| Troy and Ackerman
defined the term sebaceoma as benign neoplasm of basaloid cells
with varying numbers of mature sebocytes.
(Sebaceoma.
A distinctive benign neoplasm of adnexal epithelium differentiating
toward sebaceous cells.
Am J
Dermatopathol. 1984 Feb;6(1):7-13 ) Distinction between
sebaceous adenoma and sebaceoma may be difficult and there is an
increasing tendency to regard these two tumours as part of a continuum
of benign tumours. Some authors use the term sebaceous adenoma when half
or less than 50% of the lesion is composed of germinative and
transitional cells, and sebaceoma when greater than 50% of the lesion is
composed of germinative and transitional cells.
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Dermatopathology Cases
The term 'sebaceous
epithelioma' has been largely discarded by many pathologists as the term
'epithelioma' is confusing & has been used in different ways by various
pathologists..
Clinical presentation:
Presents as
a solitary circumscribed nodule or an ill-defined plaque. May also
present as multiple lesions, specially in Muir-Torre Syndrome.
Site: Located on the
face or scalp.
Microscopic features:
Dermatopathology Case No 27 (Images)
Histologically, sebaceoma shows irregular shaped cell masses in which
more than 50 percent cells are undifferentiated, basaloid cells together
with significant aggregates of sebaceous cells and transitional cells.
Cysts and duct-like structures contain holocrine secretion and debris.
Rippled-pattern
sebaceoma: Composed of immature sebaceous germinative
cells with some foci of advanced sebaceous differentiation. There are
small, monomorphous, cigar-shaped basaloid cells in linear rows parallel
to one another, resembling the palisading of nuclei of Verocay bodies
(rippled-pattern).
In a
rare variant of sebaceoma the tumour displayed reticulated and
cribriform basaloid epithelial islands.
Some cases show areas
resembling seborrheic keratosis.
Differential Diagnosis:
Sebaceous Carcinoma- some cases of sebaceoma are difficult to
differentiate reliably from carcinoma because of the germinative cells (mitotically
active and may display atypical nuclear features) ; Basal
cell carcinoma with sebaceous differentiation.
The tumour usually
does not recur after excision. |