2 | CASE
A 27-year-old female patient found a mass at the right back neck, which
was with a size similar to a ”fava bean” without tenderness, redness, or
swelling, and with no growth or disappearance seven months ago. The
patient described that the size of the mass gradually increased to like
an ”adult fist”, which was accompanied with mild tenderness one month
ago
(Fig.1). She was diagnosed as fibroma in the local hospital and
underwent major resection. Postoperative pathology revealed high
dysplasia of the tumor, and then the pathological section was sent to
the ”West China Hospital of Sichuan University” for pathological
examination. The immunohistochemistry results showed: S-100 (+), CD34
(+), desmin (+), H3K27Me3 (-), myogenin (+), MyoD1 (+), SMA (-), STAT-6
(-), P53 (+), NF (-), ALK-1 (-), TRK (-), and the Ki-67 positive rate
was 40%. Immunophenotypic testing revealed the presence of more
rhabdomyosarcoma components, which was combined with extensive loss of
H3K27Me3 protein. Therefore, malignant triton tumor (MTT) was diagnosed.
However, three weeks after the diagnosis, tumor recurrence was observed
and the tumor was rapidly increased to the size of an ”adult fist”
again. She visited our hospital for surgical treatment. The physical
examination showed a mass of approximately 6.4cm×6.5cm×8.9cm at the
right back neck. Magnetic Resonance Imaging (MRI) showed a mass of soft
tissue that occupied the shadow at the right back neck (Fig.2).
On
September 18, 2020, we performed surgery to completely remove the tumor.
Postoperative pathological analysis by our hospital confirmed MTT
(Fig.3). The postoperative tumor specimens were sent to “Beijing
Genetron Health Medical Laboratory Co., Ltd.” for genetic testing. The
results showed FANCD2 and NF1 gene mutations. No tumor recurrence was
observed during the postoperative follow-up, and the patient is
currently receiving chemotherapy and radiotherapy regularly.