Dr Tyson Reeve
History
80 year old male patient initially referred for left iliac fossa pain, melaena and dropping haemoglobin after increasing antiplatelet treatment. Initial CT shows large retroperitoneal abdominal mass, focal thickening in a loop of small bowel and suspicious left adrenal mass. Subsequent biopsy confirmed malignant melanoma. The patient was then referred for a staging whole body FDG PET CT .
Imaging
FDG PET CT – Vertex to toes, including diagnostic contrast enhanced CT.
Findings
PET CT scan Pre-treatment
Extensive, intensely FDG avid large volume retroperitoneal nodal metastatic disease with multiple mesenteric and omental metastatic deposits. FDG avid liver lesions, FDG avid left adrenal mass and FDG avid lesion in the small bowel and stomach. Multiple pulmonary metastases with metastatic mediastinal and left hilar lymphadenopathy. Further metastatic deposits in the right ischiorectal fossa and small subcutaneous metastases right mid back region. The findings were consistent with widespread metastatic melanoma.
PET CT scan Post-treatment
(Three months after starting treatment with Pembrolizumab immunotherapy)
Significant positive response to treatment with near complete metabolic and morphologic resolution of extensive disease in the chest, abdomen and multiple subcutaneous deposits. Multiple serosal metastases in the stomach and bowel showed complete metabolic and morphologic response to treatment.
There remained faint FDG avid residual nodal disease in the retroperitoneum wrapping around the aorta and right renal artery which corresponded to the largest metastatic deposit on the previous PET CT scan. Complete metabolic resolution of hepatic and adrenal metastases.
Summary
Excellent metabolic and morphologic response to Pembrolizumab therapy. This case highlights the amazing leaps forward in treatment of metastatic Melanoma with Immunotherapy, now resulting in complete disease remission in some cases.
