Incidental Solitary Adrenal Metastasis as the Initial Manifestation of a Solid Variant of Papillary Thyroid Carcinoma, With Emphasis on Pathologic Diagnosis and Clinical Management

Abstract

Objective: Distant metastases from papillary thyroid carcinoma (PTC) are relatively rare and may be associated with a poor prognosis. The adrenal gland is a highly unusual site of metastasis in the natural course of PTC. Herein, we describe a case of an incidentally detected metastatic solid variant of PTC in the adrenal gland of an asymptomatic patient as the initial presentation.

Case report: A 67-year-old male patient was evaluated for a 4.7-cm adrenal incidentaloma discovered during a workup for nephrolithiasis. Biochemical evaluation revealed a nonfunctioning adrenal mass. The patient underwent adrenalectomy, which revealed metastatic PTC. A subsequent thyroid ultrasound revealed an isthmic nodule. Fine needle aspiration of the nodule was cytologically suspicious for a follicular neoplasm, and gene expression analysis revealed an HRAS c.182A>G sequence variation. The patient subsequently underwent total thyroidectomy, which revealed a 1.2-cm solid variant of PTC in the thyroid isthmus. Postoperatively, the patient underwent radioactive iodine ablation.

Discussion: Our case illustrates an exceedingly rare and challenging situation-a metastatic solid variant of PTC in the adrenal gland of a patient with no prior history of PTC. When confronted with a PTC in the adrenal gland in the absence of a previously identified primary tumor, our experience suggests that the next step in management should be total thyroidectomy followed by radioactive iodine ablation.

Conclusion: A solid variant of PTC is a rare cause of an incidentally detected adrenal lesion. Multidisciplinary care team coordination is essential for accurate diagnosis and treatment plan formulation.

Keywords: CT, computed tomography; PTC, papillary thyroid carcinoma; PTH, parathyroid hormone; adrenal incidentaloma; papillary thyroid cancer; papillary thyroid cancer metastatic to the adrenal gland; solid variant of papillary thyroid cancer.

Fig. 1

Contrast-enhanced computed tomography scan shows an adrenal mass with central fluid, possibly representing necrosis, and no internal fat density. A, Axial plane image of the right adrenal gland lesion (pink arrow). B, Coronal plane image depicting the right adrenal gland lesion adherent to the liver (pink arrow).

Fig. 2

Pathologic findings of 3 lesions in a 67-year-old male patient. A, The left inferior parathyroid gland shows benign parathyroid tissue (magnification ×40; inset magnification ×200). B, The adrenal mass demonstrates a well-demarcated tumor composed of a sheet of tumor cells (magnification ×40). C, At a high magnification (×200), the eosinophilic cytoplasm, open chromatin, and occasional nuclear grooves of the sheet are readily visible. D, Diffuse and strong positivity for thyroglobulin (cytoplasmic) and TTF-1 (nuclear) supports a thyroid origin (magnification ×100). Total thyroidectomy reveals a solid variant of papillary thyroid carcinoma with angioinvasion in the thyroid isthmus, showing similar morphologic characteristics as the adrenal lesion (E) and a separate conventional papillary microcarcinoma in the right thyroid lobe (F) (magnification ×40; inset magnification ×200).