Cutaneous Melanoma



Cutaneous Melanoma


Nayela Keen, MD

Christine M. Glastonbury, MBBS









(Left) Axial CECT in a patient who had vertex scalp melanoma excised 6 months prior shows multiple nodules bilaterally in the scalp image representing metastatic spread along subdermal lymphatics. (Right) Coronal CECT reformation in the same patient shows extensive bilateral lymphadenopathy in the neck with intraparotid adenopathy image and level 2 nodes image. Note that most nodes are not particularly large, and most are less than a centimeter in this case. Some show necrosis.






(Left) Lymphoscintigraphy study in a different patient with no clinical adenopathy is shown. Technetium-99m thiosulfate colloid was injected at 4 points around site of prior resected right scalp melanoma image. (Right) Lymphoscintigraphy obtained shows injection site image with channel that divides into 2 image. Multiple sentinel nodes are appreciated image in right posterior triangle, with no activity on left. Surgical resection performed immediately after showed 0.7 cm metastatic focus in 1 node.



TERMINOLOGY


Definitions



  • Cutaneous malignancy arising from melanocytes



    • Originates in neural crest


    • Widely distributed in skin


IMAGING


General Features



  • Best diagnostic clue



    • Multiple nodal masses


  • Location



    • In females most often extremities, in males on trunk


    • 25-35% arise in H&N, most often face



      • Increased sun exposure


      • 2-3x higher melanocytic content


  • Size



    • Variable, both in superficial and deep extent



      • Tumor thickness (in mm) important for T stage


  • Morphology



    • Infiltrative lesion of skin ± ulceration of overlying epidermis


    • Ulceration is predictor of reduced survival


CT Findings



  • Most widely used modality for staging, surveillance, and assessment of treatment response


  • Primary site may not be evident: Small or previously resected



    • Look for deep extent to bone and soft tissues


  • Some melanomas have propensity for perineural spread



    • Expansion or erosion of skull base foramina


  • Nodal metastasis round, often necrotic


MR Findings



  • T1WI



    • Heterogeneous; may be hyperintense if melanin content high


  • T2WI FS



    • Heterogeneous; may be T2 hypointense if melanin content high


  • T1WI C+ FS



    • Moderate to marked enhancement


Nuclear Medicine Findings

Sep 20, 2016 | Posted by in HEAD & NECK IMAGING | Comments Off on Cutaneous Melanoma

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