ARRS 2022 Abstracts


E1762. Dermatologic Radiology: The Radiologist’s Role in Evaluation of Superficial Lesions
  1. Robin Alonge; David Grant Medical Center
  2. Jonathan Madden; David Grant Medical Center
  3. Lance Edmonds; David Grant Medical Center
Careful physical exam and biopsy are often the first methods to evaluate superficial lesions. However, skin lesions may be found incidentally during evaluation for an unrelated complaint. Alternatively, imaging of known skin lesions can be used to suggest a diagnosis, provide useful information for prognosis and management, or assess treatment response. This presentation reviews the intersection of radiology and dermatology.

Educational Goals / Teaching Points
This presentation will describe anatomy of the skin and subcutaneous tissues, review commonly used imaging modalities, discuss key imaging findings and their implications, provide a differential diagnosis for superficial lesions based on imaging findings, and describe the radiologist’s role in evaluation of skin lesions.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Superficial lesions are commonly identified and evaluated using ultrasound (US), CT, MRI, mammography, and nuclear medicine modalities such as 18F-FDG PET. Each modality has specific uses and limitations. High-frequency (20 MHz) US can be used to non-invasively measure lesion thickness, which provides prognostic information and helps guide biopsy and operative management. Lower frequency US (7.5–10 MHz) can identify lymphadenopathy. The efficacy of treatments for inflammatory and sclerotic diseases can be evaluated using serial measurements of skin thickness. CT is useful to identify osseous invasion, lymphadenopathy, and other organ involvement. MRI may provide additional clues about the nature of a lesion and is commonly used to evaluate extent of local disease, perineural invasion, and central nervous system metastatic disease. PET/CT identifies occult sites of additional disease and monitors for evidence of recurrent disease. The differential diagnosis for skin lesions is broad and includes many benign and malignant processes. Biopsy is commonly necessary for definitive diagnosis, but some imaging findings can suggest a diagnosis. For example, absence of color Doppler flow on US or enhancement on CT or MRI may suggest a cystic lesion, such as an epidermal inclusion cyst. Flow on color Doppler US, enhancement on CT or MRI, and activity on PET/CT are seen with solid lesions. Identification of sites of additional disease raises suspicion for a malignant process. The radiologist may identify incidental superficial lesions that require further evaluation. When this occurs, knowledge of specific imaging findings can help narrow the differential diagnosis. In the setting of known skin lesions, imaging can narrow the differential diagnosis, identify additional sites of disease, provide information to guide management, and assess response to treatment.

The differential diagnosis for incidentally found skin lesions is broad and includes malignant and benign conditions. Correlation with physical exam and biopsy is often necessary for accurate diagnosis. However, imaging can play an important role in narrowing the differential diagnosis, answering specific clinical questions, and guiding management.