SATB2 expression in oral sarcomatoid (spindle cell) squamous cell carcinoma: clinicopathologic and immunophenotypic characterization of 10 cases.

Objective: Sarcomatoid squamous cell carcinoma (sSCC) represents an uncommon histopathologic variant of squamous cell carcinoma (SCC). We examined the clinicopathologic and immunophenotypic characteristics, including SATB2 expression, of 10 cases of oral sSCCs.

Study Design: Archived sSCC cases diagnosed during the period 2000 to 2023 were retrieved. Lesions lacking proper histomorphological features or adequate immunohistochemical confirmation were excluded. Patient age, sex, and lesion location were recorded. All cases were immunostained against SATB2 (Clone EP281; Cell Marque).

Results: Ten oral sSCCs were identified (M:F ratio = 1.5:1; age range = 47-82 years, median = 74.5 years). The tongue was the most common anatomic site. Lesions presented as fungating or ulcerated, polypoid, and indurated masses. Microscopically, most tumors demonstrated an infiltrative population of atypical spindle cells organized in slender cords or fascicles. Rhabdoid/plasmacytoid morphology was observed in 3 cases. Immunohistochemically, all cases exhibited strong, focal-to-diffuse positivity for pancytokeratin, p63, and/or p40. Patchy, moderate-to-strong SATB2 staining was seen in 4 oral sSCCs, whereas 4 additional cases showed rare, weak-to-moderate expression.

Conclusions: Oral sSCC is uncommon and primarily exhibits spindled histomorphology, although rhabdoid/plasmacytoid features may be observed. A battery of epithelial and non-epithelial markers is required for proper diagnosis. Positive SATB2 immunostaining in oral sSCCs may pose a potential diagnostic pitfall, particularly in small biopsy specimens. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).