Cervical thymoma.

A 45-year-old woman presented with a five-year history of neck swelling and occasional difficulty in swallowing. The clinical impression was of a thyroid nodule, and fine-needle aspiration biopsy cytology revealed a monotonous lymphoid population, raising the suspicion of Hashimoto's thyroiditis. At surgery, the mass was identified at the level of the cricoid cartilage, displacing the right lobe of the thyroid gland superiorly and extending posteriorly to the prevertebral fascia. Although a frozen-section diagnosis of malignant lymphoma had been suggested at the time of surgery, permanent sections favored a diagnosis of thymoma. Surface marker studies showed the majority of cells to be of thymic T-cell phenotype, and ultrastructural examination demonstrated a dual population of lymphoid and epithelial cells, thus confirming the presence of thymoma. Cervical thymomas are extremely rare and this case report illustrates the difficulties in diagnosis; we speculate that cervical thymoma may be an underdiagnosed entity.