k Cysts and Cyst-like Lesions of the Salivary Glands 101 (b) k k (a) (c) Figure 4.7. This elderly woman shows left submandibular swelling (a). Her history includes numerous aspirations of fluid within a ranula of the left floor of mouth. Computerized tomograms of the neck show a fluid filled lesion of the submandibular region (b). A diagnosis of plunging ranula was made and the patient underwent left sublingual gland excision (c). Examination of the left floor of mouth did not show signs of ranula in this region. Scar tissue formation from her previous aspirations resulted in the development of a plunging ranula. lesion. This was perhaps the first explanation that muscle and its hiatus or cleft, and herniations scar tissue formation in the mucosa of the floor of within the mylohyoid muscle, has been studied to mouth was responsible for the development of the explain the development of a plunging ranula. In cervical mass as it descended through the cleft of their study of 23 adult cadavers, Harrison, et al. the posterior extent of the mylohyoid muscle as identified a bilateral mylohyoid hiatus to exist in a path of least resistance (Figure 4.7) (Braun and ten of their 23 specimens (43%), with the hiatus Sotereanos 1982). The anatomy of the mylohyoid being unilateral in six (26%) and bilateral in four k k 102 Chapter 4 (17%) cadavers (Harrison et al. 2013). The median structure of the floor of mouth. He believes that anteroposterior dimension of the hiatus was 7 mm some of these lesions are unrelated to the sublin- with a range of 2–11 mm, and the median medi- gual gland, such that its removal is not indicated. olateral dimension was 14 mm with a range of Specifically, he cites the existence of mucoceles 7–20 mm. The authors identified sublingual gland arising from the mucus-secreting incisal gland in tissue in nine hernias and fat in six hernias. Other the anterior floor of mouth, single or multiple authors have demonstrated that approximately one retention cysts involving the openings of the ducts third of the population has discontinuities of the of Rivinus, and retention cysts at the Wharton mylohyoid muscle such that direct invasion of the duct orifice that can resemble the sublingual gland pseudocyst through these defects of the muscle associated ranula, but that would possibly not be permits extension into the neck (McClatchey, et al. cured with sublingual gland removal. Moreover, 1984). While the pathophysiology of the plunging the author states that sublingual gland excision is ranula is now well understood from an anatomic potentially associated with significant morbidity perspective, the literature continues to identify such as injury to the Wharton duct with resultant controversy with regard to the most appropriate salivary obstruction or salivary leakage, and lin- means to treat the ranula and plunging ranula gual nerve injury (Baurmash 1992). Zhao and his (Patel, et al. 2009; Harrison 2010; Lesperance, et al. group presented an objective assessment of com- 2013; Sigismund, et al. 2013). plications associated with surgical management If anything has been learned by reading the of ranulas treated with a variety of procedures scientific literature on the topic of cyst-like lesions (Zhao, et al. 2005). These included 9 marsupi- of the salivary glands, it is the common pathogen- alizations, 28 excisions of the ranula only, 356 esis of three clinical entities: the mucocele, the sublingual gland excisions, and 213 excisions of oral ranula, and the plunging ranula. Specifically, both the sublingual gland and ranula. A total of it is their lack of an epithelial lining, and their 569 sublingual gland excisions were performed in association with a salivary gland, whether major 571 patients undergoing 606 operations. Injury to k or minor, that these entities share in common. the Wharton duct occurred in 11 of 569 patients k If the offending sublingual salivary gland is not who underwent excision of the sublingual gland removed, the lesion has a statistical likelihood with or without excision of the ranula compared of recurrence (Catone, et al. 1969; Suresh, et al. to 0 of 37 patients who did not undergo sublingual 2012). This notwithstanding, while the diagnosis gland excision. Injury to the lingual nerve occurred of the conventional, non-plunging ranula remains in 21 of patients who underwent sublingual gland straightforward, its management has historically excision compared to 0 patients who did not been variable and controversial, ranging from undergo sublingual gland excision. Of particular incision and marsupialization to sublingual gland note is that recurrence of the ranula occurred in excision. Interestingly, most mucoceles are located 1.2% of patients who underwent excision of their in the lower lip and are treated with an excision sublingual glands compared to 60% of patients of the mucocele and associated etiologic minor who underwent marsupialization or excision of salivary gland tissue of the lower lip. Ironically, the ranula only. Baurmash laments that simple although the ranula of the floor of mouth is the marsupialization has fallen into disfavor because second most common type of mucocele, removal of the excessive number of failures associated with of the ranula and the associated salivary gland, this procedure (Baurmash 1992). The recurrence in this case the sublingual gland, has not been patterns have been confirmed by other authors, uniformly accepted as standard treatment of the as well (Yoshimura, et al. 1995). As such, he ranula as it is for the lower lip mucocele. To this recommends packing the cystic cavity with gauze end, there are several published papers adamantly for 7–10 days. In so doing, he reports that the recommending that more conservative procedures recurrence rate is reduced to 10–12% (Baurmash be performed as first line therapy (Baurmash 1992, 2007). McGurk points out that the disadvantage of 2007). One such procedure is marsupialization with this procedure is that the results are unpredictable packing (Baurmash 1992). The author contends and that the packing is uncomfortable for the that routine sublingual removal is inappropriate patient (McGurk 2007). He concludes by stating therapy for several reasons. The first is that the that reliable eradication of the ranula comes from term “ranula” is loosely applied to any cyst-like removal of the sublingual gland. Further work k k Cysts and Cyst-like Lesions of the Salivary Glands 103 by this author has led to a recommendation for the development of scar tissue in the floor of conservative treatment of the oral ranula by partial mouth is such that the anatomy may be more excision of the sublingual gland (McGurk et al. obscured related to a recurrence after a marsupi- 2008). It is true that the sublingual gland excision alization and packing procedure. With this issue requires an anatomically precise approach such in mind, a sublingual gland excision should prob- that some surgeons may wish to defer the sublin- ably be performed from the outset (Figure 4.8). gual gland excision for recurrences. Unfortunately, While the anatomy of the floor of mouth might (a) (b) k k (c) (d) Figure 4.8. The excision of the sublingual gland and associated ranula from Figure 4.1. An incision is designed over the prominence of the sublingual gland and ranula, and lateral to the Wharton duct (a). Careful dissection allows for separation of the mucosa from the underlying pseudocystic membrane (b). The dissection continues to separate the sublingual gland from surrounding tissues, including the underlying Wharton duct and the lingual nerve beneath the Wharton duct (c). The specimen and ranula are able to be delivered en bloc (d). If the pseudocyst bursts intraoperatively, no compromise in cure exists as long as the sublingual gland is completely excised. The histopathology shows the non-epithelial lining (e) and the intimate association of the sublingual gland and mucus escape reaction (f). The remaining tissue bed shows the anatomic relationship of the preserved superficial Wharton duct and underlying lingual nerve (g). Wharton duct originates posteriorly in a medial position to the lingual nerve and terminates in a position lateral to the nerve. The sublingual vein can be visualized in the tissue bed lateral to the anterior aspect of Wharton duct (g). Healing is uneventful as noted in the one month postoperative image (h). k k 104 Chapter 4 (e) (f) k k (g) (h) Figure 4.8. (Continued) be considered foreign and intimidating to some are predictably treated for cure with excision of the surgeons, preservation of the lingual nerve and offending sublingual gland. While it is not essen- Wharton duct is not a difficult task, and treatment tial to remove the non-epithelial lined pseudocyst of this pathologic process with sublingual excision with the sublingual gland, it is common for the should be a curative procedure. One pathologic tightly adherent pseudocyst to be delivered with and clinical similarity of the ranula and mucocele the sublingual gland specimen (Figure 4.10). As is their derivation from salivary gland tissue. As such, documentation of a plunging component to stated previously, there does not seem to be a the ranula serves a matter of medical completeness dispute amongst clinicians as to the best surgical rather than representing an implication for surgical therapy for the mucocele, with complete surgical treatment. excision of the etiologic minor salivary tissue along with the mucus escape reaction being highly accepted (Figure 4.9). As such, it is advisable to Submandibular Gland Mucocele apply the same approach to the ranula that only Clinical experience demonstrates that patients differs from the mucocele in the anatomic region occasionally present with a neck examination in which it occurs. With regard to the ranula and consistent with a diagnosis of plunging ranula, plunging ranula, even the most extensive lesions yet without signs of ranula on oral examination.