[Sclerosing mucoepidermoid carcinoma of the thyroid gland with eosinophilia]

[Sclerosing mucoepidermoid carcinoma with eosinophilia of thyroid gland]

Sclerosing mucoepidermoid carcinoma with stromal eosinophilia of thyroid gland is represented less than 100 cases in the world literature. We present a rare case of sclerosing mucoepidermoid carcinona with stromal eosinophilia in a 69-year-old woman who has been observed for multinodular goiter for more than 3 years. Cytological examination revealed a picture most of all corresponding to a malignant neoplasm (Bethesda V). The patient underwent a thyroidectomy. Pathomorphological examination revealed a neoplasm of mixed structure with foci of cribriform structures and squamous metaplasia with areas of keratinization. According to the IHC study, the expression of TTF-1, p63, cytokeratins 5/6 were positive, while there were no expression of thyroglobulin with its positive reaction in the thyroid tissue. Additional histochemical staining with Alcian blue revealed a positive reaction with a homogeneous acellular substance of the tumor. A comprehensive morphological study with the use of additional stains made it possible to accurately establish the diagnosis, which will determine the further tactics of managing the patient.

Activating BRAF mutation in sclerosing mucoepidermoid carcinoma with eosinophilia of the thyroid gland: two case reports and review of the literature

Background

Sclerosing mucoepidermoid carcinoma with eosinophilia is a rare form of thyroid carcinoma. The underlying molecular mechanisms of sclerosing mucoepidermoid carcinoma with eosinophilia tumorigenesis remain unknown.

Case presentation

We present two cases of sclerosing mucoepidermoid carcinoma with eosinophilia, both with a concurrent papillary thyroid carcinoma. Patient 1, a 70-year-old Caucasian woman, presented with sclerosing mucoepidermoid carcinoma with eosinophilia with distant renal metastasis and coexisting papillary thyroid carcinoma. Patient 2, a 74-year-old Caucasian woman with a remote history of thyroid cancer treated with thyroidectomy, presented with locoregionally invasive sclerosing mucoepidermoid carcinoma with eosinophilia and recurrent papillary thyroid carcinoma in the thyroid bed. BRAF mutation studies were performed on the sclerosing mucoepidermoid carcinoma with eosinophilia tumors. In both cases, sclerosing mucoepidermoid carcinoma with eosinophilia was positive for the BRAF V600E mutation by polymerase chain reaction. Patient 1 is the first reported case of sclerosing mucoepidermoid carcinoma with eosinophilia with renal metastasis, to the best of our knowledge.

Conclusions

Our findings suggest, for the first time, to our knowledge, involvement of the RAS-RAF-MEK-ERK signaling pathway in the pathogenesis of sclerosing mucoepidermoid carcinoma with eosinophilia. Thus, BRAF inhibitors may prove to be a useful targeted medical therapy in the treatment of a subset of patients with aggressive sclerosing mucoepidermoid carcinoma with eosinophilia tumors who exhibit BRAF activating mutation.