Lipoblastoma is a rare
benign mesenchymal tumour of embryonal fat that occurs almost exclusively
in infants and children.
term lipoblastoma was first used by Jaffe (Recurrent lipomatous tumors of the groin: liposarcoma and lipoma pseudomixomatodes. Arch Pathol 1926;1:381–387).
et al used the term 'Lipoblastomatosis' for an infiltrating lipoblastoma
in the supra-clavicular region, anterior chest wall, and axilla
a tumor of fetal fat different from hibernoma: report of a case, with
observations on the embryogenesis of human adipose tissue. Am J Pathol
Usually occurs in infants
and young children (between 5 days to 6 years). Maturing
lipoblastomas may be present in older children and rarely in teenagers. These
may take the appearance of fibrolipoma.
commonly found in the subcutis of the upper and lower extremities.
Lipoblastomas are also located in less
common sites, including head and neck, mediastinum, lung, trunk,
mesentery, peritoneal cavity, retroperitoneum, intramuscular, and inguinal
Clinical presentation: Lipoblastoma
presents as a painless nodule or mass. The disease is presents in two
I- Superficial- (embryonal
or fetal lipoma)-Solitary
subcutaneous circumscribed slow growing lesion.
II- Diffuse - (Lipoblastomatosis)
deep-seated and ill-defined, diffuse lesion which arises in skeletal
muscle, retroperitoneum, or mesentry.
occur in association with hemangiomas, other soft tissue lesions,
intestinal neuronal dysplasia and/or macrodactyly.
The tumour presents as lobulated, soft, and encapsulated
mass with a tan yellow
creamy white cut surface.
The lesion is
paler than an ordinary lipoma, with mottled gray myxoid areas.
Lipoblastomas is subclassified into the following 4
subtypes, according to their histological features:
(1) the classic type,
characterized by a minimal myxoid component consisting of intercellular
mucin, spindle cells, and stellate primitive mesenchymal cells together with adipocytic component;
(2) myxoid lipoblastomas
abundant interstitial mucin, which comprised more than 50% of the
(3) lipoma-like lipoblastomas lacked a myxoid component and are
composed predominantly of mature adipocytes with scattered monovacuolated
and multivacuolated lipoblasts; and
(4) hibernoma-like lipoblastomas
lacked a myxoid component and are composed predominantly of
multivacuolated lipoblasts, some of which had central nuclei and granular
Summary of microscopic
Lobulated tumour composed
of mature and immature adipocytes.
fat cells resemble embryonic white fat.
A mixture of lipoblasts
in different stages of maturation- from univacuolated spindle mesenchymal
cells within the myxoid matrix to larger and
more vacuolated cells to the mature adipocytes may be present. There
are large cells with granular cytoplasm resembling hibernoma cells.
There are no atypical mitotic figures and no nuclear atypia.
The cells are present
in a stroma which is often myxoid with a rich delicate plexiform vascular
Shows rearrangements of
Confusion with myxoid liposarcoma,
well-differentiated liposarcoma and typical lipomas may occur.
Myxoid liposarcoma is rare
under the age of 10 years.
In lipoblastoma there is prominent lobulation, with maturation at the
center of the lobules.
In myxoid liposarcoma, maturation is at the
features suggestive of malignant potential, such as nuclear atypia,
mitotic figures, hyperchromasia, and hypercellularity, are relatively
uncommon in lipoblastoma.
have been reported to exhibit karyotypic abnormalities involving
chromosome 8, while lacking the translocation associated with myxoid
Depending on the size and location the tumour may compress adjacent
structures and interfere with their functions.
excision is the treatment of choice.
The diffuse form can be difficult to excise completely
which may lead to recurrence of the tumour.
followup of at least two years is suggested.