PET Scan Misses Cutaneous Melanoma Metastasis with Significant Tumour Size and Tumour Thickness.

BACKGROUND: Although PET-scan is an advanced, innovative and widely used method for monitoring patients with different types of cancer diseases, it is important to note that its application in patients with cutaneous melanoma is limited and should be reconsidered.

CASE REPORT: To affirm this new statement, we are presenting a case from our clinical practice of a patient with melanoma of the interdigital space (with resected in sano primary melanoma and performed complete lymphadenectomy) that showed locoregional and systemic progression in two months post operation. The PET scan performed within the second hospitalization (and before the second operation) did not detect the presence of any cutaneous metastases, which were clinically and histologically verified after the second operative procedure.

CONCLUSIONS: This data suggests that shortly more reliable and sensitive imaging methods for monitoring patients with cutaneous melanoma should be found. Having in mind that our patient has been operated twice in the area of the primary lesion (as the surgical wound underwent secondary healing), theoretically, the abundant cicatrization could have led to reduced glucose uptake in the surrounded cancerous tissue. Monitoring of a larger number of patients with locoregional metastases and surgical interventions in different locations would shed light on the observations shared by us.