It is therefore the general view, that a malignant spindle cell tumor in the mucosa of the larynx tract is probably a SpCC and not a sarcoma. In the larynx, true sarcomas (with the exception of chondrosarcoma) and benign mesenchymal tumors are very rare. However, when a SCC component cannot be demonstrated, the diagnosis is more difficult and SpCC must be distinguished from a number of benign and malignant processes, such as spindle cell sarcomas, nodular fasciitis, inflammatory myofibroblastic tumor and malignant melanoma. Spindle cells always express vimentin and often other mesenchymal filaments, such as myogenic markers (smooth muscle actin, muscle specific actin, desmin).Ī diagnosis of a SpCC is based on demonstration of an invasive or in situ SCC and a malignant spindle cell component. The most sensitive/reliable epithelial marker for SpCC seems to be keratin (AE1/AE3, K1) K1, K18 and EMA. Cytokeratin expression can be demonstrated in spindle cells in 40%–85% of cases. Cytokeratin and vimentin coexpression has been observed in individual tumor cells. Immunohistochemically, tumor cells in SpCC often express epithelial and mesenchymal markers. (B) Spindle cell carcinoma with abundant edematous, myxoid stroma. (A) Small islands and cords of squamous cell carcinoma and dense proliferation of neoplastic spindle cells. 12.23) and clearly separate all carcinomas into essentially three main categories: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.įig. 8. These last cells characteristically show emperipolesis of neutrophils, which has led to naming these giant cells as emperipoletic or “null” cell type.īased on the available findings, we can establish a link, not only between spindle cell neoplasms with or without morphologic differentiation toward adenocarcinoma or squamous cell carcinoma, but in addition, we can also properly categorize the giant cell component of these tumors (see Fig. 87 Immunohistochemical analysis of these cases showed that some giant cells have pneumocytic derivation, others syncytiotrophoblastic phenotype, and some lack differentiation except for positive staining for keratin antibodies. Though rare, tumors composed exclusively of giant cells can be seen as primary lung carcinomas. There are essentially four types of giant cells that may be seen in carcinomas of the lung: (1) pneumocytic type, (2) syncytiotrophoblastic type, (3) null cell type, and (4) osteoclast-like type. Once the spindle cell component of these tumors is identified, then the other component of giant cells also needs to be properly identified. Flow charts for the interpretation and proper classification of non-small cell carcinomas, and more specifically those with spindle cell component, are presented (see Figs. The authors 86 further proposed abandonment of the term “sarcomatoid” carcinoma, which is not helpful for targeted treatment purposes. Forty-two percent of the tumors initially labeled as sarcomatoid carcinoma were adenocarcinomas, whereas 14% were squamous carcinoma. The spindle cell component in these tumors was positive for TTF-1 in 41% of the cases, napsin A was present in 20%, keratin 5/6 in 9%, p40 in 8%, and desmocollin in 3%. 85 The study included a wide panel of antibodies, including keratin CAM5.2, keratin 7, TTF-1, napsin A, keratin 5/6, p40, desmocollin 3, Sox2, calretinin, and D2-40. More recently, we have evaluated the IHC profile of 86 cases that had been diagnosed either as spindle cell carcinomas, sarcomatoid carcinoma, or pleomorphic carcinoma with the concept of identifying specific differentiation within the spindle cell component. However, by current standards, adequate IHC analysis was not performed. 83,84 Introduced in 1994 as a description of 78 tumors with spindle cell and giant cell components, 45% of the cases showed histologic evidence of adenocarcinoma and 8% histologic evidence of squamous cell carcinoma. The term “pleomorphic carcinoma” has been used as a synonym for tumors similar to spindle cell carcinoma. In addition, even if one cannot further define some of these tumors with spindle cell morphology, the reality is that those tumors in particular may also represent a histologic variant of large cell carcinomas. Most of these cases can be categorized among the conventional subtypes of carcinoma. The term “sarcomatoid carcinoma” historically has been used to refer to spindle cell carcinomas-that is, carcinomas that have a “sarcoma-like” spindle cell morphology. Dabbs MD, in Diagnostic Immunohistochemistry, 2019 Sarcomatoid Carcinoma, Pleomorphic Carcinoma, and Giant Cell Carcinoma
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