Angiogenesis in gastrointestinal stromal tumors: From bench to bedside

Gastrointestinal stromal tumors (GISTs) are rare neoplasms with an estimated incidence from 0.78 to 1-1.5 patients per 100000. They most commonly occur in the elderly during the eighth decade of life affecting predominantly the stomach, but also the small intestine, the omentum, mesentery and rectosigmoid. The available treatments for GIST are associated with a significant rate of recurrent disease and adverse events. Thorough understanding of GIST’s pathophysiology and translation of this knowledge into novel regimens or drug repurposing is essential to counter this challenge. The present review summarizes the existing evidence about the role of angiogenesis in GIST’s development and progression and discusses its clinical underpinnings.

[Diagnosis and treatment of Leydig cell tumors]

BACKGROUND

Tumors of the testes not originating from germinal epithelium are a rare entity and represent a diagnostic and therapeutic challenge. Leydig cell tumors (LCT) are rare stromal tumors of the testis.

OBJECTIVES

To present current approaches in diagnostic and treatment of LCT.

METHODS

A literature search in PubMed was performed and the currently available guidelines concerning LCT were evaluated. Articles and book chapters were selected based on relevance to daily practice.

RESULTS

The low incidence of Leydig cell tumors not originating from the germinal epithelium, but from the stroma of the testis requires a standardized approach to determine relevant differential diagnosis and to optimize diagnosis and treatment depending on the current standard of knowledge and to determine whether it is benign or malignant. While more than 90% of LCT are benign and treatment is only restricted to the testis, malignant subtypes require radical surgical resection of the testicular and metastatic sites.

CONCLUSION

A standardized diagnostic and therapeutic approach as well as a prospective registry of rare LCT could facilitate further detailed analysis to improve the understanding of tumor biology resulting in optimized therapeutic guidelines including follow-up strategies.

[Diagnosis and treatment of rare testicular tumors using the example of malignant mesothelioma of the tunica vaginalis testis and Sertoli cell tumors]

BACKGROUND

Rare tumors of the testis not originating from germinal epithelium are a diagnostic and therapeutic challenge.

OBJECTIVES

To present current approaches in rare tumors of the testis using the examples of Sertoli cell tumor (SCT) and malignant mesothelioma of the tunica vaginal testis (MMTVT).

METHODS

A literature search in PubMed and the abstract databases of ASCO and ESMO was performed. Articles and book chapters were selected based on relevance to everyday treatment.

RESULTS

The low incidence of testicular tumors not originating from the germinal epithelium makes a standardized approach difficult. Diagnosis and treatment depend on the underlying diagnosis. While most SCT are benign, malignant subtypes require extensive resection including metastatic surgery if complete resection is possible. In MMTVT, multimodality treatment concepts are followed, according to the malignant mesotheliomas of the pleura.

CONCLUSION

Systematic registration of rare testicular tumors and comprehensive molecular pathological analysis are urgently needed to improve the understanding of tumor biology and to develop new therapeutic strategies.

Coexistence of Gastric Cancer and Multiple Small Gastrointestinal Stromal Tumors: Report of a Unique Case and Review of the Literature

Background

In recent years, the synchronous occurrence of tumors of different histotypes arising in the same organ has been reported more frequently in the literature. The simultaneous development of adenocarcinoma and gastrointestinal stromal tumor (GIST) has been documented rarely.

Summary

The coexistence of primary gastric adenocarcinoma and GIST has been detected incidentally on gastric mucosa, serosa or occasionally intramurally, at surgery, or gastroscopy for other reasons. We present a case of a 79-year-old male patient who underwent surgery for an advanced gastric carcinoma, where multiple nodules of GIST were incidentally discovered during the work-up of his gastrectomy specimen.

Key Message

GISTs range from small "low-risk" tumors to sarcomas. Small GISTs are found incidentally during unrelated surgery or autopsy. Multiple GISTs are extremely rare and usually associated with hereditary diseases.

Practical Implications

In any case of gastrointestinal neoplasm, the surgeon and pathologist should be alert to perform a thorough investigation. Our case could provide further awareness and insight into the entity of concurrent tumors.

Ovarian leiomyoma with myxoid stroma

Ovarian smooth muscle tumours are rare. Notable myxoid change in smooth muscle tumours is uncommon, and raises diagnostic issues that need to be considered on evaluating a spindle cell lesion with notable myxoid change. There is only one case of myxoid leiomyoma of the ovary previously reported. We here report a case of ovarian leiomyoma with areas of myxoid stroma and discuss the relevant differential diagnosis and histological features to be assessed in such a lesion.

[Specificities of sex-cord stromal tumors in children and adolescents]

Sex-cord stromal tumors (SCT) are rare pediatric tumors accounting for less than 5% of gonadal tumors in children and adolescents. They differ from those diagnosed in adults by their presentation, histology, evolution and treatment modalities. Testicular SCT occur mostly in infants less than 6 months. Testicular swelling is often the only symptom, but signs of hormonal secretion with gynecomastia may be present. Juvenile granulosa SCT is the main histologic subtype. Sertoli SCTs are much less frequent while Leydig tumors occurred in older children and adolescents. Prognosis is excellent after inguinal orchiectomy. Testis sparing surgery could be performed but indications and modalities have to be strongly defined. Ovarian SCT are diagnosed in older children and adolescents and present with abdominal symptoms and/or signs of hormonal secretion: estrogenic manifestations (isosexual pseudoprecocity, menometrorrhagia) or virilization (hirsutism, amenorrhea). Main histologic subtype is juvenile granulosa (rarely Sertoli-Leydig). If oophorectomy (or salpingo-oophorectomy) may be curative for localized disease, adjuvant cisplatin-containing chemotherapy is mandatory in case of tumor rupture or peritoneal dissemination to prevent recurrences. Because of the rarity of these pediatric tumors, concerted multidisciplinary cares are required to best adapt therapeutic strategy before any surgical intervention.

Endoscopy dissection of small stromal tumors emerged from the muscularis propria in the upper gastrointestinal tract: Preliminary study

AIM: To investigate the feasibility and safety of the treatment of an upper gastrointestinal (GI) submucosal tumor with endoscopic submucosal dissection (ESD).

METHODS: A total of 20 patients with esophageal and gastric submucosal tumors emerged from the muscular layer identified by endoscopic ultrasonography were collected from January 2009 to June 2010. Extramural or dumbbell-like lesions were excluded by an enhanced computerized tomography (CT) scan. All patients had intravenous anesthesia with propofol and then underwent the ESD procedure to resect these submucosal tumors. The incision was closed by clips as much as possible to decrease complications, such as bleeding or perforation, after resection of the tumor. All the specimens were collected and evaluated by hematoxylin, eosin and immunohistochemical staining, with antibodies against CD117, CD34, desmin, α-smooth muscle actin and vimentin to identify the characteristics of the tumors. Fletch’s criteria was used to evaluate the risk of gastrointestinal stromal tumors (GISTs). All patients underwent a follow-up endoscopy at 3, 6 and 12 mo and CT scan at 6 and 12 mo.

RESULTS: The study group consisted of 5 men and 15 women aged 45-73 years, with a mean age of 60.2 years. Three tumors were located in the esophagus, 9 in the gastric corpus, 4 in the gastric fundus, 3 lesions in the gastric antrum and 1 in the gastric angulus. Apart from the one case in the gastric angulus which was abandoned due to being deeply located in the serosa, 94.7% (18/19) achieved complete gross dissection by ESD with operation duration of 60.52 ± 30.32 min. The average maximum diameter of tumor was 14.8 ± 7.6 mm, with a range of 6 to 30 mm, and another lesion was ligated by an endoscopic ligator after most of the lesion was dissected. After pathological and immunohistochemical analysis, 12 tumors were identified as a GI stromal tumor and 6 were leiomyoma. Mitotic count of all 12 GIST lesions was fewer than 5 per 50 HPF and all lesions were at very low (9/12, 75.0%) or low risk (3/12, 25.0%) according to Fletch’s criteria. Procedure complications mainly included perforation and GI bleeding; perforation occurred in 1 patient and conservative treatment succeeded by a suturing clip and no post-operative GI bleeding occurred. All patients were followed up for 6.5 ± 1.8 mo (range, 3-12 mo) by endoscopy and abdominal CT. Local recurrence and metastasis did not occur in any patient.

CONCLUSION: ESD shows promise as a safe and feasible technique to resect esophageal and gastric submucosal tumors and the incidence of complications was very low. Clinical studies with more subjects and longer follow-up are needed to confirm its treatment value.

Study on vasculogenic mimicry in malignant esophageal stromal tumors

AIM: To investigate whether malignant esophageal stromal tumors contain PAS-positive patterned matrix-associated vascular channels, which are lined by tumor cells, but not vascular endothelial cells. That is vasculogenic mimicry (VM) independent of tumor angiogenesis.

METHODS: Thirty-six tissue samples of malignant esophageal stromal tumors were analyzed. Tissue sections were stained for Vascular endothelial growth factor (VEGF), CD31 and periodic acid Schiff (PAS). The level of VEGF, the microvascular density (MVD) and the vasculogenic mimicry density (VMD) were determined.

RESULTS: PAS-positive patterned matrix-associated vascular channels were detected in 33.3% (12/36) of tumor samples. Within these patterned channels, red blood cells were found. The level of VEGF and the MVD in tumors containing patterned channels were significantly higher than those in tumors not containing patterned channels (P < 0.05). At the same time, the malignant degree of tumors was higher, the proportions of tumors containing patterned channels were not only more, but also in the each kind of tumors containing patterned channels.

CONCLUSION: In malignant esophageal stromal tumors, a VM mechanism causes some tumor cells to deform themselves and secrete extracellular matrix; thus, PAS-positive patterned matrix-associated vascular channels appear and supplying blood to the tumors to sustain their growth and metastasis.