Complex treatment after pathohistological and immunohistochemical analysis in synchronous neoplasms - anorectal achromatic malignant melanoma and gastric extrapleural solitary fibrous tumor

A 76-year-old woman diagnosed with extremely rarelysynchronous neoplasms - rectal malignant melanoma (RMM) and a benign variant of gastric extrapleural solitary fibrous tumor (GESFT) is presented. Against the background of a literature review, the pathomorphological characteristic, the necessary immunohistochemical panel and the difficult differential diagnosis with the wide range of benign and malignant mesenchymal tumors are discussed. The necessary complex oncological treatment, directly depending on the prognostic risk factors for each of these synchronous tumors is analyzed. For the first time in the English medical literature, a clinical case with synchronous tumors - rectal achromatic malignant melanoma and gastric solitary fibrous tumor is presented. After complex treatment, including surgery and adjuvant radiotherapy of the RMM and surgery of the gastric tumor, we report a one-year disease-free survival with a good quality of life.