Relative frequency of solitary melanocytic lesions of the oral mucosa

Background: Solitary pigmented lesions of melanocytic origin are uncommon in the oral mucosa. These lesions include the oral and labial melanotic macule, oral melanocytic nevus, oral melanoacanthoma, oral melanoma and atypical melanocytic proliferation. The purpose of the study was twofold: to report a large series of solitary melanocytic lesions from one source, and to determine the relative frequency of these lesions. Methods: The study was based on a systematic search of the files of the Pacific Oral and Maxillofacial Pathology Laboratory, University of the Pacific, San Francisco for solitary pigmented melanocytic lesions (benign and malignant) accessed during the years 1984–2002. Results: Of the 89 430 biopsies accessed during the 19‐year period, 773 (0.83%) cases of solitary pigmented melanocytic lesions in the oral mucosa were identified. Oral and labial melanotic macules were the most common melanocytic lesions comprising 86.1% of the entire group and 0.7% of the total number of accessed biopsies. The vermilion border and gingiva were the most common sites (31.1% and 31.0% respectively). Oral melanocytic nevi comprised 11.8% of the entire melanocytic group and 0.1% of the total number of biopsies. The most common site was the palate (44%). Intramucosal nevi were the most common (64%), followed by compound nevi (16.5%) and common blue nevi (16.5%). Junctional nevi were uncommon (3.0%). Oral melanoacanthoma comprised only 0.9% of the entire melanocytic group and 0.008% of the total number of biopsies. Oral melanoma and atypical melanocytic proliferation were the least common lesions each comprising 0.6% of the entire melanocytic group and 0.006% of the total number of biopsies. The most common site for oral melanoma was the palate (60%). Conclusion: The palate was the most common location for both melanocytic nevi and oral melanoma. Thus, all melanocytic lesions in the palate should be viewed with caution and biopsy is recommended to rule out melanoma. Further studies are required to elucidate the entity of oral atypical melanocytic proliferation.     

Melanotic Neuroectodermal Tumor of Infancy Occurring in the Left Thigh of a 6-Month-Old Female Infant

We report an exceptional case of melanotic neuro-ectodermal tumor of infancy (MNTI) occurring in the soft tissue of the left thigh of a 6-month-old female infant. The tumor consisted mainly of small round cells (neuroblasts) arranged in cords and nests that were separated by broad fibrovascular areas. In addition, there were a few medium-sized tumor cells containing melanin pigment (melano-cytic cells) that in electron microscopy contained melanosomes as well as tonofilaments. Both tumor cell types immunostained for neuron-specific enolase (NSE) and vimentin, and the melanocytic cells reacted additionally with the antikeratin antibody KL1. Within the tumor stroma, neurofilament- and S-100-protein-positive neural cells and vimentin- and desmin-positive myofibroblasts were seen. Although densecore granules were demonstrated ultrastructurally in some neuroblasts, no immunostaining for chromogranin A, Leu-7, serotonin, or regulatory peptides was found. MNTI located in an extremity can be confused with malignant small round and blue cell tumors of childhood. The distinction between MNTI and these tumors is of clinical significance because MNTI, in most cases, is a benign tumor that, in contrast to the latter, can be cured by complete excision. The presence of a biphasic cell population with neuroblasts and melanocytic cells must be considered the main diagnostic feature of MNTI.     

上颌骨婴儿色素性神经外胚层瘤1例

婴儿色素性神经外胚层瘤是一种罕见的起源于神经嵴的色素性神经外胚层瘤,通过本病例分析其临床、CT及病理学特征,旨在提高对本病的认识,为临床诊治提供依据。     

Melanotic neuroectodermal tumour of infancy of the jaws: an analysis of diagnostic features and treatment

The purpose of this study was to integrate the available published data on melanotic neuroectodermal tumour of infancy (MNTI) of the jaws into a comprehensive analysis of its clinical/radiological features, with emphasis on the predictive factors associated with recurrence. Eligibility criteria included publications with sufficient clinical/radiological/histological information to confirm the diagnosis. A total of 288 publications reporting 429 MNTI cases were included. MNTIs were slightly more prevalent in males and markedly more prevalent in the maxilla. Most of the lesions were asymptomatic, presenting cortical bone perforation and tooth displacement. Nine lesions were malignant, with metastasis in five cases. Enucleation was the predominant treatment (67.2%), followed by marginal (18.4%) and segmental resection (6.1%). Eighty-one of 356 lesions (22.8%) recurred. Recurrence rates were 61.5% for curettage, 25.3% for enucleation alone, 16.2% for enucleation + curettage, 20.0% for enucleation + peripheral osteotomy, 11.3% for marginal resection, 10.0% for segmental resection, 30.0% for chemotherapy, and 33.3% for radiotherapy. Enucleation and resection presented significantly lower recurrence rates in comparison to curettage. Curettage appears not to be the best form of treatment, due to its high recurrence rate. As resection (either marginal or segmental) is associated with higher morbidity, enucleation with or without complementary treatment (curettage or peripheral osteotomy) would appear to be the most indicated therapy.     

Melanotic neuroectodermal tumor of infancy: a histopathological and immunohistochemical study

Melanotic neuroectodermal tumor of infancy is an uncommon neoplasm that normally occurs in the anterior maxilla of children less than 1 year of age. This is a tumor with controversial origin, although neural crest origin is proposed. This case report presents an analysis of histopathological and immunohistochemical findings in this rare tumor.     

Malignant melanotic Xp11 neoplasms exhibit a clinicopathologic spectrum and gene expression profiling akin to alveolar soft part sarcoma: a proposal for reclassification

The classification of the distinct group of mesenchymal neoplasms, first described as ‘Xp11 translocation perivascular epithelioid cell tumor (PEComa)’ and for which the term ‘melanotic Xp11 neoplasm’ or ‘Xp11 neoplasm with melanocytic differentiation’ has recently been proposed, remains challenging and controversial. We collected 27 melanotic Xp11 neoplasms, the largest series to date, for a comprehensive evaluation. Fourteen of the cases, together with eight alveolar soft part sarcomas (ASPS), nine conventional PEComas and a control group of seven normal tissues were submitted to RNA sequencing. Follow-up available in 22 patients showed 5-year overall survival and 5-year disease-free survival of 47.6 and 35.7%, respectively, which were similar to ASPS and significantly worse than conventional PEComa. Univariate analysis of location (occurring in the kidney versus not kidney), infiltrative growth pattern, nuclear pleomorphism, mitotic activity ≥2/50 high-power fields (HPF), necrosis and lymphovascular invasion were found to be associated with overall survival and/or disease-free survival. Multivariate analysis identified that location was the only factor found to independently correlate with disease-free survival. More importantly, RNA sequencing-based clustering analysis segregated melanotic Xp11 neoplasm and ASPS from other tumors, including conventional PEComa and Xp11 translocation renal cell carcinoma, and formed a compact cluster representative of the largely similar expression signature. Here we clearly define the true biologic nature of melanotic Xp11 neoplasms which are distinctive malignant mesenchymal tumors, rather than simply PEComa variants with occasionally unpredictable behavior. Meanwhile, melanotic Xp11 neoplasm and ASPS more likely represent phenotypic variants of the same entity, which is distinct from conventional PEComa and Xp11 translocation renal cell carcinoma. Based on these important findings, melanotic Xp11 neoplasm might be reclassified into a distinctive entity together with ASPS, independent from PEComa, in future revisions of the current WHO categories of tumors of soft tissue and bone for the improved reclassification. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Radiotherapy for melanotic freckles

Five patients who received radiotherapy (RT) for 7 melanotic freckles (MF, also known as Hutchinson's freckles, lentigo maligna) were reviewed 8 to 37 months after their treatment by RT. Local control and a favourable cosmetic result occurred in all patients. Treatment toxicity was minimal. Few reports about the use of RT for MF exist. Many other treatments including observation alone have been associated with high rates of recurrence, and in some cases conversion to invasive melanoma has occurred. RT appears to be a safe and effective treatment for this condition, providing that doses equivalent to 44 Gy in 11 fractions or more are given.     

Malignant Melanotic Neuroectodermal Tumor of Infancy: A Case Report

We present a case of melanotic neuroectodermal tumor in the maxilla that followed an aggressively malignant course. In the first biopsy the tumor showed a classical histological picture, while in the last biopsy only malignant undifferentiated cells were evident. The tumor recurred twice after excision, and in spite of radiotherapy and various chemotherapeutic measures the patient died within 16 months of onset. Similar cases reported in the literature are discussed.     

Effectiveness of chemotherapy in melanotic neurectodermal tumor of infancy

MNTI is an uncommon tumor mainly of infants. Surgery is the primary modality of treatment. Chemotherapy has been tried for recurrent/residual tumors. The chemotherapeutic response of 3 infants treated at a center is discussed here. All 3 infants showed good response to chemotherapy. In 2 of them complete residual tumor resection became possible; 2 of them are alive and tumor regression continues.One child had local recurrence later and was lost for follow-up.     

应用颏下动脉岛状皮瓣治疗颏部黑痣

目的:探讨颏下动脉皮瓣修复颏部黑痣的可行性及优越性.方法:对6例颏部黑痣患者行一次性黑痣切除,设计颏下动脉皮瓣Ⅰ期修复黑痣切除后的创面.结果:6例颏部黑痣患者术后皮瓣全部成活,患者及家属时术后外观满意,无挛缩现象发生.结论:颏下动脉皮瓣与颏部组织类似的特性,颜色质地好,供区隐蔽,手术操作相对简单,安全快速,是I期修复颏部黑痣的理想的方法.