PMC8254584_01
Clinical and Radiologic Response to pembrolizumab; Immunohistochemistry. (A and B) Clinical response to pembrolizumab; (A) Fungating left groin tumor and satellite nodule at baseline (September 2018), prior to starting pembrolizumab (horizontal red arrows); (B) Dramatic clinical response after 3 cycles of pembrolizumab in primary tumor and adjacent satellite nodule (December 2018) (horizontal red arrows). (C and D) Radiologic response to pembrolizumab; (C) Baseline PET-CT showing fungating and intensely FDG-avid mass (SUVmax 19.6) at the left groin (vertical white arrow) with invasion of the adductor compartment of the left thigh; (D) Follow-up PET-CT after 6 months showing marked reduction in size and metabolic uptake (SUVmax = 3.9) of the tumor (vertical white arrow). (E) Hematoxylin and eosin x20 stain confirming clear cell carcinoma: the tumor is composed of nests of cells with round nuclei, prominent nucleoli and ample clear to eosinophilic cytoplasm; (F) Immunohistochemistry for PD-L1 using the Dako 22C3 pharmDx assay, combined positive score of 45.
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Examination at our center revealed a now 25 cm fungating left inguinal nodal mass with adjacent 6 cm left upper thigh satellite nodule, with lymphedema distal to the large left groin mass (Figure 1A). An 18-F fluorodeoxyglucose (FDG) positron emission tomography CT scan (PET-CT) demonstrated a fungating mass at the left groin with invasion of the adductor compartment (Figure 1C). Wedge biopsy of this mass at our center confirmed adenocarcinoma, clear cell subtype (Figure 1E). PMS2 was preserved. PD-L1 (Dako 22C3pharmDx) CPS was 45 (Figure 1F). Complete clinical response (Figure 1A and B) and RECISTv1.1 PR on PET-CT scan (Figure 1C and D) was seen after 3 cycles of pembrolizumab.
Relevant Biochemistry and Hematology Indices during pembrolizumab treatment. Rapid reduction in serum CA-125 was observed after commencing pembrolizumab in October 2018, with CA-125 dropping precipitously from a baseline of 298 U/mL to 9.5 U/mL in December 2018, after only 3 cycles of pembrolizumab. CA-125 reached a nadir of 4.6 U/mL in February 2019. Gradual increase in CA-125 coincided with clinical disease progression in June 2019. Worsening neutropenia occurred during the course of pembrolizumab, due to underlying myelodysplastic syndrome, which was later confirmed on bone marrow examination.
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CA125 reduced from 298 to a nadir of 5.2 (Figure 2). Unfortunately, after a duration of 11 months of pembrolizumab therapy, her neutropenia continued to worsen (Figure 2). Alongside this, her CA125 level gradually rose (Figure 2).