Melanoma amelanótico diseminado / Disseminated amelanotic melanoma

El melanoma amelanótico es una de las neoplasias con mayor índice de mortalidad por su alta agresividad y baja probabilidad diagnóstica. Afecta a la población de todo el orbe, más frecuente en caucásicos, con predisposición genética y factores de riesgo como la exposición al sol. Presenta tasas de supervivencia menor a 10 por ciento a 5 años y de recurrencia elevadas; con evidencia de procesos metastásicos a distancia en órganos como cerebro, tejido celular subcutáneo, pulmón, peritoneo, hueso, lo que ensombrece el pronóstico. Se presenta el caso de una paciente de 21 años de edad que acude al hospital por presentar lesiones equimóticas, nódulos subcutáneos y cefalea hemicránea izquierda de dos meses de evolución. Se le realizó tomografías de tórax abdomen y resonancia magnética de cráneo y evidenciaron diseminación metastásica. Se realizó estudio histopatológico con inmunohistoquímica que informó melanoma amelanótico(AU)

Amelanotic melanoma is one of the neoplasms with the highest mortality rate because it is highly aggressive and the diagnostic probability is low. It affects the population of the entire globe, more frequent in Caucasians, with genetic predisposition and risk factors such as sun exposure. It presents survival rates of less than 10 percent at 5 years and high recurrence rates; with evidence of distant metastatic processes in organs such as brain, subcutaneous cellular tissue, lung, peritoneum, bone, which casts a shadow on the prognosis. We report the case of a 21-year-old patient who came to the hospital due to ecchymotic lesions, subcutaneous nodules and a two-month evolution of left hemicrania headache. She underwent chest and abdomen tomography and MRI of the skull. They showed metastatic spread. Histopathological study was performed with immunohistochemistry that reported amelanotic melanoma(AU)

Melanoma oral amelanótico metastático com acometimento neurológico e gonadal em um cão fêmea - relato de caso / [Metastatic oral amelanotic melanoma with neurologic and gonadal involvement in a female dog - case report]

Relata-se um caso de melanoma oral disseminado em uma cadela de dois anos, com protrusão de bulbo ocular unilateral e quadro convulsivo progressivo. Os exames de imagem revelaram aumento de volume nas regiões submandibular, maxilar e cerebral, padrão nodular pulmonar e aumento das dimensões ovarianas. A citologia da massa submandibular indicou proliferação epitelial maligna, enquanto a biópsia excisional foi sugestiva de melanoma amelanótico. Na necropsia, havia uma massa gengival localmente infiltrativa e nodulações brancas nos linfonodos, nos rins, no pulmão, no cérebro e nos ovários, indicativas de metástase. O diagnóstico histopatológico consistiu de neoplasia maligna metastática indiferenciada, indicativo de melanoma amelanótico. Células caracterizadas por núcleo com cromatina espessa, múltiplos nucléolos bem evidentes, mitoses atípicas e multinucleações consistiram nos principais critérios de malignidade. No espaço peritrabecular ósseo facial, havia rara diferenciação pigmentar melanocítica, confirmada histoquimicamente pela técnica de Fontana-Massom e Giemsa. Algumas células foram positivas pela imuno-histoquímica para PNL-2 e Melan-A, e o diagnóstico de melanoma amelanótico disseminado foi firmado. A indiferenciação neoplásica marcante, com disseminação metastática multissistêmica e acometimento mútuo de sítios anatômicos pouco comuns, conjuntamente com a ampla variação dos padrões celulares, foi responsável pelo desafio diagnóstico do presente caso, ressaltando o papel decisivo da imuno-histoquímica para confirmação diagnóstica. A importância clínica deste trabalho consiste ainda em alertar a comunidade clínica e científica acerca da dificuldade diagnóstica, devendo-se considerar o melanoma amelanótico como diferencial mesmo em casos de lesões orais menos perceptíveis e/ou desprovidas de pigmentação.(AU)

A case of disseminated oral melanoma in a two year old female dog with unilateral protuberance of the eye bulb and progressive seizure is described. Imaging exams revealed increase of the submandibular, maxillary and cerebral regions, nodular pattern in lungs and increased ovarian dimensions. The cytology of the submandibular mass indicated a malignant epithelial proliferation, whereas the excisional biopsy indicated an amelanotic melanoma. At necropsy, a locally infiltrating gingival mass and white nodules in the lymph nodes, kidneys, lung, brain and ovaries were observed, indicative of metastases. Histopathological diagnosis consisted of an undifferentiated malignant metastatic neoplasm. Nucleus with coarse chromatin, prominent nucleoli, bizarre mitotic figures and multinucleated cells were the major malignant features. There was a poor melanocytic pigment differentiation in the peritrabecular space of facial bones, confirmed by Fontana-Masson and Giemsa histochemical techniques. Only a few cells were immunohistochemically positive for PNL-2 and Melan-A and the diagnosis of a disseminated amelanotic melanoma was performed. The diagnostic challenge was based on marked neoplastic undifferentiation, with multisystemic metastasis and mutual involvement of uncommon anatomic sites, associated with a large variability of cellular patterns, highlighting the decisive role of immunohistochemistry for diagnostic confirmation. Therefore, the clinical importance of this study is to warn the clinical and scientific community about the diagnostic challenge, considering the amelanotic melanoma as a differential even in cases of poorly apparent and/or nonpigmented oral lesions.(AU)

Amelanotic acral melanoma misdiagnosed as verruca plantaris

Abstract: We report a case of amelanotic acral melanoma in a 42-year-old Chinese woman. Ten months previously the patient found a 2-cm asymmetric erythematous macular plaque on her left sole. The lesion was diagnosed as verruca plantaris by every physician the patient consulted. One month ago, an enlarged lymph node was detected in the left groin, which biopsy reported as metastatic melanoma. Dermoscopy suggested verruca plantaris, and positron emission tomography (PET) revealed increased glucose metabolism in the macular plaque. Finally, biopsy of the plaque revealed amelanotic melanoma. Misdiagnosis and diagnostic delay are usually associated with poorer patient outcomes. Awareness of atypical presentations of acral melanoma is thus important for decreasing misdiagnosis rates and improving patient outcomes.

Immunohistochemistry: sole tool in diagnosing a rare case of primary vaginal amelanotic melanoma

We report a rare case of vaginal amelanotic melanoma. Malignant melanomas are cutaneous and extracutaneous tumors that arise from embryological remnants of neural crest cells/melanocytes. Amelanotic melanomas at such rare locations can be misdiagnosed both clinically and radiologically. Therefore, histopathological examination and immunohistochemistry are mandatory for the diagnosis of these tumors. We diagnosed this case using histopathology and confirmed the diagnosis based on the presence of immunohistochemical markers human melanoma black 45 (HMB45) and S-100.

Primary cutaneous amelanotic melanoma and gastrointestinal stromal tumor in synchronous evolution

Abstract: Gastrointestinal stromal tumor is rare digestive tract mesenchymal tumor, most often in the wall of the stomach. It is a benign neoplasm, but it can become malignant if not treated. We report a case of gastrointestinal stromal tumor that was discovered after abdominal ultrasonography during staging of a patient with primary cutaneous amelanotic melanoma. Mutation in the tyrosine kinase receptor could explain the development of two types of tumors in the same patient.

Melanoma amelanótico acral en un paciente diabético / Acral amelanotic melanoma in a diabetic patient

Melanoma is one of the most aggressive and worse prognosis tumors. Early diagnosis is essential to offer therapeutic alternatives. Presentation may be variable. Within these the amelanotic melanoma form. We present the case of a patient treated at the ¨Hospital Regional de Talca¨, with an unclear diagnosis of melanoma at a first moment given the characteristics and location of the lesion, the history of trauma and the patient comorbidities, which after biopsy and immunohistochemical analysis, the diagnosis of amelanotic melanoma is possible.

Rare and extensive malignant melanoma of the oral cavity: report of two cases

Primary oral melanomas are uncommon malignant neoplasm of melanocytes origin. The most common site of oral melanoma is maxillary gingiva and hard palate. Oral mucosal melanoma exhibit a pathobiological behavior and clinical features different from cutaneous melanomas. Oral melanomas are often clinically silent which may consequently result in delayed diagnosis; thus, making the prognosis extremely poor

This case report presents clinical, histopathological and immunohistochemical features of two cases of advanced oral melanoma, one pigmented or melanotic melanoma in a 46-year-old female and another amelanotic melanoma in a 59-year-old male patient, with chief complaint of swelling in oral mucosa

Most oral melanomas are usually asymptomatic lesions with quick growing. Thus, the most cases are detected in late stage of diagnosis. Early diagnosis with careful examination by dentists, and early biopsy of pigmented and suspicious non-pigmented lesions would have an imperative role in more survival rate and better prognosis

Immunohlstochemical study of COX-2 in melanocytic skin lesions

Background: cyclooxygenase-2 [cox-2] is involved in pathogenesis of various skin tumors including malignant melanoma; however, there is not enough information about cox-2 expression in benign melanocytic lesions. In the present study we compared the expression levels of cox-2 in malignant melanoma and benign melanocytic lesions

Methods: In this analytical study, 42 malignant melanoma from all 4 subtypes and 38 benign melanocytic lesions including dysplastic nevus, Spitz nevus and atypical nevus were evaluated for cox-2 expression using immunohistochemistry staining and intensity of cell staining [quantitatively and qualitatively]

Results: Malignant melanoma compared to benign melanocytic lesions had significantly higher levels of staining [p<0.00l], and much more intense coloration [p<0.00l] and higher overall staining score [p<0.001]

Regarding the cox-2 staining between malignant melanoma subtypes, all four subtypes mostly had staining intensity over 60%. Also in terms of quality, the most intense staining was in the ALM, and LM and NM had moderate staining intensity. With increasing depth of involvement, cox-2 staining increases. Intensity of cell staining was also higher in cases with tumor depth of 2-4 mm

Conclusion: The results indicate the effectiveness of cox-2 in differentiating between malignant melanoma and benign melanocytic lesions, cox-2 expression correlated with the depth of invasion. Although cox-2 alone cannot be used to differentiate melanoma from benign lesions, it can be helpful in combination with other methods, in determining the prognosis and future targeted therapies

Amelanotic Melanoma Mimicking Eccrine Poroma / 대한피부과학회지

No abstract available.

Six Cases of Amelanotic Melanoma: Focused on the Difficulty of Early Differential Diagnosis / 대한피부과학회지

Amelanotic melanoma comprises only 1.8~8.1% of malignant melanomas, and is difficult to diagnose clinically due to the lack of the diagnostic evidence of clinical pigmentation. To our knowledge, it is rarely reported, and only 10 cases have been reported in the Korean dermatological literature. It presents rather conflicting features such as a pink or red macule, papule, plaque, or nodule mimicking various benign and malignant conditions; therefore, it is difficult to diagnose. We performed a review of six patients with amelanotic melanoma focusing on differential diagnosis, particularly at the time of the initial visit. Clinical impressions included pyogenic granuloma, dermatofibrosarcoma protuberans, eccrine poroma, epidermal cyst, keloid, pilomatricoma, and squamous cell carcinoma in addition to malignant melanoma. The biopsy specimens were consistent with malignant melanoma with little or no melanin pigment on hematoxylin and eosin and Fontana-Masson stains. Four of the six patients were positive for S-100 and HMB-45, but two patients were positive for S-100 only. We report these cases to remind clinicians of the necessity of including malignant melanoma in the differential diagnosis process when patients show poor and unpredictable responses to treatment after a clinical diagnosis of other benign and malignant conditions.

As múltiplas faces do melanoma cutâneo primário: série de casos / The many faces of primary cutaneous melanoma: a series of cases

Contexto: São descritos quatro casos clínicos que ilustram as múltiplas faces do melanoma cutâneo primário. Relato de caso: Caso 1: homemde 64 anos, negro, com lesão ulcerada de bordas hiperqueratóticas na região plantar esquerda há seis anos. Caso 2: homem de 79 anos, caucasiano, com lesão úlcero-vegetante no segundo pododáctilo à direita há um ano. Caso 3: homem de 56 anos, caucasiano, com mácula enegrecida no couro cabeludo. Caso 4: mulher de 71 anos, caucasiana, apresentando mácula enegrecida na região do aparelho ungueal do dedo indicador esquerdo há cinco anos. Discussão: O melanoma é responsável por 80% das mortes por câncer de pele. A sobrevida em cinco anos dos pacientes com metástases a distância é de no máximo 19%. As formas mais comuns do melanoma, de modo especial o melanoma disseminativo superficial, podem ser reconhecidas pelo acrônimo ABCDE, que descreve, em uma mácula enegrecida, características de assimetria, bordas irregulares, coloração variável, diâmetro maior que 6 mm e evolução com mudanças nas características ou crescimento. Esse acrônimo deve ser incorporado por todos os membros da equipe de saúde. Entretanto, há outras formas da doença cujo diagnóstico é desafiador, como o melanoma amelanótico. As lesões suspeitas devem ser excisadas. De acordo com análise anatomopatológica, pode ser necessária a análise do linfonodo sentinela e a ampliação das margens cirúrgicas. Conclusões: O reconhecimento das múltiplas faces do melanoma cutâneo por meio da análise de casos clínicos, tanto pela localização quanto pela semiologia é um alerta e possibilita diagnóstico precoce.

c-Kit immunoexpression patterns differ in melanotic and amelanotic canine oral melanomas / Análise qualitativa quanto à diferença da imunoexpressão do gene c-Kit em melanomas melânicos e amelânicos da cavidade oral em cães

Melanomas are the most common oral malignancy in dogs. Cell proliferation and connexin expression has been shown to differ in canine melanotic and amelanotic oral melanomas. This study aimed to analyze the c-Kit protein expression in melanotic and amelanotic melanomas from canine buccal cavity. A total of 34 canine buccal melanomas (19 melanotic and 15 amelanotic).were collected. The amelanotic melanomas presented faster evolution and higher incidence of metastasis than melanotic tumors. A significantly higher number of c-Kit positive cells were observed in amelanotic neoplasms. In addition, the intensity of c-Kit immunolabeling was predominantly stronger in amelanotic melanomas. These results confirm a potential role for c-Kit in canine oral melanomas with clear differences in expression patterns between the two histological types of tumor, melanotic and amelanotic. This study highlights the importance of a detailed study of c-Kit mutations in canine oral melanomas to better understand the molecular mechanisms implicated in the development of this disease...

Melanomas são as mais frequentes neoplasias malignas da cavidade bucal de cães. Sabe-se que a proliferação de células e expressão de conexina diferem em melanomas melanóticos e amelanóticos da cavidade bucal de cães. Este estudo analisou a expressão da proteína c-Kit em melanomas melanóticos e amelanóticos da cavidade bucal canina. Um total de 34 melanomas bucais caninos (19 melanóticos e 15 amelanóticos) foram coletados. Os melanomas amelanóticos apresentaram evolução mais rápida e maior incidência de metástase. Foi constatado um número significativamente maior de células positivas para c-Kit em neoplasias amelanóticas. Além disso, a intensidade de imunomarcação de c-Kit foi predominantemente mais forte em melanomas amelanóticos. Estes resultados confirmam um papel potencial para c-Kit em melanomas orais caninos, com diferenças claras em padrões de expressão entre os dois tipos histológicos de tumor, melanóticos e amelanóticos. Este trabalho destaca a importância de um estudo detalhado das mutações c-Kit em melanomas orais caninos para ser possível a melhor compreensão dos mecanismos moleculares envolvidos no desenvolvimento da doença...

Amelanotic Acral Melanoma Associated with KIT Mutation and Vitiligo

Amelanotic acral melanoma is rare and difficult to diagnose, both clinically and pathologically. KIT mutations are frequently found in acral melanomas and are considered a risk factor for poor prognosis. The presence of vitiligo in melanoma has been reported, and KIT is thought to be partly responsible for the dysfunction and loss of melanocytes observed in vitiligo. We report a case of amelanotic subungual melanoma with multiple metastases that was associated with KIT mutation and vitiligo. An 85-year-old man presented with a 3-year history of a tender erythematous ulcerated tumor on the left third fingertip and developed hypopigmented patches on the face and trunk. Histopathological examination of the ulcerative tumor showed aggregates of tumor cells that were pleomorphic epithelioid cells. Immunohistochemical staining of the tumor cells was positive for S100, HMB45, and c-Kit. Histopathological findings from the hypopigmented patch on the face were consistent with vitiligo. Mutation analysis showed a KIT mutation in exon 17 (Y823D). The patient had metastasis to the brain, liver, bone, and both lungs. The patient refused chemotherapy, and died 3 months after the first visit.

Oral Mucosal Amelanotic Melanoma: A Rare Case Report.

Oral cancer is a major global health problem. It is ranked as the third most common cancer in India. More than 95% of oral cavity carcinomas are of squamous cell type. Melanoma is a major health problem and originates from the malignant transformation of melanocytes. Primary mucosal melanomas of the head and neck occur less frequently than their cutaneous counterparts. Among those, oral mucosal melanoma is extremely infrequent with an incidence of 0.5% of oral neoplasms. Less than 2% of all melanomas lack pigmentation, in the oral mucosa, however, up to 75% of cases are amelanotic melanomas. Th ese are extremely rare variants and the most frequent sites in the oral cavity are the hard palate and the gingiva. Lesions that are suspected to be melanomas should be assessed both histologically and by immunohistochemistry, which are helpful in the diagnosis of amelanotic melanoma. Th ey have a poorer prognosis than the pigmented melanomas because of the delay in diagnosis and in the initiation of treatment. Th is presentation is a rare case report of oral mucosal amelanotic melanoma.

Amelanotic corneally displaced malignant conjunctival melanoma: a case report evaluated with impression cytology / Melanoma amelanótico conjuntival maligno deslocado sobre a córnea com citologia de impressão: relato de caso

Here we describe the case of a 65-year-old Caucasian female who presented with an amelanotic malignant conjunctival melanoma and highlight the clinical and pathological features of this rare entity that displayed exclusive corneal invasive growth without evidence of conjunctival tumors other than primary acquired melanosis. Impression cytology aided in the initial diagnosis. The patient underwent surgical treatment. Histopathology and immunohistochemistry revealed an invasive amelanotic melanoma limited to the cornea and exhibiting S-100, Melan A, and HMB-45 positivity. The absence of pigmentation delayed early clinical detection and treatment. Awareness of this nonpigmented melanoma is important for early recognition and appropriate management.

Os autores descrevem o caso de uma mulher branca de 65 anos que apresentava um melanoma amelanótico maligno conjuntival e destacam as características clínicas e patológicas desta entidade rara com crescimento invasivo exclusivo na córnea sem evidência de tumores na conjuntiva além de melanose adquirida primária sem pigmento. A citologia de impressão auxiliou no diagnóstico inicial. A paciente foi submetida a tratamento cirúrgico. A histopatologia e a imuno-histoquímica revelaram um melanoma amelanótico invasivo limitado sobre a córnea exibindo positividade para proteína S-100, Melan A e HMB-45. A ausência de pigmentação retardou sua identificação clínica e seu tratamento precoce. O conhecimento deste melanoma não pigmentado é importante para o reconhecimento precoce e a conduta apropriada.

Amelanotic metastatic cutaneous melanoma / Melanoma metastatico amelanotico cutaneo

Dermatoscopy of melanocytic lesions has guided the decision of when or not to biopsy a lesion. The use of this tool has increased clinical examination's sensitivity and specificity in 89% and 96% respectively. However, dermatoscopic evaluation of amelanotic or hypomelanotic melanomas, as well as metastases, can be difficult. There is still no standardization for the analysis of these pathologies, which relies mostly on their vascular pattern. We describe the dermatoscopy of acral metastatic amelanotic melanoma.

A dermatoscopia das lesões melanocíticas tem auxiliado na decisão de biopsiar ou não uma lesão. A utilização desta ferramenta aumentou a sensibilidade e a especificidade do diagnóstico para 89% e 96%, respectivamente. No entanto, a avaliação dermatoscópica de melanomas amelanóticos ou hipomelanóticos, bem como a de metástases cutâneas, pode ser difícil. Ainda falta uma padronização para a análise destas patologias, que se baseia, majoritariamente, no seu padrão vascular. Descreve-se a dermatoscopia de melanoma metastático amelanótico acral.

Melanoma anal amelanótico: reporte de caso / Anorectal amelanotic melanoma: a case report

Se presenta el caso de un paciente de 60 años de edad que presenta dolor y sensación de cuerpo extraño enla región anal, asociado a deposiciones con restos de sangre. Al tacto rectal se palpó una lesión indurada enla cara anterior del conducto anal. En la colonoscopía se evidenció una lesión proliferante elevada, pigmentada“negruzca”, de aproximadamente 2 cm de diámetro, compatible con neoplasia maligna de canal anal. Se procedió a una biopsia e inmunohistoquímica, que dio como resultado el S-100 positivo y HMB-45 negativo.Una tomografía helicoidal multicorte toraco-abdomino-pélvico descartó tumoraciones y adenomegalias metastásicas. El paciente fue sometido a una resección local parcial transanal de la tumoración pigmentada.El resultado histopatológico posquirúrgico confirmó el diagnóstico de melanoma maligno anal amelanótico(MMAA); el S-100 fue positivo; el Melan-A, positivo débil, y el KI-67, positivo. El paciente presentó una evolución favorable y fue dado de alta a los tres días de la cirugía.

We present the case of a 60 year old patient suffering pain and the sensation of a foreign body in the analregion associated with traces of blood in stools. Digital rectal exam (DRE) revealed a hardened lesion locatedon the wall of the anal canal. Colonoscopy revealed a raised proliferating lesion with a blackish color which was about 2 inches in diameter. This was compatible with an anal canal malignancy. We proceeded to a biopsy and immunohistochemistry study which tested positive for S-100 and negative for HMB-45. A multislicehelical chest, abdominal and pelvic CAT scan ruled out metastatic tumors and lymphadenopathy. The patient underwent local transanal excision of the partially pigmented tumor. Post- surgical histopathological results confi rmed the diagnosis of malignant anal amelanotic melanoma positive for S-100. The sample tested weakly positive for Melan-A and positive for KI-67. The favorable outcome of the procedure led to the patient’sdischarge 3 days after surgery.

Transient increased exudation after photodynamic therapy of intraocular tumors

To report transient increased exudation after photodynamic therapy [PDT] of three different intraocular tumors [retinal hemangioblastoma, retinal astrocytoma, amelanotic choroidal melanoma]. PDT with verteporfin [6 mg/m[2] body surface area] was delivered at a dose of 50 J/cm[2] and intensity of 600 mW/cm[2] over 83 s. All patients experienced decreased vision within a few days following PDT. Optical coherence tomography showed development of subfoveal fluid in all cases and noncystoid intraretinal edema in the eye with juxtapapillary retinal hemangioblastoma. There was complete absorption of retinal/subretinal fluid with improvement of visual acuity to 20/20 in all cases between 3 weeks to 4 months after PDT