Reflectance confocal microscopy analysis of equivocal melanocytic lesions with severe regression

BACKGROUND

The differential diagnosis between regressing nevi and melanoma might be challenging; regressing areas can represent a confounding factor for the diagnosis and the histology still remain mandatory to rule out melanoma. Reflectance confocal microscopy may add valuable information by revealing features suggestive of the nature of the melanocytic proliferation.

OBJECTIVE

To assess the impact of confocal microscopy in the management of regressive melanocytic lesions.

METHODS

The dermoscopic analysis of 92 melanocytic lesions showing that more than 30% of regressions have been retrospectively considered, among them, 32 melanocytic lesions with a 7 check point list ≥3 they were assessed at the rcm and subsequently excised. For each selected lesion, dermoscopic features of regression (white scar-like areas, blue areas, blue white areas), distribution of regressing areas (central, peripheral, or both) and the percentage of regression have been examined by an expert in dermoscopy, blinded to the histological and confocal diagnosis. Subsequently, two experts in confocal microscopy revaluated, blinded from histology, RCM images.

RESULTS

Of the 32 lesions analyzed, 23 (71.5%) were diagnosed histologically as nevi, and 9 (28.5%) as melanomas. 26 of 32 lesions (81.5%) exhibited regression >50% of the overall. On RCM, 11 lesions have been interpreted as malignant and 21 as benign. On RCM the majority of nevi exhibited regular architecture without cytological atypia. Epidermal disarray, pagetoid infiltration, disarranged dermo-epidermal junction architecture and atypical nests were considered as suspicious for malignancy. Good concordance between confocal readers has been detected.

CONCLUSION

A combined dermoscopic/confocal approach can be used for the management of lesions exhibiting dermoscopic features of regression in order to provide a more conclusive pre-histological diagnosis avoiding a high number of unnecessary excisions. Limits of this study were represented by the relatively small number of lesions and the retrospective approach. Further, prospective studies on a larger number of cases, will be necessary in order to compare the efficacy of dermoscopy alone versus dermoscopy in combination with RCM for the evaluation of regression, suspected pigmented lesions.

Sonographic evaluation of clinically occult in-transit and satellite metastases from cutaneous malignant melanoma

PURPOSE

Our purpose was to assess the potential of ultrasonography (US) in the detection of in-transit or satellite metastases.

MATERIALS AND METHODS

Following a review of the relevant literature, we present the results of a retrospective study based on 2,000 malignant melanoma patients with complete case records. Of these, we selected 600 patients who had a thick melanoma (>1 mm) at presentation but were clinically free of in-transit or satellite melanoma metastases during follow-up. All patients underwent periodic clinical and imaging investigations, as well as US examination of the site of the surgical wound and surrounding soft tissues.

RESULTS AND DISCUSSION

US raised the suspicion of in-transit or satellite metastases in 63 patients. A total of 95 lesions were identified. Average lesion diameter was 0.7 mm, and only four were larger than 1 cm. All suspected lesions were confirmed by surgery, follow-up or US-guided fine-needle aspiration (FNA) with 22-gauge needles using a freehand technique and exploiting the capillarity principle. In this series, there were apparently no false positive or false negative US results although inclusion criteria precluded correct evaluation of possible false negatives. Minimum lesion diameter allowing sonographic detection appears to be around 0.4 mm. US features of in-transit metastases have been well documented. They usually appear as solid lesions, hypoechoic relative to the surrounding subcutaneous fat and with relatively well-defined and regular contours and good US transmission. Internal structure is fairly homogeneous, and sometimes millimetresized fluid areas can be appreciated inside. Larger metastatic lesions may exhibit internal vascular signals at power Doppler imaging. These findings in dermatological sonography are almost exclusive of metastases but may also be seen in glomangioma, which, however, has intense intralesional vascularity. US-guided FNA plays an important role in diagnosis of metastases from malignant melanoma. Of the 32 nodules that were cytologically sampled, a definitive or most probable diagnosis of metastasis was made for nodules with a mean diameter of 0.7 mm (minimum 0.5 mm).

CONCLUSIONS

Sonography of soft tissues surrounding the original site of a malignant melanoma should be more widely used and associated with US-guided FNA biopsy.