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

Primary squamous cell carcinoma of the thyroid: report of three cases

We report three cases of squamous cell carcinoma of the thyroid, which is an unusual malignant tumor that needs to be distinguished from other thyroid pathologies due to its aggressive behaviour. Three men, with an average of 63 years old, presented with progressive enlargement in the neck, hoarse voice or weight loss. Physical and radiological examinations revealed clues where malignancy was suspected and surgical resections were performed. Histopathological examination of the specimens was diagnosed as squamous cell carcinoma. Proper workup excluded the possibility of any primary site of SCC other than the thyroid. All patients died within 5 months. Adjuvant therapy evaluation is still inconclusive. Complete surgical resection still remains the primary choice for cure. We believe that radical resection with clear surgical margins followed by adjuvant chemo-radiation therapy is a curative strategy for achieving any chance of long-term survival.

Is an aggressive approach justified in the management of an aggressive cancer--the squamous cell carcinoma of thyroid?

Background

Primary squamous cell carcinoma of the thyroid is an extremely rare neoplasm, with less than 50 cases reported in the world literature. The prognosis is poor with a median survival of less than six months. The death is usually secondary to progression of local disease as distant metastases are rare.

Case reports

Three cases, two males and one female presenting with sudden increase in the size of long standing thyroid swellings and associated pressure effects on the aero-digestive tract are reported. Exhaustive clinical, endoscopic, and radiological examinations did not reveal any primary site of squamous-cell carcinoma as the likely source of the metastases, or of any contiguous spread from neighboring structures. Two cases were managed by combined modality therapy including curative surgery with radiotherapy and one by radiotherapy alone.

Conclusion

Primary squamous cell carcinoma is a rare malignancy with a poor outcome inspite of combined modality therapy. Out of three reported cases, two succumbed to their disease within less than one year. Aggressive surgery in the form of curative resection along with adjuvant radiotherapy is recommended, the tumor being chemo resistant.

Primary squamous cell carcinoma of the thyroid arising in Hashimoto's thyroiditis in an adolescent

Squamous cell carcinoma is a rare thyroid neoplasm that has been described exclusively in adults. We report what appears to be the first example of a primary squamous cell carcinoma of the thyroid gland arising in a background of Hashimoto's thyroiditis in an adolescent female. The tumor was well demarcated, confined to the right thyroid lobe, and did not metastasize, although follow up has been limited. The squamous cell carcinoma was well to moderately differentiated, and the stroma contained an abundant inflammatory infiltrate rich in lymphocytes and eosinophils. The lack of goblet cells, extracellular mucin, and extensive stromal sclerosis excluded the diagnosis of sclerosing mucoepidermoid carcinoma with eosinophilia. Immunohistochemical staining revealed focal expression of cytokeratin 7 and diffuse labeling with cytokeratin AE1/AE3. The squamous cell carcinoma overexpressed p53 protein and showed increased proliferative activity, as evidenced by the high MIB-1 labeling index. In contrast, the tumor did not show immunoreactivity for thyroglobulin or thyroid transcription factor 1.

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.

A diagnostic pitfall: Nodular tumor-like squamous metaplasia with Hashimoto's thyroiditis mimicking a sclerosing mucoepidermoid carcinoma with eosinophilia

Nodular tumor-like squamous metaplasia with Hashimoto's thyroiditis is an exceptional, benign condition presenting diagnostic difficulties for the pathologist. The main differential diagnosis is a sclerosing mucoepidermoid carcinoma (SMC) with eosinophilia. One case arising in a 50-year-old Caucasian man is reported. Histologically, the nodule consisted of large nests of squamous cells surrounded by connective tissue in Hashimoto's thyroiditis. We present the different histological criteria, allowing us to eliminate an SMC and other neoplastic tumors of the thyroid. The etiology of this tumor-like lesion, which is still under debate, is discussed.

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.

Primary squamous cell carcinoma of the thyroid: report of ten cases

OBJECTIVES

To define the clinical and pathologic characteristics of primary squamous cell carcinoma of the thyroid (PSCCT), a rare tumor, and compare it to the more common secondary squamous cell carcinoma of the thyroid (SSCCT).

MATERIALS AND METHODS

A search of tumor registry and medical archives of our institution identified 24 cases of squamous cell carcinoma involving the thyroid in a 25-year period (1978-2003). Medical records and pathology specimens were reviewed. This investigation did not reveal other primary sites in 10 (PSCCT). Other primary sites were identified in 14 patients (SSCCT). Immunostaining was done for thyroglobulin, cytokeratin (7 and 19), thyroid transcription factor (TTF), calcitonin, p21, MIB-I, and p53.

RESULTS

All 10 PSCCTs presented with a rapidly enlarging neck mass. Excision was possible in 8. PSCCT had the following features on immunostaining: keratin (8/8, 100%), thyroglobulin (5/8, 62.5%), TTF positive (3/8, 37.5%), and calcitonin negative. Cytokeratins 7 and 19 were diffusely and strongly positive in the PSCCT. Expression of putative biomarkers p21, MIB-I, and p53 was elevated with PSCCT cells showing mean expression of 36%, 48%, and 39%, respectively, compared to less than 5% in non-neoplastic tissues. The mean survival from diagnosis was 8.6 months. All patients died of disease. Airway compromise was the cause of death in the majority. In SSCCT, positivity for thyroglobulin and TTF was not seen. The locations of the primary sites were: larynx (7; 50%), trachea (4; 29%), esophagus (2; 14%), and oral cavity (1; 7%). At last follow-up, 4 were alive with mean survival of 5.5 years. Six had cancer-related mortality with mean survival of 46 months.

CONCLUSION

PSCCT is an aggressive cancer with death occurring within the first year in most patients. The prognosis for patients with PSCCT is worse than SSCCT. p21, MIB-I, and p53 are overexpressed in PSCCT. Thyroglobulin and TTF can show focal positivity in PSCCT distinguishing it from SSCCT.

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.

Well-differentiated carcinoma of the thyroid

Thyroid cancer will be diagnosed in more than 20,000 individuals in the United States in 2002. Approximately 16,000 of these patients will be women. During the same year, an estimated 1300 deaths from thyroid cancer are expected. The various types of thyroid cancer include papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary carcinoma, anaplastic carcinoma, and thyroid lymphoma. Papillary, follicular, and Hurthle cell carcinoma are considered well-differentiated thyroid cancers and constitute the focus of this article.

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.

Cytokeratin 19 and galectin-3 immunohistochemistry in the differential diagnosis of solitary thyroid nodules

AIMS

The immunohistochemical expression of cytokeratin 19 (CK 19) and galectin-3 was evaluated in 69 thyroid lesions to assess their potential as markers in the diagnosis and classification of thyroid malignancy. The following were studied: 26 cases of papillary carcinoma, 12 of follicular carcinoma, 20 follicular adenomas, two medullary carcinomas, one anaplastic carcinoma and eight multinodular goitres.

METHODS AND RESULTS

Formalin-fixed paraffin-embedded thyroid tissues were stained immunohistochemically for both CK 19 and galectin-3. CK 19 expression was found in all 26 papillary carcinomas, five of 12 follicular carcinomas, two of two medullary carcinomas and one case of anaplastic carcinoma. Only five of 20 follicular adenomas were positive for CK 19, and this was in a focal distribution. Two of eight multinodular goitres stained focally positive. Galectin-3 expression was found in 22 of 26 papillary carcinomas, 12 of 12 follicular carcinomas and one of two cases of medullary carcinoma. Only two of 20 follicular adenomas were positive. Three of eight multinodular goitres showed focal galectin-3 expression.

CONCLUSIONS

Our findings suggest that the immunohistochemical localization of CK 19 and of galectin-3 is a useful adjunct to the histopathological diagnosis of a solitary thyroid lesion. The expression of CK 19 favours a diagnosis of papillary carcinoma in all its variant patterns. Galectin-3 may serve as a marker for the recognition of follicular carcinoma, particularly the minimally invasive form.