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.

Primary anorectal amelanotic melanoma with liver, lungs and lymph nodal metastases.

Anorectal melanoma (ARM) is an exceedingly rare and very aggressive malignancy. It originates from the melanocytic cells in the anorectal mucosa, which produces melanin. Other mucosal melanomas commonly found in the mucosa of the oral cavity, vulvovaginal, pharynx and urinary tract. Patients usually present with bleeding per rectum, perianal pain and difficulty in defaecation. Distinction of primary anorectal melanoma from other tumours of this region is difficult because of the lack of common imaging features. MRI is the modality of choice for its better tissue characterisation and resolution. There is no standard treatment protocol available mainly due to scarcity of data. Surgery is the mainstay therapy. Herein we present a case of a male patient in his 30s who presented with rectal bleeding and perianal pain. Haematological analysis revealed normocytic normochromic anaemia. MRI detected a mass lesion in the anorectal region. Contrast enhanced CT revealed multiple metastases in the liver, lungs, periportal, mesorectal and inguinal lymph nodes. The diagnosis of the ulcerated anorectal melanoma was established on histopathological examination. The patient underwent abdominoperineal resection (APR) followed by chemotherapy. Afterward the patient presented to the emergency room with respiratory distress for which he was on ventilator support. Sadly, the patient died after four days.

Amelanotic melanoma in a patient with trisomy 21: clinical and dermoscopic presentation.

Amelanotic melanoma is an uncommon form of melanoma; accounting for 2%-8% of all melanoma cases. In the human population, the incidence of melanoma in patients with trisomy 21 is relatively unknown. It is theorised that having an extra copy of chromosome 21 is protective against melanoma development as people with trisomy 21 also carry an extra copy of the genes on that chromosome including any that protect against cancer. A literature review revealed four other reported cases of cutaneous melanoma in persons with trisomy 21. To the authors' knowledge, this is the first case of amelanotic melanoma presenting in a patient with trisomy 21 and the fifth case of melanoma overall reported in a patient with trisomy 21.This case highlights the need for specialist referral of all new skin lesions where the diagnosis is unclear.

Neurosarcomatous amelanotic transformation of malignant melanoma presenting as malignant periopheral nerve sheath tumor: Rare case report.

RATIONALE: Malignant melanoma (MM) is notorious for its remarkable morphological variation and aberrant histopathological patterns. In addition, Malignant Periopheral Nerve Sheath Tumor (MPNST) is an uncommon but aggressive soft tissue sarcoma. Because of the common embryological origin of melanocytes and Schwann cells in the neural crest, discriminating between a particular type of MM and MPNST can be difficult, particularly when they are amelanotic. Our goal is to increase awareness among clinicians of the rare variations of MM and the importance of medical history in improving the accuracy of the final clinical diagnosis. PATIENT CONCERNS: A 68-year-old man was admitted to the hospital due to pain in his right ankle, which had persisted for 8 months, along with swelling for 4 months. Medical history revealed delayed healing of right plantar for 5 years after a traumatic injury. DIAGNOSES: The ankle mass was initially diagnosed as MPNST through biopsy. After reviewing the patient's medical history and receiving the final pathological report following amputation, we have revised the diagnosis to metastatic amelanotic desmoplastic melanoma in the ankle part and lentigo maligna melanoma in the plantar part. This is due to both lesions displaying positive markers or mutated genes in immunohistology and Gene Mutation Detection, indicating homology between the 2 tumors. INTERVENTIONS: Due to the malignant characteristics of the tumor and the patient's wishes, amputation of the right lower leg was carried out. OUTCOMES: Subsequently, the patient was treated with interferon-γ and immunosuppressant PD-1 inhibitor, and survived for 1 year after amputation. LESSONS: Clinical data, immunohistochemisty biomarkers and genes detection results can serve as valuable evidence for pathologists and clinicians in identifying the disease process. Collaborative efforts between clinicians and scientists are crucial in order to identify specific markers that can effectively differentiate between the 2 tumors, thereby enhancing the conclusiveness of the diagnosis.

Primary vulvar melanoma in an adolescent patient.

Herein we describe the case of a Black adolescent who was found to have widely metastatic melanoma originating from a primary vulvar lesion. The lesion presented as a pink, vegetative nodule of the clitoral hood which grew in size over several years and was confirmed to be melanoma on shave biopsy. This patient's amelanotic presentation in conjunction with the rare incidence of vulvar melanoma contributed to the delay in diagnosis. This case exemplifies the challenge of early recognition of potentially malignant vulvar lesions for primary care providers in adolescents.

Amelanotic subungual melanoma and chilblains.

A female patient in her 50s presented with blue discolouration of several toes and with single nail dystrophy affecting the little toenail. The nail changes were considered to be secondary to poor circulation and chilblains, which led to delay in the diagnosis of amelanotic subungual melanoma.

Multifocal primary amelanotic meningeal melanomas mimicking lymphoma: a case report and literature review.

Primary meningeal melanoma is a rare type of melanocytic cancer originating from the melanocytes of the leptomeninges. It commonly presents as a solitary mass, and multifocal amelanotic lesions were scarcely reported. Diagnosis of multifocal melanoma is particularly challenging, clinically and diagnostically, especially in the absence of cutaneous nevi and melanin pigment. Surgical biopsy result is the gold standard. In this case study, we present an uncommon case of multifocal primary amelanotic meningeal melanomas mimicking lymphomas in the skull base and near the Sylvian fissure, which serves to provide reference value to the clinical diagnosis. Physicians should be aware of the existence of this special type in the clinical work.

Characterizing melanoma in the setting of oculocutaneous albinism: an analysis of the literature.

Although it is established that individuals with albinism have increased risks for nonmelanoma skin cancers, melanomas occurring in the setting of albinism are rare. PubMed and Google Scholar were searched for individual case reports describing melanoma in individuals with oculocutaneous albinism (OCA). All published cases characterizing individuals with albinism and melanoma in the medical literature were gathered to evaluate any epidemiologic or histologic differences from melanomas arising in the general population. Frequencies of melanoma characteristics between the OCA literature cohort and general population were compared using Clopper-Pearson confidence intervals. From 1952 to 2018, at least 64 cases of melanoma in 56 individuals with albinism were reported in the global medical literature. The median age of diagnosis for melanoma in individuals with albinism was 41 years, and the median Breslow depth at diagnosis was 2.0 mm. The subtypes of melanoma were nodular in 33% and superficial spreading in 46% of these cases, respectively. Amelanotic melanomas comprised 65% of the cases in our OCA cohort; however, histologic subtypes were only available for fourteen of the amelanotic cases. Finally, 17% of melanomas in patients with albinism arose from preexisting lesions. Despite their rarity, melanomas arising in oculocutaneous albinism have distinct characteristics from melanomas arising in the general population. Clinicians should consider a differential diagnosis of melanoma for any potential skin malignancies in individuals with albinism.

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.

Anorectal malignant amelanotic melanoma: Report of a rare aggressive primary tumor.

Malignant melanoma of the anorectal region is a very rare aggressive malignant neoplasm and it constitutes 1% of all malignant lesions of this area. About 70% of these lesions are pigmented, whereas 30% are amelanotic. Demonstration of immune markers of melanoma by immunohistochemistry (IHC) is required for confirming the diagnosis of amelanotic malignant melanoma. Here, we report a case of anorectal malignant amelanotic melanoma in a 65-year-old male with no medical comorbidities, who presented with chief complaints of bleeding per rectum associated with prolapsing mass per rectum of 7 months duration. On external examination and proctoscopy, three prolapsed pedunculated fungating masses were seen externally protruding out of the rectum approximately 4 cm from the anal verge. Contrast-enhanced computed tomography of the whole abdomen and pelvis was suggestive of moderately enhancing lobulated anorectal mass with large polypoidal intraluminal component arising from anorectal walls and extension into mid-lower rectum with liver and locoregional lymph nodes metastasis. The patient was taken up for palliative local excision. Per-operatively, three large irregular highly vascular pedunculated rectal growth was seen. The growth was excised and sent for histopathological examination. Microscopic examination of mass show spindle-to-ovoid tumor cells with hyperchromatic central to eccentric nuclei arranged in intersecting fascicles with a focal alveolar pattern. The large number of atypical mitotic figures (40-50/10 High Power Field (HPF)) was seen along with areas of necrosis and the presence of few bizarre binucleated and multinucleated giant cells. A differential diagnosis of malignant amelanotic melanoma was given along with undifferentiated carcinoma, gastrointestinal stromal tumor , and Non-Hodgkin's lymphoma. On IHC, the tumor cells were reactive for HMB45, S-100, and SOX-10. Thus a diagnosis of malignant amelanotic melanoma was confirmed. The patient had symptomatic improvement.

Amelanotic melanoma of the palate: report of a case.

Primary amelanotic melanoma is an infrequent occurrence in the oral cavity. Owing to the high rate of local invasion and distant metastasis, oral amelanotic melanoma (OAM) carries a very poor prognosis. The absence of pathognomonic clinical and routine histological features in OAM is the reason for diagnosticdelay, which further worsens the prognosis. This case report discusses the masquerading nature of OAM that was clinically and histologically mimicking several malignant neoplasms. This case also demonstrates the poor prognosis of OAM. The objective of presenting this case is that the diagnostic delay of OAM can be avoided through enhanced clinical awareness and subsequent appropriate immunohistochemical investigations, in addition to the routine H&E-stained histopathological evaluation.

[Plantar melanoma: A wolf in sheep's clothing]. / Das plantare amelanotische Melanom: Ein Wolf im Schafspelz.

BACKGROUND AND FINDINGS: Amelanotic melanoma (AM) is a subtype of melanoma characterized by a diminished or lacking melanin synthesis. AM, especially ulcerated variants of the plantar region (AMP), are often clinically misdiagnosed, leading to a delay in treatment initiation. THERAPY AND FURTHER DEVELOPMENT: We present a case series of 4 AMP and give a detailed overview about clinical features and the subsequent medical history of this severe disease. CONCLUSIONS: AMP shows a variety of clinical presentations and particularly elderly patients with many accompanying medical conditions are in danger of incorrect clinical diagnoses. Therefore, we recommend to biopsy any amelanotic plantar ulcer or tumor that does not respond to treatment within 6 weeks to rule out AM.

Conjunctival amelanotic melanoma presenting as a multifocal pink lesion.

Conjunctival amelanotic malignant melanoma is a rare form of melanoma, which lacks visible pigment and is commonly located underneath the eyelids in the bulbar conjunctiva. In this report, we described a case of a Caucasian women in her 70s who presented with unilateral irritation and tenderness following cataract surgery. On eversion of the eyelid, two elevated pink lesions were noted. Tumour - Node - Metastasis staging with the American Joint Committee on Cancer staging system eighth edition was T3C and required multiple excisions and reconstruction procedures. This case exemplified the diagnostic pitfall of conjunctival amelanotic malignant melanoma, which is a potentially life-threatening disease and the importance of histopathology in the diagnostic process.

Fine-needle aspiration cytological findings in three cases of metastatic amelanotic melanoma to the parotid gland with divergent differentiation.

This report presents the clinical and pathologic findings of three cases of metastatic amelanotic melanoma to the parotid gland. Two of the patients had a primary cutaneous tumor. Fine-needle aspiration of the parotid showed clusters of epithelioid cells and/or spindle-shaped cells with vesicular nuclei, macronucleoli, and abundant eosinophilic cytoplasm. In addition, one had striking balloon-cell features. In the immunohistochemical study, the tumors expressed S-100, HMB-45 antigen, Melan-A, and SOX10, and focally smooth-muscle actin, cytokeratin, CD56, p63, and synaptophysin. The diagnosis was challenging because the tumors were clinically thought to be primary parotid lesion and showed unusual immunohistochemical labeling for SMA, cytokeratins, p63, and neuroendocrine markers. Furthermore, the long clinical history in two of the cases made the diagnosis of a metastatic lesion less likely. Diagnostic errors can be reduced by integrating cytomorphologic, histologic, immunohistochemical, and clinical findings.

Amelanotic Malignant Melanoma with a BRAF V600E Mutation Mimicking Primary Lung Cancer.

Amelanotic melanoma is a rare type of melanoma that shows little or no melanin pigmentation. When tumor lesions are not detected in cutaneous sites, the presence of melanin is the hallmark sign of malignant melanoma. We herein report a case of amelanotic melanoma with a BRAF V600E mutation mimicking primary lung cancer that was finally diagnosed on an autopsy. The current case suggests important caveats for the differential diagnosis of patients with BRAF V600E mutation-positive poorly differentiated lung tumors. In terms of the pathological diagnosis, routine immunohistochemical staining may be useful, especially in patients with a poorly differentiated lung tumor without TTF-1 expression.