case_images: PMC9192334_01
case_images: Initial presentation of an 81-year-old female with cutaneous breast cancer metastasis. (A) Histological H&E-stained image of cutaneous breast cancer metastasis, under 100X magnification (left) and higher power view, 200X magnification (right) of the metastatic adenocarcinoma, highlighted with arrows. This biopsy was obtained approximately at the first treatment timepoint. (B) PET-CT, obtained at the first treatment timepoint, revealing PET-avid uptake overlying the left pectoral muscle, highlighted with red arrow. (C) Image of the lesion pre-treatment.
case_images: fonc-12-877014-g001.jpg
case_images: PMC9192334_01_fonc-12-877014-g001.jpg
case_images: f1
case_images: Supplementary Figure 1 ), with a prominent chronic inflammatory infiltrate composed of lymphocytes and histiocytes ( Figure 1A ). Staging CT did not reveal any distant metastatic disease, and a positron emission tomography-computed tomography (PET-CT) scan demonstrated a solitary 12mm PET avid lesion on the left pectoral muscle, consistent with her physical exam findings ( Figures 1B, C ).
case_images: Treatment timeline for intralesional IL-2 injections and topical imiquimod. The patient was initially treated with IL-2 monotherapy, but showed only a partial response, after which imiquimod was added. The initial histology and PET-CT (
  Figure 1
  ) were collected at week 2, the first treatment. Following 12 weeks of clinical stability with no evidence of disease, an FNA positive for adenocarcinoma led to three more IL-2 treatments, which lead to a complete clinical and radiological response (
  Figure 3
  ).
case_images: fonc-12-877014-g002.jpg
case_images: PMC9192334_01_fonc-12-877014-g002.jpg
case_images: f2
case_images: Over the course of the next 14 weeks, she was treated with intralesional IL-2 every two weeks for a total of 7 treatments ( Figure 2 ). Our patient remained on biweekly IL-2 and imiquimod until the end of 14 weeks ( Figure 2 ).
case_images: Resolution of cutaneous metastasis following intralesional IL-2 and topical imiquimod. (A) Punch biopsy of injected site at the 14-week timepoint, 100X magnification (left) and representative section, 200X magnification (right) showing no evidence of adenocarcinoma, with chronic immune infiltrates. (B) Image of lesion post-treatment, showing complete clinical response. (C) Post-treatment PET-CT (2 weeks after the final treatment; week 34) revealing no evidence of PET-avid lesions overlying the left pectoral muscle.
case_images: fonc-12-877014-g003.jpg
case_images: PMC9192334_01_fonc-12-877014-g003.jpg
case_images: f3
case_images: At the 14-week timepoint, a cutaneous chest wall punch biopsy was performed that revealed only a lymphocytic lichenoid infiltrate with vacuolar ulceration, and no evidence of metastatic or recurrent disease ( Figure 3A ). By then, the nodule had clinically completely resolved ( Figure 3B ), and her final PET-CT scan two weeks after the last injection revealed complete resolution of the left chest wall lesion and left flank ( Figure 3C ).