Mucosal melanoma is rare and the occurrence of an invasive malignant melanoma metastasis 11 years post-initial diagnosis is equally uncommon. This is a case of a 66-year-old woman with a history of bilateral vulvar invasive melanoma, who presented with an enlarging inguinal mass with associated tenderness upon palpation. After a right inguinal excisional lymph node biopsy, the pathological findings determined the final diagnosis as metastatic melanoma. To the best of our knowledge, this is the first report of vulvar mucosal melanoma metastasis greater than 10 years after initial diagnosis and treatment in the English language. This case discusses how treatment options for metastatic mucosal melanoma pose a challenge in such cases where follow-up for medical care is lacking. It also highlights the need for further preventative techniques and research directed towards screening techniques, staging guidelines, and treatment options for mucosal melanoma.

Anorectal mucosal melanoma (AMM) is an infrequent and highly aggressive form of mucosal melanoma. Its rarity makes it challenging to clinically diagnose, and its initial symptoms are typically nonspecific such as rectal/anal bleeding (the most common symptom), anal pain, or the presence of an anal mass. The prognosis for this condition is generally poor, and its incidence appears to be increasing each year. AMMs often go undetected and/or are already metastasized at the time of diagnosis. We present a case report of a patient who initially presented with nonspecific symptoms of anemia and blood per rectum, and was later found to have stage IV melanoma of the anorectal region. There is a notable scarcity of literature on this disease, resulting in a lack of a comprehensive understanding of its nature. Most available information consists of isolated case reports rather than comprehensive studies. Although surgical resection remains the primary treatment approach, the majority of patients (over 80%) will die due to distant metastasis within five years after undergoing surgery. The five-year survival rate for anorectal melanoma is estimated to be between 6% and 22%.

Malignant primary rectal melanomas (PRM) are rare tumors. Their diagnosis is frequently delayed as these lesions are often mistaken for benign diseases, resulting in extremely poor overall survival. Histological evaluation with special immunohistochemical (IHC) stains is often indispensable for a definitive diagnosis. The main treatment for this condition involves surgical resection. Adjuvant therapy has also been long recommended. We discuss the case of a 60-year-old woman who presented with changes in bowel habits, anal pain, and perineal burning with no bleeding. A digital rectal examination revealed a nodular mass extending 5 cm from the anal verge. Rectosigmoidoscopy demonstrated an ulcerated polypoid tumor extending 4 cm from the anal verge and over 5 cm into the lower rectum. Biopsy and IHC tests confirmed the diagnosis of rectal melanoma. The patient was successfully managed with surgery followed by external beam radiotherapy and a complete response was achieved after 10 months of follow-up.

Iron deficiency anemia is a concerning finding, particularly in males and post-menopausal females, and can have numerous underlying causes. When evaluating potential sources of gastrointestinal blood loss, bidirectional endoscopy is often necessary. We report the case of an 89-year-old female with multiple comorbidities, including atrial fibrillation treated with apixaban, who presented with symptomatic iron deficiency anemia. Extensive dermatological and radiological assessments ruled out a primary source, and subsequent endoscopy identified a rare etiology: primary gastric mucosal melanoma. This case highlights the importance of thorough evaluation in identifying uncommon causes of iron deficiency anemia such as unsuspected malignancies, hereditary conditions, and different autoimmune conditions amongst other etiologies.

Mucosal melanomas (MM) are a rare type of melanomas commonly found in the vulvovaginal, anorectal, and respiratory tract. In this case report, a 71-year-old female presented to her OB/GYN clinic with dark raised mass on her right labial region adjacent to the perineum. Past medical and surgical history of note included third-degree uterine prolapse, senile vaginitis, fibrocystic changes of the breasts bilaterally, hypothyroidism, hypertension, as well as a past hysterectomy and anterior colporrhaphy. Upon further workup, the 2.7 x 1.8 x 2 cm polyploid mass was biopsied and was found to be consistent with malignant melanoma. The patient then underwent a wide local excision confirming that the lesion was a nodular vulvar melanoma with superficial ulcerations and lymphovascular invasion of the vulvar region. Post-wide local incisions were found to be healed well after the procedure and the patient was referred to a gynecological oncologist for continuous monitoring. The purpose of this case report is to bring awareness of melanomas arising in atypical regions. While MMs are rare in comparison to cutaneous melanomas (CM), the prognosis can be poor if not caught early.

Rectal bleeding in a patient with a history of hemorrhoids should not be ignored. It is often benign and resolves spontaneously without treatment. Here we present a case of anorectal malignant melanoma that presented with rectal bleeding and a prolapsed rectal mass.

Malignant melanoma (MM) of mucosal membranes (excluding anus and head-neck) is a rare but aggressive disease with poor outcomes. The knowledge of this tumor\'s development, etiology, and management is scarce, mainly due to the low case numbers. We presented eight cases and performed a comprehensive literature review on mucosal MM (between 1970 and 2020). We identified 47 manuscripts on 55 patients with primary mucosal MM (limited to urothelium and vagina) and reviewed demographics, tumor specifications (morphology, stage, etc.), management, and survival. We identified 10 manuscripts discussing treatment in 1595 mucosal and non-mucosal MM and extracted the data regarding the non-surgical treatment modalities of mucosal MM patients. In 63 cases, 48 tumors primarily occurred in the urothelium (urethra: 47, bladder: 1) and 15 in the vagina. Molecular studies in a subset of cases revealed alterations in c-KIT, NRAS, BRAF (non-V600E and V600E), TP53, and NF1. Fifty-three patients underwent surgery (with additional chemotherapy, immunotherapy, and radiotherapy in 19, eight, and eight patients, respectively). The outcome was available in 52 cases, showing 21 deaths, 10 without recurrence, two alive with disease, and five lost to follow-up. Shared genetic signatures in mucosal and skin MM suggest a similar development mechanism; however, unlike skin MM, there are less BRAF mutations and more PI3K/AKT/mTOR pathway alterations in mucosal MM. Prolonged chemotherapy (i.e., methotrexate) and immune-modulating agents (i.e., natalizumab) may be risk factors. The stage at diagnosis and proper surgical extirpation are keys to the prognosis and survival of patients.

Malignant melanoma is a highly aggressive cancer arising from the skin, retina, and mucosal lining of the respiratory, gastrointestinal (GI), or genitourinary tracts, all of which contain melanocytes. Mucosal or extracutaneous melanomas (ECMs) are rare accounting for 1% of all melanomas. We herein report a case of a metastatic mucosal melanoma presenting as occult blood loss anemia. A 58-year-old male presented with generalized weakness, anorexia, weight loss, and intermittent melena for one year. On exam, he was tachycardic, borderline hypotensive, and pale without epigastric tenderness. Labs showed severe anemia [hemoglobin, Hgb 3.8 mg/dL, mean corpuscular volume (MCV) 72 fl] for which he received two units of red cells. Endoscopy revealed an 8 mm non-bleeding, gastric ulcer with a raised border and a clean base on the wall of the gastric body. Histologic analysis was consistent with malignant melanoma displaying strong positivity for S-100, Melan A, and HMB 45 stains. The CT of the abdomen revealed multifocal metastatic disease with subcutaneous, intramuscular, and perinephric implants with suspicion of small bowel carcinomatosis. The patient underwent an excisional biopsy for the abdominal wall mass and surgical pathology confirmed melanoma. The patient is planned to be started on immunotherapy for advanced disease. Most melanomas found in the GI tract are metastatic. Mucosal melanoma presenting as a gastric ulcer is extremely rare. As a result, metastasis from other sites must be ruled out before making a diagnosis of primary gastric melanoma (PGM). In our case, a widespread disease with unknown primary elucidated the diagnosis but post-operative inspection failed to find any potential lesion on the skin, genitals, or other organs, suggesting the possible diagnosis of metastatic gastric melanoma. However, follow-up is still required to confirm the diagnosis according to the established criteria. Pathologic diagnosis of melanoma requires the identification of melanin in the cytoplasm and immunohistochemistry with specific markers such as S-100, Melan A, and HMB-45. Although the pathologic diagnosis of PGM is similar to cutaneous melanoma, preoperative diagnosis is difficult due to the extremely low incidence, lack of obvious melanin pigmentation, similar microscopic patterns as more common gastric cancers, and lack of awareness among physicians and pathologists. The prognosis of mucosal melanoma is poor, with a five-year survival rate of 25% versus 80% for cutaneous melanoma. Advanced age, surgically unresectable disease, and lymph node involvement are all poor prognostic markers. There is no standard protocol for treatment. Surgery is the only curative treatment for the resectable disease. Adjuvant chemotherapy, radiation, and immunotherapy have an established role in cutaneous melanoma but there is only limited data on adjuvant systemic therapy with mucosal melanoma. Further research is imperative to establish proper management guidelines for this rare disease entity.

Sinonasal malignant melanoma is a rare but aggressive tumor of the head and neck area. It has a poor prognosis. Common symptoms are nasal obstruction, epistaxis, or purulent rhinorrhea. Diagnosis relies on histopathology with immunohistochemistry (IHC) studies. Surgery is the essential treatment, most often supplemented by radiotherapy or immunotherapy. A 63-year-old female patient, with a history of right dacryocystorhinostomy and Parkinson\'s disease, consulted for symptoms of right nasal obstruction with increasing intensity accompanied by two episodes of mild unilateral epistaxis. Rigid optic examination showed a white-pinkish right obstructive supra-centimetric endonasal tumor. CT revealed an extensive tissue process of the right nasal cavity invading the maxillary sinus, the inferior and middle conchas. A biopsy of the lesion was conducted under local anesthesia. The immunohistochemical study has shown undifferentiated tumor with positive antibody anti PS100 and anti-melan A evoking malignant sinonasal melanoma. The patient underwent two surgeries for maxillectomies as she presented a first local recurrence. She was started on adjuvant radiotherapy. At one year of follow-up, she does not present any local or general signs of disease. Sinonasal melanoma is a particular entity of head and neck mucosal melanomas. The highest incidence is described to be in the seventh and eighth decades of life with no sex difference. IHC profiling of different melanoma subtypes showed the importance of alterations in the KIT gene, this genetic data may constitute a therapeutic target. After surgery, the important local recurrence rates and regional failure justify adjuvant radiotherapy also for resections in free margins. Most authors consider that prophylactic neck dissection is not necessary. Preoperative imaging features (CT scan) are characteristic and helpful for diagnosis. IHC is essential, has a high sensitivity for differentiating achromic melanomas from other neoplasms. Sinonasal achromic melanoma is a very uncommon tumor, invasive, and frequently associated with distant metastasis. Paraclinic examinations are essential for staging and guiding therapeutic management. Immunotherapy is a promising ground of research as it comes to metastatic and advanced disease.

Sinonasal mucosa is an area of high melanocyte density compared to other mucosa-lined sites. Sinonasal mucosal melanomas (SNMM) most commonly arise from the nasal cavity and the paranasal sinuses. Due to their obscure anatomic location and lack of early symptomatology, SNMM are often diagnosed in an advanced stage. The majority of patients who present with symptoms complain of unilateral nasal dysfunction, such as obstruction and epistaxis. We hereby report a case of an 86-year-old female, who presented with a three-year history of progressive right-sided nasal obstruction and recurrent epistaxis. Posterior rhinoscopy and endoscopy revealed a polypoid, fleshy lesion whose coloration varied from mildly pigmented to amelanotic. Inverted sinonasal papilloma was included in the differential diagnosis due to MRI findings. Post-resection histopathology indicated a mucosal melanoma. Typically, amelanotic lesions are rare, more difficult to diagnose and associated with worse prognosis due to both their aggressiveness and delayed diagnosis.