment in 16 patients

AIMS AND METHODS

Squamous cell carcinoma of the thyroid is very rare and has a poor prognosis. Treatment and outcome were retrospectively analysed in a consecutive series of 16 patients treated at the Royal Marsden Hospital, with the aim of establishing guidelines for management.

RESULTS

Twelve of the 16 patients had locoregional disease only at presentation and four had distant metastases. Eight of the 16 underwent surgery and four were given post-operative radiotherapy. Radiotherapy alone was used in six patients unsuitable for surgery. Median survival was 16 months. There were three long-term survivors; each had localized disease treated with surgery and post-operative radiotherapy. Patients treated with surgery alone all developed local recurrence. Two of six patients treated with radiotherapy alone had a partial response but all subsequently developed progressive local disease. Chemotherapy was used in two patients with no response.

CONCLUSIONS

Long-term survival is possible if disease is diagnosed early and is completely resected. Surgery should be followed by radical dose radiotherapy.

Squamous cell carcinoma arising in Hashimoto's thyroiditis

The case of a 76-year-old white woman with squamous cell carcinoma of the thyroid gland arising in a background of Hashimoto's thyroiditis is presented. Squamous cell carcinoma of the thyroid gland is a very rare and aggressive tumor, and only a few cases are reported as arising in Hashimoto's thyroiditis. Although Hashimoto's thyroiditis alone does not necessarily predispose patients to malignancy, the finding of a prominent nodule in such a patient should suggest the possibility of malignancy, and an aggressive search and treatment regimen, including surgical intervention, should be pursued.

Primary squamous carcinoma of the thyroid--a case report

We report a well-documented case of fatal thyroid cancer with histopathological characteristics of primary squamous carcinoma. A possible primary tumour elsewhere was excluded. The possible histogenesis of this unusual tumour and the therapy of choice are briefly discussed.

Squamous cell carcinoma with cyst of the thyroid

Two cases of primary squamous cell carcinoma associated with a thyroid cyst in the thyroid are described. The majority of squamous cell carcinomas reported so far have had some degree of co-existing adenocarcinoma, while the cases presented in this report had no glandular component at all. The histogenesis of squamous cell carcinoma is not clear, but at present, it is believed that most cases arise from the follicular epithelium. In our cases, in spite of an intensive examination of serially sectioned specimens, no areas of adenocarcinoma, squamous metaplasia from the follicular epithelium, or congenital squamous remnants could be found.

Adenosquamous carcinoma of the thyroid gland

A case of adenosquamous carcinoma of the thyroid gland is presented. This rare form of cancer behaves in an aggressive manner similar to anaplastic carcinoma and is characterized histologically by the intimate blending of the squamous and glandular elements. The prognostic significance of identifying areas of malignant squamous epithelium within papillary carcinoma as opposed to the much more common benign squamous metaplasia, is highlighted. The pathogenesis, differential diagnosis and management of the condition are discussed.

Squamous differentiation in thyroid carcinoma. With special reference to histogenesis of squamous cell carcinoma of the thyroid

Squamous differentiation of thyroid carcinoma was studied clinicopathologically and immunohistochemically in 29 autopsy cases. Tumor cell nests with squamous differentiation (CNSD), which histologically resembled squamous cell carcinoma, were found in 6 cases (20.7%). All of these 6 cases with CNSD had areas of undifferentiated carcinoma, representing 31.6% of 19 cases with undifferentiated carcinoma, and all but one case also showed coexisting papillary carcinoma. The CNSD were histologically associated with undifferentiated carcinoma in 5 cases, and with papillary carcinoma in one case; the CNSD were occasionally intermingled with these types of carcinoma, and there were findings suggesting a histological transition between the CNSD and undifferentiated carcinoma or papillary carcinoma. Immunohistochemistry revealed that all the CNSD were reactive with antibodies for keratin and vimentin, whereas thyroglobulin and desmin were not expressed. It was concluded that the CNSD examined here were most probably due to extensive squamous differentiation (squamous metaplasia) in undifferentiated carcinoma and papillary carcinoma. In addition, the present results may explain the fact that cases diagnosed solely as squamous cell carcinoma sometimes show a prognosis similar to that of undifferentiated carcinoma, and may well represent extensive squamous differentiation in such tumors rather than true squamous cell carcinoma of the thyroid.

Squamous cell carcinoma of the thyroid: a diagnostic dilemma

Four cases of primary squamous cell carcinoma of the thyroid gland are reported. Thorough evaluation confirmed these lesions to be of primary thyroid origin rather than from metastasis or direct invasion from contiguous structures. These cases illustrate the aggressive nature of the disease and the propensity for local and distant metastases. The clinicopathologic data presented here underscore the challenge in diagnosis and treatment of this rare entity.

Pure squamous cell carcinoma of the thyroid gland--report of an autopsy case and review of the literature

A rare autopsy case of primary squamous cell carcinoma of the thyroid gland is reported herein. A 61-year-old Japanese woman with a swelling of the left neck underwent surgery and the resulting tumor was histopathologically diagnosed as pure squamous cell carcinoma of the thyroid gland. She had had the nodule for 20 years, and it was histologically diagnosed as having been a well-encapsulated, follicular adenoma. Histopathological observation of the resected glands also revealed the coexistence of pure squamous cell carcinoma, which presumably originated from the adenoma. Postoperatively, an esophagotracheal fistula formed due to local invasion of the tumor cells. The patient's state gradually deteriorated and she died of severe bronchopneumonia and renal dysfunction, 4 months after the operation. Autopsy revealed no distant metastases, but severe septicemia caused by bacterial infection affecting the systemic organs was found, which presumably resulted in multiple organ failure.

Squamous cell carcinoma of the thyroid gland

We present the clinical manifestations and details of treatment and outcome for eight patients with squamous cell cancer arising in the thyroid gland, which is a rare entity. All patients had advanced disease, with primary tumors invading adjacent structures (the trachea, esophagus, and major vessels). In two patients, pulmonary metastases were also present. Six patients died 6 months or less after diagnosis, five from the effects of local disease. Transient palliation was obtained in four patients who underwent partial excision (three patients) and radical radiotherapy (one patient). Two patients remained free of disease at last follow-up more than 4 years after gross total tumor resection and radical radiotherapy and were presumably cured. One patient treated by partial resection and radical radiotherapy died from other causes 17 months later. His disease status was unknown. Complete excision with postoperative radiotherapy may be curative, and debulking followed by external irradiation may provide short-term palliation. Patients with unresectable tumors are best managed by supportive measures only unless a truly effective chemotherapeutic regimen is developed for squamous cell cancer of the head and neck.