3 DISCUSSION
VIPoma in adults is primarily pancreatic tumor, with the tail of the
pancreas being the most common site of origin [9]. The majority of
VIPomas in pediatric patients are ganglioneuroblastomas or
ganglioneuromas originating in the adrenal medulla or sympathetic neural
crest, in contrast to adult cases [10]. In our institution, VIPoma
has been found in only 3 patients (2.7%) among 111 with neuroblastic
tumors. Among our patients with neuroblastic tumors, minimal invasive
surgery (MIS) was performed in about 12.0% of cases, so MIS for VIPNT
seems to be an extremely rare application.
VIPNT is divided into cases preceded by diarrhea (primary type) and
cases becoming clinically evident after chemotherapy [11]. Whether
neoadjuvant chemotherapy or surgery should be prioritized for patients
with VIPNT and IDRF positivity or metastases has been controversial. In
such cases, tumor resection after a biopsy to confirm the tumor biology
and neoadjuvant chemotherapy is recommended. However, as in our case,
the effects of somatostatin analogs on VIPNT may be limited [12,13].
Kabalan et al. reported the efficacy of debulking and steroids for
symptoms in cases of primary type with unresectable VIPNT [13].
Their case was preceded by two courses of neoadjuvant chemotherapy, but
the diarrhea symptoms did not improve. Control of VIPNT symptoms may be
difficult with chemotherapy or medical treatment [11]. A surgical
approach was the first-line treatment in our case to control diarrhea.
While extirpation of the VIPNT should be the first choice, volume
reduction might be a suitable second choice in unresectable cases with
positive IDRF or amplified MYCN following chemotherapy.
MIS for VIPoma has mainly been reported in cases of pancreatic neoplasms
in adult patients [14]. Pediatric patients with solid tumors may
also enjoy certain benefits of MIS in terms of a faster recovery, less
pain, better cosmetic results, and earlier start of adjuvant treatment
[5]. The primary type of VIPNT has a favorable prognosis of 90%
[11] and may be suitable for MIS among pediatric patients. The
International Pediatric Endosurgery Group (IPEG) issued guidelines in
2010 for laparoscopic adrenalectomy based on level III evidence and
confirmed its feasibility without absolute contraindications [15].
The most important factor to consider for MIS is the tumor size. The
IPEG-issued guidelines recommend a maximum size of 6 cm in their
criteria [15]. Our case had a maximum diameter of approximately 4
cm, so complete tumor excision by laparoscopic surgery was considered
feasible. In addition, the preoperative evaluation of IDRF is also
important for performing laparoscopic surgery [16]. The risk of open
conversion should be considered preoperatively, as radiological findings
may not be compatible with the intraoperative findings [4]. Our case
was a feasible indication for laparoscopic surgery with a tumor size of
4 cm and negative IDRF.