Visceral lesions occurring during follow-up of melanoma patients: a true place for other diagnosis than melanoma metastasis

Background: Diagnosis of melanoma metastasis is often based on a combination of clinical and radiological examinations in patients with a past history of melanoma. Chemotherapeutic treatment is often proposed without histological proof of the metastatic status.

Objective: The aim of this study was to investigate a cohort of melanoma patients with invasive diagnostic procedures (IDPs) for pathological confirmation of metastasis in case of suspicious visceral lesions.

Methods: A total of 109 melanoma patients with IDPs for suspicious visceral lesion(s) were included. Data about primary melanoma, IDPs characteristics, pathological result and therapeutic consequence were collected. Patients with AJCC Stage I-III melanoma at the time of the IDP were statistically analysed for various characteristics according to the final diagnosis yielded by the IDP.

Results: A total of 64 diagnostic surgical resections, 38 CT-guided core-needle biopsies, 15 ultrasound-guided core-needle biopsies, 6 surgical biopsies and 6 per-endoscopic biopsies were performed. Main target organs were the lungs (43.5%), breasts (8.5%) and liver (8%). IDPs were well tolerated and provided adequate samples for reliable diagnoses. Among the 105 IDPs in stage I-III patients, 56 melanoma metastases (53%), 25 benign lesions (24%) and 23 other cancers (22%) were found. One IDP was not informative. Multivariate analysis showed that nodular type of the primary melanoma, time-lag between primary melanoma and IDP over 12 months and the presence of suspicious lesions outside the organ biopsied were significantly associated with melanoma metastasis diagnosis.

Conclusion: Suspected melanoma metastasis was ruled out for benign lesion or second cancer in nearly half of the stage I-III patients having undergone an IDP, therefore modifying the medical treatment.