Submandibular solid-cystic mass as the first and sole manifestation of occult thyroid papillary carcinoma: A case report

BACKGROUND: Occult thyroid papillary carcinoma (OTPC) is typically characterized by initial presentation with cervical lymph node metastasis and can be detected through ultrasound. However, the initial and sole manifestation was a submandibular solid-cystic mass. High-frequency ultrasound, enhanced multislice computed tomography (CT) scan, and thyroid function tests revealed no abnormalities, which is relatively uncommon. CASE SUMMARY: A 24-year-old Chinese female, who studied at a university in Shandong Province, presented to the clinic in June 2019 with a right submandibular mass that she had noticed 2 mo earlier. Clinical examination revealed a 2-cm, nontender, movable solid-cystic mass in the submandibular region, with no palpable thyroid mass observed. Ultrasonography revealed a 2.0 cm × 1.1 cm solid-cystic mass in the right submandibular region, and the thyroid gland showed no abnormalities. CT scan and 131I whole body follow-up scan showed that there were no abnormalities in the thyroid. However, cytology and pathology showed papillary tumor cell clusters, consistent with papillary thyroid carcinoma. Thus, we performed total thyroidectomy and right neck lymph node dissection. The pathology revealed the thyroid was detected as classical thyroid micropapillary carcinoma, and lymph nodes of levels VI central and levels II, III, IV, V on the right side showed no tumor metastasis. The patient was followed up for 2 years without significant recurrence. CONCLUSION: The presentation of a submandibular solid-cystic mass as the primary and solitary indication of OTPC is relatively uncommon. Fine needle aspiration is advised for evaluating neck masses.