Squamous cell carcinoma

B.Z. Pilch J. Bouquot L.D.R. Thompson

Definition

A malignant epithelial neoplasm originating from the mucosal epithelium of the nasal cavities or paranasal sinuses that includes a keratinizing and a non-kera-tinizing type.

ICD-O codes

Squamous cell carcinoma 8070/3 Verrucous carcinoma 8051/3 Papillary squamous cell carcinoma

8052/3

Basaloid squamous cell carcinoma

8083/3

Spindle cell carcinoma 8074/3 Adenosquamous carcinoma

8560/3

Acantholytic squamous cell carcinoma 8075/3

Synonyms

Keratinizing squamous cell carcinoma: squamous cell carcinoma. Nonkeratinizing carcinoma: Schneider-ian carcinoma, cylindrical cell carcinoma, transitional (cell) carcinoma, Ringertz carcinoma, respiratory epithelial carcinoma.

Epidemiology

Sinonasal squamous cell carcinoma is rare, accounting for <1% of malignant tumours and only about 3% of malignancies of the head and neck {169,2758}. The disease appears to be more common in Japan than in the West {2205}. It is extremely rare in children, and men are more commonly affected (about 1.5 times) than women. Patients are generally about 55-65 years of age {502,2758}.

Etiology

Reported risk factors have included exposure to nickel, chlorophenols, and textile dust, prior Thorotrast instillation, smoking, and a history or concurrence of sinonasal (Schneiderian) papilloma. Human papillomavirus (HPV) has been found in some cases, especially those associated with inverted Schneiderian papilloma {303}, but a definite etiologic role has not been clearly established. Formaldehyde, despite the results of animal experiments, has not been found to be a definite risk factor in humans {502,1443,1571,2205,2904}.

Localization

Sinonasal squamous cell carcinomas occur most frequently in the maxillary sinus (about 60-70%), followed by the nasal cavity (about 12-25%), ethmoid sinus (about 10-15%) and the sphenoid and frontal sinuses (about 1%)

{131,502}. Squamous cell carcinoma of the nasal vestibule should be considered a carcinoma of the skin rather than sinonasal mucosal epithelium {2566}.

Clinical features

Symptoms include nasal fullness, stuffiness, or obstruction; epistaxis; rhinor-rhea; pain; paraesthesia; fullness or swelling of the nose or cheek or a palatal bulge; a persistent or non-healing nasal sore or ulcer; nasal mass; or, in advanced cases, proptosis, diplopia, or lacrimation {131,502,2758}. Radiologic studies such as CT scan or MRI may delineate the extent of the lesion, the presence of bony invasion, and extension to neighbouring structures such as the orbit, pterygopalatine or infratemporal spaces.

Macroscopy

Sinonasal squamous cell carcinomas may be exophytic, fungating, or papillary; friable, haemorrhagic, partially necrotic, or indurated; demarcated or infiltrative.

Tumour spread and staging

Nasal cavity carcinomas can spread to adjacent sites in the nasal cavity or to the ethmoid sinus, or can extend to involve

Nasal Squamous Cell Carcinoma

Fig. 1.6 A Non-keratinizing papillary squamous cell carcinoma. Multiple complex papillary projections lined by thickened epithelium. Lymphocytic response is present at the pushing border of infiltration. B Squamous cell carcinoma, non-keratinizing. Islands of cohesive tumour cells invading into the underlying stroma. Surface carcinoma in-situ is seen.

Fig. 1.6 A Non-keratinizing papillary squamous cell carcinoma. Multiple complex papillary projections lined by thickened epithelium. Lymphocytic response is present at the pushing border of infiltration. B Squamous cell carcinoma, non-keratinizing. Islands of cohesive tumour cells invading into the underlying stroma. Surface carcinoma in-situ is seen.

Squamous Cell Carcinoma Situ
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Fig. 1.7 A Nasal verrucous carcinoma "Church-spire" type hyperkeratosis, parakeratosis and a broad pushing border of infiltration in a non-atypical epithelium support the diagnosis. B Basaloid squamous cell carcinoma. A characteristic feature is the presence of comedonecrosis in the center of the neoplastic lobules. Surface is ulcerated.

the contralateral nasal cavity, bone, maxillary sinus, palate, skin and soft tissues of the nose, lip, or cheek, cribriform plate, or cranial cavity. Maxillary sinus carcinomas may spread to the nasal cavities, palate, other paranasal sinuses, skin or soft tissues of the nose or cheek, orbit, cranial contents, or the ptery-gopalatine and infratemporal spaces {131,2418}. Lymph node metastases are less common than in squamous cell carcinomas of other sites in the head and neck.

Histopathology

Keratinizing squamous cell carcinoma

This tumour is histologically identical to squamous cell carcinomas of other mucosal sites in the head and neck. There is histologic evidence of squa-mous differentiation, in the form of extracellular keratin or intracellular keratin (pink cytoplasm, dyskeratotic cells) and/or intercellular bridges. Tumour cells are generally apposed to one another in a "mosaic tile" arrangement. The tumour may be arranged in nests, masses, or as small groups of cells or individual cells. Invasion occurs as blunt projections or ragged, irregular strands. There is often a desmoplastic stromal reaction. The carcinomas may be well, moderately, or poorly differentiated.

Non-keratinizing (cylindrical cell, transitional) carcinoma

This is a distinctive tumour of the sinonasal tract characterized by a plexi-

form or ribbon-like growth pattern. It invades into the underlying tissue with a smooth, generally well-delineated border. Therefore, definite evidence of stromal invasion may be difficult to appreciate, although a degree of invasion by irregular small nests or strands may be present. There is typically a lack of maturation in the epithelial nests or ribbons, as in transitional cell carcinoma of the urinary tract, which this tumour subtype resembles. Cytologic atypia is present to a significant degree. As its name implies, this tumour does not generally evince histologic evidence of keratinization, although some degree may be seen. When keratinization is significant, there is morphologic overlap with keratinizing squamous cell carcinoma. Occasional mucus-containing cells can be seen. The tumour may be moderately or poorly differentiated; the latter type is difficult to recognize as squamous, and must be differentiated from olfactory neuroblas-tomas or neuroendocrine carcinomas.

Variants of squamous cell carcinoma

Variants of squamous cell carcinoma are rare in the sinonasal tract. They are similar to the analogous tumours occurring with greater frequency in other sites in the head and neck and are more completely described in the corresponding sections.

Verrucous carcinoma of the nasal and paranasal sinuses is very rare. It is a low-grade variant of squamous cell carcinoma characterized by a papillary or warty exophytic mass of very well-differentiated, keratinized epithelium {899,1955, 2118,2278}. The maxillary sinus is the most common site, followed by the nasal fossa. Rare nasopharyngeal lesions have encroached on the nasal sinus {1199,1872}.

Papillary squamous cell carcinoma {2488} is an exophytic squamous cell carcinoma with a papillary configuration composed of thin fingers of tumour surrounding fibrovascular cores. Basaloid squamous cell carcinoma is uncommon in the sinonasal tract {2786}. It is an aggressive variant of squamous cell carcinoma that is characterized by rounded nests of cytologically highly atypical and mitotically-active basaloid epithelial cells, with high nuclear/cyto-plasmic ratios and hyperchromatic nuclei. There is often comedo-type necrosis. A pseudoglandular or strandlike arrangement, reminiscent of the architecture of an adenoid cystic carcinoma, is often present, as is the production of basement membrane-like material. Squamous differentiation is invariably present, either in basaloid nests, as separate foci of tumour, or as surface epithelial carcinoma or carcinoma in-situ. Spindle cell carcinoma is characterized by a biphasic pattern of squamous cell carcinoma as well as a generally much larger component of malignant spindled cells, reminiscent of a sarcoma. The squamous component may be scant or even inapparent on light microscopy. In the latter circumstance, immunohisto-

Severe Squamous Cell Carcinoma
Fig. 1.8 Schneiderian papilloma with keratinization is associated with an area of malignant transformation into a squamous cell carcinoma with severe cytologic atypia.

chemical or ultrastructural evidence of epithelial differentiation is required for the diagnosis. The spindle cell component is characteristically immunohistochemically vimentin-positive, and keratin positivity may be scant, difficult to demonstrate, or even absent.

Adenosquamous carcinoma is uncommon in the sinonasal tract, and is more completely described in the sections on oral and laryngeal tumours. Briefly, it is generally considered as a variant of squamous cell carcinoma in which a surface mucosal component of squamous cell carcinoma is present. There is also a component of carcinoma with definite glandular differentiation in the form of ductules or tubules, often intimately admixed with the squamous cell carcinoma. The mere presence of intracellular mucin is not sufficient for the diagnosis.

Acantholytic squamous cell carcinoma is exceedingly rare in the sinonasal tract.

Precursor lesions

Precursor lesions for sinonasal squa-mous cell carcinomas are considerably less well defined than for oral or laryn-geal carcinomas. The sinonasal Schneiderian (inverted) papilloma appears to be a precursor lesion; the frequency of association has been estimated at about 10% {173}. Although squa-mous metaplasia may precede the development of sinonasal squamous carcinoma, a predisposing role for such metaplasia in the development of carcinoma has not been clearly established.

Prognosis and predictive factors

Patients with nasal squamous cell carcinomas generally present earlier than patients with maxillary cancers and, not surprisingly, fare better than the latter group. Nasal squamous cell carcinomas rarely metastasize to lymph nodes, and recurrences, when they occur, do so quickly {131}. Advanced local disease worsens the prognosis. The overall 5-year survival for nasal squamous cell carcinomas is about 60%. Squamous carcinomas of the maxillary sinus have a more ominous prognosis. They are likely to be large and extensive when diagnosed. Prognosis correlates with stage. Patients with the non-keratinizing type of carcinoma tend to do better than those with the keratinizing type {502}. The overall 5-year survival of patients with maxillary sinus squamous carcinoma is about 42% {131}.

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Responses

  • rebecca toscano
    Can b cell lymphoma tumours be mistaken for squamous cell tumours?
    4 years ago

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