Sarcomatoid (spindle cell) carcinoma of the head and neck mucosal region: a clinicopathologic review of 103 cases from a tertiary referral cancer centre

Abstract

Sarcomatoid carcinomas are biphasic tumors proven to be monoclonal dedifferentiated forms of conventional squamous carcinomas. This study evaluates their clinicopathologic characteristics in head and neck mucosal sites and the problems in distinguishing them from other spindle cell tumors. A total of 103 cases with a confirmed diagnosis of sarcomatoid carcinoma accessioned in the pathology department of a tertiary referral cancer centre over a period of 7 years (2004-2010) were studied. An algorithm used for their diagnosis is presented. Ages of the patients were 22-90 years (median 53 years), and male:female ratio was 3.7:1. Site distribution was oral cavity (n = 65, 63.1%), larynx (18, 17.5%), oropharynx/hypopharynx (12, 10.7%), maxilla (6, 5.8%) and metastatic nodes (2, 1.9%). A large number of patients (95%) presented with a mass lesion of less than 1 year duration. Histopathologically, epithelial differentiation was evident on morphology in 48 (46.6%) cases, only on IHC in 34 (33%) cases, and in 21 (20.4%) no epithelial differentiation was seen. Typically, tumors were polypoidal (92, 89.3%) and ulcerated (95, 92.2%) with cells arranged predominantly in fascicles (59, 57.3%) or storiform pattern (17, 16.5%) amidst collagenous (50, 48.5%) or myxoid matrix (35, 34%). Anaplasia (2+/3+) and mitosis >10 per 10 HPF were noted in 96 (93.2%) cases. IHC was done in 82 cases; 55 (66.7%) showed positivity for epithelial markers with aberrant expression of mesenchymal markers in 43 (41.7%). Diagnosis of sarcomatoid squamous carcinoma is challenging because of overlapping histopathological features with other spindle cell tumors. Understanding their clinicopathologic characteristics facilitates their diagnosis and appropriate clinical management.

Fig. 1

Distribution of spindle cell lesions in head and neck, 2004–2010 (n = 171)

Fig. 2

Approach to the diagnosis of spindle cell neoplasms from mucosal based sites in the head and neck on biopsy material

Fig. 3

Age range of patients

Fig. 4

Site distribution of cases

Fig. 5

Section showing typical polypoidal configuration of the tumor with ulceration of the overlying mucosa (H&E ×40)

Fig. 6

Epithelial differentiation evident on light microscopy showing tumors with nests of frank squamous carcinoma intimately admixed with sarcomatoid elements (H&E ×100)

Fig. 7

Epithelial differentiation evident on light microscopy showing overlying carcinoma in situ (H&E ×40)

Fig. 8

Lymph node metastasis of a case of sarcomatoid carcinoma (H&E ×40)

Fig. 9

a–c Epithelial differentiation in sarcomatoid carcinomas identified at the immunohistochemistry (IHC) level with varying proportion and intensity of positive staining. a Focal strong positivity for cytokeratins (CK). b Diffuse strong positivity for p63. c Diffuse weak positivity for high molecular weight cytokeratins (HMWCK). d, e Aberrant mesenchymal marker expression on IHC. d Strong and diffuse positivity for vimentin. e Focal weak positivity for smooth muscle actin (SMA). e Strong diffuse positivity for calponin

Fig. 10

Fasciculated arrangement of tumor cells mimicking a mesenchymal malignancy (H&E ×40)

Fig. 11

Spindled tumor cells separated by abundant myxoid matrix

Fig. 12

Tumor cells separated by collagenous matrix

Fig. 13

Marked anaplasia with atypical bizarre mitotic figures (H&E ×100)