Cutaneous malignant melanoma (CMM) is one of the most aggressive forms of skin cancer, accounting for about 90% of deaths from cutaneous neoplasms, and its incidence has increased significantly in recent years. According to the 2012 European criteria for diagnosis and treatment of malignant melanoma, diagnosis should be based on the combination of clinical features, dermoscopic data and histological examination, preferably after excisional biopsy. Tumour thickness and other parameters for local staging according to the AJCC classification should be included in the pathology report. Although many factors influence the prognosis and course of the disease, it has been established in a number of studies that tumour thickness is the most important parameter. Therapy of malignant melanoma in its initial stages mostly consists of wide local excision with 1 to 2 cm margins, and sentinel lymph node biopsy that is usually performed in cases of tumours with a thickness greater than 1 mm. We present the case of a 58-year-old Bulgarian male with cutaneous superficial spreading malignant melanoma, in which, after complete excision, histological examination established an inaccurate tumour thickness (0.7 mm), with consequent inadequate staging and further management. After reassessment of the results in another institution (as well as their confirmation by two additional independent histopathology laboratories in our country 1.92 mm), in the National Oncological Hospital where the patient was initially evaluated, sentinel lymph node biopsy was not performed, contrary to the generally accepted European and World standards. With the present case we raise some current issues regarding diagnosis and therapy of Bulgarian patients (not only in the case presented) with malignant melanoma in the 21st century, and discuss the urgent need for external quality control procedures and standardization of the histopathologic reporting, which is of paramount importance in the staging and subsequent management of these patients.