RESUMO
Melanocytic matricoma is a rare, biphasic adnexal tumor. It typically presents as a pigmented papule on the sun-damaged skin of elderly patients. Histopathology shows a dermal nodule composed of basaloid cells, ghost cells, and deeply pigmented dendritic melanocytes. The basaloid cells are usually positive for ß-catenin and these tumors show overlapping histopathological and molecular features with pilomatricoma. Here, we review the literature on melanocytic matricoma and present three new cases. We suggest different terminology to reflect the overlapping features with pilomatricoma that recognizes that melanocytic matricoma is likely to be a variant of pilomatricoma associated with melanocytic hyperplasia. Although melanocytic matricoma is usually considered benign, malignant transformation has been reported. This highlights the need for increased awareness of this entity.
Assuntos
Doenças do Cabelo , Neoplasias de Anexos e de Apêndices Cutâneos , Pilomatrixoma , Neoplasias Cutâneas , Idoso , Doenças do Cabelo/patologia , Humanos , Melanócitos/patologia , Neoplasias de Anexos e de Apêndices Cutâneos/patologia , Pilomatrixoma/patologia , Neoplasias Cutâneas/patologiaRESUMO
A rare skin tumor (melanocytic matricoma), 6 mm in diameter, was diagnosed on the skin of the back in a 66-year-old man. It was composed of two cellular types: 1. epithelial cells with hair follicle differentiation and 2. dendritic melanocytes. After two years of follow-up there are no signs of a relapse or generalisation of the tumor.
Assuntos
Doenças do Cabelo/patologia , Melanócitos/patologia , Pilomatrixoma/patologia , Neoplasias Cutâneas/patologia , Idoso , Diferenciação Celular , Humanos , Masculino , Pele/patologiaRESUMO
BACKGROUND: Pilomatricomas are tumors that emulate the differentiation of matrix cells of the hair follicle, showing cortical differentiation, with sequential expression of K35 and K31 keratins. Beta-catenin gene is frequently mutated in pilomatricoma, leading to beta-catenin nuclear accumulation, and to downstream expression of LEF1. Skin matrical tumors other than pilomatricoma are very rare, and comprise purely matrical tumors and focally matrical tumors. We aimed at studying cortical differentiation, beta-catenin pathway and expression of the follicular stem-cell marker PHLDA1 in a series of matrical tumors other than pilomatricoma. METHODS: In 36 prospectively collected tumors, K31, K35, CK17, LEF1, HOXC13, beta-catenin and PHLDA1 expressions were evaluated. Five pilomatricomas were used as controls. RESULTS: In 18 purely matrical tumors (11 matrical carcinomas, 4 melanocytic matricomas, 3 matricomas) and 18 focally matrical tumors (11 basal cell carcinomas, 3 trichoepithelioma/trichoblastomas, 4 others), sequential K35, HOXC13 and K31 expressions were found, indicating cortical differentiation. Germinative matrix cells were always CK17-, and showed nuclear beta-catenin accumulation, with LEF1 and PHLDA1 expressions. CONCLUSIONS: Nuclear beta-catenin and LEF1 expression was highly conserved in matrical tumors, and suggested a common tumorigenesis driven by Wnt pathway activation. PHLDA1 was consistently expressed in matrical tumors and in areas of matrical differentiation.
Assuntos
Doenças do Cabelo/patologia , Queratinas Específicas do Cabelo/biossíntese , Neoplasias Cutâneas/patologia , Fatores de Transcrição/biossíntese , beta Catenina/biossíntese , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Feminino , Doenças do Cabelo/metabolismo , Humanos , Imuno-Histoquímica , Queratinas Específicas do Cabelo/análise , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/metabolismo , Fatores de Transcrição/análise , Adulto Jovem , beta Catenina/análiseRESUMO
Melanocytic matricoma is a rare cutaneous adnexal tumor occurring in humans with only 13 cases reported in the literature. The typical lesion is a circumscribed pigmented nodule on sun-damaged skin. Most cases have occurred in elderly men. The tumor contains a mixed population of matrical cells, supramatrical cells, shadow or ghost cells, and dendritic melanocytes. We report two cases of melanocytic matricoma in two elderly women with unusual histopathological features such as cystic degeneration and focal granulomatous inflammation, which are considered to be atypical for this entity.
Assuntos
Neoplasias Cutâneas/patologia , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Melanócitos/metabolismo , Melanócitos/patologia , Pessoa de Meia-Idade , Neoplasias de Anexos e de Apêndices Cutâneos/patologia , Neoplasias de Anexos e de Apêndices Cutâneos/ultraestrutura , Pilomatrixoma/patologiaRESUMO
Matricoma is benign follicular neoplasm with the same constituent cells as pilomatricoma but with a different silhouette. Matricoma consists mostly of solid aggregations of matrical cells, as opposed to pilomatricoma, which is often a cystic lesion. We herein describe a case of agminated pigmented matricoma. A 27-year-old Japanese man visited our hospital complaining of three separate, pigmented, firm and sessile nodules on the back. Histopathologic examination revealed mostly solid aggregations of matrical and supramatrical cells located mainly within the dermis and the upper part of the subcutis. Shadow cells were present mostly within the aggregations. At higher magnifications, occasional indication of inner sheath differentiation, in addition to differentiation toward hair in the form of shadow cells, could be discerned in the center of the aggregations. The matrical and supramatrical cells within the aggregations were relatively uniform in size and shape, and contained several mitotic figures. Heavily pigmented melanocytes were present within the aggregations of matrical and supramatrical cells, and heavily pigmented melanophages were found in adjacent stroma. Pigmentation is a rare event in benign and malignant adnexal tumors, and to our knowledge, no similar case has been reported.
Assuntos
Melanócitos/patologia , Neoplasias Cutâneas/patologia , Pigmentação da Pele , Adulto , Humanos , MasculinoRESUMO
Introduction: Onychocytic matricoma (OCM) is a benign acanthoma of the nail matrix that presents with longitudinal melanonychia and nail thickening. Only 18 previously reported cases of OCM are in the literature since it was first described in 2012. Case Presentation: The purpose of this case report was to report a unique presentation of OCM in the toenail of a Black patient as well as to review the clinical presentation, histologic features, and management of this rare entity. Previously described cases presented on the fingernails and were predominantly in white males. Conclusion: OCM is a benign entity that may mimic a nail unit melanoma or squamous cell carcinoma especially when pachyonychia is present. Despite some clinical clues to suggest a diagnosis of OCM, a nail matrix biopsy is often required to rule out malignancy.
RESUMO
Melanocytic matricoma is a rare dermal tumor that typically presents on the sun-damaged skin of older patients. While there is controversy in the literature regarding the proper characterization of this tumor, there are certain histological and immunohistochemical features that have been described. This report presents a case of melanocytic matricoma with several unusual features that were initially feared to be malignant melanoma. Careful histologic and immunohistochemical analysis was required to rule out malignant melanoma and make the correct diagnosis. Given the rarity of melanocytic matricoma and the potential for it to mimic malignant melanoma, it is important for pathologists to keep melanocytic matricoma on the differential and be aware of the clinical, histological, and immunohistochemical features of this tumor.
RESUMO
Malignant melanocytic matricoma (MMM) is an extremely rare skin malignant neoplasm composed of epithelial cells with matrical differentiation and dendritic melanocytes. We found only 11 cases reported in the literature to date according to the databases consulted (PubMed/Medline, Scopus, and Web of Science). Here, we report a case of MMM in an 86-year-old woman. A histological examination showed a dermal tumor with a deep infiltrative pattern, without an epidermal connection. On immunohistochemical staining, tumor cells were positive for cytokeratin AE1/AE3, p63, and beta-catenin (nuclear and cytoplasmic staining) and negative for HMB45, Melan-A, S-100 protein, and androgen receptor. Melanic antibodies highlighted scattered dendritic melanocytes in tumor sheets. The findings did not support the diagnosis of melanoma, poorly differentiated sebaceous carcinoma, and basal cell carcinoma, but supported the diagnosis of MMM.
RESUMO
In this paper, we report the case of a 71-year-old man with an 8-year history of melanonychia on the right little finger, who referred to our hospital because the color of pigmented area had gradually darkened and the width had expanded. Physical examination revealed longitudinal melanonychia with brown color (4 mm in width). Dermoscopic examination revealed multiple white round clods and splinter hemorrhages. No micro-Hutchinson sign was observed. We performed a punch biopsy (diameter 3 mm) of the nail matrix for diagnosis. Histopathological examination revealed irregular acanthosis of epithelium of the nail bed and distal matrix, which consisted of basaloid cells without nuclear atypia. Several zones exhibited cell whorls reminiscent of squamous eddies. The whorls were composed of large pink cells arranged in an onion peel-like fashion. The basaloid cells tested negative for human papillomavirus in situ hybridization and p16 staining. The morphology of white round clods (milia-like cysts in metaphoric term) observed in dermoscopic analysis corresponded to squamous eddies in histopathology. Considering these features, ungual seborrheic keratosis (SK) with longitudinal melanonychia was diagnosed, which is an atypical site for SK. We suggest that the dermoscopic finding of milia-like cysts may be useful for the diagnosis of ungual SK.