Myoepithelial carcinoma of the salivary glands

1What is known

The diagnosis requires a tumor that is unequivocally malignant and exclusively myoepithelial. In the series that set those criteria, 15 of 25 tumors were in the parotid, 15 arose in a pre-existing benign mixed tumor and 10 arose on their own². In a 51-case series the parotid and the palate were equally common³.

A tumor that arises in a pre-existing pleomorphic adenoma is called carcinoma ex pleomorphic adenoma. It accounted for 54% of 48 cases in one series and was linked to worse outcomes than tumors arising on their own⁴.

2Outcomes

In SEER, 290 patients with major salivary gland tumors had a median overall survival of 142 months, with 53% alive at 10 years and 38% at 15. Of patients with a recorded stage, 14.5% had lymph-node involvement and 6.6% had distant spread at diagnosis¹.

In a 48-case series, 12 of the 44 patients with follow-up (27%) developed distant metastases, most often in the lung. None of the 23 patients whose tumors had no necrosis did⁴. In the 25-patient series, 47% of the 17 patients followed developed metastases and 29% died of the disease².

3Genetics

In a genomic study of 40 tumors, 70% carried a gene fusion, most involving PLAG1. FGFR1::PLAG1 was found in 18% and TGFBR3::PLAG1 in 15%, and the latter was absent from 723 other salivary tumors⁵. EWSR1 rearrangement has been reported in the clear cell type⁶.

4Treatment reports

Surgery is the main treatment. In SEER, 55.2% of patients had surgery alone and 44.8% had surgery with radiotherapy, and radiotherapy was associated with better survival only after statistical adjustment¹. In the pooled literature, radiotherapy after surgery reduced local and regional recurrence⁷.

5The literature

Papers naming the disease that mention this form in title or abstract, by year. Assigned by keyword⁸.

Browse all of them in the directory. See the published cases.

6Most cited papers

7Newest papers

8References