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Page 2 of 25 Singh et al. Mini-invasive Surg. 2025;9:28 https://dx.doi.org/10.20517/2574-1225.2024.75

tomography (CT) and DOTATATE PET/CT, highlighting their importance in improving diagnostic
accuracy, evaluating treatment response, and detecting recurrence.

Key anatomy of the paranasal sinuses
The anterior skull base consists of the ethmoid, frontal, and sphenoid bones. It plays an essential role in
maintaining communication between the paranasal sinuses and the nasal cavity. Malignancy in this region
can disrupt normal respiratory and mucociliary clearance pathways. A detailed understanding of the
ostiomeatal unit (OMU) drainage system is crucial for surgeons managing sinonasal diseases and tumors.
[1]
The most common histologic type of sinonasal cancer is squamous cell carcinoma (SCC) .

The ethmoid bone contains three key components. The cribriform plate forms the roof of the nasal cavity.
The ethmoidal labyrinth contains the ethmoid air cells and extends to the lamina papyracea, which forms
the lateral nasal wall. The perpendicular plate contributes to the nasal septum [Figure 1] .
[2]

The paranasal sinuses share drainage pathways that ultimately terminate in the nasal cavity. The anterior
and posterior ethmoid air cells are separated by the basal lamella of the middle turbinate. The anterior
ethmoid air cells drain into the middle meatus before reaching the nasal cavity, while the posterior ethmoid
air cells drain into the superior meatus and then the sphenoethmoidal recess (SER). The frontal sinus drains
through the frontal recess into the ethmoid infundibulum and then into the middle meatus .
[2]
The anterior ethmoid, maxillary, and frontal sinuses share a common drainage pathway into the middle
meatus via the OMU. The OMU is formed by the uncinate process and adjacent passages. The maxillary
sinus drains through the maxillary ostium into the infundibulum, which joins with drainage from the
anterior ethmoid air cells. The infundibulum empties into the hiatus semilunaris, which also connects with
the drainage pathway of the frontal sinus, before draining into the middle meatus [Figure 2] . Anatomic
[2,3]
variants of these sinuses and drainage pathways are common .
[4,5]
The sphenoid sinus drains into the SER of the superior meatus before emptying into the nasal cavity
[Figure 3]. Primary sphenoid sinus tumors are rare, accounting for 1%-2% of paranasal sinus tumors .
[6]
The pterygopalatine fossa (PPF) is an anatomically complex space bordered by the posterior wall of the
maxillary sinus anteriorly, the pterygoid bone posteriorly, the palatine bone medially, and the greater wing
of the sphenoid superiorly. It communicates with the nasal cavity through the sphenopalatine foramen. The
pterygomaxillary fissure connects this space laterally with the infratemporal fossa and communicates
anteriorly and superiorly with the inferior orbital fissure, which transmits the infraorbital nerve, artery, and
vein. The V2 segment of the trigeminal nerve traverses the cavernous sinus and enters the PPF through the
[7,8]
foramen rotundum, while the vidian nerve and artery pass through the vidian canal [Figures 4 and 5] . All
these structures may be compressed or invaded by sinonasal tumors. A thorough understanding of these
anatomic relationships is essential for accurate tumor mapping and surgical planning to minimize
complications.

CT and MR approach to sinonasal tumors
The initial symptoms of sinonasal neoplasms include nasal obstruction, sinus pain, epistaxis, headache,
[9]
proptosis, visual changes, and ophthalmoplegia . Endoscopy allows visualization of only the superficial
portions of the tumor, while imaging enables assessment of the full submucosal extent . In many cases, a
[9]
specific diagnosis based on imaging alone is not possible due to limited specificity and significant overlap in
the imaging appearances of different tumors on CT and magnetic resonance (MR) . The primary goals of
[10]