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 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 melanomas are often diagnosed at an advanced stage.

In this case report, a 62-year-old woman was diagnosed with lymph node metastasis from melanoma in the groin. Initially the primary tumour was unknown. The entire skin was examined without any suspicious moles. A PET-CT scan showed an area on the left heel with increased activity. The element surprisingly showed an amelanotic melanoma. Amelanotic melanomas have a significantly worse prognosis compared to pigmented melanomas, presumably because they are detected later and may be very difficult to detect clinically. This case shows the importance of paying attention to unpigmented elements when searching for a primary tumour.

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.

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.

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.

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.

A red scaly patch diagnosed as hypomelanotic melanoma.

Early detection of melanoma is important and the diagnosis of amelanotic/hypomelanotic melanoma (AHM) is challenging. Nevertheless, dermatoscopy has been shown to improve diagnostic accuracy for non-pigmented skin lesions as well as pigmented lesions, and several algorithms for cutaneous neoplasms evaluation are available. We present a hypomelanotic melanoma detected on an asymptomatic patient at routine skin examination utilising a dermatoscopic decision algorithm. General practitioners, also known as primary care practitioners, are likely to be the first practitioners to encounter a skin cancer on a patient with further necessary actions.

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.

Dermoscopic features of nevoid melanoma: a retrospective study.

BACKGROUND: Nevoid melanoma (NeM) is a rare variant of melanoma resembling melanocytic nevus. The aim of the study was to systematically review the dermoscopic features of NeM. METHODS: A hospital-based retrospective study was conducted. Dermoscopic features of NeMs diagnosed through excisional biopsy between January 2015 1, and March 1, 2021, were compared to superficial spreading melanomas (SSMs) matched by Breslow's thickness. Then, a literature search was performed. Electronic searches on PubMed database via Medline were conducted to retrieve any manuscript reporting detailed dermoscopic features of histopathologically confirmed NeM. RESULTS: A total of 60 malignant melanomas (MM) comprising 20 NeM and 40 SSM were collected. Twelve out of 20 (60%) NeM showed a nevus-like appearance, including reticular and globular patterns, and in 35% of these cases it was detected because of dermoscopic changes. Then, a total of seven original manuscripts were retrieved from the literature review, comprising 56 cases overall. NeM showed nevus-like pattern in 53% of the cases, multicomponent pattern in 21% and amelanotic in 9%. Enlargement, irregularly distributed dots/globules, irregular pigmentation, and atypical vascular pattern were found in NeM with nevus-like appearance. NeM with multicomponent pattern were characterized by irregular pigmentation, blue-white veil, irregular dots and atypical vascular pattern. Amelanotic NeM is rare and show atypical vascular pattern and milia-like cysts. CONCLUSIONS: Dermoscopy of NeM is challenging as it frequently shows a nevus-like pattern, but clues and detection of dermoscopic changes may help to identify it.

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.