Cystadenocarcinoma of the Sublingual Gland: A Rare Subvariant of Salivary Gland Carcinoma.

Cystadenocarcinoma is a malignant tumor that has undergone various classifications due to its wide variety of pathological forms since the World Health Organization (WHO) classification in 2005. We present a case involving a 72-year-old man who reported pain and swelling in the left floor of his mouth during eating. Examination demonstrated a thumb-sized, mobile mass with elastic softness. Resection of the sublingual gland tumor and left submandibular neck dissection were performed under general anesthesia. The lesion was encased in a thin fibrous capsule and consisted of tall columnar epithelium with papillary proliferation of homogeneous eosinophilic columnar cells with minimal pleomorphism. It demonstrated continuous proliferation from the sublingual gland, extracapsular invasion, infiltrative growth, and mild nuclear atypia, leading to a diagnosis of cystadenocarcinoma. Owing to multiple lymph node metastases, left radical neck dissection was performed 21 months post surgery. The patient remains disease-free 85 months after surgery.