Download: Sebaceous adenoma

 Sebaceous adenoma (Benign tumor of sebaceous gland: Sebaceous adeno + oma)

Sebaceous adenoma:  Benign cutaneous adnexal neoplasm arising from sebaceous glands.

  • Local recurrence may occur due incomplete removal.
  • In Muir-Torre syndrome, multiple sebaceous adenomas are associated with visceral cancers, such as adenocarcinoma of the colon, stomach, duodenum, genitourinary tract ,endometrium and hematologic malignancy.
  • One significant feature of Muir-Torre syndrome is the favorable prognosis of the associated cancers.
  • On immunostain, a loss of nuclear staining for MLH-1 or MSH-2 is highly suggestive of the syndrome.
  • Sex: M=F, Age: After 50 yrs.

 

    Microscopic:

  • Tumor is multilobulated with frequent connection to the epidermis, may be ulcerated.
  • Sharply demarcated from the surrounding tissue.
  • Proliferation of sebaceous lobules consisting of central, larger, mature sebaceous cells with clear, bubbly cytoplasm (sebocytes), peripheral, smaller, basaloid cells and transitional cells.

 

  • Sebocytes contain pale-staining, foamy-to-bubbly cytoplasm, and central hyperchromatic nuclei.
  • Smaller basaloid cells contain round vesicular nuclei and basophilic cytoplasm.
  • Transitional cells show eosinophilic cytoplasm.
  • Nuclear hyperchromatism, prominent nucleoli and abnormal mitotic activity are rare.
  • Ratio between the sebocytes and basaloid cells is about 50% in sebaceous adenoma.
  • If the tumor shows >50% basaloid cells, it is called Sebaceoma (Sebaceous adenoma, basaloid type or Sebaceous epithelioma).

Fig 1. Tumor is multilobulated, sharply demarcated from the surrounding tissuefig-1

Fig 2. Proliferation of sebaceous lobules consisting of central, larger,  mature sebaceous cells with clear, bubbly cytoplasm (sebocytes),  and peripheral, smaller, basaloid cells.  fig-2

Fig 3. Proliferation of sebaceous lobules consisting of central, larger,  mature sebaceous cells with clear, bubbly cytoplasm (sebocytes),  and peripheral, smaller, basaloid cells fig-3

Fig 4. . Proliferation of sebaceous lobules consisting of central, larger,  mature sebaceous cells with clear, bubbly cytoplasm (sebocytes),  and peripheral, smaller, basaloid cells fig-4

 

 

Deba P Sarma, MD, Omaha