The diagnosis of malignant melanoma (MM) in children is difficult due to its uncommon occurrence as well histological similarities to Spitz nevus. A case of MM of the foot in an 11-year-old boy is reported illustrating the histological overlap between Spitz nevus and MM. In our patient, both the primary foot lesion and the regional inguinal metastases were amelanotic, further increasing the diagnostic difficulty. The literature on MM in children is limited and the documentation of such unusual cases is necessary to improve the knowledge on this disease.
Melanoma of the sinonasal cavity has a high incidence of amelanotic presentation. Its diagnosis is difficult for clinicians and pathologists because of its hidden location and lack of pigmentation at the microscopic level. We reported a case of amelanotic melanoma of the maxillary sinus that showed aggressive extension to the oral cavity after extraction of the maxillary tooth. Histologically, the lesion resembled a plasmacytoid tumour. Diagnosis was made through the positive immunohistochemical staining for S100 and HMB-45.