Sebaceoma associated with seborrheic keratosis

Area of Science:

• Dermatopathology
• Oncology

Background:

• Sebaceoma is a rare benign adnexal tumor originating from sebaceous glands.
• The co-occurrence of sebaceoma and seborrheic keratosis is exceptionally rare, with only one prior report in medical literature.
• Distinguishing these tumors is crucial for accurate diagnosis and management, particularly to rule out rare genetic syndromes.

Observation:

• A 69-year-old female presented with a multicolored plaque on her left breast.
• Dermatoscopy revealed a central orange area with globules, indicative of dilated glands, and a peripherally pigmented brown and gray region.
• Histopathology confirmed a central sebaceoma and peripheral seborrheic keratosis.

Findings:

• Histopathological examination confirmed the coexistence of sebaceoma and seborrheic keratosis within the same lesion.
• Immunohistochemical analysis for mismatch repair proteins (MSH6, MSH2, MLH1, PMS2) showed preserved nuclear expression.
• This preserved expression ruled out Muir-Torre syndrome, a condition associated with sebaceous neoplasms and colorectal cancer.

Implications:

• This case adds to the limited literature on the combined occurrence of sebaceoma and seborrheic keratosis.
• The findings underscore the importance of thorough histopathological and immunohistochemical evaluation in diagnosing rare skin neoplasms.
• Excluding Muir-Torre syndrome is critical for patient management and genetic counseling.