CT assessment of woodworkers' nasal adenocarcinomas confirms the origin in the olfactory cleft

Abstract

Background and purpose: Endoscopic endonasal surgery let us observe that woodworkers' nasal adenocarcinomas originate in the olfactory cleft. Our aim was the identification of CT imaging features that corroborate the olfactory cleft as the site of origin for woodworkers' adenocarcinoma.

Materials and methods: We designed a retrospective study to compare CT scans of 27 unilateral olfactory cleft adenocarcinomas with 30 cases of nasosinusal polyposis (NSP) and 33 healthy sinus controls. Enlargement of the olfactory cleft, lateralization of the ethmoidal turbinate wall, and contralateral bulging of the nasal septum were measured on coronal scans passing through crista galli and posterior half of both ocular globes. Comparisons have been performed by using analysis of variance and the Bonferroni procedure.

Results: The nasal septum was significantly bulging across the midline in adenocarcinoma (4.6 +/- 3 mm; range, -0.1-13.7 mm) compared with NSP (0.7 +/- 1 mm; range, -2.1-2.3 mm) or healthy sinus controls (0.5 +/- 1 mm; range, -1.2-2 mm) (P < .001). The olfactory cleft was significantly wider in adenocarcinoma (15.1 +/- 4.5 mm; range, 8.6-25.7 mm) than in NSP (3.6 +/- 0.4 mm; range, 2.8-4.6 mm) or healthy sinus controls (3.3 +/- 0.7 mm; range, 1.4-4.6 mm). The ethmoidal labyrinth width was significantly smaller on the pathologic side in adenocarcinoma (7.2 +/- 2.7 mm; range, 3.2-14.2 mm) than in the control groups (P < .001). Whereas the angle between the conchal lamina and vertical midline was close to zero degrees in NSP (0.03 +/- 2.25 degrees ; range, -5 degrees -3 degrees ) and healthy sinus controls (0.45 +/- 2.13 degrees , range, -5 degrees -5 degrees ), it reached 39.76 +/- 13.83 degrees (P < .001) in adenocarcinoma.

Conclusions: Radiologists should suspect nasal adenocarcinoma on sinus CT scans showing a unilateral expanding opacity of the olfactory cavity.

Fig 1.

Anatomic terminology.

Fig 2.

Measurement of widths on a coronal scan passing through the crista galli and the posterior half of both ocular globes. The midline is defined by the xy line joining the bases of the crista galli and the vomer bone on the nasal floor. A perpendicular line zt is drawn tangent to the inferior limits of both ocular globes, cutting xy in O and the nasal septum line in C. The OC segment is equal to zero when the nasal septum is straight on the midline and is measured as positive when the C point is displaced opposite to the pathologic side and as negative in reverse conditions. The AE segment on the zt line measures the nasoethmoidal cavity total width and is decomposed into the following subsegments: AB for the width of the healthy ethmoidal labyrinth, BC for the width of the healthy olfactory cleft, CD for the width of the olfactory cleft on the pathologic side (in patients, the CD segment measures the median opacity without recognizable bony lamella, located between the nasal septum and the squeezed ethmoidal labyrinth on the pathologic side), and DE for the width of the ethmoidal labyrinth on the pathologic side (in patients, the DE segment measures the lateral opacity squeezed onto the orbital wall, in which ethmoidal bony lamellas are still recognizable).

Fig 3.

Measurement of the ECL angle between the midline xy and the conchal lamina. The conchal lamina is the upper part of the ethmoidal turbinate wall (Fig 1). A line lm is drawn tangent and parallel to the conchal lamina on the pathologic side to measure the ECL angle. In patients, the line lm also represents the border between the median opacity without recognizable bony lamella and the lateral opacity squeezed onto the orbital wall in which ethmoidal bony lamellas are still recognizable.

Fig 4.

CT scan demonstrates significant enlargement of the olfactory cleft in the adenocarcinoma (ADC) group compared with NSP and healthy sinus controls (HSC) (P < .05). A, OC, bulging of the nasal septum across the midline. B, CD, width of the pathologic olfactory cleft. C, DE, width of the ethmoidal labyrinth on the pathologic side. D, ECL, angle between the midline xy and the conchal lamina. NS indicates not statistically significant.

Fig 5.

Endoscopic surgical view of a woodworkers’ adenocarcinoma originating in left olfactory cleft. IT indicates inferior turbinate; MT, middle turbinate; NS, nasal septum; T, tumor into the olfactory cleft.

Fig 6.

More examples of woodworkers’ adenocarcinomas. A, The inferior part of the ethmoidal labyrinth is reduced to a thin opaque layer with the tumor penetrating into the maxillary sinus through the fontanelle area (arrow). B, CT scan of an anosmic woodworker, which led to the early diagnosis of a small adenocarcinoma of the right olfactory cleft (arrow). The right olfactory cleft is opacified with a slight bulging of the corresponding nasal septum to the left and of the conchal lamina to the right. Note that there is still a small space filled with air under the cribriform plate and between the conchal lamina and the septum in the left olfactory cleft. C, The slow-growing tumor originating in the olfactory cleft (below the cribriform plate) sequestrates a small triangle (arrow) of ethmoidal cells under the ethmoidal roof (which lies more cranially) by lateralizing (not invading) the conchal lamina. D, MR image confirms the origin in the olfactory cleft with retention in the squeezed ethmoidal labyrinth (long arrow) (note the triangle of ethmoidal cells under the ethmoidal roof) and maxillary sinus (short arrow).