Ritwik and Brannon Journal of Medical Case Reports 2012, 6:287 http://www.jmedicalcasereports.com/content/6/1/287 to 5.0cm with a mean of 2.4cm. Sixteen of the 42 cases had reliable patient history reporting a 2.1 year duration of the tumor before definitive diagnosis. Twenty-four cases with follow-up information of at least 2 years were treated by local surgical excision. Follow-up ranged from 2 to 39 years (mean 9.2 years). Recurrences were reported in three cases for a recur- rence rate of 13.0%. The three recurrent cases were all on the hard palate and recurred 2 years, 3 years, and 5 years after the initial surgery. Other lesions Data for the two cystadenomas, one sialadenoma papilli- ferum and the four myoepitheliomas are presented in Additional file 1: Table S2. Discussion We attempted to outline the clinical features and biologic behavior of benign neoplasms arising from minor salivary glands in children and adolescents. It is acknowledged that there are limitations to the interpretation of data from a retrospective study such as this. For example, the clinical findings and other pertinent information recorded on sub- mitted pathology request forms are unfortunately highly variable and often lack complete information and the same is true for reported cases. While more pediatric cases have been reported cumu- latively in other published salivary gland series, any cor- relation between patient-specific details and the clinical lesion cannot be made. The approach of our study limits the number of accepted cases, but yields more clinically relevant information. The patients in the LSUSD series were only from the state of Louisiana, thus representing patients from a single geographic area and a single insti- tution experience. The cases accepted from the literature review represent a more global pediatric population, in- cluding Hispanic and Asian children, who were not represented in our LSUSD series. Since the socioeco- nomic status of the children was not known in our study, the association of socioeconomic status to the in- cidence as well as prognosis of the lesions could not be explored. Epithelial neoplasms originating in the minor salivary glands account for approximately 15% of all salivary gland neoplasms [29,30]. In the current LSUSD series, 2.3% of the benign epithelial minor salivary gland neo- plasms occurred in patients below 19 years of age, which is in close agreement with the series of Waldron et al. and Kusama et al. who found an incidence of 3.1% and 4.6%, respectively [30,31]. A PA is composed of a wide spectrum of epithelial and mesenchymal tissue derived from cells with ductal and myoepithelial features and it is by far the most common salivary gland neoplasm in children [1,32]. Although it is Page 3 of 6 commonly stated that neoplasms of minor salivary glands rarely occur prior to the second decade [33], we found that, when combining the well-documented litera- ture cases with our LSUSD cases, 28.6% of PAs arising from minor salivary glands in children occurred during the first decade of life. Cumulative data assessment revealed a female gender predilection of 2.8:1 and a pre- dilection for the hard and/or soft palate (69.1%). Information regarding the biologic behavior of minor salivary gland PAs in children and adolescents is, in gen- eral, underprovided. The risk of recurrence of PAs has been speculated to be lower if arising from the minor salivary glands rather than the major glands [34]. In fact, Chau and Radden reported follow-up on 27 intra-oral PAs in patients over a wide age range (second to eighth decade) treated by excisional biopsy and found no recur- rences (mean follow-up period 5.3 years), including in two neoplasms which were incompletely excised and two where the tumor extended to the surgical margins [35]. Additionally, Budnick reported a PA in the upper lip of a 17-year-old black woman which was incom- pletely excised and had no evidence of recurrence on 3 years of follow-up [7]. The recurrence rate of PAs in minor salivary glands of children in our study was 13.0%, which is of clinical significance. This recurrence rate was recorded from 24 well-documented pediatric and adolescent PAs with an average follow-up duration of 9.2 years. The three recurrent PAs involved the hard palate, with one causing bone resorption, one with no bone involvement [19] and one case did not state if there was bone involvement [3]. The assessment for pos- sible causes of recurrence in the three cases varied. The size of the lesion was recorded in two of the three recur- rent cases; both were 2.0cm or less in diameter. With regards the surgical margins of these recurrent cases, Byars et al. [3] did not comment on the state of the sur- gical margins, Shaaban et al. [19] reported the surgical margins in the definitive excision were free of tumor and, in the LSUSD case, the margins could not be defini- tively determined as treatment consisted of tumor exci- sion with curettage of the involved palatal bone, making assessment difficult to evaluate with certainty. In the cases with no recurrence, the surgical margins were not described with any degree of certainty, making it impossible to adequately explore margin involvement as an absolute predictor of recurrence. However, in four of the newly reported LSUSD cases with follow-up of 8 months, 5 years, 8 years and 24 years, the surgical margins were free of tumor. Of those, the case that was followed for 5 years had a focus of tumor in the capsule, but did not recur. A myoepithelioma is a benign tumor composed of various proportions of plasmacytoid, spindle, epithelioid, and clear cells that exhibit myoepithelial differentiation