Imaging findings of malignant skin tumors: radiological-pathological correlation

Abstract

Sometimes, radiologists encounter malignant skin tumors (MSTs) during image interpretation. As MSTs require different clinical management modalities for each histological subtype, accurate preoperative diagnosis is essential. The histological subtypes of MST can be easily assessed by visual inspection or biopsy. Therefore, the significant role of radiological imaging in MSTs is to evaluate the extent of local invasion, nodal involvement, and distant metastasis, and the histological estimation of MSTs by radiological imaging has not been reported until a few years ago. However, recent studies have revealed characteristic radiological features for differential diagnosis of MSTs, such as configuration, intratumoral homogeneity, signal intensity, cyst formation, and hemorrhage. Other important clinical data for determining the histological subtype of MST include age, gender, and site of occurrence. MSTs can be categorized as epidermal, melanocytic, adnexal, and mesenchymal tumors based on the origin and have distinctive characteristics. Hence, this review article was designed to describe the clinical and radiological features of MSTs.

Keywords: Computed tomography; Magnetic resonance imaging; Positron emission tomography; Skin neoplasms.

Fig. 1

Pathological and MRI database in our institution. SCC = squamous cell carcinoma, BCC = basal cell carcinoma, MM = malignant melanoma, BD = Bowen’s disease, AK = actinic keratosis, AC = appendageal cancer

Fig. 2

An 86-year-old male with basal cell carcinoma on the nose. a Sagittal fat-suppressed T2-weighted image showing an elevated oval mass (arrow) with cystic foci (arrowheads). b Sagittal T1-weighted image showing an oval mass (arrow). c Histological specimen (H&E stain; scale bar, 5 mm) showing a well-defined mass in the dermis with multiple cystic cavities with mucinous contents (arrows)

Fig. 3

An 86-year-old male with squamous cell carcinoma on the lower leg. a Sagittal fat-suppressed T2-weighted image showing an elevated and flattened mass (arrow) with superficial ulcer formation and linear hyperintensity (arrowheads). b Sagittal T1-weighted image showing a mass (arrow) with superficial irregular margins (arrowheads). c Histological specimen (H&E stain; scale bar, 5 mm) showing invasive squamous cell carcinoma nests surrounded by stromal components with infiltration cells (arrows)

Fig. 4

A 74-year-old male with malignant melanoma on the toe. a Sagittal fat-suppressed T2-weighted image showing a flattened subcutaneous mass (arrow) with bone marrow edema-like signal (arrowhead). b Sagittal T1-weighted image showing an isointense mass (arrow) with intratumoral hyperintensity. c Macroscopic specimen (cut surface) showing intratumoral hemorrhage or melanin deposition (arrow)

Fig. 5

A 60-year-old male with porocarcinoma on the upper back. a Axial T2-weighted image showing a pedunculated mass (arrow) with T2-hyperintese foci (arrowheads). b Axial T1-weighted image showing slight hyperintensity compared with muscle. c Histological specimen (H&E stain; scale bar, 5 mm) showing a well-defined mass in the dermis with multiple cystic areas (arrows)

Fig. 6

A 66-year-old male with hidradenocarcinoma on the sole. a Sagittal T2-weighted image showing an elevated huge mass (arrow) with different-sized hyperintense foci (arrowheads). b Histological specimen (H&E stain; scale bar, 5 mm) showing a mass with multiple necrotic areas (arrows)

Fig. 7

A 77-year-old male with extramammary Paget disease on the perineal region. a Axial T2-weighted image showing a hyperintense cutaneous mass (arrow). b Sagittal T2-weighted image showing a cutaneous mass (arrows) with horizontal spread. c Histological specimen (H&E stain; scale bar, 5 mm) showing a horizontally spreading mass within the dermis (arrows)

Fig. 8

A 81-year-old female with a proliferating trichilemmal tumor on the scalp. a Oblique sagittal T1-weighted image showing an elevated mass with nonspecific signal intensity (arrow). b Oblique sagittal T2-weighted image showing heterogeneous hypointensity (arrow). c Histological specimen (H&E stain; scale bar, 5 mm) showing a well-circumscribed mass with multiple keratinization (arrows)

Fig. 9

A 38-year-old female with sebaceous carcinoma on the cheek. a Axial T2-weighted image showing a pedunculated mass with hyperintensity (arrow). b Coronal T1-weighted image showing a hyperintense mass relative to the muscle (arrow). c Histological specimen (H&E stain; scale bar, 5 mm) showing a pedunculated mass with interventional sebocytes (asterisks)

Fig. 10

A 79-year-old female with Merkel cell carcinoma on the eyelid. a Axial T2-weighted image showing an elevated cutaneous mass with homogeneously mild hyperintensity (arrow). b Axial apparent diffusion map image showing marked restricted diffusion (0.5 × 10⁻³ mm²/s) (arrow). c Histological specimen (H&E stain; scale bar, 5 mm) showing a hypercellular mass in the dermis and subcutaneous tissue

Fig. 11

A 91-year-old male with angiosarcoma on the scalp. a Coronal T1-weighted image showing a horizontally spreading lesion (arrow) with a nodule (arrowhead). b Coronal fat-suppressed T2-weighted image showing elevated lesions with an obtuse angle with mixed hyper- and hypointensity (arrows). c Histological specimen (H&E stain; scale bar, 1 mm) showing atypical endothelial cells with massive hemorrhage in the dermis

Fig. 12

A 27-year-old female with dermatofibrosarcoma protuberans on the hip. a Axial T1-weighted image showing a subcutaneous mass (arrow). b Axial T2-weighted image showing a hyperintense mass (arrow) with linear hypointensity (arrowheads). c Histological specimen (H&E stain; scale bar, 5 mm) showing tumor nests with fibrous tissue in the dermis (arrows)

Fig. 13

A 73-year-old female with mycosis fungoides on the foot. a Axial T1-weighted image showing an extensive skin thickening with a bulky subcutaneous mass (arrow). b Axial T2-weighted image showing a subcutaneous mass with homogeneous intermediate signal intensity (arrow)