An unusual infiltrative basal cell carcinoma with osteoclastic stromal changes mimicking carcinosarcoma: a case report

A 91-year-old man presented with an ulcerated nodule on his left lower eyelid. The tumor showed an epithelial component composed of basaloid and clear cells and a stroma that contained many osteoclastic giant cells. Strong, diffuse expression for cytokeratin 17 and p63 was noted in the epithelial component, whereas no staining was present in the sarcomatoid stroma, suggesting that the osteoclast-rich stromal component represented an unusual benign stromal reaction to the carcinoma rather than a manifestation of carcinosarcoma. Further supporting this interpretation was the absence of mitotic figures and low Ki-67 proliferation index (of approximately 1%) in the stromal cells. We herein reported a case of unusual infiltrative basal cell carcinoma, accompanied by a clear cell carcinomatous features and concurrent benign osteoclastic stromal changes.

Study of D2-40 immunoexpression of the spindle cell areas of a metaplastic basal cell carcinoma (sarcomatoid basal cell carcinoma)

Sarcomatoid basal cell carcinoma (BCC) is rare. In the literature, data on the prognosis of such a variant is somewhat contradictory. D2-40 immunoexpression has been shown to have prognostic connotations in carcinomas of organs other than the skin. However, although D2-40 immunoexpression has been investigated in "common" (nonsarcomatoid) BCC, it has not yet been studied in the spindle cell component of a sarcomatoid BCC. We present a sarcomatoid BCC on the neck of an 87-year-old man that has grown rapidly over the last few months. The sarcomatoid component of the tumor expressed several types of cytokeratins, such as AE1/AE3, CK 5/6, 34betaE12, and CAM 5.2. It was also positive for p63 and for D2-40 in a diffuse pattern.