P63 is a helpful tool in the diagnosis of a primary cutaneous carcinosarcoma

Cutaneous carcinosarcoma: a rare diagnosis

Carcinosarcoma is a rare malignant tumor that is a combination of carcinoma (cancer of epithelial tissue) and sarcoma (cancer of mesenchymal tissue). In practice, it is more common to have either carcinoma or sarcoma individually, but it is novel to have a combination of the two; as a result, few cases have been reported. Carcinosarcoma typically occurs in visceral organs and is rare in the skin. We present the case of a 68-year-old man with a lesion on his left zygomatic cheek that was revealed to be a biphasic malignant neoplasm. Multiple stains provided evidence of both epithelial and mesenchymal components within the lesion. Treatment for such a diagnosis typically involves a combination of wide local excision or plastic surgery for reconstruction purposes, both of which were used with this patient. This case describes the identification of cutaneous carcinosarcoma using immunohistochemical tests and emphasizes the uniqueness of such a diagnosis that requires early attention and appropriate selective treatment.

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.

Soft Tissue Pseudosarcomas

Soft tissue pathology is one of the most challenging areas of diagnostic pathology, not only because of the morphologic diversity of such lesions, but also because of their rarity and pathologists' subsequent lack of exposure to these tumors. Many lesions mimic malignant mesenchymal neoplasms, collectively referred to as "pseudosarcomas." The list of proliferations that can simulate a sarcoma is extensive and heterogeneous. This review addresses malignant, nonmesenchymal neoplasms; mesenchymal neoplasms that histologically mimic sarcomas but are benign; and benign reactive soft tissue lesions that are neither neoplastic nor malignant, but have worrisome clinical and/or morphologic features.