Primary Amelanotic Melanoma Research Articles

Primary amelanotic malignant melanoma masquerading as adenocarcinoma prostate – A pathological dilemma

ABSTRACT A rare disease at an aberrant location can mimic a usual presentation of another disease. We report a case of primary amelanotic malignant melanoma of the prostate with clinical and histological characteristics that closely mimic poorly differentiated adenocarcinoma prostate.

Primary Anorectal Amelanotic Melanoma: Case Report and Review of Literature

Primary amelanotic melanoma of rectum is a very rare tumor accounting for less than 2% of melanomas. It is a highly aggressive tumor that often tends to invade lymph nodes or metastasize in the early course of disease. The prognosis of this tumor is very bismal with five year survival of less than 20%. We report a case of primary amelanotic melanoma of anorectum in which preoperative biopsy was inconclusive, thus highlighting the role of immunohistochemical markers to reach to a correct diagnosis. This is the first case of amelanotic anorectal melanoma reported from Nepal.

Urethral Caruncle Masquerading a Primary Amelanotic Melanoma, the Risk of a Poor Prognosis due to Misdiagnosis

Objective: Primary malignant urethral melanoma is a rare condition, concerning less than 1% of melanomas and 4% of all urethral cancers. The early treatment of urethral melanoma is extremely important due to the tendency to early metastasis.
 Case report: 88-year-old Caucasian lady presented vaginal bleeding. At first Gynaecological examination an urethral caruncle with otherwise normal trans-vaginal ultrasound was diagnosed. The patient not reassured asked for a second consultation opting to remove the reddish fleshy polypoid lesion protruding from the urethra. Histology revealed a urethral amelanotic melanoma. The patient underwent an excission of the urethral lesion. Urologist, oncologist and gynaecologist at tumor board meeting, considering patient’s age and negative PET, decided for conservative management with close clinical and imaging follow-up.7 months after, vaginal bleeding recurred and a nodule on the anterior vaginal wall was detected and biopsied and resulted a pigmented melanoma. The patient underwent a wide margin excision. At 10 months follow-up there were no evidence of recurrence nor distant metastasis. She started a prophylactic immunotherapy with Nivolumab; at her third administration she presented only asthenia as side effect.
 Conclusion: It is importanto to keep in mind the urethral amelanotic melanoma to allow an early removal or biopsy, preventing diagnostic delay/misdiagnosis and aiding either in better patient management or outcome.

ATYPICAL MELANOMA MIMICKING A VASCULAR TUMOR : CLINICAL AND DERMOSCOPIC FINDINGS

Introduction: Completely amelanotic melanomas are rare and therefore often misdiagnosed. Analysis of dermoscopic features of the vascular pattern appears to be a reliable method to suggest these particular diagnosis. Case Presentation: we report a case of an atypical primary cutaneous melanoma of plantar localization which clinically mimicked an angiomatous tumor. Clinical examination showed an angiomatous lesion of 10 cm long axis, located on the lateral part of the left sole. The two adjacent nodules measured 3 cm each, one was angiomatous and the other erythematous. There were also multiple left inguinal adenopathies. Dermoscopic evaluation of the lesion revealed the lack of a pigmented network and a rich vascular bundle made of polymorphous linear vessels, dotted vessels, white lines and milky red areas. The patient underwent excision of an angiomatous nodule. The definitive diagnosis was provided by immunohistochemistry (tumor cells expressed S100 and Melan A). . Brain and thoracic-abdominal-pelvic CT scan showed bilateral nodular lung involvement and a segment VI liver lesion. We concluded to the diagnosis of a primary amelanotic metastatic melanoma stage 4. Clinical Discussion: The term amelanotic refers to tumors that have no pigmentation on visual and dermoscopic inspection. Amelanotic and hypomelanotic melanomas are rare. They could mimic many benign and malignant tumors. There are three forms of AM. The papulonodular form represents 58% and could be misdiagnosed as a vascular tumor, which was the case of our patient. The contribution of dermoscopy is valuable in the clinical orientation in case of amelanotic melanoma. There is a correlation between the stage of the melanoma and the vascular pattern(s) observed as well as their distribution. The prognosis of amelanotic melanoma is characterized with a lower survival rate and a high risk of recurrence. The treatment of amelanotic melanoma is similar to the pigmented counterpart. Conclusion: In order to avoid therapeutic delay, melanoma should be considered whenever there is a suspicious plantar lesion even in the absence of pigmentation. Dermoscopy is a non-invasive technique that could help in the diagnosis.

Rare and Aggressive Primary Amelanotic Melanoma in Anorectal Region: A Case Series

Anorectal amelanotic melanoma is a rare and aggressive disease with high morbidity and mortality. A conclusive diagnosis of anorectal amelanotic melanoma poses a challenge to pathologists and clinicians due to the protean nature of this entity, be it in its initial clinical assessment appearing as non pigmented polypoidal growths usually mistaken for haemorrhoids or anorectal polyps. Histomorphologically, these entities get categorised in bewildering array of diagnoses like spindle cell carcinoma, Gastrointestinal Stromal Tumour (GIST), High grade sarcomas and even lymphoma. Thus Immunohistochemistry (IHC) remains a vital tool for conclusive diagnosis. The purpose of the present case series is to discuss in detail about the three patients all aged above 55 years and clinically assessed with anorectal polypoidal growths. All three cases on histopathological evaluation were diagnosed as spindle cell neoplasm with no discernible melanin pigments. The IHC performed on all three cases turned positive for S-100 and Human Melanoma Black 45 (HMB 45). This case series highlights the challenging and bewildering nature of presentation of anorectal amelanotic melanomas, by virtue of its rarity and hence justifies the need for it to be considered as a possible differential diagnosis.

Primary amelanotic melanoma of the male urethra: A rare entity and diagnostic challenge.

Malignant melanoma (melanoma) is a tumor of melanocytes that usually presents as cutaneous lesions. While melanoma can infrequently appear as a primary tumor elsewhere in the body, it is extremely rare in the urethra and even rarer as amelanotic malignant melanoma. We report the case of a 66-year-old male who presented with painless gross hematuria and lower urinary tract obstructive symptoms in the recent 2 weeks prior to his visit to our clinic. History and physical examination, including external genital examination, abdominopelvic sonography, and urine culture, were not conclusive. Cystourethroscopy revealed a creamy pink fragile mass located in the anterior proximal urethra that extended to the mid portion. Pathological examination of this lesion confirmed the diagnosis of amelanotic malignant melanoma using immunohistochemistry. Radical cystourethrectomy with ileal conduit was subsequently conducted. Although this tumor is extremely rare, urologists and pathologists should consider malignant melanoma as a diagnosis in patients with urethral tumor because of the likelihood of early metastasis and, consequently, poor prognosis. Complete surgical removal of the tumor and use of effective therapies can improve outcomes in these patients.

Primary amelanotic melanoma of the cervix: A case report with review of literature

Primary malignant melanoma arising from the uterine cervix is extremely rare. It may be misdiagnosed, especially when amelanotic, in which case immunohistochemistry is useful in reaching the diagnosis. We present a case of 67-year-old postmenopausal patient presenting with bleeding per vaginum. Per speculum examination revealed an ulceroproliferative growth involving the cervix. Microscopic examination showed sheets of pleomorphic cells with prominent eosinophilic nucleoli and intranuclear inclusion. On histopathological examination, possibilities of poorly differentiated carcinoma and amelanotic melanoma were kept. On immunohistochemical analysis, tumor cells were strongly positive for HMB-45, S-100, and vimentin. Keeping in view the histopathological and immunohistochemical findings, diagnosis of amelanotic melanoma of cervix was given. Pertinent literature is also reviewed.

Giant Primary Amelanotic Scalp Melanoma: Report of a Rare Case and Review of the Literature

Giant Primary Amelanotic Scalp Melanoma: Report of a Rare Case and Review of the Literature

Urogenitalis lokalizációjú mucosamelanoma primer és áttétes esetei klinikánkon

Both primary and metastatic cases of mucosal melanoma in urogenital localization are rare tumors. Only 4-5% of all primary melanomas do not arise from the skin. Extracutaneous melanomas have a complex clinical presentation, but these aggressive tumors have a poor prognosis. In our department, we found 7 patients with malignant melanoma of the genitourinary tract in the past few years. The 7 cases were: primary amelanotic melanoma of the female urethra, a primary melanoma of the bladder, two primary melanomas of the penis, a metastatic melanoma of the urethra and another to the testis and a metastatic melanoma of the bladder with melanuria. We retrospectively analyzed the available data to describe the presentation, management, and clinical outcome of the patients. In the three inoperative cases, palliative, urologic surgical procedures and systemic antitumor therapy were performed. Two of the four primary urogenital tumors were localized to the penis. In one case, local recurrence developed after surgical treatment, but with a radical, repeated surgery, the patient has been asymptomatic for a year and a half. In the other, neglected case, the penis melanoma spread through the urethra and the inguinal lymph nodes two years after radical surgery and inguinal block dissection. In the female primary urethral melanoma case, the first histological study reported a primary mesenchymal tumor, and the recurrent tumor that occurred one and a half years later showed melanoma diagnosis. Radical surgery performed because of urethral involvement resulted in a 5-year asymptomatic state, followed by local recurrence and distant metastasis. In the fourth case of a primary bladder melanoma, the rapid progression of the disease and the BRAF positivity of the tumor suggested that not the firstly diagnosed bladder melanoma was the primary tumor. The occurrence of urinary tract melanoma is very rare and its discovery happens often in a disseminated state, so the expected prognosis of the cases is also poor. The most important factors for increasing therapeutic efficacy are early diagnosis and radical surgical intervention. Tumors appearing in different localizations require different urological surgical approaches. The literature recommendations for treatment are not uniform. Their prognosis is worse compared to the cutaneous melanoma, which may be due to clinical and pathological diagnostic difficulties. The latest targeted and immunotherapeutic agents can significantly improve the survival of metastatic patients. Orv Hetil. 2019; 160(10): 378-385.

Primary amelanotic malignant melanoma of the esophagus: a case report

BackgroundPrimary amelanotic malignant melanoma of esophagus, which is a subtype of primary malignant melanoma of the esophagus (PMME), is a very rare disease with a poor prognosis. We herein report a case of the amelanotic type of PMME.Case presentationAn 86-year-old woman was admitted to our hospital with symptoms of dysphagia. An endoscopic examination and constructed radiography revealed an elevated and semipedunculated lesion with an ulcer in the lower thoracic esophagus accompanied by another submucosal lesion of the esophagus. She was diagnosed with esophageal squamous cell carcinoma by a preoperative endoscopic biopsy. We performed thoracoscopy- and laparoscopy-assisted subtotal esophagectomy with lymphadenectomy. Based on the surgical specimens, although there were no melanocytes, we made a diagnosis of a malignant melanoma immunohistochemically; the tumor cells were positive for S-100 protein and HMB45 focally and partially for Melan-A.ConclusionWe experienced a case of primary amelanotic malignant melanoma, and the patient has remained disease-free for 1 year since the surgery. Since the diagnosis of amelanotic type of PMME is difficult, it should be made by the combination of a morphological examination, pathological examination, and immunohistochemistry.

Primary Amelanotic Anorectal Melanoma with Upper Gastrointestinal and Brain Metastases

The anorectum is a rare anatomic location for primary melanoma. In many cases the disease is undetected or is misdiagnosed as a benign polyp or hemorrhoids until it reaches an advanced state. The prognosis is poor, due to delayed diagnosis and early distant metastasis. Involvement of the upper gastrointestinal (GI) tract is very rare in anorectal melanoma and has been described in only a few case reports. An 83-year-old man presented with a 24-hour history of confusion, slurred speech and gait difficulty of abrupt onset. A computed tomography (CT) scan of the brain revealed three hemorrhagic lesions of 18mm, 14mm and 11mm in their greatest dimension in the cerebral hemispheres, specifically the left and the right frontal regions and the left temporal lobe, which were considered to be metastases. Subsequently, upper GI endoscopy revealed multiple small nodules involving the stomach and the duodenum. A non-pigmented anorectal mass 2cm in diameter was found on colonoscopy. Biopsy of the lesions in the stomach and duodenum revealed that they shared the same histopathological and immunohistochemical characteristics as the anorectal tumor. The tumor cells were diffusely positive for S-100 protein, HMB-45, Melan-A and MITF-1 antigens. Based on these findings, the diagnosis was made of primary anorectal melanoma with secondary metastases in the upper GI tract. Primary anorectal melanoma is a rare aggressive malignancy with a tendency to metastasize early, due to its abundant vascular system, although metastasis to the stomach and duodenum is rare. The diagnosis of melanoma is based on the histological features and immunohistochemical stains.

Vaginal primary amelanotic melanoma with survival beyond expectation: A rare case report

Vaginal malignancies are uncommon, constituting 1%–2% of all the female genital tract malignancies. Even rare are melanomas of the vagina with an annual incidence of 0.026/100,000 women worldwide, and amelanotic variant constitutes only 2% of all the vaginal melanomas. Here, we report a case of primary vaginal amelanotic melanoma in a 70-year-old woman, initially treated with wide local excision followed by adjuvant chemotherapy. After six and half years of follow-up, the patient developed a recurrence in the left inguinal nodal region with a suspicious pulmonary nodule and is now under treatment. Amelanotic melanoma has varied clinical presentation and microscopic appearance with the absence of characteristic pigmentation, leading to a diagnostic delay and thus carries a poor prognosis. Therefore, it is prudent to have a high index of suspicion for these rare tumors. Hence, we report this case of primary vaginal melanoma, amelanotic variant with a surprisingly long survival of nearly 7 years for information and pertinent discussion.

Aberrant CD68 expression is a rare pitfall in the diagnosis of primary amelanotic malignant melanoma in ascites fluid

Aberrant CD68 expression is a rare pitfall in the diagnosis of primary amelanotic malignant melanoma in ascites fluid

A novel BRAF mutation in association with primary amelanotic melanoma with oral metastases

In the context of amelanotic melanoma, little is known on the genetic or molecular background that determines the onset of this peculiar phenotype of melanoma and its sites of metastatic spread. However, it appears that amelanotic melanomas frequently lack BRAF mutations. To report the genetical analysis of one case amelanotic melanoma developing oral metastasis. The BRAF mutational status of the primary lesion was assessed by both Sanger sequencing and pyrosequencing. Both methodologies showed changes in three nucleotides: C1796T; G1798A and T1799A. These mutations should result in a rare double aminoacid substitution in codons 599 and 600 of the BRAF protein (BRAF T599I/V600K). This unusual mutation was associated with an uncommon clinical phenotype of the primary tumour and with an unusual site of metastatic spread. In the lack of comparable data, a potential association between the unusual mutation and clinical findings remains a matter of further studies.

肺原発無色素性悪性黒色腫の一切除例

肺原発無色素性悪性黒色腫の一切除例

Primary amelanotic malignant melanoma of the small intestine diagnosed by esophagogastroduodenoscopy before surgical resection

A 67-year-old man, presenting with anemia and suspected gastric cancer, was referred to our hospital, where he underwent esophagogastroduodenoscopy (EGD). Biopsy revealed densely populated semi-circular cells with abundant cytoplasm that were positive for S-100 protein, melanoma antigen, and HMB-45, resulting in a diagnosis of malignant melanoma. A gastrointestinal barium study for further exploration demonstrated a filling defect 6 cm in size at the ligament of Treitz. Follow-up EGD of this finding revealed an ulcerated, half-circumferential lesion with a distinct ulcer mound extending from the ascending part of the duodenum to the jejunum, and additional biopsy also indicated malignant melanoma. Computed tomography scans showed wall thickening from the ascending part of duodenum to the proximal jejunum, whereas positron emission tomography revealed accumulation at the upper gastric body, the duodenum to the jejunum, and the left adrenal gland. Systemic exploration of the patient, including the skin, anus, and eyeballs, revealed no other lesions, and primary small intestinal malignant melanoma with metastasis to the stomach and adrenal gland was diagnosed. Partial duodenojejunectomy, partial gastrectomy, and left adrenalectomy were performed, and adjuvant chemotherapy with dacarbazine, nimustine hydrochloride, and vincristine sulfate was administered. No postoperative recurrence has been observed in the past 3 years.

Amelanotic melanomas presenting as red skin lesions: a diagnostic challenge with potentially lethal consequences

To characterize epidemiologic and clinical features of red primary amelanotic melanomas, an atypical presentation of melanoma that is underemphasized in patient and physician education. Review of a prospectively collected melanoma database identified 46 patients with red amelanotic melanomas, whose clinical features were compared with 329 patients with pigmented melanomas from the same database and same timeframe from January 1964 to September 2005. Red amelanotic melanomas represented 3.9% of all melanomas recorded in our database and accounted for nearly 70% of amelanotic melanomas. Melanoma was included in the clinical differential diagnosis in 32% of red amelanotic melanomas vs. 94% of pigmented melanomas (P<0.001). Red amelanotic melanomas more commonly underwent shave biopsy (55 vs. 12%, P<0.001) and more likely had positive deep margins (35 vs. 9%, P<0.001) but had comparable risks of metastasis and mortality. Red amelanotic melanomas are often misdiagnosed clinically but carry a mortality risk comparable to pigmented melanomas. Clinicians screening for melanoma should be more vigilant in considering melanoma in the differential diagnosis of red skin lesions.

Primary Amelanotic Melanoma of Vulva in a Young, Lactating Female

Primary amelanotic melanoma of the vulva is extremely rare and it is a unique variant which is difficult to differentiate from other epithelial and nonepithelial malignancies due to absence of melanin pigmentation. It can be easily mistaken for other malignancies both clinically and pathologically. The difficulties in diagnosis and treatment aggravate the poor prognosis. This case highlights the rare case of vulval amelanotic melanoma occurring in a young lactating female.

Large Neglected Ulcerated Melanoma Mimicking Extramedullary Plasmacytoma

Amelanotic melanoma, a renowned impersonator, has taken on a new persona. A 63-year-old woman was seen in the emergency room with a chief complaint of back pain after a fall and was discovered to have a 15-cm fungating mottled gray mass independent of bone on the right elbow. Initial workup discovered lytic calvarial lesions, anemia (Hb 7; Hct 20%), and circulating plasma cells consistent with plasma cell myeloma. Biopsy of the elbow mass displayed sheets of plasmacytoid cells, some reactive for CD138. Flow cytometry revealed a substantial portion of the plasma cells in the tumor that were kappa restricted consistent with cutaneous plasmacytoma. The elbow mass was initially signed out as extramedullary involvement by her myeloma. Reevaluation of the mass after the patient experienced an explosive growth of multinodular jet black malignant melanoma on ipsilateral breast revealed MART-1 and S-100 reactivity of the majority of the cells. In retrospect, the elbow mass was a neglected primary amelanotic malignant melanoma with neoplastic plasma cells participating in its chronic inflammatory infiltrate.

Primary amelanotic melanoma of the breast: combating a rare cancer

Malignant melanoma is the foremost cause of metastasis to the breast from extramammary solid neoplasm. However primary melanoma of the breast is a distinct rarity. Primary melanoma involves the skin and less commonly the glandular parenchyma of the breast. We herein describe a case of primary amelanotic melanoma of the breast parenchyma in a 32-year-old female managed with a combination of surgery, adjuvant radiotherapy and immunotherapy. This case report aims to increase awareness of unusual neoplasms of the breast which might require a different surgical and adjuvant therapeutic approach.