Diagnostically challenging lesions in head and neck pathology.

There are a variety of diagnostically challenging lesions in the head and neck region. Contact ulcer usually occurs within specific clinical parameters (vocal abuse, post-intubation and gastro-esophageal reflux), which should be documented in correlation with the granulation tissue-like response affecting the posterior vocal cords. Spindle squamous cell carcinoma (carcinosarcoma) presents a variably cellular spindle cell proliferation, often with surface epithelial ulceration. The clinical presentation of a firm, polypoid mass in the larynx, combined with the histomorphologic features of a spindle cell tumor, can be confirmed to be of epithelial origin when a portion of the overlying epithelium is seen to blend with the spindle cell component, or when ancillary studies authenticate the epithelial origin of the tumor. The diagnosis of a verrucous squamous cell carcinoma can only be made accurately with an accurate clinical history. The very well differentiated histologic appearance, a broad pushing border of infiltration, a bland epithelial proliferation with scant mitotic activity and "church-spire"-type keratosis coupled with the clinical presentation of a large, locally destructive lesion, can confirm the diagnosis of verrucous carcinoma. A wide variety of disorders can result in midline destructive disease clinically, but a specific etiology must be sought to provide appropriate clinical management. Angiocentric T/NK-cell lymphoma of the sinonasal tract is one such disease. The atypical lymphoid cells are usually angiocentric and angiodestructive in their growth pattern. Identification of the atypical cells in the early stages of disease may be difficult, often requiring multiple biopsies over time with the application of immunohistochemical stains or molecular studies to accurately identify the nature of the infiltrate. Cystic squamous cell carcinoma in the neck is almost always a manifestation of metastatic tumor and not a brachiogenic carcinoma. When specific histomorphologic features are noted (a large, unfilled cyst lined by a ribbon-like or endophytic growth of a "transitional"-appearing squamous epithelium with a limited degree of anaplasia), most of these tumors demonstrate primaries in Waldeyer's ring, often of a very small size. Adequate clinical work-up (pan-endoscopy, extensive radiographic imaging and random biopsies or prophylactic tonsillectomy) is mandatory in order to limit the radiation-therapy ports and to document the location of the primary, yielding an excellent long-term prognosis.