Melanotic Neuroectodermal Tumor of Infancy



Melanotic Neuroectodermal Tumor of Infancy


Jeremy Wallentine, MD

Cyril Fisher, MD, DSc, FRCPath









The neuroblastic small cells image separated by a fibrocollagenous stroma image demonstrate an alveolar pattern of growth in this melanotic neuroectodermal tumor of infancy (MNTI).






Epithelial cells with abundant eosinophilic cytoplasm and melanin pigment image form glandular structures with scattered small neuroblastic cells image in this MNTI.


TERMINOLOGY


Abbreviations



  • Melanotic neuroectodermal tumor of infancy (MNTI)


Synonyms



  • Retinal anlage tumor


  • Melanotic progonoma


  • Melanotic ameloblastoma


Definitions



  • Rare, fast-growing, pigmented neoplasm, likely of neural crest origin


ETIOLOGY/PATHOGENESIS


Disputed Histogenesis



  • Current studies support neural crest (neuroectodermal) origin


CLINICAL ISSUES


Epidemiology



  • Age



    • Most present in 1st year of life (> 90%)


Site



  • Most involve craniofacial sites



    • Upper and lower jaw



      • Maxilla (69%)


      • Mandible (6%)


    • Skull (11%)


  • Unusual sites



    • Epididymis, mediastinum, brain, shoulder, and skin


Presentation



  • Rapidly enlarging, firm, expansile mass


  • Erosion into adjacent bone


  • Nontender


  • Intact overlying mucosa


  • Bluish discoloration


Laboratory Tests



  • Elevated urinary vanillylmandelic acid may be present


Treatment



  • Complete local excision



    • Local recurrence rate: 10-15%


    • Usually recurs in 1st postoperative year


Prognosis



  • Benign to intermediate clinical course



    • Recurrence rate: 10-15%


    • Metastatic spread in < 5%


IMAGE FINDINGS


General Features



  • Well-demarcated radiolucent lesion


  • Capacity for local destruction


MACROSCOPIC FEATURES


Gross Features



  • Firm


  • Well circumscribed


  • Gray to blue-black cut surface

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Melanotic Neuroectodermal Tumor of Infancy
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