Figure 2: Imaging of the intrathoracic SFT before redebulking
surgeryA coronal chest-CT showing a large heterogeneous tumor mass infiltrating
the mediastinum, pleura, pericardium and diaphragm. In addition, the
expansion of the left lung is significantly reduced. B and C:
Transversal fusion (B) and maximum intensity projection (C) of
[68Ga]DOTATATE/PET-CT showing the SFT and further
lesions in the pericardial fat tissue with variable and focally
increased SSTR-expression.
From the first day after her admission, the patient required continuous
intravenous glucose infusions (intravenous glucose 20% with infusion
rates of up to 40 ml/hour) overnight, in order to prevent fatal
hypoglycemic episodes. Since the tumor showed SSTR-expressing lesions in
[68Ga]DOTATATE/PET-CT, an adjuvant treatment with
a somatostatin-analogue, Octreotide, was started. While uptitration of
Octreotide to a dose of 800 µg/day subcutaneously (4 x 200 µg) improved
hypoglycemic episodes, continuous glucose infusions were still necessary
to maintain tolerable blood glucose levels above 50 mg/dl (2.8 mmol/l)
(Figure 3).
After weighing the potential age-related risks and benefits, with
informed consent of the patient, another debulking surgery was
performed, removing great portions of the gelatinous, liquified tumor by
suction and manual extirpation. Histological examination of the resected
tissue again confirmed the diagnosis of the SFT, with fusiform
neoplasia, elevated mitosis rates (5 per HPF) and without necrosis.
Immunohistology showed that tumor cells were CD34(+), STAT6(+), EMA(-),
CK1/3(-), and SMA(-), with a MIB-1 determined proliferation rate of
15%. According to Demicco et al 2017 [22], the tumor was classified
as low risk. Glucose infusions could be terminated immediately after the
surgery. Due to the inability to achieve R0 resection and the rapid
tumor progression after her initial debulking surgery, the patient
continued on Octreotide-treatment aiming at a suppression of tumor
proliferation and a reduction of hypoglycemic episodes in the future
with now reduced tumor mass. Ten days after surgery Octreotide was
replaced with Lanreotide (120 mg/month subcutaneously) to allow a longer
interval between injections. After the first application of Lanreotide
the patient was discharged. No hypoglycemic episodes have been reported
since the redebulking surgery (Figure 5)