Metastatic Melanotic Neuroectodermal Tumor of Infancy: Report of a Case and Review of the Literature

Melanotic neuroectodermal tumors of infancy (MNTI) are rapidly growing pigmented tumors that occur predominantly within bony head and neck structures. There are fewer than 400 cases reported in the literature with the majority affecting the maxilla. Locations in other intraosseous and extraosseous structures have been characterized, including the mandible (6% of MNTIs). Infants in the first year of life are primarily affected. Surgical resection is the primary treatment modality with and without adjuvant chemotherapy for malignant tumors, which comprise less than 25 cases in the literature, and of metatstatic mandibular tumors, which has only been documented in one other case. The purpose of this investigation is to review associated literature and present a case highlighting treatment considerations of a metastatic mandibular MNTI. We present the case of a six month old boy with a rapidly growing bluish mass of the right mandible. Preoperatively incisional biopsy led to a diagnosis of MNTI and subsequent surgical planning involved hemimandibulectomy from the right mandibular condyle to the left posterior body region with one centimeter margins. At the time of initial surgery, enlarged lymph nodes removed from the neck demonstrated abnormality consistent with metastatic spread of the tumor. Islands of tumor cells were noted: small, round, bluestaining cells resembling neuroblasts with mitotic activity as well as pigmented cells containing melanin. Because of regional node metastasis, chemotherapy was completed following surgery. The patient recovered and was followed without evidence of recurrence. At 3.5 years postresection, a secondary reconstruction was completed using a fibula osteocutaneous free flap combined with a costochondral rib graft. In reviewing similar cases of malignant MNTI reported in the literature, a search of the MEDLINE database until 2014 was performed. These were evaluated based on management type and outcome, including surgical and chemotherapeutic treatments and the incidence of recurrence or metastasis.