Rationale: Papillary thyroid cancer accounts for up to 85% of all cases of thyroid carcinoma. This disease entity is notorious for metastatic invasion of adjacent lymph nodes, including the cervical lymph nodes, potentially presenting as a growing lateral neck mass. However, these lesions tend to be recognized and diagnosed soon due to the palpable mass.
Patient concerns: This report describes a very rare case of a huge slow-growing neck metastasis based on a 6 mm papillary thyroid microcarcinoma. This patient presented with a painless, but continuously growing right lateral neck mass. Aside from that, no specific complaints were mentioned.
Diagnosis: The underlying cause of this patient's neck mass turned out to be an occult papillary thyroid microcarcinoma (Ø 6 mm) with metastatic invasion and subsequent cystic degeneration of cervical lymph nodes. Accurate diagnosis was made after surgical intervention through histopathological analysis.
Interventions: The patient underwent complete resection of the cervical mass in conjunction with total thyroidectomy and right cervical neck dissection, followed by adjuvant iodine- and chemotherapy.
Outcome: Margin free surgical resection without any postoperative complications could be achieved. The patient received iodine supplementation and remained free of recurrence during regular clinical follow-ups for 2 years. The therapy was curative.
Lessons: This case report emphasizes the importance of a thorough diagnostic work-up including preoperative tissue sampling of any cervical neck mass, since a benign appearance on imaging does not exclude a malignant process.