Poorly Differentiated Extraocular Sebaceous Carcinoma Masquerading as an Abscess

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Extraocular sebaceous carcinoma (SC) is an uncommon, aggressive neoplasm.
• Risk factors include genetic mutations, UV exposure, radiation, and immunosuppression.
• Typical presentation involves head and neck lesions in older individuals.

Observation:

• A 63-year-old male presented with a painful, enlarging subcutaneous mass on his left arm.
• The lesion was diagnosed as a poorly differentiated extraocular SC.
• Patient had a history of colon cancer but declined genetic workup.

Findings:

• Poorly differentiated extraocular SC can be aggressive and metastatic.
• Tumor size >2 cm, rapid growth, high grade, and poor differentiation are risk factors for metastasis.
• This case highlights a rare presentation on the arm.

Implications:

• Wide local excision and sentinel lymph node biopsy are recommended for aggressive SC.
• Management should assess for metastatic spread to guide further treatment (surgery, radiation, therapeutics).
• Further genetic workup may be beneficial in select cases.