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 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.

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.

Variante amelanótica en melanoma cerebral primario: a propósito de un caso / Primary intracranial melanoma, amelanotic variant: Case report

El melanoma cerebral primario es un tumor muy infrecuente (0,07% de las neoplasias primarias del SNC). Generalmente muestra un abundante contenido en melanina, y solo en contadas ocasiones se han descrito variantes hipoamelanóticas. Presentamos el caso de una paciente con clínica de cefalea, paresia braquial izquierda y síndrome lobar frontal. La RM mostró una masa frontal derecha con captación homogénea de contraste. Como tratamiento, se realizó una resección quirúrgica completa. El estudio anatomopatológico fue diagnóstico para melanoma, con muy escaso contenido en melanina y alto índice proliferativo. Se realizó un estudio de extensión exhaustivo para descartar otra localización primaria. Debido a varias complicaciones intercurrentes, la paciente evolucionó desfavorablemente, sin llegar a recibir otros tratamientos. La variante amelanótica de los melanomas cerebrales primarios no ha sido descrita con detalle previamente. Repasamos la literatura al respecto y discutimos los detalles de manejo y diagnóstico de esta entidad clínica (AU)

Primary brain melanoma is a very rare tumour (only 0.07% of primary CNS neoplasms) which usually shows with abundant melanin content; whereas hypo/melanotic variants have been scarcely described. We introduce the case of a female patient with headache, left brachial paresis and frontal lobar syndrome. The MRI image showed a right frontal mass with homogeneous contrast uptake. As treatment, a complete surgical resection was performed. Pathology was diagnostic for melanoma, with very low melanin content and a high proliferative index. A thorough extension study was performed to rule out an extracranial primary origin. Due to several intercurrent complications, the patient evolved unfavorably, not being able to receive further treatment. The amelanotic variant of primary intracranial malignant melanomas has not been described in detail previously. We will review the literature, focusing on the particularities of management and diagnosis of this clinical entity (AU)

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.

Primary intracranial melanoma, amelanotic variant: Case report.

Primary brain melanoma is a very rare tumour (only 0.07% of primary CNS neoplasms) which usually shows with abundant melanin content; whereas hypo/melanotic variants have been scarcely described. We introduce the case of a female patient with headache, left brachial paresis and frontallobar syndrome. The MRI image showed a right frontal mass with homogeneous contrast uptake. As treatment, a complete surgical resection was performed. Pathology was diagnostic for melanoma, with very low melanin content and a high proliferative index. A thorough extension study was performed to rule out an extracranial primary origin. Due to several intercurrent complications, the patient evolved unfavorably, not being able to receive further treatment. The amelanotic variant of primary intracranial malignant melanomas has not been described in detail previously. We will review the literature, focusing on the particularities of management and diagnosis of this clinical entity.

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.

Spontaneous subcapsular and perirenal haemorrhage with retroperitoneal haematoma in a patient with ovarian melanoma metastases.

A 47-year-old woman was admitted to our clinic for intensive pain in the left flank region. The transvaginal ultrasound showed a left adnexal solid mass with ascites. She had undergone surgical removal of skin melanoma in 2008, but in September 2019, intracardiac metastasis resulting from it had been discovered. CT performed in March 2020 had been negative for other metastases. A full abdomen ultrasound was not performed. During the night, the patient began to show signs and symptoms of hypovolaemic shock. The patient was urgently transferred to the operating room for a video laparoscopy. A vast left retroperitoneal haematoma was diagnosed along with voluminous enlargement of the left ovary. We proceeded with a left adnexectomy and blood transfusion. Subsequent contrast-enhanced CT revealed a left subcapsular, perirenal haematoma and a voluminous retroperitoneal haematoma. Kidney metastasis was also seen. The final histological diagnosis was metastatic amelanotic malignant melanoma of the ovary.

Uveal amelanotic melanoma in a ragdoll cat.

A 13-year-old castrated male ragdoll cat's left eye was evaluated for dyscoria, iridal thickening and color change of 2 years duration, as well as elevated intraocular pressure. The primary lesion seen on ophthalmic examination was a pale pink-white mass observed in the dorsomedial aspect of a diffusely thickened iris. Metastatic workup revealed hepatic and splenic nodules, but cytology was inconclusive. The left eye was enucleated, and histopathology was consistent with uveal amelanotic melanoma.

Mélanome uvéal amélanotique chez un chat ragdoll. L'oeil gauche d'un chat mâle ragdoll castré âgé de 13 ans fut évalué pour dyscorie, épaississement iridien et changement de couleur présent depuis deux ans, de même que pour une pression intra-oculaire élevée. La lésion primaire vue lors de l'examen ophtalmique était une masse blanc-rosée pâle observée à l'aspect dorso-médial d'un iris épaissi de manière diffuse. Une vérification pour métastases révéla des nodules hépatiques et spléniques, mais la cytologie était non-concluante. L'oeil gauche fut énucléé et l'histopathologie était compatible avec un mélanome uvéal amélanotique.(Traduit par Dr Serge Messier).

Oral amelanotic malignant melanoma: a case report.

Amelanotic malignant melanoma is an extremely rare and aggressive oral tumor. Herein we report the case of a 42-year-old woman presented with a painful growth in anterior maxillary region. Intra-oral examination showed a non-pigmented exophytic mass occupying the anterior maxillary sector. Incisional biopsy with immunohistochemistry examination revealed a malignant melanoma as it strongly expressed melan A and S-100. Facial computed tomography showed extension to the maxillary bone and hard palate. After thoraco-abdominal computed tomography revealing absence of metastasis, tumor resection was performed respecting 2cm security margin. Oral localization of malignant melanoma is rare especially its amelanotic variant. Lack of pigmentation makes the diagnosis more difficult, usually resulting in treatment delay and making the prognosis even worse. Early detection by histological and immunochemistry examination combined to wide resection are the keys to improving the survival for patients with oral amelanotic melanoma.

Amelanotic Meningeal Melanoma with Leptomeningeal Dissemination: A Case Report and Systematic Literature Review.

BACKGROUND: Meningeal melanoma is a rare tumor of the central nervous system, whose amelanotic variant is called "amelanotic meningeal melanoma" (AMM). AMM does not produce melanin and therefore does not exhibit typical short T1 and short T2 signal on magnetic resonance imaging and thus can be easily misdiagnosed and be inappropriately managed. To date, only 4 AMM cases have been reported in the English literature. Here, we report the fifth case. CASE DESCRIPTION: A 26-year-old female patient presented with a 4-month history of progressive headache and nausea, the conventional magnetic resonance imaging demonstrated a posterior fossa mass accompanied by diffuse leptomeningeal dissemination. Repeated cerebrospinal fluid cytology screening showed negative results. The functional magnetic resonance examinations, including diffusion-weighted imaging, proton magnetic resonance spectroscopy, and dynamic susceptibility contrast perfusion-weighted imaging, provided complementary information. The final diagnosis of AMM was made by immunohistochemistry. Despite gross total excision of the tumor, the disease progressed, and the patient died 10 months after diagnosis. CONCLUSIONS: Our experience with this case demonstrated that meningeal melanoma should be included in the differential diagnosis when an intracranial mass is accompanied by leptomeningeal dissemination, and especially when proton magnetic resonance spectroscopy and dynamic susceptibility contrast perfusion-weighted imaging indicate a malignant tumor whereas diffusion-weighted imaging does not. And the loss of a typical melanin signal should not server as an excluding criterion for meningeal melanoma.