Silent intrathyroid parathyroid carcinoma.

Area of Science:

• Endocrinology
• Oncology
• Surgical Pathology

Background:

• Parathyroid carcinoma is a rare malignancy.
• Intrathyroidal parathyroid carcinoma presents unique diagnostic challenges due to its rarity and atypical location.
• Asymptomatic presentation further complicates early detection.

Purpose of the Study:

• To report a challenging case of incidentally discovered intrathyroidal parathyroid carcinoma.
• To emphasize the diagnostic difficulties associated with asymptomatic parathyroid tumors.
• To highlight the importance of preoperative evaluation for suspicious thyroid nodules.

Main Methods:

• Case presentation of a 59-year-old male with an incidental thyroid mass.
• Diagnostic workup included ultrasound, CT scan, and fine needle aspiration biopsy (Bethesda V).
• Surgical management involved total thyroidectomy with fluorescence angiography; histopathology confirmed parathyroid carcinoma.

Main Results:

• A large thyroid nodule (5.2 × 4.9 × 2.8 cm, EU-TIRADS 4) was initially suspected as thyroid cancer.
• Histopathological examination unexpectedly revealed parathyroid carcinoma.
• The parathyroid glands were visualized in typical locations during surgery, distinct from the tumor.

Conclusions:

• Asymptomatic intrathyroidal parathyroid cancer poses a significant diagnostic challenge for clinicians.
• Preoperative testing of parathyroid hormone and serum calcium is recommended for patients with solid thyroid nodules classified as Bethesda IV-V.
• This case underscores the need for a high index of suspicion for rare endocrine malignancies.