Immunohistochemial typing of spindle cells tumors of larynx: a single entity or distinct histotypes?

Lane originally described polypoid tumors of the upper aerodigestive tract, showing a pseudosarcomatous overgrowth and minimal foci of squamous cell carcinoma (SCC), and pursuing a relatively indolent clinical course. Subsequent studies questioned the separation of polypoid SCC with prominent stroma as a clinicopathologic entity distinct from other laryngeal spindle cell neoplasms and included polypoid squamous cell carcinoma in the heterogeneous group of the so-called spindle cell carcinomas. This study was aimed at morphologically and immunohistochemically characterizing a series of laryngeal tumors with spindle cell features to assess whether the identification of different subtypes is feasible and of clinical relevance. Polypoid squamous cell carcinomas (four cases) were characterized by a prominent spindle cell component, including myofibroblasts, which expressed vimentin and, focally, smooth-muscle actin but not epithelial antigens, associated with minimally invasive SCC. These features reliably allowed distinction of polypoid SCC from spindle cell carcinoma (eight cases) and fibro- and leiomyosarcoma (one case each), whereas widely invasive SCCs with prominent stroma (five cases) shared some morphologic and immunophenotypic features with polypoid squamous cell carcinoma. In view of the distinctive histologic and immunohistochemical features of the tumors with spindle cell component reported herein and of the still unsettled prognosis of these tumors, we suggest keeping them as separate entities. In our opinion, this separation is justified by the apparently different prognosis of distinct histotypes.