Case 465 -- A 68 year-old female with an incidental thyroid cyst

Contributed by Amer Heider, MD and Robert Peel, MD
Published on line in May 2006

The patient is a 68 year-old female with a past medical history of acne status post neck irradiation at the age of 18, migraine headaches, hypertension, and hyperlipidemia, who was found to have an incidental thyroid cyst on neck ultrasound while undergoing evaluation for her migraine headaches. She was clinically euthyroid and her TSH was 3.05 (normal = 0.35 to 5.5). Her family history is negative for endocrine neoplasm.


Ultrasound demonstrated 1.4 cm thyroid cyst in the right lobe. CT scan of the neck confirmed a presence of a hypodense right thyroid nodule, measuring 1.5cm in greatest dimension, and also demonstrated calcifications in the posterior aspect of the nodule with no extracapsular spread. She, subsequently, had an ultrasound-directed FNA.


The FNA smears were suspicious for papillary thyroid carcinoma; however, a cytologically atypical follicular lesion such as a hyalinizing trabecular adenoma could not be excluded. Therefore, establishing a definitive diagnosis based on histologic assessment of the lesion was recommended.

The patient subsequently underwent a total thyroidectomy and central compartment node dissection. Intraoperatively, the right lobe was noted to be diffusely multinodular without gross invasion of adjacent structures. The left thyroid lobe was similar in size and shape.


Received was an 11.7-gram total thyroidectomy specimen (7.0 x 3.5 x 1.5 cm). The external surface was rubbery and tan-red. On cross-section, the cut surface demonstrated two well-circumscribed, solid, distinct white masses within the mid portion of the right lobe, measuring 0.3 x 0.2 x 0.3 cm and 1.2 x 1.0 x 1.0 cm, respectively. The remainder of the cut surfaces showed spongy, red-tan, multinodular parenchyma. The specimen was entirely submitted for histologic examination.

Also received was a 2.5 x 2.0 x 0.5 cm portion of lobulated adipose tissue. On dissection, it contained two rubbery tan lymph nodes, measuring 1.0 cm and 0.5, in greatest dimension, respectively.


The right lobe of the thyroid exhibited two well-circumscribed encapsulated lesions (Figs. 1, 2, and 3). The first lesion had a thick fibrous capsule with calcifications, and was composed of large cells with overlapping oval to round nuclei. Irregular nuclear contours and chromatin clearing were noted. Occasional nuclear pseudoinclusions, and nuclear grooves were also seen. (Figs. 4, 5, and 6)

The second lesion had a thin fibrous capsule and was composed of medium to large size cells forming a trabecular pattern. The cytoplasm of the tumor cells contained perinuclear pale body with slight yellow tinge. Numerous nuclear pseudoinclusions, and occasional nuclear grooves, were noted. The background showed hyalinization and a fibrovascular stroma. (Figs. 7, 8, 9, 10, 11, 12, 13 and 14)


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