When Medical Management Is Not Enough: A Case Report of Progressive Thyromegaly Secondary to Hashimoto Thyroiditis.

A man in his mid-fifties with a more than 30-year history of hypothyroidism secondary to Hashimoto thyroiditis and a strong family history of thyroid disease was referred for a surgical evaluation after developing rapidly progressive thyromegaly associated with anterior neck discomfort, hoarseness, increasing neck fullness, and obstructive sleep apnea due to an enlarging neck circumference. His hypothyroidism had remained well controlled with daily levothyroxine therapy for decades, providing adequate biochemical control and symptomatic relief for his metabolic symptoms without prior evidence of significant thyroid enlargement. Despite this long-standing stability over a relatively short period following decades of clinical stability, he experienced an unexpected and rapid increase in thyroid size over a relatively short period, resulting in progressive compressive symptoms. Physical examination and imaging demonstrated an enlarged thyroid with compressive features to the adjacent cervical vasculature and structures, raising concerns for worsening airway compromise and other long-term compressive sequelae. Owing to the severity of the thyroid enlargement and compressive symptoms, it was determined that the best management was with surgical intervention. This case describes the unusual, delayed development of rapidly progressive compressive thyromegaly after more than three decades of stable Hashimoto thyroiditis managed with levothyroxine, an atypical clinical course that emphasizes the need for continued surveillance despite long-term biochemical control. Although hypothyroidism may remain metabolically controlled with thyroid hormone replacement, clinicians should remain vigilant for progressive structural thyroid disease and the development of compressive symptoms, as timely surgical intervention may be required.