Primary squamous cell carcinoma of the thyroid

This is a rare primary neoplasm of the thyroid, accounting for about 1% of thyroid neoplasms. Approximately 130 cases have been published.

Clinical features

It is a disease of the elderly. Patients commonly present with rapidly enlarging neck swelling and obstructive symptoms.

Immunohistochemistry

Differential diagnosis

• carcinoma showing thymus-like differentiation (CASTLE): this is a relative indolent neoplasm.

• squamous foci in adenocarcinoma

• mucoepidermoid carcinoma and sclerosing mucoepidermoid carcinoma with eosinophilia

• primary oesophageal / upper aerodigestive squamous cell carcinoma with invasion of the thyroid: these are cytokeratin 10/13 positive.

Prognosis

Primary squamous carcinoma of the thyroid is a highly lethal neoplasm.

References

Lam, K. Y., Lo, C. Y., Liu, M. C. Primary squamous cell carcinoma of the thyroid gland: an entity with aggressive clinical behaviour and distinctive cytokeratin expression profiles. Histopathology 2001;39:279-286.

This page last revised 21.12.2001.