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Thirty cases of poorly differentiated carcinomas of the skin were examined for the expression of vimentin. All cases expressed cytokeratins; in addition, 12 cases were positive for vimentin. These were all non-reactive with antibodies to S100 protein, HMB45 and desmin. The finding of vimentin in poorly differentiated squamous cell carcinomas underscores the need for caution in the use of immunohistochemical stains for tumor typing. Cutaneous squamous cell carcinomas are an addition to the list of epithelial tumors which are known to coexpress vimentin intermediate filaments. Other carcinomas which consistently express vimentin include those of renal, endometrial, thyroid, pulmonary, ovarian, salivary gland, adrenal and more recently, those of breast and prostatic origin.

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MB, BS, FRCPA, Pal V. Rajagopalan, MB, BS, DLO, MS \s=b\ Cartilaginous metaplasia in the larynx is distinguished from true cartilaginous neoplasms by the occurrence of fibroblast-like cells at the periphery of islands of cartilage and a progressive transition of these cells to chondrocytes toward the center. Also present in the transitional zone was diffuse intercellular stromal acid mucopolysaccharide and dense aggregates of elastin fibers. The importance of distinguishing these metaplastic lesions from true neoplasms is emphasized. (Arch Otolaryngol 1981;107:573-575) Carti l agi nous lesions of the larynx are rare and may be either metaplastic or neoplastic in origin. An awareness of the occurrence of meta¬ plastic foci of cartilage in soft tissues of the larynx and their distinction (Dr Iyer). from true neoplasms that arise from the preexisting laryngeal cartilages is important because of the more ag¬ gressive behavior of neoplastic le¬ sions.The object of this article is to report a case of cartilaginous metaplasia in the larynx and to describe features that distinguish it from neoplastic cartilaginous lesions. REPORT OF A CASEA 66-year-old man was seen initially with a history of intermittent hoarseness of voice of four months' duration. He had a history of occupational vocal abuse. On clinical examination, there was restricted mobility of the left vocal cord. Findings from a laryngogram showed that the left ventricle of the larynx was occupied by a polypoid lesion. The polyp was removed and submitted for pathologic examination. After the operation, the patient continued to be hoarse. This became worse and he had exertional dyspnea develop during the next five months. Microlaryngoscopy disclosed a left ventricular lesion at the same site as the initial lesion. It was not attached to any of the laryngeal cartilages. This lesion was excised and submitted for pathologic examination. Six months after the second operation, the patient was asymptomatic and there has been no sign of recurrence of the laryngeal lesion. PATHOLOGIC FINDINGSIn the laboratory, each of the two operative specimens was processed in a similar way. Paraffin-embedded sections, 6 µ thick, were prepared and stained with hematoxylin-eosin, Miller's elastic stain, Alcian blue at pH 2.5, and combined Miller's elastic stain-Alcian blue.The biopsy specimen removed at the first operation was a polyp measuring 17 X 5 x 2 mm, and that from the second operation was a polypoid piece of tissue partly covered by mucosa and measuring 13 x 5 x 2 mm. Micro¬ scopic examination of both the speci¬ mens disclosed, in each case, features typical of a "vocal polyp." This was evidenced by dilated blood vessels with focal areas of hemorrhage and myxoid degeneration in the connec¬ tive tissue underlying the stratified squamous epithelium lining the polyp (Fig 1). In addition, in each specimen, there was an incompletely excised focus of cartilaginous metaplasia in