PMC7793656_01
(A) Squamous cell carcinoma with perinodal extension into fat (4X magnification). (B) Cross section through the CT portion of the PET/CT prior to the initiation of immunotherapy. The largest lymph node measures 5.6 x 4.3 cm transverse (arrows). (C) Noncontrast CT of the pelvis obtained approximately 1 month after initiation of immunotherapy reveals decreasing lesion size (arrowheads) now measuring 4.2 x 3.8 cm (arrowheads). Subsequent contrast enhanced CTs at 3 months (D) and 36 months (E) after initiation of immunotherapy show no evidence of residual nodal disease.
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f1
He underwent 4 cycles of neoadjuvant chemotherapy with TIP (paclitaxel, ifosfamide, and cisplatin) and then underwent partial penectomy with lymph node dissection and was found to have bilateral inguinal lymph node metastases with extranodal extension, along with a positive right obturator pelvic lymph node metastasis (stage IV TxN3M0) (Figure 1A). Surveillance imaging May of 2017 revealed increasing hypermetabolic right pelvic adenopathy (biopsy-proven, largest lymph node measuring 5.6 x 4.3 cm) along with new bone metastasis in the right anterior acetabulum (Figure 1B). Imaging 3 months after starting pembrolizumab showed complete resolution of lymph node metastasis with no evidence of metastatic disease (Figures 1C, D). Surveillance scans have continued every 2 months to show no evidence of metastatic disease 38 months after starting pembrolizumab with last follow-up 8/2020 (Figure 1E).
PMC7793656_02
(A) H&E stain from lymph node metastasis (10X magnification). (B) F18-FDG PET/CT Coronal MIP projection obtained prior to initiation of immunotherapy. The yellow arrow indicates the dominant lesion, while the yellow arrowheads indicate additional nontarget and/or suspicious lesions. (C) PD-L1 stain showing strong membranous staining in the tumor cells (10X magnification). Follow-up PET/CT (D) approximately 3 months after initiation of immunotherapy reveals resolution or near resolution of the nontarget lesions with decrease in dominant lesion. There is new focus of radiotracer accumulation in the right hilum, which is of unclear clinical significance (red arrowhead). The six months follow-up PET/CT (E) reveals grossly symmetric FDG avid hilar regions (red arrowheads) suggesting possible development of sarcoidosis of sarcoid-like reaction, an uncommon but reported finding in immunotherapy. There has been interval enlargement of the dominant lesion and re-emergence of some suspicious lymph nodes (yellow arrow and arrowhead).
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f2
He underwent bilateral inguinal lymph node dissection, which showed a positive right inguinal lymph node with extranodal extension (Figure 2A). He was followed with surveillance scans and 5 months following completion of radiation, was found to have avid lymphadenopathy in the subcarinal region and right hilum of the chest, along with progression of adenopathy in the retroperitoneum and pelvis (Figure 2B), of which biopsy confirmed chemotherapy and radiation refractory metastatic squamous cell carcinoma. His PD-L1 was markedly positive with a CPS (combined positive score) of 130 (Figure 2C). Based on the tumor strongly positive's PD-L1 status, he was started on pembrolizumab 3/2019 and surveillance scans 3 months thereafter showed marked improvement in adenopathy (Figure 2D). Imaging 10 months after starting pembrolizumab showed some progression of adenopathy but overall his disease has been controlled since starting pembrolizumab 18 months ago (Figure 2E), consistent with partial response (PR) and disease control from stabilization of an otherwise deadly tumor within months.