Case Report
The patient is an 89 year old female who presented for preoperative
clearance for a knee replacement surgery in May 2020 and was found to
have a pulmonary nodule on chest x-ray. She reported left sided
abdominal pain after eating at that time. She underwent a CT scan of the
chest which showed an irregularly shaped nonspecific density involving
the left lower lobe of the lung measuring 11 mm as well as multiple
bilateral pulmonary nodules measuring 2 to 4 mm. She then underwent a
PET scan which showed a 6 cm hypermetabolic mass in the proximal stomach
with associated hypermetabolic perigastric lymphadenopathy. The lung
lesions were PET negative and thought to be non-malignant. She underwent
an EGD in October 2020 which showed a fungating mass in the gastric
cardiac. Pathology was consistent with a poorly differentiated invasive
adenocarcinoma, intestinal type.
The patient was deemed not to be a surgical candidate due to advanced
malignancy and age. She was started on chemoradiation with carboplatin
and paclitaxel. She completed 45 Gray and 5 cycles of chemotherapy. A
PET/CT following completion of these therapies showed multifocal PET
avid metastatic disease in the liver as well as metastatic
lymphadenopathy to the portacaval and left para-aortic lymph nodes. Next
generation sequencing was obtained and showed a PD-L1 CPS score of 50.
In February 2021 the patient initiated pembrolizumab 200 mg IV every 3
weeks. After three cycles a surveillance CT in May 2021 showed
resolution of the mass in the proximal stomach as well as resolution of
the adjacent perigastric lymphadenopathy. Multiple subcentimeter
low-density lesions were again visualized in the liver.
In June of 2021, after three cycles of immunotherapy, the patient
developed a ruptured left knee popliteal cyst associated with
significant pain. She became much more sedentary because of this and
also began to experience lack of appetite and fatigue. Thyroid studies,
ACTH, and morning cortisol were all within normal levels. There was
therefore no evidence that this was related to treatment with
immunotherapy at the time. Treatment was held to allow time for the
patient to recover. She showed significant improvement and at follow-up
in August 2021 was back to her baseline. CT imaging performed at that
time showed a decrease in size in the hepatic lesions, with a decrease
in the largest lesion from 2.6 cm to 0.8 cm. The portacaval and
para-aortic lymph nodes were also noted to have decreased in size. The
gastric mass was again not visualized. Given that the imaging showed
continued improvement in the disease despite the patient not having
received immunotherapy since May 2021, the decision was made to continue
to monitor off of all therapy.
Imaging was again performed in February 2022 with only one of three
liver metastases still visible (Figure 1). The previously identified
portacaval lymph node had resolved. She was again continued off of
therapy given the remarkable durable response she attained with only
three doses of immunotherapy.