Skin metastasis from solid and soft tissue primary malignancies overall are rare. However, cutaneous metastases from certain soft tissue malignancies are seen not too infrequently in the clinic especially by dermatologists. Clinically, the presence of cutaneous metastasis is usually a finding of advanced disease stage and generally indicates a poor prognosis. Cutaneous lesions are often overlooked on 18F-Fluorodeoxyglucose (FDG) Positron emission tomography with computed tomography (PET/CT), with the appearance of radiotracer uptake not well appreciated. Common confounding factors are post-surgical changes or inflammatory lesions in the soft tissue body wall which can demonstrate nonspecific 18F-FDG uptake. We present three cases of soft tissue metastases from primary solid organ malignancies spanning the range of clinical occurrence: a 62-year-old female with cutaneous metastasis from primary breast cancer which only became apparent on exams, a 59-year-old female with cutaneous and soft tissue metastatic nodules from a non-small cell lung carcinoma on presentation. Finally, we present a case of sarcomatoid carcinoma arising from squamous cell carcinoma of the bladder with disease progression despite chemotherapy and radiation. In this last case, the patient developed a vesiculo-cutaneous fistula draining a malignant effusion along with a subcutaneous chest wall 18F-FDG avid nodule, indicated widespread metastatic disease. All of these cases, demonstrated resistance to first-line therapy and a widespread metastatic disease state with poor prognosis overall. Additionally, in these cases, the recognition and subsequent biopsy of the cutaneous metastases led to changes in the clinical management.
Published on: December 08, 2020
Citation: Lubin D, Allahyari M, Benjamin S, Basnet A, Wojtowycz A, Jafroodifar A. 2020. Case Reports of Cutaneous and Subcutaneous Metastasis from Primary Solid Organ Tumors by 18F-FDG PET/CT. J Med Imaging Case Rep 4(2): 74-78.