Sentinel node mapping in vulvovaginal melanoma using SPECT/CT lymphoscintigraphy

We report 2 cases of vulvovaginal melanoma in which sentinel node mapping, performed using Tc-99m filtered sulfur colloid SPECT/CT lymphoscintigraphy, added important information to that provided by planar imaging and played a critical role in surgical planning and subsequent managementIn the first case, lymphoscintigraphy planar imaging showed only foci of tracer uptake in the right groin and an equivocal focus in the left groinSPECT/CT precisely localized these radioactive foci to the right and left inguinal sentinel nodesThe patient then underwent bilateral inguinal sentinel node samplingIn the second case, F-18 FDG PET/CT performed prior to lymphoscintigraphy demonstrated a moderately FDG-avid right inguinal lymph node that was indeterminate in natureSPECT/CT revealed this lymph node to be a radioactive sentinel lymph node that was seen in the right groin on planar imagingThe patient then underwent right inguinal sentinel node samplingBecause pathologic study showed metastasis to the sentinel node, a planned pelvic exenteration was canceled, and the patient was referred for systemic treatmentPreoperative SPECT/CT lymphoscintigraphy is ideal for mapping the unpredicted lymphatic drainage pathways within the complex pelvic anatomy and this technique may also be used in the preoperative workup of other gynecologic malignancies.