Malignant melanoma is a formidable tumor originating from melanocytes of neural crest origin, found in various anatomical locations, primarily in the skin, followed by the eyes and mucosal membranes. This tumor stands out due to its remarkable phenotypic diversity. Transdifferentiation, the process of differentiation into cell lineages other than the one from which the tumor originated, and phenotypic plasticity, characterized by changes in behavior, morphology, and physiology in response to different environmental conditions, can make melanoma a diagnostic conundrum for unwary pathologists. In this case report, we present a challenging case of melanoma with cartilaginous transdifferentiation to shed light on its clinical, pathological, and molecular aspects.

Adrenal gland metastases from malignant melanoma are a common but poorly characterised condition. Their lack of consistent clinical features and poor response to immune checkpoint inhibitors pose a significant diagnostic and therapeutic challenge to practitioners. This case report describes a 78-year-old male with no prior history of melanoma presenting with nonspecific abdominal symptoms and unintentional weight loss who was found to have undifferentiated bilateral adrenal gland metastases from malignant melanoma. Despite ongoing investigations, the primary site of the adrenal gland metastases remained unknown, prompting the consideration of primary adrenal melanoma as a diagnosis. The patient underwent four cycles of treatment with immune checkpoint inhibitors, nivolumab and ipilimumab, followed by maintenance therapy and subsequent adrenal metastasectomy. Despite therapeutic efforts, the patient\'s tumour was resistant to treatment and became undifferentiated. The patient continued with palliative care until his death, more than three years after the onset of symptoms. The clinical features, pathophysiology, diagnosis, treatment, and prognosis of this patient\'s disease are discussed in detail to help inform the management of similar cases.

BACKGROUND: Cutaneous malignant melanomas rarely occur in the eye, usually in the eyelids or the conjunctiva. Conjunctival malignant melanomas are even rarer. Most melanomas are dark in color as they are pigmented. However, amelanotic conjunctival malignant melanomas, a scarce variant of the cancer, can be challenging to diagnose accurately.
METHODS: We present two cases of white Caucasian Swedish-born women who were diagnosed with unilateral amelanotic malignant melanoma in the conjunctiva of the eye. In the first case, the patient was an 81-year-old woman who was suffering from redness and foreign body sensation in the left eye. The initial diagnosis was blepharitis. Three biopsies were taken, which showed malignant melanoma in the eyelid and the conjunctiva. Unfortunately, the eye and the rest of the orbit could not be saved, and the patient had to undergo an orbital exenteration. In the second case, the patient was a 50-year-old woman, and the tumor was localized in the temporal conjunctiva of the left eye. The initial diagnosis was pinguecula, but at the time of surgery, the physician suspected conjunctival intraepithelial neoplasia. The tumor was not completely removed, so adjuvant brachytherapy and local chemotherapy were used. The eye was preserved. No neck and/or lung metastasis was detected in either case at the time of diagnosis.
CONCLUSIONS: Conjunctival amelanotic malignant melanomas should be suspected when tumors are present in the eye and/or the eyelids. By suspecting amelanotic malignant melanoma, the delay in treatment can be shortened. Treating them as soon as possible is essential to minimize the risk of metastasis.

Primary spinal malignant melanoma (PSMM) is a rare cancer of the central nervous system (CNS), and PSMM of the spinal nerve root is even more extraordinary. PSMM of a nerve root can mimic the radiographic appearance of benign nerve sheath tumors, thus resulting in misdiagnosis until tissue diagnosis can be made. A 53-year-old African American woman presented with pain primarily involving the left aspect of her neck and shoulder for 2 years. Magnetic resonance imaging (MRI) of the cervical spine demonstrated a T1-hyperintense, T2-hypointense, homogenously enhancing, dumbbell-shaped, intradural extramedullary mass extending out through the left C2-3 foramen. A midline incision was used to perform a C2 and C3 laminectomy, and the mass was removed from the cavity. The histopathologic profile was consistent with the diagnosis of malignant melanoma. The present case report adds to the 110 cases of PSMM and the 20 cases of PSMM of the spinal nerve root in the existing body of literature. Radiographic and clinical features resemble that of the much more common schwannoma or neurofibroma requiring immunohistochemical analysis for definitive diagnosis. The optimal treatment for PSMM has not yet been defined due to its rarity and it is therefore important to report such cases in order to share our clinical experiences and provide data to other clinicians treating this uncommon disease.

Malignant melanoma is a melanocyte-derived tumor known for its aggressive clinical behavior. Melanocytes originate from the neural crest, which also gives rise to neural tissues. Malignant melanoma can occasionally exhibit neural differentiation. We report a case of a 70-year-old male with malignant melanoma exhibiting neural marker positivity in the absence of typical melanoma markers. The patient initially presented with a dark nodule on his left heel, which was confirmed as malignant melanoma through cytology. Surgical resection and lymph node dissection were performed, revealing atypical melanocytes. Despite postoperative nivolumab treatment, metastases in the brain and lungs were observed. Histological examination of the brain tumor showed neural differentiation markers (thyroid transcription factor 1 (TTF-1), cytokeratin 7 (CK7), AE1/AE3, and epidermal growth factor receptor (EGFR)) with negative melanoma markers. The patient eventually succumbed to the disease despite multiple treatments. An autopsy revealed multiple organ tumors (brain, duodenum, stomach, liver, and bile duct) negative for melanoma markers but positive for neuroendocrine markers (CD56, synaptophysin, and chromogranin A). This case suggests two possibilities: the coexistence of malignant melanoma with neuroendocrine tumors or a transformation of melanoma into a neuroendocrine phenotype. This case highlights the need for clinicians to consider the potential for melanoma to lose typical markers and transform into neuroendocrine cancer.

OBJECTIVE: Malignant melanoma is a tumor with a poor prognosis that can metastasize distally at an early stage. Terrein, a metabolite produced by Aspergillus terreus, suppresses the expression of angiogenin, an angiogenic factor. However, the pharmacological effects of natural terrein have not been elucidated, because only a small amount of terrein can be extracted from large fungal cultures. In this study, we investigated the antineoplastic effects of terrein on human malignant melanoma cells and its underlying mechanisms.
METHODS: Human malignant melanoma cell lines were cultured in the presence of terrein and analyzed. Angiogenin production was evaluated using ELISA. Ribosome biosynthesis was evaluated using silver staining of the nucleolar organizer region. Intracellular signaling pathways were analyzed using western blotting. Malignant melanoma cells were transplanted subcutaneously into the backs of nude mice. The tumors were removed at 5 weeks and analyzed histopathologically.
RESULTS: Terrein inhibited angiogenin expression, proliferation, migration, invasion, and ribosome biosynthesis in malignant melanoma cells. Terrein was shown to inhibit tumor growth and angiogenesis in animal models.
CONCLUSIONS: This study demonstrated that terrein has anti-tumor effects against malignant melanoma. Furthermore, chemically synthesized non-natural terrein can be mass-produced and serve as a novel potential anti-tumor drug candidate.

Combined tumours are those composed of two benign tumours or a benign and malignant tumour or two malignant tumours occurring within the same tumour population. The incidence of combined tumours is very rare. Due to the rarity of these tumours, their biological behaviour remains unlashed. Incisional biopsy of a 48 years old female patient with single, diffuse tumour mass in the oral cavity showed combined tumour or collision tumour of malignant melanoma and squamous cell carcinoma. This was confirmed with immunohistochemistry study. The incidence of combined tumour of malignant melanoma and squamous cell carcinoma in oral cavity is extremely rare. To the best of our knowledge based on the previous literature records, this is the first case report of its kind where there is incidence in the human oral cavity.

BACKGROUND: Several cathepsins have been identified as being involved in the development of cancer. Nevertheless, the connection between cathepsins and skin cancers remained highly elusive.
METHODS: A bidirectional Mendelian randomization (MR) analysis was performed to investigate the causal association between cathepsins and skin malignancies. The genome-wide association studies (GWAS) data for cathepsins, malignant melanoma (MM), and basal cell carcinoma (BCC) were obtained from European research. The primary method employed was inverse variance weighted. In addition, MR-Egger, weighted median, weighted mode, and simple mode were also executed. Sensitivity analysis was performed using Cochran\'s Q test, MR-Egger, and MR-PRESSO.
RESULTS: From univariable MR (UVMR), cathepsin H, and S were determined to have a causal relationship with BCC. Additionally, cathepsin H was identified as associated with MM. Multivariable MR (MVMR) showed that after correcting for risk factors of skin carcinoma, cathepsin H was detected to be protective against BCC, whereas cathepsin S has been observed as a risk factor for BCC. No substantial pleiotropy and heterogeneity were identified in the sensitivity analysis.
CONCLUSIONS: This study was the first to establish a direct link between cathepsins and skin malignancies. Cathepsin H and S have the potential to serve as new biomarkers for BCC, offering valuable assistance in the prompt identification, treatment, and prevention of the disease. Nevertheless, additional clinical trials are required to validate our findings.

BACKGROUND: Iris nodules are frequently noted as clinical manifestations of neurofibromatosis type 1 but the other intraocular manifestations are rare. The purpose of this study is to present a patient with a phthisic eye who underwent enucleation for a cosmetic reason after 15-year follow-up and also to review 14 patients with enucleation described in the literature.
METHODS: A 17-year-old man with neurofibromatosis type 1 from infancy underwent the enucleation of phthisic left eye and also had the resection of eyelid subcutaneous mass lesions on the left side for a cosmetic reason. He had undergone four-time preceding surgeries for eyelid and orbital mass reduction on the left side in childhood and had developed total retinal detachment 10 years previously. Pathologically, the enucleated eye showed massive retinal gliosis positive for both S-100 and glial fibrillary acidic protein (GFAP) in the area with involvement of the detached retinal neuronal layer, together with a more fibrotic lesion along the choroid which were, in contrast, negative for both S-100 and GFAP. The choroid, ciliary body, and iris did not show apparent neurofibroma while episcleral neurofibroma was present.
METHODS: In review of enucleated eyes of 14 patients in the literature, buphthalmic eyes with early-onset glaucoma on the unilateral side was clinically diagnosed in 9 patients who frequently showed varying extent of hemifacial neurofibromatosis which involved the eyelid and orbit on the same side. Pathologically, neurofibromas in varying extent were found in the choroid of 12 patients. One patient showed choroidal malignant melanoma on the left side and fusiform enlargement of the optic nerve on the right side suspected of optic nerve glioma. The phthisic eye in another patient showed massive retinal gliosis similar to the present patient.
CONCLUSIONS: In summary of the 15 patients with neurofibromatosis type 1, including the present patient, buphthalmic or phthisic eyes with no vision were enucleated for cosmetic reasons and showed choroidal neurofibroma in most patients and massive retinal gliosis in two patients including the present patient.

Primary melanoma of the oral cavity is extremely rare, accounting for 0.2-8% of all melanomas. Lesions arising from mucosal melanocytes occur most frequently on the gingiva or palate. Mucosal melanomas carry a worse prognosis than cutaneous melanomas. Very few studies have been published due to rarity of disease. 46 year old lady presented with black colored lesion over left side of her tongue for 6 weeks. On examination there was 3 × 2.5 cm black colored patch over left lateral part of tongue in middle 1/3rd, not crossing midline. Tip and base of tongue were free. Biopsy was suggestive of malignant melanoma of tongue. Patient underwent surgery (wide local excision of left lateral border of tongue lesion + left selective neck dissection). Final Histopathological report revealed malignant melanoma of tongue with all margins free, Depth of invasion 3 mm, Lympho-vascular invasion present, and no perineural invasion, left level III cervical lymph node metastases. Patient thus received adjuvant RT. Immunotherapy was also advised in multidisciplinary clinic, but patient was non-compliant. Early diagnosis will be promoted by careful oral examination and early biopsy of pigmented and non-pigmented masses. Early diagnosis and treatment will improve the prognosis of patients with oral malignant melanoma.