Primary Cutaneous Carcinosarcomas

Abstract

To present and define diagnostic criteria for primary cutaneous carcinosarcomas (CSs). Neoplasms of 6 patients with primary cutaneous CSs were retrospectively analyzed. A panel of histopathologic parameters and immunophenotypic expression of distinct markers of differentiation were investigated. All cases had medium-to-poorly differentiated squamous cell carcinoma representing the epithelial component intermingled with a variable amount of malignant sarcomatous tissue proliferation. The authors identified 3 distinct morphological criteria for the diagnosis of primary cutaneous CSs with features of (1) a clearly defined dual neoplasm with explicit morphological characterization using histology and immunohistochemistry with distinct marker panels while, (2) metastases from distant sites and true collision neoplasms must be excluded, and (3) recognition of the neoplasm as a solid coherent proliferation with careful exclusion of sarcomatous stromal changes in the surrounding neoplasm stroma has to be assured. The low incidence of this entity and a plethora of different synonymous terms in the dermatopathologic literature often cause diagnostic problems and hamper the accurate comparative analysis of cases published previously. Herein, the authors propose defining criteria and a clearly defined morphological approach to contribute to more accurate dermatopathologic diagnoses and provide an unprecedented summary on this neoplastic entity.

A Case of Primary Cutaneous Basal Cell Carcinosarcoma

“…Although the pathogenesis of CS is unknown, there are two hypotheses, i.e., the monoclonal and the multiclonal hypotheses [3]. The monoclonal hypothesis proposes that undifferentiated totipotent neoplastic cells undergo multiple pathways of terminal differentiation into histologically recognizable mesenchymal and epithelial components.…”

Primary Cutaneous Carcinosarcoma: A cutaneous neoplasm with an exceptional presentation

“…2 In CCS cases, Mohs micrographic surgery is the treatment of choice and has been reported to result in a cure rate of ≥98%; in contrast, a recurrence rate of 33% has been reported without this surgery. 4 As such, close observation of the patient is required if Mohs surgery is not performed. There is no evidence to support the use of adjuvant radiotherapy.…”

“…The prevalence of metastasis in CCS with a basal cell epithelial component has been reported in 2% of cases. 4,5 sarcomatous component is formed of an osteosarcoma, chondrosarcoma, fibrosarcoma or malignant fibrous histiocytoma. 3 The diagnostic criteria for a CCS include an absence of transitional areas in the malignant components and lack of cytokeratin expression in the sarcomatous components.…”

“…3 However, Müller's criteria should be additionally considered to more thoroughly confirm the diagnosis. 4 According to Müller et al, a CCS is a malignant entity composed of two welldefined cell populations as evidenced by conventional histology (i.e. haematoxylin and eosin stains) and an adequate immunohistochemical panel.…”

“…Metastases from distant sites and sarcomatous changes in the stroma of the neoplasm should also be excluded. 4 There are at least four aetiopathogenic theories to explain the genesis of CCS. Of these, the monoclonal theory is particularly important as it justifies the rapid growth of the lesion by implicating the metaplastic transformation of the sarcomatous component.…”