Primary cystic and solid neuroendocrine tumor of the retroperitoneum: A case report

RATIONALE

Primary neuroendocrine tumors (NETs) of the retroperitoneum are extremely rare. The purpose of this case report is to highlight the unusual growth pattern and radiologic features of primary retroperitoneal NETs.

PATIENT CONCERNS

A 46-year-old woman was found to have a retroperitoneal cystic and solid mass during a physical checkup.

DIAGNOSES

The mass was mainly multiseptated in the cystic portion and had a bead-like, lobulated appearance. The solid portion showed restricted diffusion on diffusion-weighted imaging and obvious homogeneous enhancement. The cystic portion showed ring-like and septal enhancement. The patient was diagnosed with a grade 2 (G2) NET of the retroperitoneum after surgery.

INTERVENTIONS

The patient underwent resection of the large retroperitoneal tumor.

OUTCOMES

The patient returned 20 months later with tumor recurrence in the retroperitoneum. She was enrolled in a clinical trial for sulfatinib, and the mass was considerably reduced in size after 4 months. During a nearly 1.5-year follow-up, the mass gradually became slightly enlarged. The expression of somatostatin receptor 2 (SSTR2) was detected, and somatuline was administered as the current treatment.

LESSONS SUBSECTIONS

When a retroperitoneal mass presents as a well-defined cystic or solid hypervascular mass with a fibrous capsule, a primary retroperitoneal NET should be considered in the differential diagnosis.

Contrast-enhanced multiple-phase imaging features of intrahepatic mass-forming cholangiocarcinoma and hepatocellular carcinoma with cirrhosis: A comparative study

The intrahepatic mass-forming cholangiocarcinoma (IMCC) is frequently misdiagnosed as hepatocellular carcinoma (HCC) in patients with cirrhosis, by numerous radiologists and clinical doctors, which results in the incorrect therapeutic treatment. A retrospective case-control study was conducted, and the contrast-enhanced multiple-phase (CEMP) computed tomography (CT) and magnetic resonance imaging (MRI) findings of 22 pathologically confirmed IMCC patients and 22 HCC controls with underlying liver cirrhosis were analyzed at the present hospital, from January 2010 to December 2015. In addition, serum tests were conducted and clinical symptoms of patients evaluated. A statistical analysis revealed that the enhancement pattern, signal on MRI delayed phase (P<0.001), maximum diameter, capsule retraction, portal vein invasion, bile duct dilation and abdominal lymphadenectasis characteristics were different between IMCC and HCC patients with cirrhosis. On CEMP CT and MRI analysis, the most frequently occurring enhancement patterns of IMCC were progressive patterns (P=0.001 or P<0.001). Conversely, the most frequently occurring enhancement patterns present in HCC were the washout patterns (P<0.001). Therefore, the diagnosis of IMCC in cirrhotic patients should be verified with CEMP CT and MRI analysis for the future, to determine presence or absence of progressive and/or peripheral rim-like enhancement, a hyperintensive delayed phase with capsule retraction, portal vein invasion, bile duct dilation, abdominal lymphadenectasis and increased levels of CA199.

Distribution of TMEM100 in the mouse and human gastrointestinal tract--a novel marker of enteric nerves

Identification of markers of enteric neurons has contributed substantially to our understanding of the development, normal physiology, and pathology of the gut. Previously identified markers of the enteric nervous system can be used to label all or most neuronal structures or for examining individual cells by labeling just the nucleus or cell body. Most of these markers are excellent but have some limitations. Transmembrane protein 100 (TMEM100) is a gene at locus 17q32 encoding a 134-amino acid protein with two hypothetical transmembrane domains. TMEM100 expression has not been reported in adult mammalian tissues but does appear in the ventral neural tube of embryonic mice and plays a role in signaling pathways associated with development of the enteric nervous system. We showed that TMEM100 messenger RNA is expressed in the gastrointestinal tract and demonstrated that TMEM100 is a membrane-associated protein. Furthermore TMEM100 immunoreactivity was restricted to enteric neurons and vascular tissue in the muscularis propria of all regions of the mouse and human gastrointestinal tract. TMEM100 immunoreactivity colocalized with labeling for the pan-neuronal marker protein gene product 9.5 (PGP9.5) but not with the glial marker S100ß or Kit, a marker of interstitial cells of Cajal. The signaling molecule, bone morphogenetic protein (BMP) 4, was also expressed in enteric neurons of the human colon and co-localized with TMEM100. TMEM100 is also expressed in neuronal cell bodies and fibers in the mouse brain and dorsal root ganglia. We conclude that TMEM100 is a novel, membrane-associated marker for enteric nerves and is as effective as PGP9.5 for identifying neuronal structures in the gastrointestinal tract. The expression of TMEM100 in the enteric nervous system may reflect a role in the development and differentiation of cells through a transforming growth factor β, BMP or related signaling pathway.

An analysis of esophagectomy and other techniques in the management of high-grade dysplasia of Barrett's esophagus

Barrett's esophageal (BE) metaplasia is a premalignant condition of the distal esophagus that develops as a consequence of gastroesophageal reflux disease. The progression to carcinogenesis results from progressive dysplastic changes of the metaplastic epithelium through low-grade and then high-grade dysplasia (HGD) to eventually adenocarcinoma of the esophagus. The management of HGD is controversial with proponents for each of the three major management strategies: endoscopic surveillance, endoscopic ablative therapies, and esophagectomy. The aim of the study was to define and discuss the various management strategies of HGD arising from BE metaplasia. There is a paucity of randomized controlled data from which to draw definitive conclusions. All strategies for the management of HGD are reasonable options and are complimentary. BE with HGD is a malignant lesion. A multidisciplinary approach individualizing therapy should be undertaken when possible. Esophageal resection should be reserved for otherwise healthy patients. Endoscopic techniques are viable alternatives to surgery.

Patterns of operative mortality following esophagectomy

Esophagectomy has one of the highest mortality rates among all surgical procedures. We investigated the type and frequency of complications associated with perioperative mortality after esophagectomy. We performed a retrospective review of all perioperative deaths following esophagectomy for esophageal cancer at the Mayo Clinic, Rochester from 1993 through 2009. Of 1522 esophagectomies, perioperative mortality occurred in 45 (3.0%). The majority who died were male (82%); median age was 72 years (range 46-92). The median age-adjusted Charlson comorbidity score was 6. Twenty-three (51%) underwent neoadjuvant chemoradiotherapy. The type of esophagectomy was transthoracic in 27 patients (60%), transhiatal in eight (18%), tri-incisional in seven (16%), left thoracoabdominal in one (2%), and transabdominal in one (2%). A mean of 3.2 major complications occurred prior to death (median 2.5, range 1-8), with the most common being pulmonary complications occurring in 30 patients (67%) and anastomotic complications in 20 (44%). The primary underlying cause of death was pulmonary complications and anastomotic complications in 18 patients (40%) each, respectively, abdominal sepsis in three (7%), fatal hemorrhage in three (7%), and pulmonary embolism, stroke and multisystem organ failure in one each (2%), respectively. Patients died a median of 19 days (range 3-98) following esophagectomy. Most patients who died following esophagectomy experienced multiple serious complications rather than a single causative event. Major pulmonary and anastomotic complications were implicated in the vast majority of perioperative mortality, and should remain the focus of efforts to improve clinical outcomes.

Does FDG-PET add information to EUS and CT in the initial management of esophageal cancer? A prospective single center study

PURPOSE

There is no algorithm for the initial staging of esophageal cancer that is considered standard of care. This prospective blinded study analyzes the utility of FDG-PET as an adjunct to EUS and CT for the management of patients with esophageal cancer.

METHODS

Between December 2003 and October 2006, patients diagnosed with esophageal carcinoma underwent EUS, CT, and FDG-PET at their initial evaluation. Two thoracic surgeons were given staging EUS results and CT scan reports. They were asked if the patient needed surgical resection, neoadjuvant chemotherapy followed by resection, or palliation. With each case, one surgeon was unblinded to the FDG-PET results. The treatment decisions of each surgeon were compared to determine if PET altered clinical management.

RESULTS

A total of 50 patients (45 male, 5 female) were enrolled and data were prospectively collected. Forty-three (86%) had adenocarcinoma and 7 (14%) had squamous cell carcinoma. EUS was completed in 88% (44) of cases while 6 (12%) were incomplete secondary to tight stenosis. Nineteen were treated with surgery, 25 with neoadjuvant chemotherapy and surgery, and 6 with palliative chemoradiation. In 49 of 50 patients, the surgeons came to identical management decisions independent of PET results. In the one case that the treatment decision differed, the EUS was incomplete. The agreement on treatment strategy was 98% (kappa= 0.97, 95% CI 0.93-0.99).

CONCLUSION

This study shows that the addition of FDG-PET to EUS and CT offers little information to the initial treatment stratification of patients with esophageal cancer. However, in patients with incomplete EUS, FDG-PET may have some clinical utility.

Diurnal rhythmicity in intestinal SGLT-1 function, V(max), and mRNA expression topography

Mechanisms underlying the circadian rhythmicity in intestinal sugar absorption remain unclear. To test whether this rhythmicity is caused by changes in Na(+)-glucose cotransporter 1 (SGLT-1) function, we measured phloridzin-inhibitable sugar fluxes as an index of SGLT-1 activity. Jejunum obtained from rats killed at 6-h intervals during a 12-h light-dark cycle (CT0 is circadian time 0 h, time of light onset) were mounted in Ussing chambers, and 3-O-methylglucose (3-OMG) fluxes were calculated before and after addition of phloridzin. 3-OMG-induced change in short-circuit current and absorptive flux were significantly greater at CT9 than at CT3. This increase was phloridzin inhibitable. Kinetic studies indicated a significant increase in SGLT-1 maximal velocity (V(max)) at CT9. Food intake between CT3 and CT9 was <10% of the daily total, indicating that the increased SGLT-1 activity was anticipatory. Diurnicity of SGLT-1 mRNA was confirmed by Northern blotting. Expression topography analyzed by in situ hybridization revealed more intense labeling along the entire villus axis at CT9 and CT15 compared with CT3 and CT21. We conclude that diurnicity in intestinal sugar absorption is caused by periodicity in SGLT-1 V(max).

Enrichment of rab11, a small GTP-binding protein, in gastric parietal cells

Parietal cell secretion of acid requires the coordinated fusion of H(+)-K(+)-adenosinetriphosphatase (ATPase)-containing tubulovesicles with a secretory canalicular target membrane. We have previously reported the presence of rab2 on parietal cell tubulovesicles (L. H. Tang, S. A. Stoch, I. M. Modlin, and J. R. Goldenring. Biochem. J. 285: 715-719, 1992). Since 60% of the small GTP-binding protein sequences obtained from parietal cells were > 95% homologous with human rab11 (J. R. Goldenring, K. R. Shen, H. D. Vaughan, and I.M. Modlin. J. Biol. Chem. 268: 18419-18422, 1993), we sought to study rab11 in gastric parietal cells. A complete rab11 sequence was obtained, and the deduced amino acid sequence of rabbit rab11 was identical to that for human. Rab11 mRNA was present throughout the gastrointestinal mucosa. mRNA for both rab11 and rab2 were enriched in isolated parietal cells compared with chief cells. A polyclonal antiserum against rab11 labeled a single 25-kDa band in isolated parietal cells. Immunostaining of rat fundic tissue demonstrated prominent staining of parietal cells. Rab11 staining cosegregated with alpha-H(+)-K(+)-ATPase staining in enriched preparations of rabbit parietal cell tubulovesicles. These results suggest that rab11 is enriched in parietal cells and is associated with intracellular tubulovesicles.

Identification of a small GTP-binding protein, Rab25, expressed in the gastrointestinal mucosa, kidney, and lung

Small GTP-binding proteins have been implicated in the regulation of many dynamic cellular processes. The carboxyl termini of parietal cell small GTP-binding proteins were cloned using a 3'-rapid amplification of cDNA ends (RACE) technique with a degenerate oligonucleotide primer based on the WDTAGQE consensus GTP-binding sequence. Six out of 53 clones demonstrated a novel Rab sequence, now designated Rab25. The complete sequence was obtained using 3'-RACE and revealed a deduced amino acid sequence having 63% identity with Rab11. The deduced amino acid sequence demonstrated a carboxyl-terminal CCQNI and also a novel GTP-binding site sequence of WDTAGLE. Nevertheless, recombinant Rab25 was able to bind GTP on blot. A major 1.2 kilobase Rab25 message was detected throughout the gastrointestinal mucosa and in lung and kidney tissue. No message was detected in brain, heart, liver, or skeletal muscle. In gastric tissue, Rab25 was absent in the bowel wall; among mucosal cells, it was highly enriched in parietal cells compared to chief cells. Rab25 mRNA was also detected in several colon carcinoma lines including LIM1215 and HT-29. The results indicate that Rab25 represents a novel member of the Rab family with an epithelial distribution.