Sebaceous Carcinoma with Involvement of the Oral Cavity: A Case Report of a Rare Occurrence

Introduction

Sebaceous carcinoma (SC) is an aggressive, rare cutaneous malignancy. It shows striking predilection for the skin of the eyelid, face, neck, and scalp, but may arise on any cutaneous site.. Extraorbital sites overall account for only approximately 25% of SCl, and the head and neck region is involved in 70% of cases. Involvement of the oral cavity in SC is rare. Hereby we present a case of cutaneous SC with direct extension and involvement of the oral mucosa.

Case presentation

A 25-year-old male presented with a painless ulcerated lesion on the left commissure area persisting for a duration of 3 months. The past medical history was unremarkable. Extra-oral examination showed a markedly ulcerated, exophytic, irregularly shaped mass of the left commissure extending to the labial and buccal mucosa. The lesion straddled the point of transition between mucosa and skin. The clinical differential diagnosis included squamous cell carcinoma, basal cell carcinoma, and salivary gland malignancy. On histopathological examination, a poorly differentiated malignant epithelial neoplasm with sebaceous differentiation was identified. Upon immunohistochemical testing, the neoplastic cells were strongly reactive for AE1/3, EMA, and CD15. In addition, CAM 5.2 and Ber-EP4 were also focally positive toward the periphery of the neoplastic islands. SOX10 was negative. The final diagnosis of sebaceous carcinoma was rendered. The patient was referred for oncologic treatment but lost to follow-up.

Conclusion

This case illustrates a rare case of SC with extension beyond its typical cutaneous boundaries into the oral mucosa. The presentation of SC in this manner underscores the complexity of diagnosing and managing such uncommon manifestations of skin cancers. This case reinforces that SC should be included in the differential diagnosis of lesions involving both skin and oral cavity and careful evaluation of both histopathology as well as immunohistochemistry is essential for accurate diagnosis.