Sebaceous tumours are relatively rare tumours of the skin.
adnexal tumours with sebaceous differentiation vary from well-differentiated to poorly-differentiated varieties.
Recognition of these lesions is important:
multiple sebaceous tumours of the skin should be examined for other
visceral malignancies, eg. colonic, hematologial, urothelial, kidney,
endometrial etc - (Muir-Torre syndrome).
is an aggressive tumour and must be distinguished from epidermal
hyperplasia and Fordyce's spot / Montgomery's tubercle are not true
Sebaceous hyperplasia is not associated with Muir-Torre
syndrome and must be distinguished from sebaceous adenoma which is
often associated with Muir-Torre syndrome.
There is an
increasing tendency to regard sebaceoma and sebaceous adenoma as part
of a continuum of benign tumours which some term simply as sebaceous
adenoma whereas others have suggested the term sebomatricoma.
Clues to diagnosis:
Presence of sebocytes or tubules resembling
sebaceous duct ; vacuolated cells with or without indentation of the
nucleus; ductal structures lined by crenulated corneocytes ; holocrine secretion; histochemical demonstration of
intracellular lipid .
Reagents Useful in the Differential Diagnosis of Sebaceous
Lazar AJF, Lyle S, Calonje E. Sebaceous
neoplasia and Torre–Muir syndrome. Current diagnostic pathology
- Oil Red-O: Adipophilic
special stain; must have fresh frozen material.
Newly characterized antibody against a protein associated with
intracytoplasmic lipid vesicles; works on formalin-fixed,
Membrane Antigen (EMA): Highlights mature sebocytes.
- BerEP4: Seen in most basal
cell carcinomas, but is not usually present in sebaceomas.
- Cytokeratin 7 (CK7): Present
in most sebaceous neoplasia, usually absent in basal cell
Use of these antibodies in panels,
perhaps including other markers for lesions entering the
differential diagnosis in a particular case, is usually more
helpful than application of a single immunohistochemical stain.
Muir-Torre syndrome is
inherited as an autosomal dominant trait.
This is a variant of the
hereditary non-polyposis colonic carcinoma syndrome and is due to mutations of the mis-match
criteria for diagnosis include presence of sebaceous neoplasm
(adenoma, sebaceoma and occasionally sebaceous carcinoma) internal
malignancy (Example: Colorectal carcinoma).
The sebaceous tumours are often
difficult to classify precisely.
The tumours show marked cystic
Recent studies suggest that immunohistochemistry on the
sebaceous tumours for mismatch repair genes may identify patients with
Other visceral malignancies
have been reported in the larynx, genitourinary tract, ovary and
Keratoacanthoma, epidermal cysts and colonic polyps have
also been reported in this syndrome.