Oral Sarcomatoid Squamous Cell Carcinoma: Clinicopathologic and Immunophenotypic Characterization Including SATB2 Expression in 10 Cases

Introduction

Sarcomatoid or spindle cell carcinoma (sSCC) is a rare histopathologic variant of squamous cell carcinoma exhibiting spindled cytomorphologic features and frequent loss of epithelial differentiation markers. Recently, SATB2 expression has been reported in cases of oral sSCC. Herein, we present the clinicopathologic and immunophenotypic characteristics including SATB2 expression of 10 cases of intraoral sSCC.

Material and Methods

Archived sSCC cases diagnosed over a 23-year period (2000-2023) were retrieved from the electronic laboratory databases of Oral Pathology Consultants at The OSU. Cases lacking proper morphologic features or sufficient immunohistochemical confirmation were excluded from the study. All sSCC cases were immunostained for SATB2. Patient age, gender and lesion location were recorded.

Results

Ten oral sSCC cases were identified among 6 men and 4 women (M:F ratio=1.5:1; age range=47-82y, median=74.5y). Five cases involved the tongue, 2 each the mandible and mandibular gingiva, and one the buccal/labial mucosa. Clinically, lesions presented as large, occasionally polypoid and ulcerated, erythematous, indurated or firm masses, measuring 3-8cm (mean=4.3cm). Microscopically, all tumors demonstrated an infiltrative population of atypical spindle cells with nuclear hyperchromatism, pleomorphism, increased mitoses, and varying amounts of eosinophilic cytoplasm. A prominent rhabdoid phenotype was observed in 3 cases. Immunohistochemically, all cases exhibited strong, focal-to-diffuse, positivity for epithelial markers including pancytokeratin, CAM5.2 and p63/p40. Focal, moderate-to-strong, nuclear SATB2 immunoreactivity was observed in 4 cases with 20-40% of carcinoma cells showing positivity, while 3 additional cases showed rare, weak-to-moderate SATB2 immunoexpression.

Conclusions

Oral cavity sSCC is a rare epithelial malignancy with sarcomatoid characteristics including spindle and rhabdoid morphology. A panel of epithelial and non-epithelial markers is required for proper diagnosis. We observed variable SATB2 immunostaining in 70% of oral sSCC cases, posing a potential diagnostic challenge with these rare neoplasms, particularly in small biopsy specimens.