Slow-growing amelanotic malignant melanoma of the esophagus with long survival: a case report and review of the literature

Vitiligo and tumor response in a patient with amelanotic melanoma undergoing nivolumab treatment

Vitiligo, an acquired depigmenting disorder of the skin that reacts against normal melanocytes, sometimes occurs as an immune-related adverse event in the treatment of melanoma with immune checkpoint inhibitors. It has been known that the occurrence of vitiligo is associated with a favorable therapeutic response in patients with melanoma, but it is not yet clear whether the association also applies to amelanotic melanoma, a minor subtype of melanoma with little or no melanin pigmentation. We report a patient with amelanotic melanoma of the esophagus who responded well to nivolumab treatment. Shortly after the tumor response, vitiligo was found on the patient’s forearms. This case suggests that the occurrence of vitiligo is associated with a favorable response to nivolumab treatment for amelanotic melanoma.

Primary amelanotic malignant melanoma of the esophagus: a case report

Background

Primary 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 presentation

An 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.

Conclusion

We 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.

A report of amelanotic malignant melanoma of the esophagus diagnosed appropriately with novel markers: A case report

The present case study reported of amelanotic malignant melanoma of the esophagus. A 68-year-old man underwent laparoscopic distal gastrectomy for early gastric cancer diagnosis. After gastrectomy, endoscopic examination revealed a protruded lesion lying adjacent to the melanosis area of the esophagus. Histology of the biopsy specimen suggested malignancy, but the diagnosis could not be made. The patient underwent trans-thoraco-abdominal curative subtotal esophagectomy. Immunohistochemical examination of the resected specimen was negative for HBM-45 and Melan-A. However, immunohistochemical examinations of SOX10 (Sry-related HMg-Box gene 10) and KBA.62, which are not associated with melanosome, were strongly positive, and tyrosinase was notably positive. A diagnosis primary of amelanotic malignant melanoma of the esophagus that consisted of only premelanosomes was made. The present findings suggest that, in the diagnosis of malignant melanoma, SOX10 and KBA.62 may be useful, particularly in diagnosing amelanotic malignant melanoma.