PMC4408619_01
Axial (a-h) and sagittal (i, j, k) reconstructed CT images showing a clear involvement of bone structures within the skull base. It is remarkable that the tumor showed infiltration and destruction of the tabula interna in many sites (arrows), (i, j, k) which corresponds to the extension and adhesion to the dural layer
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F1
Initial computed tomography (CT) images showed a large, erosive process infiltrating the sphenoidal body, left petrosal tip, and cavernous sinus, as well as extending into the clivus [Figure 1]. Nevertheless the tumor showed a clear erosive growth with an expansive destruction of the described bone structures [Figure 1] and there was evidence of possible dural adhesions to the tumor [Figure 2].
Axial (a_) and sagittal (s_) contrast enhanced T1-weigthed (ceT1) and T2-weighted MRI images showing a heterogeneous lesion involving the clivus, (a, b, j, k, n, o) sphenoidal bone, (c, d, g, h, k, o) sphenoidal wing, (b, i) as well as extending to the left petrosal apex and cavernous (b, d, g, h, i, m) sinus
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F2
Magnetic resonance imaging (MRI) scans confirmed the presence of a large tumor with the above described characteristics [Figure 2]. Nevertheless the tumor showed a clear erosive growth with an expansive destruction of the described bone structures [Figure 1] and there was evidence of possible dural adhesions to the tumor [Figure 2].
MRI angiographic scans show the relationship between the tumor and major vessels of the skull base. The intracavernous and supraclinoidal segment of the left internal carotid was surrounded and compressed by the tumor (c, d, e, g). However, sufficient blood supply to the left medial and anterior brain arteries provided by the right carotid circulation through the Willis circle (e, f, g), as well as a slow tumor growth enabling collateralization, can explain the lack of neurological deficits besides the ones produced by a direct tumor compression of cranial nerves
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F3
The petrocavernosal left internal carotid was completely surrounded by the tumor [Figure 3].
Microsurgical tumor biopsy performed with neuronavigation (a) through a transnasal transesphenoidal approach. After osteotomy of the esphenoidal sinus (b), the tissue showed a strong tendency to bleed (c). The destruction of the tabula interna and adhesions to the dura made the opening of subarachnoidal space almost unavoidable (d) and muscle (e) was used to close the dural defect. Esphenoidal bone (1), tumor (2), subarachnoidal space (3), and muscle graft (4)
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F4
The procedure was performed under navigation guidance [Figure 4a]. At opening the esphenoidal sinus it was demonstrated a brown-green tissue with multiple hemorrhagic areas and a trabecular aspect [Figure 4b]. Despite a careful dissection, following tumor excision exposed the subarachnoidal space and cerebrospinal fluid (CSF) flowed through a small perforation [Figure 4c and d]. The gap was sealed by using muscle graft [Figure 4e], fibrinogen-fibrin-based sponge (TachoSil ) and reabsorbable gelatine (Mabagelan ) applied in a multilevel pattern.