Adamantinoma is a rare malignant bone tumor that most commonly affects the tibia of individuals between 10 to 40 years old. It has an unknown origin and can present as either a lytic cortical lesion or an intramedullary lesion with scattered radiodense areas. Adamantinoma is difficult to diagnose by imaging alone and may be mistaken for fibrous dysplasia, though adamantinoma typically lacks bowing, ground glass appearance, and causes cortical disruption at a younger age.

1. ADAMANTINOMA
Adamantinoma is a rare
primary malignant bone
tumor with a poorly
understood histogenesis. It
has also been referred to as
malignant angioblastoma,
dermal inclusion tumor,
ameloblastoma, primary
epidermoid carcinoma of
bone, and carcinoma
sarcomatodes.

2. ADAMANTINOMA
Approximately 165
cases have been
reported in the
literature, with all
but 18 located in
the tibia. Other
bones affected are
the jaw, ulna,
humerus, femur,
and fibula.

3. ADAMANTINOMA
The mid-diaphysis of
the long bones is the
location in 75% of
cases. The lesions
are extremely rare in
the spine. Most
patients are
between 10 and 40
years of age.

4. ADAMANTINOMA
Radiographically,
adamantinomas may be
difficult to differentiate from
other lesions because they can
be situated in either the cortex
or the medullary space.
Cortical lesions may assume a
lytic bone blister appearance,
may appear as sawtooth loss
of cortical bone with ragged
margins, or may present as a
multichambered, bubbly lesion.

5. ADAMANTINOMA
The typical intramedullary lesion
is usually one large,
circumscribed area of
radiolucency with a mottled
increase in density scattered
throughout the length of the
lesion. Less commonly, a
reticulated, honeycombed type
of presentation occurs. Long-
standing tumors produce marked
cortical thickening and spool-
shaped bulges of the outer
cortex in an eggshell fashion.

6. ADAMANTINOMA
Gradual expansion of
bone with eventual
cortical disruption and
the development of a
soft tissue mass occurs.
Periosteal response is
minimal and, if present,
is usually of the
laminated variety.

7. ADAMANTINOMA
The most difficult and
almost indistinguishable
differential diagnosis is
fibrous dysplasia, though
the presence of periosteal
response, moth-eaten
destruction, no bowing or
ground glass appearance,
and younger age should
allow correct diagnosis.