Endocrine Abstracts

Autoimmune Hypothyroidism is a common clinical condition with a suggested prevalence of up to 12% of the population. The subsequent enlargement of the thyroid gland caused by circulating thyroid antibodies can cause neck discomfort warranting a referral to the thyroid ultrasound (USG) clinic. The USG characteristics of autoimmune hypothyroidism can be challenging to grade and the atypical appearances often makes it difficult to exclude a mitotic lesion. We have set forward few recommendations and clinical perspectives to overcome some of these challenges and minimise misdiagnosis.

Case 1: 30 yrs F with established Hashimoto’s on Levothyroxine and under the care of Rheumatology for suspected mixed connective tissue disease. Thyroid USG performed for neck discomfort demonstrated markedly hypoechoic 2x2x4 cm nodule with an ill-defined border containing considerable punctate microcalcifications (U5). Several bulky lymph nodes were also noted in levels III and IV but with normal morphology. Subsequent FNA was reported to be in keeping with THY5 and the patient underwent total thyroidectomy. The biopsy was then reported as benign in keeping with nodular Hashimoto’s thyroiditis with oncocytic metaplasia.

Case 2: 52 yrs F with previous history of thyroidectomy for Hashimoto’s thyroiditis and IgG4 disease on a background of other autoimmune diseases such as Raynauds and fibromyalgia. After presenting with dysphagia underwent USG assessment which identified an incidental hypoechoic vascular lesion (7x5mm) at the left thyroidectomy bed (U3). FNA demonstrated lymphoid cell infiltrate consistent with Hashimoto thyroiditis.

Case 3: 33 yrs F presented after noticing a new neck lump. USG assessment demonstrated both the thyroid lobes to be heterogeneous, slightly hypoechoic with fibrous stranding and patchy areas of increased vascularity in keeping with underlying thyroiditis. In the right lobe, 1.5 x 1.5 x 1.3 cm heterogeneous predominantly hypoechoic, ill-defined nodule with areas of macro- as well as micro-calcifications were noted. The nodule seemed to invade into the overlying strap muscle in the anterior aspect. There was profound peripheral and internal vascularity (U5). Suspicious looking bulky lymph nodes were noted at levels 3 and 4 with mixed vascularity. Thyroid antibodies were elevated; FNA consistent with lymphocytic thyroiditis and a reactive lymph node. These cases highlight the potential setbacks and misdiagnosis of thyroid pathology if an underlying disease process is not appropriately investigated. We would recommend a clinician’s interpretation of the sonographic findings along with the routine measurement of thyroid function and thyroid antibodies and an MDM referral as appropriate.