Mediastinal basaloid carcinoma arising from thymic cysts in two dogs

Abstract

Mediastinal masses in dogs were diagnosed as basaloid carcinoma associated with multiple thymic cysts (MTCs). The masses were composed of MTCs and proliferating intracystic neoplastic basaloid cells, which immunohistochemically diffusely expressed p63 and cytokeratin 19. A gradual transition from the basal cell layers lining the cysts walls to the neoplastic cells was seen, and it was indicated that the neoplastic cells had originated from the basal cell layers of the cysts. To the best of our knowledge, this is the first report of basaloid carcinoma occurring in the mediastinal cavity in dogs. Although these tumors were demonstrated to be rare origins, basaloid carcinoma should be included in the differential diagnoses for canine mediastinal tumors.

Spindle‐cell thymoma colliding with a bronchogenic cyst in a Yorkshire terrier

“…In a study summarizing several cases of pharyngeal remnant cysts, including one found in the cranial mediastinum, authors found varying types of epithelium, but all cases had cilia 19 . More authors have justified a thymic or branchial cyst diagnosis based on the presence of partially to fully ciliated epithelial cells in the cyst lining 20 . In summary, our diagnosis of bronchogenic cyst is supported histologically by the presence of ciliated pseudostratified epithelium and mucus within the cyst lumen.…”

“…19 More authors have justified a thymic or branchial cyst diagnosis based on the presence of partially to fully ciliated epithelial cells in the cyst lining. 20 In summary, our diagnosis of bronchogenic cyst is supported histologically by the presence of ciliated pseudostratified epithelium and mucus within the cyst lumen. It is evident future studies are needed to develop a consensus on histologic criteria for bronchogenic cysts when compared to other thymic cysts.…”