GNB is a pediatric tumor and extremely rare in adults. Less than 50 cases of GNB have been reported in adults .GNB can occur any site of from the base of the skull to the pelvis, most frequently in adrenal gland(35%) , retroperitoneum gangia (30%–35%), and posterior mediastinum (20%) ,pelvis (2-3%)[8],but also located in same rare site like brain,cervical region[9].
Only a few cases have been reported gastric GNB in english literature. Sandoval reported a case of multifocal ganglioneuroblastomas, who had a right cervical tumor, a left posterior mediastinal. tumor, bilateral adrenal tumors, and bony and bone marrow metastases. the gastric involvement was only detected by meticulous exploration during laparotomy[10]. Here, we describe a rare case of gastric GNB resected completely by laparoscopy in a 73-year-old male elder.
The international neuroblastoma pathology classification defined the histological features and proposed four tumor categories:NB , GNBn, GNBi and GN. The four tumor categories are divided in two distinct prognostic groups: favorable histology and unfavorable histology [1, 11](see table 1).The tumor type of our case was GNBi , favorable histology.
In 1993, the international classification INSS published a surgicopathologic staging system used for the staging of the disease[7] (see table 2). This stage system has some limitation, like patients who are yet to have surgery. The behavior of neuroblastic tumor can be affected by many factors. Most important prognostic factors are age at the diagnosis,primary site of tumor,histology,disease stage , status of NMYC, chromosome 11q status and DNA ploidy[12-15].These factors were incorporated into the International Neuroblastoma Risk Group (INRG) classification system to establish a consensus for pretreatment classification (see table 3). Neuroblastoma is classified into four categories: very low-risk, low-risk, intermediate-risk, or high-risk.
The clinical manifestations of GNB are different. The most common symptoms are abdominal mass, abdominal pain, abdominal swelling ,and effect of metastasis[6, 16]. Vomiting, diarrhea and poor feeding were also identified in a small proportion of patients.[17]This case presented upper abdomen pain along with abdominal swelling.
CT and magnetic resonance imaging (MRI) with contrast can provide valuable diagnosis information for GNB. CT can be used to find the primary site of the tumor and approximately 50% of GNBs have calcification[4]. The features of GNBs on enhanced CT can ranging from well marginated masses with homogeneous enhancement to irregular, cystic, hemorrhagic, or locally invasive masses[4, 18]. On MRI, GNB is typically homogeneous with enhancement and appears high signal intensity on T2-weighted images and low signal intensity on T1-weighted images[19]. In our case, CT scan revealed irregular soft tissue mass in gastric antrum with unclear boundary, and dynamic analysis revealed a mild heterogeneous enhancement, without calcification.
The final diagnosis depends on histopathological examination and immunohistochemical staining. GNB are composed of both mature ganglion cells and neuroblasts. For immunohistochemical staining, NSE, Syn, CgA, S-100, CD30 are often positive in tumor tissues[20, 21]. In our case, the histopathological and immunohistochemical features were line with GNBi. The tumor was classified as Stage 1 according to INSS.
There are no treatment guidelines for adults GNB. The treatment principle is derived from pediatric experience. The therapeutic strategy includes surgery, chemotherapy, and radiotherapy.The radical surgery is the best and main treatment available for GNBs[7, 22-24]. If the tumor is not completely removed or in metastatic stage, chemotherapy should be performed[25].Patients with NMYC amplification or deletion of the short arm of chromosome 1 are related to poor prognosis[13, 15]. Surgery and postoperative chemotherapy can be treatment choice for these patients and chemotherapy schedules with higher dose intensity are recommended. Chemotherapy regimens utilized include include cisplatin, etoposide, vincristine, cyclophosphamide, and doxorubicin[26]. Recenlty, topotecan and temozolomide have been used in patients with relapsed disease and demonstrated a significant antitumor activity[27, 28]. In inoperable, unresectable and metastatic cases, radiotherapy should be considered for symptom palliation associated with metastatic masses[29]. Boris Decarolis et al[30] reported that GNBi have excellent prognosis and cytotoxic treatment has no substantial effect on it. Surgery alone is enough for the treatment of GNBi and does not need to be radical if tumor residuals were smaller than 2 cm.
Disease recurrence has been found to occur mostly in the first two years after surgery. Therefore, the patients should be followed every 3 months for the first and second years, then every 6 months. Attention to the symptoms and careful physical examination are fundamental, Bolzacchini et al[31] suggested that complete blood count, urinary catecholamine analysis, and imaging of the site of the primary tumor should be performed at every examination. I-131MIBG scintigraphyan can help to detect bone metastasis. It is recommended to perform I-131MIBG scintigraphy every 6 months in the first and second year.
In our case, the patient was in stage 1 disease of GNBi, could receive surgery treatment without adjuvant chemotherapy or radiotherapy. There was no sign of recurrence or metastasis in one year after operation. However, long-term follow-up is needed.
In conclusion , we have presented a case of a 73-year-old man with gastric GNBi, and was resected completely by laparoscopic approach. Our report suggested that although the rarity of gastric GNB as a primary site of origin, it should be considered in the differential diagnosis of gastric masses in adult. Radical surgery is sufficient for the treatment of GNBi and long-term follow-up should be performed.