An Unusual Hybrid Salivary Gland Tumor: Molecular Analysis Informs the Potential Pathogenesis of This Rare Neoplasm

Clinicopathological analysis of hybrid carcinomas of the salivary glands: A systematic review

Hybrid carcinomas (HC) are the association of two or more malignant neoplasms arising within the same topographical area. The present study is a systematic review of HC of the salivary glands. This study aimed to assess HC clinicopathological features and molecular profile. Observational studies, case series, and case reports were included. PubMed, Scopus, EMBASE, Lilacs, Web of Science, and gray literature were searched until June 2024. A total of 18 articles including 34 patients were included. HC of the salivary glands is presented as a painless mass affecting mainly the parotid gland of adults with a preference for male patients. Histologically, adenoid cystic carcinoma and epithelial-myoepithelial carcinoma were the most prevalent association, being surgical excision with radiotherapy the most common treatment. It's seen that the most aggressive component might guide the patient's treatment and prognosis. Further molecular studies are necessary to determine if HC are distinct entities or biologically identical to the individual neoplasms. In conclusion, this systematic review may contribute to a better understanding of this rare lesion, their biological behavior, treatments employed, and the outcome of these patients.

Hybrid Carcinoma of the Parotid Gland: An Extremely Rare Three Cases with an Immunohistochemical Analysis and a Review of the Literature

Salivary hybrid carcinoma (HC) is defined as when two or more kinds of carcinoma exist at the same location in a single mass. We reestimated and examined three cases of salivary gland HC. Case 1 involved a 76-year-old male. Case 2 involved a 74-year-old female. Case 3 involved a 66-year-old male. Histologically, case 1 involved a combination of salivary duct carcinoma (SDC) and squamous cell carcinoma (SqCC). Immunohistochemically, the former was positive for gross cystic disease fluid protein (GCDFP)-15 and androgen receptor (AR). Case 2 involved a combination of SqCC and neuroendocrine carcinoma. Immunohistochemically the latter was positive for synaptophysin and neural cell adhesion molecule (NCAM). Case 3 involved a combination of SDC and epithelial-myoepithelial carcinoma (EMC). Immunohistochemically, the former was positive for GCDFP-15 and AR, whereas the inner cells of the latter were positive for cytokeratin 7, and the outer cells of the latter were positive for actin. Because of the transitional zone between SDC and EMC, it was speculated that high-grade SDC arose from low-grade EMC.

Coexistence of salivary duct, myoepithelial and epithelial-myoepithelial carcinomas in the parotid gland: a case report and literature review

Few reports have described two or more histologically-distinct carcinoma types within the same salivary gland. A 62-year-old man presented to our hospital after detecting a mass in the right parotid gland. Computed tomography revealed a tumor (5.1 × 5.0 cm) within the right parotid gland. Tumor resection with lymph node dissection was performed. The proliferation of three morphologically-different tumor cells was demonstrated on histopathologic examination (salivary duct carcinoma [SDC], myoepithelial carcinoma and epithelial-myoepithelial carcinoma [EMC]). The shape of the inner layer of cells in the EMC was similar to the SDC. Specifically, it appeared that the cells were a mixture of the two tumors with reciprocal transfer in the same area. Immunohistochemical staining showed that the SDC cells and the EMC inner cells were positive for AR, HER2 and p53. Thus, we suggest that our case represented a high-grade transformation.