New aspects in parotid gland surgery.

We present our results of current research on parotid gland surgery at our clinic. a) Histopathological characteristics of pleomorphic adenomas, especially of capsular alterations like thin capsule areas, capsule-free regions, satellite nodules, and pseudopodia in the different subtypes were analyzed in 100 consecutive patients. 51 pleomorphic adenomas were classified as stroma-rich type, 35 as cell-rich-type, and 14 as classical subtype. 97% of all tumors showed areas with very thin (< 20 mm) capsules. Stroma-rich tumors showed the absolute greatest regions of very thin capsules and exhibited focal absence of encapsulation in 71% of the tumors. 11% of the cell-rich and 43% of the classical subtype tumors also presented capsule-free areas. Satellite nodules and pseudopodia were present in 33% of the stroma-rich tumors, respectively 23% in cell-rich, and 21% in classical subtype tumors. Therefore, enucleation or local dissection of the pleomorphic adenoma can not be a sufficient surgical treatment of this special tumor entity. We recommend lateral or total parotidectomy as the treatment of choice. b) To ascertain the incidence of clinically apparent and occult lymph node metastases in patients with major salivary gland cancers we analyzed 160 consecutive patients that underwent parotidectomy and neck dissection. Histologically confirmed positive neck was found in 53% of all cases. The histology of the primary tumor had a significant influence on the incidence of lymph node metastasis: Highest incidence of 89% (16/18) was found in undifferentiated carcinomas, however also so-called low-risk tumors showed a rate from 22% to 47%. Of the 139 patients with clinical N0 neck 45% had occult neck metastasis. In conclusion neck dissection should be considered as an integral part of the surgical concept in major salivary gland cancer patients.