Tornwaldt’s Cyst – Comments on Clinical Cases

Tornwaldt’s cyst represents a benign tumor which develops in the midline of the nasopharyngeal mucosa. Due to the fact that it doesn’t usually cause any symptoms, it is often discovered incidentally during a nasal endoscopy or another imaging investigation (either CT or MRI). Treatment is only advised when the cyst becomes symptomatic. In this paper, the authors aim to illustrate the optimal approach when dealing with a Tornwaldt’s cyst and to underline the importance of a correctly executed endoscopic surgery.


Introduction
Tornwaldt's cyst is a benign nasopharyngeal structure that results from a developmental remnant and which may cause clinically signifi cant symptoms. It is named after Gustav Ludwig Tornwaldt who established it as a pathological entity in 1885, despite being previously discovered by Mayer in 1840 during an autopsy.
The overall incidence of Tornwaldt's cyst varies from one author to another. Therefore, whilst some authors report an incidence of 1.4% to 3.3% in autopsy specimens, others describe the cyst based on MRI fi ndings ranging from 0.2% to 5% of the cases [1]. Generally speaking, a Tornwaldt's cyst is an uncommon discovery, with no gender predilection, which may occur at any age, especially in the 2 nd and 4 th decades of life [2].
From an embryologic point of view, Tornwaldt's cysts form as a result of the notochord retracting from its contact point with the endoderm of the primitive pharynx, as the former ascends through the clivus in order to create the neural plate. Therefore a persistent communication appears between the roof of the nasopharynx and the notochord.

Discussions
There are two types of Tornwaldt's cysts depending whether the orifi ce of the remnant is obstructed or not. Thus, the fi rst type is described as cystic when the orifi ce is obliterated.
Secondly, Tornwaldt's cysts may appear as crusting when Abstract Tornwaldt's cyst represents a benign tumor which develops in the midline of the nasopharyngeal mucosa. Due to the fact that it doesn't usually cause any symptoms, it is often discovered incidentally during a nasal endoscopy or another imaging investigation (either CT or MRI). Treatment is only advised when the cyst becomes symptomatic. In this paper, the authors aim to illustrate the optimal approach when dealing with a Tornwaldt's cyst and to underline the importance of a correctly executed endoscopic surgery.
there are adhesions that do not close the orifi ce entirely [3].
The cyst is lined by respiratory epithelium that may present areas of squamous metaplasia especially once it's obstructed and it develops an infl ammatory process.
Tornwaldt's cyst is usually located in the midline of the posterior nasopharyngeal wall, but it may also be found slightly off midline, especially extending upwards and backwards toward the occipital bone. Therefore, Tornwaldt's cyst lies posteriorly of the path taken by Rathke's pouch as it descends from the sella turcica. By understanding this localization, we can easily enlist several differential diagnoses to rule out.
Most Tornwaldt's cysts are small and asymptomatic, but they may develop symptoms as their volume increases due to mucous secretion. This happens either spontaneously or secondary to infl ammation when edema of the orifi ce leads to further aggravation of the pathophysiological cycle ( Figure 1).

Results
Asymptomatic small cysts require no treatment. If the lesion is large, symptomatic or close to the Eustachian tube torus, surgical marsupialization under general anesthesia is the treatment of choice. Drainage alone can lead to recurrence. Endonasal approach with 0 degree rigid endoscope is recommended for small cysts, while for large lesions the transoral retrovelar approach using a 70 degree endoscope is preferred [6]. Surgery can be performed using cold instruments, powered instruments (microdebrider) or by laser technique (longer operation time and higher costs).
The cyst must be drained and the aspirate sent for culture and antibiotic sensitivity (Figure 4). After complete drainage we resect the anterior wall of the cyst, without any damage on the prevertebralis muscles or fascia ( Figure 5).
At the end of the procedure the surgical fi eld is represented posteriorly by the prevertebral muscles, without any rhinopharyngeal obstruction and a normal nasal airfl ow.
Marsupialization using a microdebrider is a fast method and provides less bleeding and less trauma on the surrounding tissues [7]. The cyst wall must be removed and sent for histopathological examination in order to confi rm the diagnosis.

Conclusion
Tornwaldt's cyst is a benign tumour, usually located in the midline of the posterior nasopharyngeal wall. MRI is considered the best imaging examination to diagnose this infl ammatory benign cyst. It is commonly asymptomatic and requires no treatment. If the cyst is large or symptomatic the treatment of choice is marsupialization, which assures no recurrences.
Complete drainage and microbiological sampling is required in order to initiate the adequate therapy. A normal airfl ow is achieved after surgery which ensures a good quality of life for the patient.