[Parotid tumors of non-glandular origin: local and distant metastases in the parotid gland].

BACKGROUND

Secondary involvement of the parotid gland by nonsalivary gland malignancies is relatively common. Especially if the primary site is unknown, distinguishing a primary neoplasm from a metastasis can be difficult.

PATIENTS

This text reviews 10 metastatic lesions to the parotid gland from 252 consecutive parotid tumors. Moreover we present the metastasis of an oat cell carcinoma as initial presentation of a lung tumor.

RESULTS

The percentage of metastatic tumors of the parotid gland in our study group was 4%, representing 32% of all malignancies. The majority (80%) originate from primary tumors in the head and neck region with skin cancer being the most important primary site (70%). In 40% the parotid gland metastasis was the first manifestation of a malignancy.

CONCLUSIONS

The distinction between primary salivary gland tumor and metastasis is of particular importance for therapy and prognosis. The possibility of a metastatic tumor should always be considered when primary salivary gland tumors have histologic features similar to those of tumors occurring in other regions of the body (squamous carcinoma, melanoma, adenocarcinoma, clear cell, oat cell, and undifferentiated carcinoma). The skin of the head and neck is of primary interest during clinical examination, followed by the mucosa of the upper respiratory and digestive tract. Histologic and especially immunohistochemical characteristics can be helpful in identifying the primary tumor. If metastases to the parotid gland are the only manifestation and if they only spread to regional lymph nodes, more aggressive surgical treatment may be beneficial.