Preliminary study of the lymphatic drainage system of the nose and paranasal sinuses and its role in detection of sentinel metastatic nodes

Conclusions The normal nasal lymphatic drainage runs via the facial vessels into the neck lymphatic nodes of levels I–II and this drainage pattern was found in our patients with sinonasal tumors. We found only one true-positive sentinel lymph node (SLN). Our pathological material was very limited and so further investigations are required before any valid conclusions can be drawn concerning the clinical value of SLNs in nasal tumors. Objectives To detect the lymph collection route of the nasal fossae and paranasal sinuses and to identify the first echelon in the tumor metastatic cascade in order to prevent the risk of occult metastases in N0 necks in patients with primary head and neck squamous cell carcinoma (SCC). Material and methods Our control group comprised 30 patients (20 females; age range 19–50 years) suffering from chronic otitis media who had an anatomically normal nose and a cNO neck on palpation. The pathological group comprised 6 patients (2 females; age range 40–85 years) suffering from sinonasal tumors: 3 SCC, 1 recurrent melanoma, 1 ameloblastoma and 1 inverted papilloma. All had a clinically staged cNO neck on palpation and CT. In the control group, lymphoscintigraphy was carried out by means of unilateral injection of radioactive gold into the head of the inferior turbinate. The tracer was identified using a gamma camera 3 and 6 h after the injection. In the pathological group the chosen tracer was technetium, which was administered 1 day prior to surgery by means of injections into the heads of the inferior and middle turbinates, into the nasal septum and into the retromaxillary gingival mucosa. The tracer was identified transcutaneously using a navigator probe in the gamma camera at 15 min, 30 min and 1 h post-injection. A mark was drawn on the skin corresponding to the hot spot of the SLN. The study was repeated 30 min before surgery. The neck incision was selected according to the location of the SLN. A hand-held gamma probe was used in the operating theatre to detect in situ the radioactivity of the surgical excisional nasal area and the cervical SLN. Once the SLN was excised its radioactivity was confirmed ex situ, taking into account that the activity counts were at least three times greater than background. Postoperatively, all SLNs were histopathologically examined and cytokeratin staining was carried out immunohistochemically using the monoclonal antibody cocktail AE1/AE3. Results In the control group, intense activity at the injection tracer site and lower activity in the submandibular area (level I) were detected in 26.6% of cases. Nasal radioactivity persisted for 6 h post-injection and submandibular radioactivity increased, also reaching the area corresponding to neck node level II (70%). In two cases (6.6%), radioactivity was observed in the retropharyngeal nodes. In the pathological group, the SLN was found in the submandibular area (level I) in three cases, and in the ameloblastoma patient three SLNs were found at levels I–II. Three cases were false positives, and no metastases were detected using any of the histopathological procedures. The only one true positive corresponded to a female with an SCC of the maxillary infrastructure with invasion of the gingival mucosa. The histopathological code was 1 and a metastasis was detected on hematoxylin–eosin examination. In the other two cases no SLNs were detected.