Comparison of Malignant Skin Tumor Thickness and Relative Depth of Invasion Estimates from Preoperative MR-Microscopy and Pathological Evaluation

Abstract

Tumor thickness and relative depth of invasion are prognostic parameters considered when developing treatment plans for malignant skin tumors. Although conventional magnetic resonance (MR) imaging techniques cannot identify small tumors, use of microscopy coils considerably improves spatial resolution. Some studies have shown that this technique is efficacious in preoperative assessment of relative depth of invasion; however, its ability to provide accurate measurements of tumor thickness remains unconfirmed. The purpose of this pilot study was to evaluate the usefulness of preoperative MR-microscopy in determining tumor thickness and relative depth of invasion of malignant skin tumors. Magnetic resonance images of malignant skin tumors in seven female patients (six with basal cell carcinoma and one with malignant melanoma) were obtained using a 1.5 T system and a 47-mm or 23-mm microscopy coil. Tumors were then excised, fixed, dehydrated, embedded, and stained with hematoxylin and eosin. We then compared MR-microscopy and pathology values for thickness and relative depth of invasion of each tumor. Both techniques produced similar measurements of tumor thickness and relative depth of invasion. MR-microscopy is very useful for accurate preoperative estimation of not only relative depth of invasion, but also thickness of malignant skin tumors.