The rare differential diagnosis of a S-100 positive neoplasia of the parotid gland

Introduction:

A 40-year-old patient presented with a growing painful and reddening mass at the angle of the jaw for three months. From our findings by clinical examination and imaging, we suspected a cervically metastatic superinfected neoplasia.

Methods:

After open biopsy of the parotid gland, histopathological assessment was difficult. With S-100 positivity, the most important differential diagnosis was malignant malignoma. The FDG-PET showed a metabolic response of the parotid gland suspicious of malignancy and a moderate metabolic response in the bilateral cervical lymph nodes. A cranial MRI showed no cerebral metastases and dermatologic examination was unremarkable.

Results:

Our oncological board recommended a total, if necessary radical parotidectomy and bilateral neck dissection. With unclear dignity in the intra-surgical rapid section analysis, we performed a total parotidectomy with neck dissection (macroscopically R0) instead. Our pathology considered the disease from the family of histiocytic-dendritic cell neoplasias with infiltration of the salivary gland and lymph nodes as low grade neoplasia. SOX-10 negativity excluded malignant malignoma. To limit diagnosis, we had to request multiple reference pathologies.

Conclusions:

With S-100 positivity in histopathological examination, malignant malignoma has to be considered as an important differential diagnosis. Searching for the primary tumor should involve PET-CT and dermatologic examination. Total tumor resection and, if lymph nodes are suspicious, neck dissection are recommended to avoid recurrence. No data is available on the use of radiation therapy. Regular tumor aftercare including MRI controls are necessary.

Publication History

Publication Date:
23 April 2019 (online)