Incidental Parathyroid Adenoma Mimicking Tumor Recurrence in a Patient With Follicular Thyroid Carcinoma

Advances in ultrasound for the diagnosis and management of thyroid cancer

BACKGROUND

Ultrasonography (US) is increasingly being employed by endocrinologists and surgeons in the diagnosis and management of patients with thyroid nodules and thyroid cancer. Recent consensus guidelines from the American Thyroid Association highlight the importance of this modality by recommending that patients with thyroid nodules should undergo further evaluation with cervical US to stratify the risk of malignancy. Likewise, ultrasound is advocated for the preoperative and postoperative diagnosis of cervical lymph node metastases.

SUMMARY

This article will summarize the US characteristics that impart a suspicious appearance on thyroid nodules and cervical lymph nodes as well as those findings that are reassuring. Likewise, the indications for thyroid nodule and lymph node fine-needle aspiration will be reviewed. Finally, this article will briefly discuss adjunctive tools in US such as elastography, percutaneous ethanol ablation, and radiofrequency ablation.

CONCLUSIONS

US may be used to help stratify the risk of malignancy in thyroid nodules and cervical lymph nodes. This tool further aids in the diagnosis of malignancy when used in conjunction with fine-needle aspiration. US plays an important role as both a diagnostic and therapeutic tool in the evaluation of patients with neck masses.

Parathyroid adenomas seen in the clinical follow-up of patients with differentiated thyroid carcinoma: a diagnostic dilemma

The coexistence of nonmedullary thyroid carcinoma and parathyroid adenoma is an uncommon clinical entity. In most of the previously published studies, thyroid carcinomas are diagnosed incidentally during or after the treatment of parathyroid disease, mostly in the pathology specimens. Here, we report 2 cases of parathyroid adenoma who presented years after the treatment of differentiated thyroid carcinoma. Neither of the patients had symptoms of hypercalcemia and hyperparathyroidism, and parathyroid adenomas were diagnosed on routine physical examination of the neck and on routine monitoring of serum calcium levels.

Silent parathyroid adenoma mistakenly interpreted on FDG-PET as thyroid cancer metastasis in a patient with elevated thyroglobulin and negative I-131 whole body scan and removed by radioguided minimally invasive surgery

Detection of recurrent and metastatic thyroid cancer remains a considerable challenge in patients presenting with rising thyroglobulin levels but with negative I-131 whole body scintigraphy. Such is the case in this patient with follicular thyroid cancer in whom subsequent FDG PET scanning showed a solitary hypermetabolic cervical lesion. With definitive management and multidisciplinary approach in mind, radioguided surgical excision came into play through the use of Tc-99m sestamibi, leading to successful removal of the lesion. Histopathology, however, revealed a parathyroid adenoma. This highlights the importance of considering differential diagnoses in apparent cases of recurrence to avoid potential pitfalls.