Immunohistochemical features of a papillary squamous cell carcinoma of the endometrium with transitional cell differentiation

Abstract

An 84-year-old woman underwent hysterectomy due to a friable endometrial mass infiltrating almost half way through the myometrial wall. The tumor consisted of papillary structures with thin fibrovascular cores covered by several layers of pleomorphic cells. The deeply located neoplastic cells were ovoid with a pale eosinophilic cytoplasm resembling urothelial cells. A diagnosis of papillary squamous cell carcinoma of the endometrium with transitional cell differentiation was made. Although she recovered well after surgery, she died one year later because of disseminated disease. In an attempt to obtain new insights into the physiopathology of this very rare tumor, an immunohistochemical panel with 32 markers was performed. The neoplastic cells were positive for cytokeratin 5, vimentin, p63, p21, VEGF, Ki67, BAG1, and bcl-2. The expression of BAG-1 and bcl-2 may suggest that anti-apoptotic stimuli are preponderant in this neoplasm.

Figure 1

Squamous cell component showing fibrovascular cores covered with several layers of neoplastic cells (hematoxylin and eosin, ×200).

Figure 2

Transitional cell-like component of the tumor showing neoplastic cells with pale eosinophilic cytoplasm (hematoxylin and eosin, ×400).

Figure 3

P63 expression (nuclear staining) throughout the thickness of the neoplastic epithelium (immunohistochemistry, ×200).