Oncocytic Lipoadenoma was
first described in 1998,
by Dr M. Hirokawa et al
( Department of Pathology, Kawasaki Medical School, Kurashiki,
M. Hirokawa et al reported
in a 66-year-old Japanese woman who presented with a left
This tumour is still not included in the current WHO
classification of salivary gland neoplasms.
Oncocytic lipoadenoma is an
exceedingly rare neoplasm of the salivary gland composed of
oncocytic epithelium and adipose tissue. Only 20 cases have been
reported in the literature.
|(5) Lipoadenoma and
adenolipoma are tumours composed of epithelial and lipomatous
elements and have been described in many anatomic sites, including
the skin, breast, parathyroid, thyroid, and salivary gland.
Oncocytic lipoadenoma, where the
epithelial component consists of oncocytes has been reported only in
salivary glands ( parotid and submandibular glands).
|(6) This tumour has
not been reported in any minor salivary glands.
|(7) The appearance of
the cut surface of the tumour may vary from tan to brown to yellow,
depending on the amount of adipose tissue present.
|(8) The tumours
are composed of a mixed population of oncocytes and adipocytes in
varying proportions . The oncocytes are round to polygonal with
distinct cell borders and abundant granular, eosinophilic cytoplasm,
arranged in nests and small acini.
The adipocytic component of the
tumours range from 5 to 70 % and the adipocytes have the appearance
of mature fat.
The oncocytes either show close
intermingling with the fatty cells or they may form discrete
circumscribed oncocytic nodules within a lipoma-like background.
Neither the oncocytic nor the lipomatous components
of the tumors show any cellular pleomorphism or mitoses.
majority of the reported oncocytic lipoadenomas exhibit
Among the various salivary gland tumors with a prominent oncocytic
component, oncocytic lipoadenoma is most likely to be mistaken for
oncocytoma. Both are well circumscribed tumours comprised of
classical eosinophilic oncocytic cells. Oncocytomas, however, are
composed exclusively of oncocytes and lack the lipomatous component
characteristic of oncocytic lipoadenoma.
presence of adipose tissue similarly allows for separation of
oncocytic lipoadenoma from stroma poor Warthin tumour, Warthin
tumour with nodular oncocytic proliferation, and oncocytic
differential diagnosis also includes sialolipoma. Sialolipoma is
characteristically composed predominantly of adipose tissue with
admixed islands of salivary gland acini, ductal, myoepithelial and