Melanotic Neuroectodermal Tumor of Infancy



Melanotic Neuroectodermal Tumor of Infancy


Jeremy Wallentine, MD

Cyril Fisher, MD, DSc, FRCPath





Key Facts


Terminology



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


Clinical Issues



  • Most present in 1st year of life


  • Commonly involve craniofacial sites



    • Maxilla (69%)


  • Rapidly enlarging expansile mass


  • Elevated urinary vanillylmandelic acid may be present


Microscopic Pathology



  • 3 distinct components



    • Clusters of small round neuroblastic cells


    • Primitive gland-like structures


    • Fibrocollagenous stroma


Top Differential Diagnoses



  • Neuroblastoma



    • Sheets and lobules of small round hyperchromatic cells


  • Alveolar rhabdomyosarcoma



    • Aggregates and nests of poorly differentiated small hyperchromatic cells


    • Characteristic immunohistochemical and cytogenetic findings


  • Primitive neuroectodermal tumor



    • Sheets of small-medium round blue cells


    • Characteristic t(11;22)


  • Congenital epulis



    • Characteristic location in labial aspect of dental ridge


    • Protruding round or ovoid nodule






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


MICROSCOPIC PATHOLOGY

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

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