Giant extra gastrointestinal stromal tumor of lesser omentum obscuring the diagnosis of a choloperitoneum

Extra-gastrointestinal stromal tumor arising in the lesser omentum with a platelet-derived growth factor receptor alpha (PDGFRA) mutation: a case report and literature review

BACKGROUND

Gastrointestinal stromal tumors (GIST) arising from sites other than the gastrointestinal (GI) tract, termed extra-gastrointestinal stromal tumors (EGIST), are rare. Among EGIST, those with platelet-derived growth factor receptor alpha (PDGFRA) mutations are even rarer, with only a few cases reported. About 80% of GIST has KIT mutations, and 10% of GIST have PDGFRA mutations, which commonly affect the TK2 domain (exon 18). Among the exon 18 mutations, the D842V substitution is limited to gastric GIST. In EGIST, the degree of KIT and PDGFRA mutations varies on where the location of the tumor is, and it is suggested that omental EGIST is similar to gastric GIST. Adjuvant imatinib therapy is recommended for high-risk GIST; however, it is known that imatinib is less effective against GIST with a PDGFRA D842V mutation.

CASE PRESENTATION

A 75-year-old man was referred to our hospital with an extrinsic tumor of the lesser curvature of the gastric body. Intraoperative findings showed a tumor located outside of the lesser omentum with no connection between the tumor and the gastric wall. The tumor was subsequently resected. Pathological examination indicated a GIST arising in the lesser omentum measuring 70 mm in its longer dimension. Because the tumor had a PDGFRA mutation (D842V substitution), imatinib was suspected to lack efficacy to the tumor. Thus, although the tumor was considered clinically to have a high risk of recurrence, adjuvant imatinib therapy was not indicated. The patient has been free of recurrence for 29 months since the surgery.

CONCLUSION

We described a case of EGIST with a PDGFRA mutation arising in the lesser omentum. And we reviewed 57 cases of omental EGIST and showed that the clinicopathological characteristics and mutation status in omental EGIST were very similar to gastric GIST. In particular, PDGFAR D842V mutation rate in omental EGIST seemed as high as that in gastric GIST. These results suggested that omental EGIST is strongly related to gastric GIST, so the behavior of omental EGIST might be akin to gastric GIST. However, further studies are required to determine the prognosis and the necessity of adjuvant therapy for EGIST with a PDGFRA mutation.

Characteristic of extra luminal gastric stromal tumor arising from the lesser curvature of the stomach: A case report

RATIONALE

Gastrointestinal stromal tumor (GIST) is one of the most common malignant mesenchymal tumors of the gastrointestinal tract. They generally arise from the fourth layer (muscularis propria) and rarely from the second or third layer. Although the manifestations of gastric stromal tumors are diverse, to our knowledge, there are only several cases of an extra-gastric stromal tumor in the literature appearing with a pedunculation. Pedunculated large GISTs are not frequent and compress the neighboring organs. When they were huge, it is difficult to differentiate the origin of the masses. Thus, in the clinical setting, physicians should pay more attention to the pattern of manifestation of the gastric stromal tumor.

PATIENT CONCERNS

A 62-year-old man had no gastrointestinal symptoms or significant medical and family histories. During the health examination with US, a cystic-solid tumor was found below liver. The results of the physical examination were unremarkable, and routine laboratory data on admission did not show any abnormal findings.

DIAGNOSIS

Computed tomography of the abdomen showed a mixed echoic mass measuring 10 × 8 × 8 cm and located below the liver, adjacent to the gastric antrum. After endoscopic ultrasound-guided fine-needle aspiration, cytopathology showed that the specimen was filled with red blood cells, and it had no malignant cells. Histopathology revealed that the mass was a GIST, and immunohistochemical analysis showed the following: CD117(+), CD34(+), desmin(-), Dog-1(+), Ki-67% <1%, and smooth muscle actin(-).

INTERVENTIONS

Surgical resection was performed on the patient.

OUTCOMES

The lesion was diagnosed as a gastric stromal tumor with a pedicle and an old hemorrhage. The patient's recovery was uneventful. After surgery, computed tomography at the 6-month and 1-year postoperative follow-up visits did not reveal relapse or any metastasis.

LESSONS

In the clinical setting, physicians should pay more attention to the pattern of manifestation of the extra-gastric stromal tumor in patients with a pedicle or hemorrhage. Additionally, endoscopic ultrasound-guided fine-needle aspiration can be used to make an accurate preoperative diagnosis of such diseases, and its findings can serve as an important basis for surgical excision of the lesions.

A Huge Pelvic-Abdominal Malignant GIST Tumour in a Patient with Neurofibromatosis Type 1: Case Report and Literature Review

Gastrointestinal stromal tumours are rare tumours of the gastrointestinal tract (GIT) accounting for 0.1%–3% of all gastrointestinal tumours. The most common location is the stomach (55%) followed by the small bowel (31.8%), colon (6%), other various locations (5.5%), and the oesophagus (0.7%). They may also occur in extraintestinal locations. The signs and symptoms of GIST depend on the tumour's location and size. Gastrointestinal bleeding is one of the most common symptoms. Other signs and symptoms include abdominal discomfort, pain or distention; intestinal obstruction, and weight loss. The association between the development of GISTs and neurofibromatosis 1 (NF1) has been established. NF1-associated GISTs tend to have a distinct phenotype, and the absence of KIT/PDGRFα mutations in turn has implications on further management when they do not respond well to imatinib treatment. Here, we present one of the largest GISTs reported in the literature with a total volume of 25.3 × 20 × 14 cm + 27.9 × 23 × 8 cm and an overall weight of 7.3 kg, which developed in a 43-year-old female patient with NF1 and was resected on an emergency basis due to the rapid deterioration and development of abdominal compartment syndrome. Pathology assessment showed a malignant GIST composed of spindle cells with elongated nuclei with necrosis, marked pleomorphism and numerous giant cell. The mitotic count was >15/50 HPF, Ki 67 was 80%, and the lymphovascular invasion was clear. Immunohistochemistry investigations showed that Vimentin, CD117, and DOG1 were positive, while BCL-2 and CD99 were focal positives. Pan-CK, S-100, CD34, Desmin, SMA, and HMB-45 were negatives.

Gastrointestinal stromal tumor of the lesser omentum: a case report and review of the literature

A 72-year-old woman visited our hospital for a routine health examination and underwent abdominal ultrasonography, which revealed an intra-abdominal tumor. Abdominal computed tomography and magnetic resonance imaging showed a well-defined solid mass of ~3 cm in diameter lying adjacent to the stomach. The mass was preoperatively diagnosed as gastrointestinal stromal tumor of the stomach. At laparotomy, a well-encapsulated tumor was found in the lesser omentum. It was slightly adherent to the stomach wall but was removed without difficulty. Therefore, only enucleation of the tumor was performed. The excised tumor, which was 35 × 30 × 25 mm³ in size, had a white cut surface without necrosis or hemorrhage. According to the pathological findings, the tumor was classified as a very low-risk gastrointestinal stromal tumor originating in the lesser omentum. Gastrointestinal stromal tumor of the lesser omentum is very rare, and surgical resection is the only effective treatment modality.

Extragastrointestinal stromal tumour of the lesser omentum: A case report and literature review

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EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have an aggressive biological behaviour.

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There have been only a few previous reports of EGISTs arising in the lesser omentum.

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Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors.

Introduction

Extragastrointestinal stromal tumours (EGISTs) are very uncommon compared to their gastrointestinal counterparts. Most of them originate from the intestinal mesentery and the omentum.

Case report

A 70 year-old Caucasian woman presented with a bulky abdominal mass which on laparotomy was found to originate from the lesser omentum and was completely resected. Histological examination revealed spindle cells with severe pleomorphism and high mitotic activity. Immunohistochemically, the tumour cells showed strong positivity for c-kit (CD117), DOG-1 and human haematopoietic progenitor cell antigen (CD34). An exon 11 deleterious mutation was identified and thus regular dosing of 400 mg imatinib mesylate was initiated.

Discussion

There have been only a few previous reports of EGISTs arising in the lesser omentum. Although EGISTs seem to have morphological and immunohistochemical similarities with GISTs, their pathogenesis, incidence, genetic background and prognosis are not completely known because they are extremely rare. It is strongly believed that such tumours originate from cells, which have similar pathological characteristics and biological behaviour as the intestinal cells of Cajal. In most series of EGISTs, a female predominance, a greater size and a higher mitotic index than GISTs were observed.

Conclusion

EGISTs are very rare mesenchymal tumours which originate from cells outside the gastrointestinal tract and tend to have a more aggressive biological behaviour than their GI counterparts. Complete surgical resection is the most effective treatment associated with the use of imatinib in the presence of adverse prognostic factors. In any case a strict follow-up is necessary due to high recurrence rates.

Clinicopathological features and prognosis of omental gastrointestinal stromal tumor: evaluation of a pooled case series

Clinicopathological features and prognosis of omental GISTs are limited due to the extremely rare incidence. Therefore, the aim of the present study was to investigate the clinicopathological features and prognosis of omental GISTs. Omental GISTs cases were obtained from our center and from case reports and clinical studies extracted from MEDLINE. Clinicopathological features and survivals were analyzed. A total of 99 cases of omental GISTs were enrolled in the present study. Omental GISTs occurred predominantly in greater omentum (78/99, 78.8%). The majority of tumors exceeded 10 cm in diameter (67/98, 68.3%) and were high risk (88/96, 91.7%). Histological type was correlated with tumor location and mutational status. The five year DFS and DSS was 86.3% and 80.6%, respectively. Mitotic index was risk factor for prognosis of omental GISTs. Prognosis of omental GISTs was worse than that of gastric GISTs by Kaplan-Meier analysis. However, multivariate analysis showed that the prognosis was comparable between the two groups. The majority of omental GISTs were large and high risk. Mitotic index was risk factor for prognosis of omental GISTs. The prognosis was comparable between omental and gastric GISTs.

Extragastrointestinal stromal tumor of lesser omentum: a challenging radiological and histological diagnosis

Extragastrointestinal stromal tumors (EGISTs) are a rare subgroup of gastrointestinal stromal tumors (GISTs), arising from outside the walls of gastrointestinal tubular organs. We report a case of an EGIST of the lesser omentum that represented a diagnostic challenge. Due to its atypical radiologic findings, it was preoperatively mistaken for pedunculated hepatic hemangioma. Histopathologically, it showed epithelioid structure and c-kit negative, very uncommon for GIST. Only a few cases of EGISTs have been previously reported. We discuss imaging and histological features, emphasizing potential pitfalls.

A rare case of giant gastrointestinal stromal tumor of the stomach involving the serosal surface

INTRODUCTION

Although rare, gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors affecting the gastrointestinal tract.

PRESENTATION OF CASE

Here we report the case of a 43-year-old man complaining of abdominal pain along with a painless and palpable mass, which was confirmed on magnetic resonance and multislice computed tomography. Laparotomy revealed a nodular grayish-white firm noninfiltrative mass (39×27×14cm, 6109g) that was well localized within the extramuscular and peritoneal surface of the anterior wall of the stomach; complete tumor resection was performed. Histopathological examination revealed features typical of GIST, including increased cellularity, increased mitotic activity, and spindle shaped cells as well as positive immunoreactivity for KIT, CD34, and vimentin.

DISCUSSION

A review of literature revealed that GISTs of the size and weight similar to the present case has been rarely reported. GIST most frequently involves the stomach. Although the etiopathogenesis of this disease remains unclear, few well-documented familial cases have been associated with GIST syndromes.

CONCLUSION

The primary treatment preferred is complete surgical excision of the tumor.