Pathology of the Head and Neck

Lesions of Squamous Epithelium Chapter 1 19Fig. 1.16. Papillary squamous cell carcinoma.a Tumour consists of papillae with acentral fibrovascular core, covered by neoplasticsquamous epithelium. b The coveringepithelium is composed of pleomorphic cellsresembling carcinoma in situMacroscopically, PSCCs present as papillary, friableand soft tumours, ranging in size from 2 mm to 4 cm.The main histologic feature of PSCCs is the papillarygrowth pattern that comprises the majority of the tumour(Fig. 1.16a). Papillae consist of a central fibrovascularcore covered by neoplastic squamous epithelium.The covering epithelium may be composed of immaturebasaloid cells or may be more pleomorphic, resemblingcarcinoma in situ (Fig. 1.16b). It is usually non-keratinisingor minimally keratinising.Multiple lesions can be found, consisting either of invasivePSCCs or mucosal papillary hyperplasia. Stromalinvasion is often difficult to demonstrate in biopsy specimens,and sometimes additional biopsies are needed tomake the diagnosis of an invasive PSCC. A dense lymab278, 287, 309]. However, recent studies do not supportthis notion. It appears that some of the reported cases oftransformation of VC to SCC after radiotherapy were ofmixed (hybrid) tumours. Moreover, similar transformationcan also occur after surgical treatment of VC [237,240, 275, 353]. Radiotherapy is now believed to be an appropriatemode of treatment for oral VC [177] and laryngealVC [275].1.3.4.5 PrognosisIn his original report, Ackerman noted metastasis in theregional lymph node in only one of the 31 patients, andno distant spread was observed in his series [5]. Furtherstudies confirmed his observation that pure VCs do notmetastasise [107, 274]; cases of VC with metastases werereally a hybrid carcinoma that had not been detected atinitial biopsy.Verrucous carcinomas therefore have a good prognosis;the overall 5-year survival rate is 77% [196]. It is importantto recognise hybrid tumours, as foci of a conventionalSCC in a VC indicate the potential for metastasis.Orvidas et al. reported that a patient with a hybridcarcinoma of the larynx died of the disease [274]. Patientswith hybrid carcinomas must be treated aggressivelyas if they had a conventional SCC [274].1.3.5 Papillary Squamous Cell CarcinomaICD-O:8052/3Papillary squamous cell carcinoma (PSCC) is an uncommonvariant of SCC originally described by Crissman etal. in 1988 [75]. Its main characteristics are a papillarygrowth pattern and a good prognosis.In the head and neck, PSCCs show a predilection forthe oropharynx, hypopharynx, larynx, and the sinonasaltract [75, 99, 110, 161, 343, 355]. They also occur inother parts of the body, such as the skin [15], uterine cervix[292], conjunctiva [215], and thymus [209].1.3.5.1 AetiologyIt has been postulated that human papillomavirus(HPV) infection might be an important aetiologic factorin PSCCs, similar to squamous papillomas [343]. However,the reported prevalence of HPV infection in PSCCsvaries from 0 [75] to 48% [30, 343] and does not differsignificantly from the reported overall prevalence ofHPV infection in head and neck SCCs [238]. Therefore,the significance of HPV infection in the pathogenesis ofPSCCs remains unclear.1.3.5.2 Pathologic Features