The Impact of Evaluation In Pediatric, Adolescent and Young Adult Head and Neck B Turpin1, J Pressey1, R Nagarajan1, B Weiss1, A Dasgupta2 1Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, USA. 2Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, USA.

Introduction Results Regional lymph node disease (N1) has been shown to be an independent • Six pediatric and AYA patients (6 mo – 21 yrs) with head and neck RMS (1 embryonal, 1 spindle , 1 anaplastic, and 3 fusion positive RMS) prognostic factor in patients with rhabdomyosarcoma (RMS), and size and underwent successful SLN biopsy without complication. PET avidity have been explored as determinants of clinically significant • Sites of primary disease included nasal cavity (1), buccal (2), masticator space (1), palate (1), and ethmoid sinus (1). lymph node disease. Here we demonstrate that pediatric and adolescent • Two to 3 sentinel lymph nodes were excised per patient. and young adult (AYA) head and neck RMS sentinel lymph node (SLN) • Lymphoscintigraphy and/or lymphazurin revealed one or more SLNs in one lymph node basin in 4 patients, and one or more SLNs in 2 lymph node evaluation has the potential to: basins in 2 patients. Unanticipated SLN locations were identified in 2 patients (contralateral cervical chain) (example detailed in Fig 2). • Pathologic evaluation confirmed N1 disease in 3 of 6 patients. Nodal disease confirmed by SLN evaluation in 2 lymph node basins would not have • Confirm metastatic sites in a minimally invasive manner and been considered N1 by conventional imaging, resulting in a modification of systemic (1 patient) and/or locoregional (2 patients) therapy (Fig 2). • Reveal unrecognized sites of lymph node .

Furthermore, we demonstrate the unique spectrum of head and neck lymph Any lymph Any lymph Lymphoscintigraphy Unanticipated site of drainage and highlight the relevance in systemic and locoregional RMS Fig. 1 node > 1 cm Change in therapy Age Diagnosis Primary site node SUV or lymphazurin guided lymphoscintigraphy or therapy. short axis based on SLN result? >2.5 (PET) SLN microscopy lymphazurin uptake? (MRI/CT)

Method 6 mo Fusions positive RMS Left buccal space Yes No Negative (0/3) No No Yes (bilateral anterior Yes (regional and 4 yo Fusion positive RMS Left ethmoid sinus Yes Yes Positive (2/2) • Two to 4 hours before the operative procedure, 125 mCi of filtered cervical chain) systemic) technetium-99m sulfur microcolloid was injected in 4 quadrants around the tumor (intradermal and/or mucosal) (Fig 1A). 5 yo RMS with diffuse anaplasia Right masticator space Yes Yes Positive (1/2) No No • Standard planar lymphoscintigraphy was then performed, and SPECT-CT Yes (bilateral 14 yo Embryonal RMS Right soft palate No No Negative (0/2) No was used to facilitate anatomic localization of the sentinel nodes (B). jugulodigastric) • Intraoperatively, 3mL of lymphazurin 1% dye (Isosulfan Blue, United 14 yo Fusion positive RMS Right nasal cavity No No Positive (2/3) DNo Yes (regional) States Surgical Corp, Norwalk, Conn) was injected surrounding the site. 21 yo Spindle cell RMS Left buccal space No No Negative (0/2) No No • A hand-held γ probe was used to identify the area of maximal signal and thus guide dissection (C). • Lymph nodes with radioactivity were removed until the remaining γ count in the nodal basin was 10% of the first identified lymph node and was consistent with the background. In addition, any blue lymph nodes were Conclusions removed (D). Radioactive or blue nodes were considered sentinel nodes. Fig 2 • Head and neck SLN evaluation in pediatric and AYA patients is safe and feasible. Fig 1 • SLN evaluation can safely guide the rational selection of nodes for biopsy in pediatric and AYA head and neck RMS patients. • Sites of lymph node metastases in patients with head and neck may not be predicted by site of primary tumor. • SLN evaluation can identify sites of nodal A B A B C metastases not recognized by conventional imaging and should be incorporated in head and neck RMS staging evaluations. Fig. 2. A) MRI primary tumor: Coronal T1-weighted image following D intravenous contrast administration shows a heterogeneous mass • SLN evaluation in head and neck RMS patients has C D (asterisk) centered within the left ethmoid air cells and superior left nasal cavity, with extension into the adjacent left orbit, maxillary sinus the potential to change locoregional and systemic and through the cribriform plate into the anterior cranial fossa (arrow). therapy. B) MRI neck: Coronal fast inversion recovery-weighted image shows a large lymph node (curved arrow) inferior to the left parotid gland. A smaller lymph node is seen in the right neck (straight arrow). C) Lymphoscintigraphy: Axial image of the neck from a SPECT/CT lymphoscintigraphy study obtained following the injection of filtered technetium-99m sulfur colloid into the left paranasal sinus mass shows Acknowledgements We thank Trisha Weil RN for a focus of activity within the right neck (straight arrow). Additional assistance with figure 1. activity is present in the pharynx secondary to dripping from the injection (curved arrow). D) Sentinel lymph node from right neck showed a microscopic focus of metastatic tumor (arrow) (H&E 200x). Correspondence [email protected]