The incidence of the intersinus septa attached to the posterior wall (
dorsum sellae) of the ST was observed in 8.1% of cases and these were observed in only post-sellar sphenoidal sinuses.
A CT scan of the head demonstrated a large mixed-density sellar/suprasellar mass with expansion of the sella turcica (Figure 1) and erosion of the
dorsum sellae. An MRI scan of the brain and sella demonstrated a heterogeneously enhancing T1 iso-intense, T2 mixed-intensity sellar mass with suprasellar extension measuring 3.8 x 2.3 x 2.2 cm (Figures 2,3).
Length (L): Distance from the tip of the
dorsum sellae to that of the tuberculum sellae.
Those tumours related to the most rostral extension of the notochord in the
dorsum sellae will present as sellar and parasellar chordomas.
Dorsum sellae (DS): A square portion of bone on the body of the sphenoid posterior to the sella turcica or hypophysial fossa.
If BA lies lateral to the margin of the cavus or
dorsum sellae or it bifurcates above the plane of the superasellar cisternae, it may be considered elongated (from the Greek dolichas) and an ectasy means distention and is considered when the diameter of the artery is greater 4.5 mm.9
His cranial radiographs revealed an enlarged sellae turcica and destruction of
dorsum sellae. Computed tomography (CT) revealed a homogeneous, enhancing, and isodense mass in the intra- and suprasellar region without any calcification.
The posterior boundary of the pituitary fossa is formed by the
dorsum sellae, the supero-lateral angles of which are raised to form the posterior clinoid process.
It slopes backward and downward from the
dorsum sellae to the foramen magnum in the occipital bone.
The
dorsum sellae were eroded, but posterior and anterior extension of the tumor was minimal (Figure 1, A).
Different morphological types of sella turcica according to Axelson et al: (a) normal sella turcica, (b) oblique anterior wall, (c) sella turcica bridge, (d) double contour of floor, (e) irregular
dorsum sellae, (f) pyramidal shape.