55 y/o male with PMH of DM, HTN, hypothyroid, arthritis, and smoking noticed a pimple sized swelling on his right upper back, progressively increasing in size and pain, associated with chills last week but no fever with some pus expressed previously by his wife. He never had these symptoms before. His wife was able to drain some pus one week ago by squeezing. After that the opening sealed and the swelling increased.
Physical exam showed an approximately 3 x 3 cm erythematous, uniform, raised, very tender lesion over the superior portion of the right scapula.
Ultrasound obtained with the linear probe in the ED showed a 2 x 5 x 5 cm structure with a heterogeneous center surrounded by hypoechoic material. Color Doppler indicated punctate areas of vascularity within the heterogeneous center that were concerning for possible malignancy with superimposed abscess. A formal ultrasound was obtained that described “no significant Doppler flow”. The impression on the report stated: “Large cystic lesion in the right shoulder with mixed internal echogenicity. Differential considerations include epidermal inclusion cyst and sebaceous cyst, superimposed infection with other etiologies not excluded.”
The lesion was drained of copious purulent and sebaceous material, and the patient was discharged with antibiotics with the diagnosis of an infected sebaceous cyst.
Learning points: Color Doppler of suspicious lesions can reveal vascularity that is suggestive of malignancy. Demonstrated vascularity is much more suggestive of malignancy if individual vessels can be traced longitudinally through the mass, versus random points within the mass that cannot be traced.
– Sarah Massatt, MS4