Clinicopathological, dermoscopic features and circumstances of diagnosis of amelanotic or hypomelanotic melanoma: A prospective multicentric study in the French private medical sector.

BACKGROUND: Amelanotic or hypomelanotic melanomas (AHM) are difficult to diagnose, and are often diagnosed late, with a high Breslow index and a poor prognosis. PATIENTS AND METHODS: A total of 226 volunteer dermatologists consulting in private practice in France completed an online form for each new histologically proven case of melanoma diagnosed at their clinic in 2020. This anonymised survey collected data on the clinical, dermoscopic, and histological features of melanoma, as well as the circumstances of diagnosis and initial management. A group of 145 AHM was single out and compared to the 1503 pigmented melanomas (PM) from the same cohort. RESULTS: 1503 pigmented melanomas (PM) and 145 AHM (8.8% of these melanomas) were identified and included. In the AHM group, the mean age at diagnosis was 65 ±â€¯16 years, with no significant difference from the PM control group. AHM were not predominantly on the face and neck area, and there were no differences based on gender. Warning signs (local progression and bleeding) were significantly more frequent in the AHM group than in the PM group. AHM were more frequently ulcerated and nodular, with a higher median Breslow thickness than in the PM group (1.56 vs. 0.5 mm), and mitoses were more frequent. Dermoscopy was widely used and proved useful for distinguishing benign lesions, and for highlighting the vascular polymorphous pattern of malignant lesions. Patients noticed the suspicious lesion themselves in most cases of AHM (73.2%), as opposed to their general practitioner (17.2%) or entourage (9.5%). A total body skin examination enabled detection of 19.3% of AHM and 21.3% of PM where the patient consulted for another lesion, or for an unrelated reason. CONCLUSION: AHM are difficult to diagnose for the clinician because of the paucity or absence of pigmentary criteria. Knowledge of dermoscopic vascular patterns is critical and could help reduce the median Breslow index of AHM at the time of detection. Self-examination of the skin should be encouraged, and simple algorithms for earlier detection of skin cancers should be promoted among health professionals and the general population.

The combination of dermoscopy and reflectance confocal microscopy increases the diagnostic confidence of amelanotic/hypomelanotic lentigo maligna.

The dermoscopic diagnosis of amelanotic/hypomelanotic lentigo maligna/lentigo maligna melanoma (AHLM/LMM) may be very difficult in its early stages because of lack of pigment. Reflectance confocal microscopy (RCM) is an imaging technique that is especially helpful for the diagnosis of lentigo maligna. To determine the diagnostic performances of dermoscopy and RCM in the diagnosis of AHLM/LMMs we evaluated dermoscopic and RCM images of consecutive cases of histopathologically confirmed AHLM/LMMs, amelanotic/hypomelanotic basal cell carcinoma and squamous cell carcinoma (AHBCCs/AHSCCs), amelanotic/hypomelanotic benign lesions (AHBLs), and actinic keratoses (AKs) from five participating centers. Sensitivity, specificity, accuracy, predictive values, and level of diagnosis confidence were calculated for both diagnostic procedures. Both dermoscopy and RCM showed diagnostic performance >97% in the diagnosis of AHLM/LMMs versus AHBCC/AHSCCs and their combination slightly improved diagnostic performance, with accuracy increasing from 98.0% to 99.1%. Similarly, RCM in combination with dermoscopy showed a tiny increase in the diagnostic performance in the diagnosis of AHLM/LMMs versus AHBLs (accuracy increased from 87.2% to 88.8%) and versus AKs (accuracy increased from 91.4% to 93.4%). Although the increase in diagnostic performance due to RCM was modest, the combination of dermoscopy and RCM greatly increased the level of confidence; high confidence in the diagnosis of AHLM/LMMs versus AHBLs increased from 36.2% with dermoscopy alone to 76.6% with dermoscopy plus RMC. Based on our results, dermoscopy and RCM should be complementary to improve not only diagnostic accuracy but also the level of diagnostic certainty in the diagnosis of AHLM/LMMs.

Primary amelanotic melanoma of anorectum - a rare case report with diagnostic challenge.

Anorectal melanoma is an exceptionally rare and aggressive form of cancer. One per cent of anorectal malignant tumours are anorectal malignant melanomas, which are exceedingly uncommon. We report a case of a 47-year-old woman who experienced painless rectal bleeding. On examination, an irregular lump was seen in the posterior rectal wall, measuring 4 × 3.7 cm. Biopsies were obtained under endoscopic guidance for histomorphology and immunohistochemistry. The biopsy examination showed nests of tumour mass in the lamina and muscularis mucosae. The tumour mass was composed of round to oval cells having enlarged nuclei, conspicuous nucleoli, and a scant amount of cytoplasm. No melanin pigmentation was noted in the tumour cells. HMB-45, S-100, and vimentin were all detected by immunohistochemistry. A definitive diagnosis of amelanotic malignant melanoma was rendered. The patient underwent abdominoperineal resection with a hysterectomy and bilateral salpingo-oophorectomy. Anorectal melanoma presents with bleeding per rectum and is often misdiagnosed as internal haemorrhoids or adenocarcinoma clinically. Amelanotic melanoma, which lacks melanin pigment, is difficult to diagnose. Patients who appear with rectal bleeding should have a malignant melanoma evaluation as a possible differential diagnosis, and suitable diagnostic procedures, such as a colonoscopy and a biopsy with immunohistochemistry, should be carried out to arrive at a conclusive diagnosis.

Comparative expression of cyclooxygenase 2 and Ki67 in amelanotic and conventional oral melanomas

BACKGROUND: Oral melanomas have some histopathological resemblance with its cutaneous counterpart; howev-er, an aggressive behavior is more common in tumors that occur in the oral cavity. Several markers have been suggested as indicative of tumoral progression and aggressiveness, such as cyclooxygenase 2 (COX-2) and Ki67. MATERIAL AND METHODS: In this study, we have compared the expression of COX-2 and Ki67 in a series of amelanotic (n = 7) and melanotic oral melanomas (n = 22). The cases were selected from 4 pathology laboratories and sub-mitted to the immunohistochemical (IHC) reactions. We analyzed the IHC staining based on a qualitative - using visual scores; and a computer-assisted method (quantitative) using scanned slides and software for digital analysis. RESULTS: COX-2 was expressed in all oral melanomas; however, its intensity was significantly higher in the amelanotic ones (P < 0.001). Similarly, a high Ki67-positivity index was observed in the amelanotic than melanotic ones (P < 0.001). CONCLUSIONS: Based on these results, we suggest that amelanotic oral melanomas have marked pro-inflammatory and high-proliferative phenotype, justifying their more aggressive behavior compared with the melanotic ones

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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.

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.

Un melanoma amelanótico con metástasis a la glándula tiroides. Descripción clinico-patológica de un caso / Amelanotic anorectal melanoma metastatic to the thyroid gland. A case report

A pesar de su rico aporte vascular, las metástasis en la glándula tiroides son eventos raros. Los carcinomas renales, colorectales, de pulmón y mama son las fuentes más frecuentes de metástasis. Presentamos el caso de una mujer de 75 años de edad, con el antecedente de un melanoma anorrectal amelanótico avanzado, operado un año antes, que se presentó con un crecimiento nodular rápido de la glándula tiroides, por lo que fue sometida a una tiroidectomía parcial. Histopatológicamente, el lóbulo tiroideo mostró una infiltración difusa por melanoma amelánico. Aunque se han publicado algunos casos de metástasis de melanoma en la glándula tiroides, la mayoría de ellos son de origen cutáneo por lo que, a nuestro entender, nosotros presentamos el primer caso de un melanoma anorrectal con metástasis a la glándula tiroide (AU)

Despite its rich vascular supply, metastases to the thyroid gland are rare. Renal, colorectal, lung and breast carcinomas are the most frequent sources of metastases. We report the case of a 75-year-old woman who presented with a rapid nodular enlargement of the thyroid gland, for which she underwent a partial thyroidectomy. She had a history of advanced amelanotic anorectal melanoma surgically treated one year previously. Histopathologically, the thyroid lobe showed diffuse infiltration by an amelanotic melanoma. Although a few cases of metastases of melanoma to the thyroid gland have been reported, the majority are derived from a cutaneous primary; to the best of our knowledge, this is the first reported case of an anorectal melanoma with metastasis to the thyroid gland (AU)

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.

Dermoscopic clues in the diagnosis of amelanotic and hypomelanotic malignant melanoma / Pistas dermatoscópicas no diagnóstico de melanoma maligno amelanótico e hipomelanótico

The clinical identification of amelanotic malignant melanoma (AMM) and hypomelanotic malignant melanoma (HMM) becomes difficult due to the lack of pigmentation and to the diverse clinical presentations. Dermoscopy is very useful in these cases, increasing the level of suspicion of malignancy. We report 4 cases of amelanotic malignant melanoma and hypomelanotic malignant melanoma with characteristic dermoscopic findings. Dermoscopy under polarized light demonstrates vascular polymorphism, globules and milky-red areas, in addition to chrysalis and multiple blue-gray dots.

A identificação clínica de melanoma maligno amelanótico e hipomelanótico torna-se difícil devido à falta de pigmentação e às diversas apresentações desse tipo de tumor. A dermatoscopia é muito útil nestes casos, aumentando o grau de suspeição de malignidade. Relatamos 4 casos de melanoma maligno amelanótico e melanoma maligno hipomelanótico com achados dermatoscópicos característicos. A dermatoscopia com luz polarizada demonstra polimorfismo vascular, glóbulos e áreas vermelholeitosas, assim como crisálides e múltiplos pontos azul-acinzentados.

Suboclusión intestinal secundario a melanoma amelánico metastásico / Intestinal subocclusion following metastatic melanoma: case report

El Melanoma Amelánico (MA) es una de las variantes clínicas de Melanoma Melánico (MM), encontrándose aproximadamente en el 2% de los casos de (MM). El melanoma es el tumor con mayor predilección por metastizar en el intestino delgado. El diagnóstico de estas lesiones se hace con la ayuda del examen histopatológico y marcadores de inmunohistoquímica. El pronóstico de (MA) no muestra variación en relación con el (MM) pigmentado y continua dependiendo de la edad del paciente, sexo, localización y espesor de la lesión. Se debe tener en cuenta que el (MA) a menudo tiene un nivel de invasión Clark IV o V en el momento del diagnóstico debido a que sus características clínicas retardan la sospecha diagnóstica. La cirugía se considera útil en pacientes con metástasis de melanoma en el tracto gastrointestinal, ya que, a pesar de una media de superviviencia de 6-12 meses, que proporciona buen alivio con baja morbilidad y mortalidad. Se presenta un caso de un hombre de 56 años de edad que a los 53 años se le resecó nevus en región costal izquierda sin estudio de anatomía patológica, reingresando a dicha edad por cuadro de suboclusión intestinal por melanoma amelánico secundario a lesión primaria cutánea. Se realizó resección radical intestinal cutánea y dacarbacina 5 ciclos de 5 días. Después de unos cuantas semanas, demostró múltiples nódulos dispersos en ambos pulmones y una RM cerebral mostró múltiples nódulos delimitados en ambos hemisferios cerebrales. Su condición clínica comenzó a deteriorarse rápidamente con evidencia de enfermedad metastásica generalizada. El paciente murió 5 meses después de iniciado el diagnóstico.

The Amelanic Melanoma (AM) is one of the clinical variants of the Melanic Melanoma (MM), corresponding to the 2% of the cases of MM. The malanoma is the tumor with major predilection for metastases in the small intestine. The diagnosis of these injuries can be made with the help of the histopathology examination and immunohistochemical markers. The prognosis of the AM does not show change as regards the pigmentate MM and continue depending in the age of the patient, sex, location and thickness of the injury. You must know that the MA often has a level of invacion Clark IV or V at the moment of the diagnostic because his clinical characteristics slow down the diagnostic suspicion. The surgery is useful in patients with gastrointestinal tract metastasis of melanoma, due to provides good mitigation with low morbidity and mortality in the 6-12 months of survival. We present a case of a 56 -year-old man who at the age of 53 was resected a nevus in the left costal region without study of pathological anatomy, re-entering at the above mentioned age for a subocclusion intestinal syndrome for amelanic melanoma secondary to primary cutaneous injury. Radical intestinal resection and cutaneous resection was made and 5 cycles of dacarbacine for 5 days. After few weeks, it demonstrated multiple nodules dispersed in both lungs and a cerebral RM showed multiple nodules delimited in both cerebral hemispheres. His clinical condition began to deteriorate rapidly with evidence of widespread metastatic illness. The patient died 5 months after initiated the diagnosis.

A cystic amelanotic melanoma metastasis to the brain: case report / Metástasis cerebral de un melanoma amelanótico quístico

As far as we know, cyst formation in intracranial melanoma is rare, and only 15 cases of intracranial a melanotic melanoma have been reported until now. A yellowish mass was observed in the frontal lobe. The content of the cyst consisted of old hematoma, xantho chromic fluid and necrotic tissue, was evacuated and the cyst wall was totally resected. No abnormal pigmentation was noted in the cyst wall and surrounding brain tissue. The imaging features of metastatic melanomas are distinctive due to the presence of melanin and the propensity for hemorrhage. Both hemorrhage and melanin can produce T1-weighted hyper intensity andT2-weighted signal intensity loss

Que sepamos, la formación quística de un melanoma intracraneal es rara y sólo se han descrito 15 casos de melanoma intracraneal amilanocítico. Se observó una masa amarillenta en el lóbulo frontal. El contenido del quiste consistía en un hematoma antiguo, con líquido xantocrómico tejido necrótico que se evacuó, con resección total de la pared del quiste. No se encontró ninguna pigmentación anormal en la pared ni en el tejido cerebral adyacente. Las imágenes de los melanomas metastásicos son muy peculiares, debido a la presencia de melanina y a la propensión a la hemorragia. Ambos, hemorragia y melanina pueden producir hiper señal enT1 e hiposeñal en T2

Melanoma maligno amelanótico de la mucosa nasal / Amelanotic malignant melanoma of nasal cavity

El melanoma maligno de origen mucoso del tractosinonasal es un tumor infrecuente. De las localizacionesmucosas ORL la cavidad nasal es la mas común. Noobstante la inespecificidad de los síntomas y la inaccesibilidadde la fosa nasal para el autoexamen retrasan eldiagnóstico. El tratamiento de elección es la asociaciónde cirugía y radioterapia. El pronóstico es malo debido ala alta incidencia de recidiva local y de metástasis tardías.Presentamos el caso clínico de un paciente varónde 60 años, su manejo clínico y terapéutico

Primary mucosal malignant melanoma of the nasal cavityis an unusual tumour. Interestingly, the nasal cavityrepresents the most common site of mucosal melanomain Otolaryngology. However, the symptoms are non-specificand the relative inaccessibility of the nasal cavity to selfexamination,often delays diagnosis. Surgery, accompaniedby radiation, is the election treatment. Theprognosis is poor because a high rate of local recurrenceand late metastasis. We present the case of a male patient60 years old, describing the diagnostic and therapeuticsmethods that we´re carry on

Melanoma amelanótico / Amelanotic melanoma

El melanoma amelanótico (MA) representa entre el 1,8 y el 8,1 de los melanomas, debido a la falta de pigmento suelen producirse errores diagnósticos que demoran el tratamiento y reducen la sobrevida de estos pacientes. Reportamos 2 casos de esta patología poco frecuente. El primer caso en un varón 51 años, sano con antecedente de un nevo congénito en dorso que había sangrado. Al examen presentaba una lesión tumoral rosada oscura. El caso 2 se presentó en una mujer de 19 años, sana que consultó por una placa en pierna color rosada, asintomática (AU)