Gastrointestinal autonomic nerve tumor presenting as high-grade sarcoma. Case report and review of the literature

Gastrointestinal Autonomic Nerve Tumor of the Colon

Gastrointestinal autonomic nerve tumor (GANT) is an uncommon subtype of gastrointestinal stromal tumor that is morphologically similar to conventional stromal tumors but has ultrastructural features of neural differentiation. Of the approximately 58 cases of GANT reported to date, most have arisen in the small intestine or stomach, but none, to our knowledge, in the colon or rectum. Accordingly, we report the first case of colonic GANT and document its histologic, ultrastructural, and immunohistochemical characteristics. These were not unlike those of GANT arising elsewhere in the alimentary tract, including interlacing spindle cells, skenoid fibers, axonal cytoplasmic processes, dense core neurosecretory granules, and immunoreactivity to vimentin and NSE. The rarity of GANT in the large intestine should not preclude ultrastructural evaluation of colorectal stromal tumors for neural features.

Gastrointestinal autonomic nerve tumors: a clinical review

PURPOSE

Gastrointestinal autonomic nerve tumors (GANTs) are believed to be rare accounting for 1 % of all malignant gastrointestinal tumors. Many gastrointestinal surgeons and gastroenterologists are unaware of this entity. This review aims to highlight the salient clinical features and prognosis of GANTs.

METHODS

Using the common search engines and manual cross-referencing, a search of the English literature was conducted for "gastrointestinal autonomic nerve tumor."

RESULTS

All of the published literature on GANTs is either case reports or small case series. From 49 retrieved articles, a total of 107 GANT cases were collected with a mean age of 54 years and equal male to female preponderance. The most commonly affected site was small bowel followed by stomach. Esophageal and colorectal GANTs were less frequent. Clinical presentation was variable ranging from non-specific symptoms, abdominal pain, weight loss, iron-deficiency anemia, to obstruction and gastrointestinal bleeding. Acute presentation due to free rupture or perforation with subsequent peritonitis was extremely rare. Endoscopic and radiological investigations were valuable in tumor localization and determination of distant spread. Thirteen patients were lost to or had no follow-up, leaving 94 patients for long-term outcome analysis. All patients were treated by radical surgical resection of the involved organ as this offered the only hope of cure. Local recurrence, metastases, or both developed in 40 % of cases despite radical surgical resection. Resection for local recurrences and hepatic metastases was feasible in some selected cases. Response to adjuvant chemoradiation was poor and imatinib mesilate was effective in cases of metastatic or inoperable CD117-positive GANTs.

CONCLUSION

Radical surgical resection of GANTs is the mainstay of treatment. The aggressive behavior after radical resection coined with the poor response to adjuvant chemotherapy call for the urgent need to develop new adjuvant therapies.

Gastrointestinal autonomic nerve tumors: A surgical point of view

AIM: Gastrointestinal autonomic nerve tumors are uncommon stromal tumors of the intestinal tract. Their histological appearance is similar to that of other gastrointestinal stromal tumors. We report two cases and performed an analysis of the literature by comparing our findings with the available case reports in the medical literature.

METHODS: Two patients were admitted with abdominal tumor masses. One occurred in the stomach with large multiple liver metastases and the second originated in Meckel´s diverticulum. The latter site has never been reported previously. Both patients underwent surgery. In one patient gastrectomy, right liver resection and colon transversum resection were performed to achieve aggressive tumor debulking. In the other patient the tumor bearing diverticulum was removed.

RESULTS: Postoperative recovery of both patients was uneventful. Histological examination, immunohistochemical analysis and electron microscopy revealed the diagnosis of a gastrointestinal autonomic nerve tumor. The patient with the tumor in Meckel’s diverticulum died 6 mo after surgery because of pneumonia. The patient with liver metastases have been alive 13 years after initial tumor diagnosis and 7 years after surgery with no evidence of tumor progression. In light of our results, we performed a thorough comparison with available literature reports.

CONCLUSION: Radical surgical resection of gastrointestinal autonomic nerve tumors seems to be the only available curative approach to date, and long term survival is possible even in large metastasized tumors.

The Big Eye in the 21st century: the role of electron microscopy in modern diagnostic neuropathology

Electron microscopy (EM) remains a powerful and even essential tool in modern diagnostic neuropathology. tumors are still encountered that defy histological or immunohistochemical classification, and EM can often provide answers in these cases. Tumors of the CNS for which EM is useful include unusual or atypical variants of meningioma, ependymoma, and schwannoma; oligodendroglioma-like tumors composed of small "clear" cells; and small "blue cell" tumors of childhood. EM is of great value in identifying site of origin for metastatic adenocarcinomas of unknown origin-an under-recognized and under-utilized potential for this technique. EM is useful in the diagnosis of peripheral nerve sheath tumors and gastrointestinal autonomic nerve tumors. EM is also important in the evaluation of certain congenital, inherited and metabolic diseases-including ceroid lipofuscinoses, CADASIL syndrome, certain myopathies, and mitochondrial encephalomyopathies--and of certain toxic and drug-induced peripheral neuropathies. An important application of EM is its utility in initiating a workup of an atypical tumor or metabolic condition, for which clinical and histological clues point in no obvious direction. In these situations, EM may provide either an answer outright (including answers to questions not asked) or important clues that guide further workup and narrow the range of diagnostic possibilities.

Gastrointestinal autonomic nerve tumor: immunohistochemical and molecular identity with gastrointestinal stromal tumor

Gastrointestinal autonomic nerve tumor (GANT) is a gastrointestinal neoplasm that ultrastructurally recapitulates the enteric neural plexus. This study identifies and defines the features of 10 cases of this rare mesenchymal tumor and compares its clinicopathologic and molecular genetic features with the data on gastrointestinal stromal tumor (GIST). The majority of patients in this series presented at an older age (mean 64 years). Tumors arose from the stomach (6), small intestine (2), and retroperitoneum (2). Mean tumor size was 14 cm; however, four neoplasms were <6 cm. Histologically, tumors were spindled or epithelioid; one epithelioid tumor demonstrated a previously undescribed rhabdoid histologic phenotype. All tumors were positive for CD117 (KIT), while eight of 10 were positive for CD34. In contrast, only two were positive for S-100, and all were negative for actin and desmin. Five GANTs demonstrated GIST-specific gain-of-function mutations in the juxtamembrane domain of the c-kit gene (50%). Three of 10 patients died of disease in 22-30 months, one patient died in the postoperative period, and one patient died of complications of CML. The clinicopathologic, histologic, immunohistologic, and molecular features of GANT are similar to GIST, indicating that GANT merely represents a phenotypic variant of GIST.

Plexosarcoma: endoscopic ultrasound and electron-microscopic characteristics of a stromal tumor

Endoscopic ultrasound is useful for managing submucosal masses; however, some of these lesions can be difficult to classify except with full histological and electron microscopic evaluation. A 72-yr-old woman was seen with upper GI bleeding. Endoscopy showed a 1.7-cm sessile ulcerated submucosal mass in the duodenal bulb. Endoscopic ultrasound revealed an echolucent submucosal mass arising from the fourth echolayer, the muscularis propria of the duodenal wall. These findings suggested that the lesion was a leiomyoma. The patient eventually had the lesion resected because of recurrent bleeding. Histologically it was a spindle cell tumor that on electron microscopy showed neuronal elements consistent with a plexosarcoma, or gastrointestinal autonomic nerve tumor. These lesions account for some one third of all gastrointestinal stromal tumors. Despite their low grade malignant histologic appearance, local recurrence or hepatic metastases occur in about 70% of patients.

High mitotic index associated with poor prognosis in gastrointestinal autonomic nerve tumour

AIMS

Three gastrointestinal autonomic nerve tumours (GANT) were characterized by immunohistochemistry and flow cytometry. Two of the three cases occurred in the small intestine, while the third was found in the stomach. Besides the immunohistochemical and ultrastructural description, the aim of this study was to examine the relation between the known and accepted predictive factors (ploidy data, the S-phase fraction, the mitotic and MIB-1 index and the size of the tumour) and the survival of the patients.

METHODS AND RESULTS

The immune profile showed that 3/3 cases were vimentin and NSE, 2/3 were synaptophysin and PGP 9.5 positive, while 1/3 also showed S100 positivity. Ultrastructurally, all the cases had dense core granules, one of them contained skenoid fibres. The flow cytometry revealed diploid DNA in all cases, however, significant differences could be seen in the proliferative activity of the individual neoplasms.

CONCLUSIONS

In spite of the published data of gastrointestinal stromal tumours (GIST) generally, neither the MIB-1 index and the ploidy data nor the size of the primary tumour helped to predict the clinical progression of the examined GANTs. However, the high proliferative activity (57 mitoses/10 HPF) and the elevated S-phase fraction (24%) was associated with advanced, metastatic and recurring disease in case 3. On the basis of these three cases, high mitotic activity is the most reliable factor in predicting aggressive clinical behaviour.

Gastrointestinal autonomic nerve tumor: a common type of gastrointestinal stromal neoplasm

Seven of 15 gastrointestinal stromal tumors from the author's file were classified as plexosarcomas when examined by electron microscopy and immunohistochemistry. Electron microscopy was essential for the diagnosis.

Gastrointestinal autonomic nerve tumor with giant abscess. A case report and literature review

We report a gastrointestinal autonomic nerve tumor of the stomach with a giant abscess. The patient had fever and pain and was found to have anemia and an abdominal mass. X-ray and endoscopic examination showed a gastric submucosal tumor with a fistula to the gastric lumen. Partial gastrectomy was performed and no metastasis was found. On gross examination, the excised tumor was seen to be a submucosal solid tumor with a giant abscess. Alpha streptococci and anaerobic gram-negative rods were cultured from the pus of the abscess. The tumor resembled a gastric myogenic tumor composed of spindle cells, partly showing storiform and epithelioids. Tumor cells showed positive staining for vimentin and neuron-specific enolase but were negative for desmin, alpha-smooth muscle actin, and S-100 protein. Ultrastructural examination showed remarkable interdigitation of cytoplasmic processes with neurosecretory granules between the tumor cells. This lesion was similar to previously described gastrointestinal autonomic nerve tumors. Gastrointestinal autonomic nerve tumors are a rare, distinct subtype of gastrointestinal stromal tumors; although several cases of focally necrotic tumors have been reported, there has been only one report of the tumor with an abscess, as in our case.

Gastrointestinal autonomic nerve tumors: immunohistochemical and ultrastructural studies in cases of gastrointestinal stromal tumor

The gastrointestinal autonomic nerve tumor (GAN tumor) is an uncommon stromal tumor with a morphological feature resembling the cell processes of the enteric plexus, and was originally termed a plexoma or plexosarcoma. Light microscopic studies show the GAN tumor most often consists of spindle-shaped cells indistinguishable from a smooth muscle tumor or Schwann cell tumor. Immunohistochemical and ultrastructural examinations of 18 cases of gastrointestinal stromal tumor (GIST) were performed. During ultrastructural examination, all of the 12 cases which were immunohistochemically positive for S-100 protein or neuron-specific enolase (NSE) showed synapse-like structures containing dense core neurosecretory granules measuring 100-200 nm, and 40-60 nm endocytoplasmic vesicles. These results suggest that most GIST of neurogenic origin are tumors derived from the myenteric nerve plexus.

Gastrointestinal autonomic nerve tumor: further observations regarding an ultrastructural and immunohistochemical analysis of six cases

Gastrointestinal autonomic nerve tumor (GANT) is a specialized form of stromal neoplasm whose ultrastructural features support a myenteric plexus derivation and provide the basis for its diagnosis. GANT actual frequency, relationship to skeinoid fibers, and CD34 expression status are some of the controversial aspects of this entity. Out of 14 gastrointestinal stromal tumors gathered during a 1-year period, six (42%) instances were diagnosed as GANT by electron microscopic study of at least five ultrathin sections per case. Additionally, GANTs were immunohistochemically investigated with a panel of nine antibodies including CD34. Ultrastructurally, every GANT case showed diagnostic findings and evidence of skeinoid fibers, whereas immunohistochemically all except one were CD34 positive. Immunoreactivity for neuron-specific enolase, synaptophysin, and vimentin was a common occurrence as well. In conclusion, GANT seems to be more frequent than hitherto recognized, skenoid fibers are a regular feature of GANT, and a positive CD34 immunoreaction does not discriminate between GANT and other non-smooth muscle, non-schwannian neoplasms.

Inflammatory cell-rich gastrointestinal autonomic nerve tumor. An expansion of its histologic spectrum

Gastrointestinal autonomic nerve (GAN) tumor is an uncommon neoplasm of the gastrointestinal tract. Its histologic appearance is similar to other gastrointestinal stromal tumors. Ultrastructural demonstration of neural differentiation is required for its definitive diagnosis. Recently, we encountered two examples of GAN tumor that occurred in the body of the stomach and the cervical esophagus; the latter site has never been reported previously. These tumors showed unequivocal evidence of neural differentiation ultrastructurally, confirming the diagnosis of GAN tumor. Histologically, they were composed of swirling fascicles of spindle cells as well as a minor component of epithelioid cells, similar to that described previously. In addition, a cuff of lymphoid cells was noted at the peripheral part of both tumors and a scattering of mature plasma cells, lymphocytes, and foam cells was intermingled with the tumor cells. Such histologic features have not been described hitherto and can potentially be misinterpreted as features of inflammatory pseudotumor, inflammatory fibrosarcoma, or follicular dendritic cell tumor. There is a lack of CD34 expression in both tumors, but it would be premature to draw any conclusions about the potential usefulness of this observation.