International Journal of Clinical Case Reports 2015, Vol.5, No. 35, 1-4
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superficial but may infiltrate the muscles, occasionally
becoming fixed to the subjacent tissues and therefore,
becoming immovable. Deep seated lesions may
produce only a slight surface elevation and may be
well-encapsulated, more diffuse, and less delineated
than the superficial variants. This more diffuse form
generates the clinical impression of being a fluctuant
tumour (Wood and Goaz, 1997). Most intra-oral
lipomas are composed of mature fat cells that differ
little in microscopic appearance from the normal fat
cells that surround the tumour (Greenberg et al., 2008;
Neville et al., 2009). The tumour is usually well
circumscribed and may be surrounded by a thin
fibrous capsule. A distinct lobular arrangement of the
cells is also often seen. The most common microscopic
variant of intra-oral lipomas is the fibrolipoma
characterised by a significant fibrous component
intermixed with lobules of fat cells. The other variants
are
(Rajendran and Sivapathasundharam, 2009; Neville
et al., 2009)
Angiolipomas- revealing a mixture of mature fat
cells and numerous small blood vessels;
Spindle cell lipomas- with variable amount of
uniform appearing spindle cells, typically in conjunction
with lipomatous components (i.e, when appearing
with mucoid components, however, in such cases,
impression of a myxoid lipoma is made);
Pleomorphic lipomas- with presence of spindle
cells with bizzare hyperchromatic giant cells; and
Intra-muscular (infiltrating) lipomas- which are
more deeply seated and have an infiltrative growth
pattern and extend between the skeletal muscle
bundles.
When the spindle cells are of smooth muscle origin,
the term myolipoma may be used. The term
“angiomyolipoma” is commonly applied when the
smooth muscle appears to be derived from the walls of
arterioles (Lia and Lin, 1974). On rare occasions,
isolated ductal or tubular adnexal structures are
scattered throughout the fat lobules, in which case, the
term “adenolipoma” is applied. Perineural lipomas
have also been reported. Rarely, chondroid or osseous
metaplasia may be seen in lipomas and in such cases,
chondroid lipoma, osteolipoma, ossifying lipoma, or
ossifying chondromyxoid lipoma are often the best
terminologies cited. Also, rare have been reports of
hibernomas i.e a benign neoplasm of brown fat
occurring in the oro-pharyngeal region. The above
noted combinations of histological features (Wood and
Goaz, 1997) are of no prognostic significance although
the clinical appearance in terms of color and tissue
consistency may vary in accordance with the specific
types noted. Hormonal influences during adolescence
on embryonic multi-potential connective tissue cells
that remain sub-clinical were also considered in the
differentiation of lipoma formation suggesting such
lesions to be of congenital origin
(Greer and
Richerdson, 1973). Trauma and chronic irritation have
also been proposed to play a role in the development
of lipomas, however, trauma is widely accepted as a
positive factor in the discovery rather than aetiology
of these lesions
(Hatziotis, 1971; Greer and Richerdson,
1973; Perri de Carvalho et al., 1987). In some areas
devoid of fatty tissue, metaplastic transformation of
connective tissue is suggested to be the origin in the
development of such lesions. Furthermore, fibroblast
and muscle cells have also said to be possible
precursor cells in these areas
(Mahabir et al., 2000).
Currently, in addition to radiographic examinations to
assess bone involvement and extent of intra-osseous
variants, MRI has become the imaging modality of
choice, especially in cases of sialolipomas. MRI is
considered to be a technological advancement that has
greatly facilitated the diagnosis in the head and neck
region for soft tissue pathologies, even making the
treatment plan more accurate, moreso in lesions of
aggressive character
(Sakai et al., 2006).
In some cases, intra-lipomas of the buccal mucosa
region cannot be distinguished from herniated buccal
fat pad without history of sudden onset post-trauma
being non-evident. Lipomas of oral and pharyngeal
region are however otherwise simple to differentiate
from other lesions, although spindle cell and pleomorphic
types must be distinguished from liposarcomas. When
metaplastic calcified tissue is present, the lesion may
be confused with soft tissue chondromas or osteomas.
Multiple head and neck lipomas have been observed
in neurofibromatosis, encephalo-cranio-cutaneous
lipomatosis, multiple familial lipomatosis, Gardener
syndrome, and Proteus syndromes
(Rajendran and
Sivapathasundharam, 2009). Lipoma, in cases, may be
part of congenital alterations and extremely rare forms
of intra-oral lipoma have been described by Mahabir
et al.
(2000) where the lesion was found in association
with congenital cleft palate. Another case of congenital
lesion was described by Perri de Carvalho et al. (1987)
