Melanotic neuroectodermal tumour of infancy arising in anterior fontanelle

A case is described of a melanotic neuroectodermal tumour which developed in the anterior fontanelle of the skull of a Melanesian girl during the first 7 mth of life.     

Melanotic progonoma

A case of melanotic progonoma detected in an infant is presented. Microscopically, the tumor was found to consist of a rough fibrous connective tissue stroma with groups of minor monomorphic lymphocyte-like cells and glandular-like cavities that were lined with melanin-containing hyperchromatic rounded and flattened epithelioid cells. The tumor occurs rarely and is a matter of some difficulty in its histologic diagnosis.     

Melanotic neuroectodermal tumour as a predominant component of an immature testicular teratoma. Case report with immunohistochemical investigations.

A case of melanotic neuroectodermal tumour (MNT), or so-called retinal anlage tumour, as a predominant component of an immature testicular teratoma is presented. The patient was a 17-year-old man who furthermore had a mature mediastinal teratoma. The MNT was composed mainly of two cell types: small immature neuroblast-like cells and large columnar or cuboidal epithelial-like cells with or without melanin granules. The tumour cells were arranged in solid formations, nests, cords, alveolar and pseudoglandular structures with cleft-like or glomeruloid-like spaces. Myogenic differentiation was found in minor foci. Immunohistochemistry showed both neuroepithelial and mesenchymal features with positive staining reaction for neuron-specific enolase (NSE), S-100 protein (S-100), melanoma antigen (HMB45), cytokeratin and vimentin. Vimentin, desmin and actin were present in the myoid cells. To the best of our knowledge this is the first reported case of MNT originating in the testis. As this tumour component occurred in an immature teratoma, neuroectodermal differentiation of germ cell origin is considered most likely.     

Melanotic progonoma of the brain

The first occurrence of a melanotic progonoma in the brain is reported. The patient was three months old at the time of onset of symptoms and 18 months of age at the time of death.The pigmented component of the tumor was identical to that seen in tumors in other locations, but the major mass of tumor was composed of well differentiated cerebral tissue. Tabulation of the 77 examples of the tumor reported is presented. The tumor is benign and is curable by surgical excision.The evidence for the neural crest origin of the pigmented epithelium and the normal function of the neural crest in the embryo are reviewed. A pathogenetic mechanism based on the organizing and inducing capabilities of the neural tissue is advanced.     

Melanotic neuroectodermal tumor of infancy

A case of melanotic neuroectodermal tumor of infancy was presented. This tumor occurred in the right maxillary alveolar ridge of 3-month-old female infant, showing bluish enlargement of alveolar mucosa with the displacement of central deciduous incisor. We described the gross, microscopic, and ultrastructural findings of this tumor. This case appears to be the first case of MNTI, reported in a Korean.     

Melanotic paraganglioma of the posterior mediastinum

A melanotic paraganglioma occurred in a 57-year-old woman, located in the left paravertebral space of the upper mediastinum. It was totally resected. During a 5 year follow up period neither tumour reccurrence nor metastasis were observed. Histological examination of the tumour revealed a paraganglioma with monomorphous chief cell like elements which were arranged in a zellballen pattern. Immunohistochemical results also were in accordance with the diagnosis since neuron-specific enolase, chromogranin and synaptophysin were found in tumour cells whereas keratin was not. Additionally, neurosecretory granules were found in tumour cells during electron microscopy. A peculiar feature of the tumour was its strong pigmentation due to melanin located within the tumour cells and tumour associated melanophages. The simultaneous expression of functional properties of two different neural crest derived cells in one tumour stresses the close relationship between all neural crest elements and is in accordance with the observation of other melanotic, non-melanomatous tumours.Dedicated to Prof. Dr. Dr. mult. h.c. W. Doerr on the occasion of his 80th birthday     

Melanotic schwannoma of the acoustic nerve

Melanotic schwannoma is a rare neoplasm, with only 23 previously reported cases. We report an additional case of a melanotic schwannoma arising from the acoustic nerve in a 74-year-old man who had a probable forme fruste of neurofibromatosis. We briefly review the literature of this neoplasm and discuss theories regarding the histogenesis of these tumors.     

Melanotic oncocytic metaplasia of the nasopharynx

Two cases of melanotic oncocytic metaplasia occurring in the nasopharynx are reported. One presented with serous otitis media and the other with tinnitus. Nasoscopic examination revealed a small brown nodule obstructing the Eustachian tube in both cases. While oncocytic metaplasia of the nasopharynx is not too uncommon, melanin pigmentation of the nasal or nasopharyngeal mucosa is very rare. To our knowledge, their combination has not been described.     

Melanotic oncocytic metaplasia of the nasopharynx

We present three cases of melanotic oncocytic metaplasia of the nasopharynx. Case 1 and Case 2 were a 70‐ and a 61‐year‐old woman, and Case 3 was a 74‐year‐old man. Although Case 1 was asymptomatic, Cases 2 and 3 had hoarseness. All cases were Japanese and their nasopharyngeal examination revealed single or multiple black nodules measuring a few millimeters in diameter. In each case, biopsies were performed to rule out malignancy. Histological examination showed respiratory mucosa with oncocytic metaplasia and melanin pigments. Immunohistochemically, S‐100 protein and melan‐A positive dendritic melanocytes were observed in the basal layer of the oncocytes. Melanotic oncocytic metaplasia is extremely rare, and so far only 21 cases have been reported in the English literature to our knowledge. It has been reported in only older Asians, predominantly in males; there have been only three female patients including our two cases. All of our cases were long‐time smokers, which supports the previously described hypothesis that smoking may be a predisposing factor for melanin pigmentation. Since melanotic oncocytic metaplasia may clinically mimic a malignant tumor, it is important to be aware of this lesion.