Sebaceoma (Sebaceous Epithelioma)

Sebaceoma (Sebaceous Epithelioma)
David Cassarino, MD, PhD
Key Facts
Terminology
  • Sebaceous epithelioma is older term (discouraged)
  • Benign proliferation of mature sebaceous cells with predominant basaloid cell population
Etiology/Pathogenesis
  • Some cases are part of Muir-Torre syndrome
    • Autosomal dominant disease due to mutations in mismatch repair genes MLH1, MSH2, MSH6
    • Multiple sebaceous tumors including sebaceous adenomas > carcinomas and sebaceomas
Clinical Issues
  • Rare tumors; typically occur in adults
  • Most common on the face
  • Usually single but may be multiple, especially in MTS patients
Microscopic Pathology
  • Nodular, dermal-based adnexal tumor
  • Well-circumscribed, noninfiltrative appearing
  • Composed mostly of basaloid cells
  • Minor population of clear cells with multivacuolated cytoplasm, consistent with mature sebaceous cells
    • Show nuclear hyperchromasia with indentations
  • Basaloid cells may show mild cytologic atypia and increased mitotic figures
  • Sebaceous cells do not show significant atypia or mitotic activity
Top Differential Diagnoses
  • Basal cell carcinoma with sebaceous differentiation, sebaceous carcinoma, sebaceous adenoma, trichoblastoma with sebaceous differentiation
Low magnification of a sebaceoma shows a dermal-based basaloid to clear cell neoplasm with peripheral basaloid cells surrounding central collections of clear cells image and sebaceous secretions.
High magnification of a sebaceoma shows a predominantly basaloid population of cells surrounding several large clear cells image with abundant, multivacuolated cytoplasm.
TERMINOLOGY
Synonyms
  • Sebaceous epithelioma (older term, should be discouraged)
Definitions
  • Benign proliferation of mature sebaceous cells associated with a predominant basaloid cell population
ETIOLOGY/PATHOGENESIS
Unknown in Most Cases
  • Some cases are part of Muir-Torre syndrome (MTS)
    • Autosomal dominant disease due to mutations in mismatch repair genes MLH1, MSH2, MSH6
    • Patients present with multiple sebaceous tumors including sebaceous adenomas, sebaceomas, and sebaceous carcinomas
    • Also associated with internal malignancies including gastrointestinal carcinomas (most common), genitourinary, breast, and ovarian tumors
  • Rare cases arise in nevus sebaceous of Jadassohn
CLINICAL ISSUES
Epidemiology
  • Incidence
    • Rare tumors
  • Age
    • Typically occur in adults
Site
  • Often occur on face, but may also present on trunk
Presentation
  • Slow-growing papular to nodular lesion
    • Usually single, but may be multiple, especially in MTS
  • Flesh-colored to yellowish
Treatment
  • Surgical approaches
    • Complete conservative excision is curative
Prognosis
  • Excellent; very low malignant potential
    • Possible transformation to sebaceous carcinoma in longstanding lesions
MACROSCOPIC FEATURES
Size
  • Usually measure between 0.5-3 cm in diameter
MICROSCOPIC PATHOLOGY
Histologic Features
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Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Sebaceoma (Sebaceous Epithelioma)

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