Pathology of the Head and Neck

16 N. Gale · N. Zidar1a b cFig. 1.14. Spindle cell carcinoma. a Squamous cell carcinoma inassociation with pleomorphic spindle cells. b Pure spindle cellcomponent: pleomorphic cells with large hyperchromatic nuclei. cPositive staining for cytokeratin in spindle cellsAdditional important prognostic features are: localisationand depth of the tumour [74, 77, 130, 233, 246],presence of extracapsular spread in lymph node metastases[85, 109, 155, 335], and pattern of tumour growth atthe invasive front [57, 58, 76, 382].The prognostic value of some other parameters, i.e.differentiation of the tumour [166, 280, 376] and DNAploidy [23, 98, 350, 378], is controversial.The treatment of choice is complete excision of thetumour. For small tumours at some locations, such asthe glottic larynx, the primary treatment is radiation. Inlarge tumours, surgery is usually followed by radiotherapy.Patients with advanced, unresectable tumours, withor without metastases, are treated by concurrent chemotherapyand radiotherapy [117].giving rise to both epithelial and mesenchymal components[66, 354].1.3.3.1 AetiologySimilar to conventional SCCs, SpCCs have been aetiologicallyrelated to cigarette smoking and alcohol consumption[356]. It has been suggested that SpCCs maydevelop after radiation exposure; however, some authorsbelieve that this is not a major aetiologic factor [356].The reported incidence of radiation-induced SpCCs ofthe head and neck is between 7.7 and 9.1%; they developafter a latent period of 1.2 to 16 years after radiation exposure[210, 356].1.3.3 Spindle Cell CarcinomaICD-O:8074/3Spindle cell carcinoma (SpCC) is a biphasic tumourcomposed of conventional SCC and a malignant spindlecell component. Synonyms for SpCC are sarcomatoidcarcinoma, carcinosarcoma, collision tumour and pseudosarcoma.It has been described in various sites of the body includingthe upper and lower respiratory tract, breast,skin, urogenital and gastrointestinal tracts, and salivaryglands [31]. In the head and neck, SpCC occurs most frequentlyin the larynx [36, 108, 213, 356] and oral cavity[13, 96, 304], followed by the skin, tonsils, sinonasaltract and the pharynx [13, 375].The histogenesis of this tumour is controversial, butthere is mounting evidence that SpCC is a monoclonalneoplasm originating from a non-committed stem cell1.3.3.2 Pathologic FeaturesMacroscopically, SpCCs are usually exophytic polypoidor pedunculated tumours, with frequent surface ulceration.Less often, SpCCs manifest as sessile, endophyticor ulcero-infiltrative tumours [31, 356].Microscopically, SpCCs consist of a SCC componentand a spindle cell component. The former is representedby in situ carcinoma or by an invasive SCC, and is oftensmall, requiring multiple sections for demonstration(Fig. 1.14a) [210].The spindle cell component usually forms the bulkof the tumour. Spindle cells are often pleomorphic, withlarge hyperchromatic nuclei, prominent nucleoli, andnumerous mitoses (Fig. 1.14b). They are arranged in fasciclesor whorls and can assume many histologic patterns,the most common being that of a malignant fibroushistiocytoma or fibrosarcoma [213, 356]. Foci of